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CHEMISTRY _ FUNCTION OF FOOD INGREDIENTS _FSM 3101_

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					      CHEMISTRY & FUNCTION OF FOOD INGREDIENTS (FSM 3101)

                              LABORATORY MANUAL


Content:

   1. Introduction, laboratory safety, and sampling procedure.
   2. Boiling process and the effect of added ingredients
   3. Effect of moisture on the characteristic and shelf life of food.
   4. Effect of different starches on food product characteristics.
   5. Effect of fiber on food product.
   6. Effect of different fats and oils on food product characteristics.
   7. Melting point and composition of oils.
   8. Emulsification and flavor of oils.




                                                                           1
TITLE: INTRODUCTION,              LABORATORY          SAFETY,       AND      SAMPLING
PROCEDURE.


            LABORATORY SAFETY GUIDELINES FOR STUDENTS

The laboratory component of food service chemistry courses at Faculty of food science
and technology is considered an integral part of the study of food service chemistry.
Activities and explorations will encourage discovery, verification of accepted theories,
and hands on practice with techniques and instrumentation. Laboratory experiments
planned by the faculty of the department of food service management and are instructive,
efficient, enjoyable and safe. Although everything is done to maximize safety in the
laboratory, certain unavoidable potential hazards exist. Each student can help to maintain
a safe environment for everyone working in a laboratory by preparing properly for the
experiment and by planning the work to be done. Additionally, it is necessary to arrive
promptly at the beginning of the laboratory in order that the lecture regarding theory,
special safety considerations/hazards, and chemical waste management regarding
substances used/operations performed is clearly understood. It is the policy of the
department of food service management that should a student miss this lecture,
participation in the laboratory is denied. Appropriate conduct is required at all times,
and concentration on work is expected.
Guidelines presented in this manual are designed for the student in order to provide a
reference to the general safety regulations and proper laboratory practices endorsed by
the department of food service management. Used in conjunction with the guidance of
the faculty, these guidelines provide a coherent plan to follow with respect to the
prevention of injury and damage to property.
Since laboratory is an integral component of the course, the contents of this manual are
subject to testing/grading. All students must understand the information in this
document, and must sign the declaration on the last page of this manual prior to
undertaking any work in the laboratory.

I. General Safety Requirements, Information, and Practices

1.    Personal Protective Equipment must be used in accordance with the hazards of the
substances/equipment being used.

         Safety goggles must be worn at all times in all chemistry laboratories by
   students, visitors, and faculty. A student found without goggles twice during a
   chemistry laboratory will be asked to leave for the remainder of the experiment and
   will receive a failing grade for the day. Repetition of the violation may result in a
   recommendation by the Department that the student withdraw from the course.
    Chemically resistant gloves and aprons should be used when working with
   toxic and/or corrosive materials. Check the reagent bottle or the Material Safety Data
   Sheet (MSDS) for toxicity and corrosivity potential(s). See Section IV for
   information on MSDS forms.


                                                                                        2
       Face shields must be worn whenever the potential for explosion exists, or
   whenever one is in doubt regarding the potential for explosion.

2.   Safety/Emergency Equipment must be located during the first lab session, and its
use must be understood.

    Fire Extinguishers, Safety (drench) Showers, Eye Wash Fountains and basic
   First Aid Equipment are available in each teaching laboratory. The instructor will
   point out the location and explain the proper use of these items during the first lab
   period.

    Dust pans and brushes are available in each teaching laboratory for clean up of
   broken glass. Broken glass containers are available in each laboratory for proper
   disposal of these materials. Never place broken glass in the trash can.

    A portable Emergency Spill Response kit for hazardous chemical clean up is
   located in Dana 236. When in doubt about how to clean up any spill, consult a faculty
   member.

3.    If the fire alarm sounds or an order is issued for emergency evacuation, all flames
must be extinguished and electrical heating equipment turned off. Students must
immediately exit, move away from the building, and congregate in order that attendance
can be taken. *Note: Physically challenged individuals may exit in order to make use of
building ramps. Students working elsewhere (i.e. research laboratories) will exit
according to the directive provided by the instructor.

4.    Fume hoods must be turned on and used whenever an activity involves production
of unpleasant or hazardous vapors, use of air or water reactive reagents, use of highly
corrosive or flammable materials, or any time when there may be uncertainty as to the
result of a reaction. Work in non- functioning fume hoods is prohibited.

5.    Flames (i.e. Bunsen burners) should never be left unattended, and should never be
used when heating a volatile/flammable substance or mixture. Hot plates or heating
mantles (connected to power mites/Variacs (that allow for temperature control) should be
selected for the activity. No open flames are permitted in the lab when volatiles are
being used outside of a fume hood.

6.    All fires / accidents must be immediately reported to the instructor, including minor
cuts/burns.

7.     Food consumption/smoking/drinking are never permitted in any chemical
laboratory.

8.    Oral contact with anything which is not food while working in the laboratory is
forbidden. This includes (but is not limited to) food, beverages, chemicals, pens, pencils,




                                                                                         3
fingers, hoses and pipettes (Note: Never pipette anything by mouth. Bulbs are available
for drawing liquid into pipettes).

9.   No unauthorized experimentation is permitted under any circumstances. Students
may not perform experiments other than those specifically approved by the instructor.
Additionally, any procedural changes must also be approved prior to initiation.

10. Inspect equipment prior to use. All clamps must be tight, rubber hoses secure and in
good condition, glassware free of chips/cracks, electrical cords in good condition, etc.
Discard questionable materials and replace them with new pieces. Report any
questionable equipment to the instructor.

11. Never work alone. Unsupervised work is not permitted. For students enrolled in
regular classes, no availability exists for laboratory work outside of scheduled laboratory
classes. Note: exceptions to this rule may be made only in the case of students in upper
level courses or in the case of student assistants. These exceptions must be explicitly
approved by the instructor/supervisor.

12. Beware of glass/porcelain. The vast majority of lab accidents involve cuts from
glass or burns from hot glass/porcelain. In the rush to clean up after a lab, students often
neglect to allow sufficient time for equipment to cool down.

13. Appropriate clothing must be worn at all times. Feet should be totally protected (no
sandals), and clothing should adequately cover the body and not be overly loose. Lab
coats/aprons are encouraged.

14. Long hair must be tied back/secured.

15. Neatness in the laboratory is imperative. It is not only essential to successful work,
but also effective in the reduction of accidents. The work area should be kept clear of all
materials except those needed for the immediate task.

16. Read all labels carefully. Be certain that the proper chemical is being dispensed.
Check the warning labels for toxicity/hazards, and refer to the MSDS (see Section IV of
this document) if necessary.

17. Never pour unused chemicals back into the reagent bottle. Never put a pipette
directly into a reagent bottle. Strive to estimate the amount of reagent required.

18. No chemicals, apparatus, or equipment may be removed from any laboratory for
any reason whatsoever without the instructor‟s knowledge and consent.

19. Report any equipment failure to the instructor. Never attempt to adjust it without
guidance.




                                                                                          4
20. Questions regarding safety/good lab practice should be immediately posed to the
instructor. When in doubt, ask before acting!

II. Emergency Procedures

The severity of an injury may be difficult to determine initially, therefore all injuries,
fires, and explosions must be reported to the instructor at once. Any injury that cannot be
handled with a simple bandage must be handled by a physician, either at Health Services
or at the Emergency Room of Saratoga Hospital.

1.   If you cannot help during an emergency, get out of the way of people who can.

2.     Fire: Report all fires immediately to the instructor, and leave the laboratory at
once. Do not attempt to extinguish a fire unless an instructor is not nearby or unless
someone is in immediate danger of serious injury. See Section I, #2 for the location of
fire alarms.

3.    Clothing fires: If clothing catches fire, call for help, get under the safety shower
and pull the chain. If not near a shower, grab the nearest fire blanket, drop to the floor
and roll in it. Note: Never wrap vertically in a fire blanket as the chimney effect might
draw flame upward toward the face. If neither safety shower nor fire blanket is close by,
drop to the floor and roll. Important: Never use a carbon dioxide fire extinguisher on a
person as the intense cold may result in severe injury.

4.     Chemicals in the eye(s): If any chemical has splashed into the eyes, immediately
call for help and rush to the eyewash fountain. Push the paddle (which will allow water
to flow spontaneously without further effort), and hold the lid(s) of the affected eye(s)
open. Flush eyes for a minimum of 15 minutes! An instructor will notify Health
Services, and arrange for transportation.

5.    Chemical spills on the body: If chemicals are spilled over a large area of the body,
go under the safety shower and pull the chain. Remove any affected clothing. If
chemicals are spilled over a small area of the body, flush with cold water and wash with
soap. In either case, notify the instructor in order that the MSDS sheet can be checked
for toxicity, corrosivity, etc. If needed, the instructor will arrange for transportation to
Health Services.

6.    Ingestion of a chemical: If any chemical is swallowed or gets into the mouth, rinse
it out and spit. Immediately notify the instructor who will follow the procedure in #5
above.

III. Admission to Laboratories and Supervision of Work

1.   No person is permitted access to any non-public area within the Department of
Food service management unless specific, approved business is being conducted.




                                                                                          5
2.   Access to the storeroom and cold room is limited to student assistants and research
students unless A FACULTY MEMBER IS PRESENT.

3.    Visitors are permitted only with approval of the instructor in charge of a given
laboratory. All visitors are subject to the safety regulations (including goggles) of the
Department.

4.    No student may work in an instructional laboratory unless a supervisor authorized
by the Department is in attendance. While the supervisor may be absent for short periods
of time, a student who continues to work after the supervisor has left for the day, or who
works after the laboratory has been formally closed is guilty of a serious breach of
departmental regulations.

IV. Material Safety Data Sheets

Material Safety Data Sheets (MSDS) provide information designed to protect individuals
from hazards that may be associated with use of a chemical. MSDS forms are available
in the Office of the Department of Food service management during normal
teaching/office    hours.       They    may      also   be   accessed    online     at
www.msdssearch.com/DBLinksN.htm. Particularly recommended on this website are
the databases provided by Cornell University and Vermont SIRI.

Although instructors will provide safety information regarding the specific chemicals
used in each experiment, students are encouraged to routinely examine MSDS data for
required reagents. Typical information found on an MSDS includes the following:

          CATEGORY                                 TYPE OF INFORMATION
NAME OF SUPPLIER                            Address and Emergency Contact numbers
NAME OF THE CHEMICAL                        Common synonyms are listed
PHYSICAL AND CHEMICAL                       Melting/boiling pts., molecular weight, etc.
PROPERTIES
PHYSICAL HAZARDS                            Data on flammability, reactivity, corrosivity
TOXICITY DATA                               Permissible Exposure Limits/Threshold
                                            Limit Values
HEALTH HAZARDS                              (Acute & Chronic) Signs, Symptoms, Routes
                                            of Entry, Identification of Carcinogens, etc.
STORAGE AND HANDLING                        Personal Protective Equipment; proper
INFORMATION                                 storage
EMERGENCY AND FIRST AID                     Emergency Treatment; Fire and Spill
PROCEDURES                                  Handling

A sample MSDS form is included on page 10 of this manual. Be sure to review its
format.




                                                                                           6
V. Laboratory Conduct and Student Responsibilities

1.    All students are expected to demonstrate mature judgment and common sense in
their work and conduct while working in the laboratory. Horseplay, practical joking,
working while under the influence of alcohol or drugs, or any other form of conduct
deemed unsafe by the instructor is unacceptable and is grounds for immediate dismissal
from the laboratory.

2.    All spills must be promptly cleaned up. Ask the instructor for advice on how to
clean up and dispose of any spilled chemical.

3.    Make certain that all apparatus is clean and put away at the end of the laboratory.
Double check to be sure that reagent bottles are tightly closed and stored in the proper
place. Leave the lab bench clean and dry.

4. Any reaction mixtures or products that must be stored until the next laboratory must
be labeled with the contents, the date, the name of the experimenter, and a notation
indicating any hazards associated with the material.

5.    All hazardous waste accumulated during lab must be brought to the Satellite
Hazardous Waste Collection Area and placed in the appropriate container. Seal the
waste container before leaving.

VI. Chemical and Equipment Safety

Assume that all chemicals are hazardous, and treat them accordingly. Although the
following guidelines are by no means comprehensive/complete, the specific hazards and
policies associated with various chemicals/equipment provide a basis for safe laboratory
practice.

1.    Many common organic solvents are under suspicion as potential carcinogenic
agents. Among these are Dichloromethane, Carbon Tetrachloride, and Chloroform. Treat
all organic solvents with respect and minimize contact with both the liquid and the
vapors.

2.    Methanol is very toxic and can cause blindness if ingested. It can be absorbed
through the skin and contact should be avoided. If accidental contact occurs, wash
thoroughly with soap and water.

3.    Addition of strong oxidizing agents to organic matter may lead to fire/explosion.
Common oxidizing agents used in the laboratory include nitric acid, nitrates, nitrites,
chlorates, and compounds with “per” in their name (example: potassium permanganate).

4.   Due to their extremely hazardous nature, the following chemicals and equipment
may not be handled by students* except under the direct supervision of an instructor:




                                                                                       7
                       CHEMICALS                 EQUIPMENT
                     Elemental Bromine            Gas Cylinders
                        All Cyanides               UV Lamps
                      Hydrofluoric Acid         Vacuum Equipment
                    Perchloric Acid (>6M)            Lasers
                           Nicotine

*Upper level students engaged in research must be specifically trained prior to using any
of the above.

5.  COMPOUNDS OF HEAVY METALS, ESPECIALLY LEAD, ARSENIC,
ANTIMONY, BISMUTH AND MERCURY ARE VERY TOXIC. CHROMATES
AND DICHROMATES ARE CAPABLE OF PRODUCING ULCEROUS SORES,
AND ARE CARCINOGENIC.     MINIMIZE CONTACT WITH THESE
SUBSTANCES.

6.   ALL   COMPOUNDS      LABELED “STENCH”, MALODOROUS
COMPOUNDS (EXAMPLES: MERCAPTANS, LOW MOLECULAR WEIGHT
ORGANIC ACIDS, AMINES), AND COMPOUNDS THAT EVOLVE TOXIC
VAPORS MUST BE USED IN THE HOOD.

7.   Drying ovens are not approved for flammable substances. Under no circumstances
may any flammable material be stored in one. Drying ovens are used only for drying
non-flammable solids that are wet with/have absorbed water. All chemicals stored in
drying ovens must be properly labeled (see Section V, #4 of this document).

8.   Sodium and Potassium metal react violently with water. Magnesium metal is very
flammable. Obtain advice from an instructor prior to their use.

9.   Ethers have a tendency to form dangerously explosive peroxides over time. Never
attempt to open old ether can, unless there is certainty regarding lack of peroxide
formation. Open all cans of ether under a hood with the sash pulled as low as possible.
Never store ether in a glass container.

10. Considerable heat is often evolved when concentrated liquids are diluted with water.
The concentrate in always added to water; never the reverse. (Example: pour
concentrated acid into water).

11. Gas cylinders may only be used by research/upper level students who have been
specifically trained in safety considerations. When using cylinder gas, make certain that
the cylinder is firmly anchored (strapped). Avoid bumping the cylinder regulator. If the
cylinder does not open easily, consult the instructor. Never use a pipe wrench on a
cylinder.

12. Work involving either pressure or vacuum should be done only with equipment
expressly designed for this purpose. Proper shielding is required.


                                                                                       8
13. Cryogenic substances such as dry ice, liquid nitrogen, and liquid ammonia may be
used only after special training by an instructor occurs.

14. Consider electrical hazards carefully. Certain instruments have high voltage
components. Report malfunctioned equipment to the instructor.

15. Any apparatus with moving pulleys or shafts (pumps, power tools) presents special
safety concerns. Loose clothing poses a particular hazard when working with this type of
equipment.

Example:
HYDROCHLORIC ACID - HYDROCHLORIC ACID SOLUTION
Hazard Characteristic Code: C1
===============================================================
                          Physical/Chemical Characteristics
===============================================================
Appearance and Odor: CLEAR, COLORLESS, LIQUID, CHLORINE ODOR.
Boiling Point: 230F, 110C
Decomposition Temperature: UNKNOWN
Solubility in Water: COMPLETE
pH: <2
Corrosion Rate (IPY): UNKNOWN
===============================================================
                           Fire and Explosion Hazard Data
===============================================================
Extinguishing Media: USE WATER FOG, CARBON DIOXIDE, FOAM, OR DRY
CHEMICAL.
Special Fire Fighting Proc: WEAR FIRE FIGHTING PROTECTIVE EQUIPMENT
AND A FULL FACED SELF CONTAINED BREATHING APPARATUS. COOL FIRE
EXPOSED CONTAINERS WITH WATER SPRAY.
Unusual Fire And Explosive Hazards: COMBUSTION OR HEAT OF FIRE MAY
PRODUCE HAZARDOUS DECOMPOSITION PRODUCTS AND VAPORS.
 ===============================================================
                                   Reactivity Data
===============================================================
Stability: YES
Condition to Avoid (Stability): HIGH HEAT, OPEN FLAMES AND OTHER
SOURCES OF
IGNITION
Materials to Avoid: STRONG OXIDIZING AGENTS
Hazardous Decomposition Products: WHEN HEATED TO DECOMPOSITION, EMITS
TOXIC HYDROGEN CHLORIDE FUMES. WILL REACT WITH WATER TO
PRODUCE HEAT & TOXIC FUMES.
Hazardous Poly Occur: NO
Conditions to Avoid (Poly): NOT APPLICABLE




                                                                                      9
===============================================================
                                  Health Hazard Data
===============================================================
LD50-LC50 Mixture: LD50 (ORAL RAT) IS 900 MG/KG
Route of Entry - Inhalation: YES
Route of Entry - Skin: YES
Route of Entry - Ingestion: YES
Health Hazard Acute and Chronic: ACUTE: CORROSIVE! INHALATION CAN
CAUSE COUGHING, CHOKING, & INFLAMATION OF THE RESPIRATORY
TRACT. SWALLOWING CAN CAUSE BURNS TO MOUTH & G.I. TRACT. EYE
CONTACT CAN CAUSE SEVERE BURNS & DAMAGE. SKIN CONTACT CAN
CAUSE SEVERE BURNS AND DEEP ULCERS & DISCOLOR SKIN. CHRONIC:
CONCENTRATED VAPORS MAY CAUSE EROSION OF TEETH.
Carcinogenicity - NTP: NO
Carcinogenicity - IARC: NO
Carcinogenicity - OSHA: NO
Explanation Carcinogenicity: HYDROCHLORIC ACID IS NOT LISTED BY IARC,
NTP, OR OSHA AS A CARCINOGEN.
Signs/Symptoms of Overexposure: INFLAMMATION OF THE NOSE, THROAT,
UPPER RESPIRATORY TRACT, EYES, SKIN AND MUCOUS MEMBRANES.
VERY CORROSIVE AND CAN CAUSE SEVERE BURNS AND DAMAGE. LONG
TERM EXPOSURES SELDOM OCCUR DUE TO THE CORROSIVE PROPERTIES
OF THE ACID.
Medical Condition Aggravated By Exposure: PERSONS WITH A HISTORY OF
AILMENTS OR WITH A PRE-EXISTING DISEASE INVOLVING THE EYES, SKIN,
OR RESPIRATORY TRACT MAY BE AT INCREASED RISK FROM EXPOSURE.
Emergency/First Aid Proc: INHALATION: REMOVE TO FRESH AIR.
RESUSCITATE IF NOT BREATHING. GET MEDICAL ATTENTION. EYES:
IMMEDIATELY FLUSH WITH PLENTY OF WATER FOR 15 MINUTES HOLDING
EYELIDS OPEN. GET IMMEDIATE MEDICAL ATTENTION. SKIN: REMOVE
CONTAMINATED CLOTHING. WASH WITH SOAP AND WATER. GET
IMMEDIATE MEDICAL ATTENTION. INGESTION: DO NOT INDUCE
VOMITING. GIVE NOTHING BY MOUTH IF UNCONSCIOUS, GET IMMEDIATE
MEDICAL ATTENTION.
 ===============================================================
                         Precautions for Safe Handling and Use
==============================================================
Steps If Material Released/Spill: SMALL SPILL: FLUSH WITH WATER AND
NEUTRALIZEWITH            ALKALINE        MATERIAL.      SEWER NEUTRALIZED
MATERIAL WITH EXCESS WATER. LARGE SPILL: EVACUATE AND
VENTILATE AREA. IF POSSIBLE, STOP LEAK. DIKE TO RETAIN RUN OFF.
NEUTRALIZE & PICK UP WITH ABSORBENT MATERIAL.
Neutralizing Agent: SODA ASH, LIME OR OTHER SUITABLE ALKALINE
MATERIAL.
Waste Disposal Method: DISPOSAL SHOULD BE MADE IN ACCORDANCE WITH
ALL APPLICABLE FEDERAL, STATE AND LOCAL LAWS AND REGULATIONS.



                                                                       10
DISPOSE IN A RCRA-APPROVED WASTE FACILITY OR SEWER THE
NEUTRALIZED SLURRY WITH EXCESS WATER IF LOCAL ORDINANCES
ALLOW.
Precautions-Handling/Storing: STORE IN A COOL, DRY, WELL VENTILATED
AREA. KEEP CONTAINERS TIGHTLY CLOSED WHEN NOT IN USE. PROTECT
CONTAINERS FROM PHYSICAL DAMAGE & DIRECT SUNLIGHT.
Other Precautions: DO NOT TAKE INTERNALLY. DO NOT BREATHE MIST.
AVOID PROLONGED OR REPEATED BREATHING OF VAPOR. AVOID
CONTACT WITH EYES. USE WITH ADEQUATE VENTILATION. WASH
THOROUGHLY AFTER HANDLING. FOR INDUSTRIAL USE ONLY.
==============================================================
                                Control Measures
==============================================================
Respiratory Protection: IF VENTILATION DOES NOT MAINTAIN INHALATION
EXPOSURES BELOW PEL (TLV), USE NIOSH/MSHA APPROVED FULL
FACEPIECE CHEMICAL CARTRIDGE RESPIRATOR OR A SUPPLIED AIR FULL
FACEPIECE RESPIRATOR OR AIRLINED HOOD.
Ventilation: A SYSTEM OF LOCAL EXHAUST IS RECOMMENDED TO KEEP
EMPLOYEE EXPOSURES BELOW THE TLV.
Protective Gloves: NEOPRENE OR RUBBER GLOVES
Eye Protection: CHEMICAL SAFETY GOGGLES WITH FACE SHIELD
Other Protective Equipment: EYE WASH STATION AND SAFETY SHOWER.
IMPERVIOUS BOOTS, APRON, OR COVERALLS AS REQUIRED.
Work Hygienic Practices: OBSERVE GOOD PERSONAL HYGIENE PRACTICES
AND RECOMMENDED PROCEDURES. DO NOT WEAR CONTAMINATED
CLOTHING OR FOOTWEAR.
Suppl. Safety & Health Data: AVOID PROLONGED OR REPEATED EXPOSURE. DO
NOT GET ON SKIN OR IN EYES. DO NOT BREATHE VAPORS OR MISTS.
PROTECT FROM MOISTURE.

Label Required: YES
Common Name: 84417 HYDROCHLORIC ACID
Signal Word: DANGER!
Acute Health Hazard-Moderate: X
Contact Hazard-Severe: X
Fire Hazard-None: X
Reactivity Hazard-None: X
Special Hazard Precautions: CORROSIVE LIQUID! ACUTE-INHALATION:
IRRITATION OF THE RESPIRATORY TRACT. INGESTION: BURNS TO MOUTH
& G.I. TRACT. EYE: SEVERE BURNS & DAMAGE. SKIN: SEVERE BURNS AND
DEEP ULCERS. CHRONIC: EROSION OF REMOVE TO FRESH AIR.
RESUSCITATE IF NOT BREATHING. GET MEDICAL ATTENTION.
EYES: IMMEDIATELY FLUSH WITH WATER FOR 15 MINUTES HOLDING
EYELIDS       OPEN.     GET    MEDICAL ATTENTION. SKIN:  REMOVE
CONTAMINATED CLOTHING. WASH WITH SOAP AND WATER. GET MEDICAL
ATTENTION. INGESTION: DO NOT INDUCE VOMITING. GIVE NOTHING BY



                                                                   11
MOUTH IF UNCONSCIOUS. GET IMMEDIATE MEDICAL ATTENTION.
Protect Eye: Y
Protect Skin: Y
Protect Respiratory: Y


                              SAMPLING PROCEDURE

Sampling is done in a wide variety of research settings. Listed below are a few of the
benefits of sampling:

   1. Reduced cost: It is obviously less costly to obtain data for a selected subset of a
      population, rather than the entire population. Furthermore, data collected through
      a carefully selected sample are highly accurate measures of the larger population.
   2. Speed: Observations are easier to collect and summarize with a sample than with
      a complete count. This consideration may be vital if the speed of the analysis is
      important.
   3. Greater scope: Sometimes highly trained personnel or specialized equipment
      limited in availability must be used to obtain the data. A complete census
      (enumeration) is not practical or possible. Thus, surveys that rely on sampling
      have greater flexibility regarding the type of information that can be obtained.

It is important to keep in mind that the primary point of sampling is to create a small
group from a population that is as similar to the larger population as possible. In essence,
we want to have a little group that is like the big group. With that in mind, one of the
features we look for in a sample is the degree of representativeness - how well does the
sample represent the larger population from which it was drawn? How closely do the
features of the sample resemble those of the larger population?

Samples are always drawn from a population, the aggregate from which the sample is
drawn. The population to be sampled (the sampled population) should coincide with the
population about which information is wanted (the target population). Sometimes, for
reasons of practicality or convenience, the sampled population is more restricted than the
target population. In such cases, precautions must be taken to secure that the conclusions
only refer to the sampled population. Before selecting the sample, the population must be
divided into parts that are called sampling units or units. These units must cover the
whole of the population.

One of the most common sampling techniques used is the quartering technique. It is a
method used by analytical chemists to reduce the sample size without creating a
systematic bias. This technique involves combining the collected sub-samples into a
composite sample and repeating the quartering procedure until a desired sample size is
achieved. Quartering can be conducted on a smooth and clean concrete surface or on a
plastic tarp where collected material will not be lost and foreign material will not be
introduced. The following steps are performed:



                                                                                         12
(a) Place the sub-samples on the surface and mix thoroughly by turning the entire
composite sample over at least three times. Compaction by static or vibratory forces
should be avoided.
(b) Shovel the entire sample into a conical pile by depositing each shovelful on top of the
preceding one.
(c) Flatten the conical pile to a uniform thickness and diameter by spreading with a
shovel. The material should have a diameter about four to eight times the thickness.
(d) Divide the flattened mass into four equal quarters with a shovel or trowel.
(e) Remove two diagonally opposite quarters for further quartering.




             FOOD SERVICE CHEMISTRY LABORATORY SAFETY


                                       AGREEMENT


I have read the Laboratory Safety Guidelines for Students published by the Department

of Food service management of Faculty of Food Science and Technology, and I

understand its contents. I agree to abide by all of its rules at all times in any laboratory in

which chemical operations are occurring. I understand that violation of safety regulations

may result in my expulsion from the laboratory and that continued infractions may result

in my being withdrawn from the course.



_______________________________                         _____________________________
           Signature                                               Print Name


Legibly

Date____________________________                         Course: ___________________

Laboratory Section________________                       Room #:

Desk #__________________________




                                                                                            13
                                    EXPERIMENT 1


TITLE: EFFECT OF MOISTURE ON CHARACTERISTICS AND SHELF LIFE OF
FOOD.


PURPOSE: The purpose of this experiment is to determine the moisture content, water
activity (aw), and shelf life of foods, as well as to comprehend the relationship between
these properties.


LEARNING OUTCOMES:

   1. Demonstrate the ability to examine moisture content and water activity, and their
      effect on the shelf life of foods.
   2. Demonstrate the ability to explain the interrelationship between moisture content,
      water activity, and shelf life.
   3. To collect, tabulate, analyze and evaluate obtained experimental data.
   4. To collaborate with other students in the experiment as well as in documentation
      of the experiments.


INTRODUCTION:

The water content of foods varies widely. Determination of water or moisture content is
one of the most important and most widely used measurements in food processing
because of the significance effect of water on the stability and quality of foods. The
determination of moisture content in food sample is very essential for a few reasons. We
know that any process involved in food manufacturing need raw ingredients. In order to
verify the validity of the raw materials, a few things need to be made sure of, including
the moisture content. The higher the water content in a food material, the more
preservatives are required. This is due to the fact that most of the microorganisms tend to
grow rapidly in food with high water content. For this reason, many foods with known
high water content are dried to prevent its spoilage by the microorganisms. Excess
moisture in mixes can cause clumping and the moisture content will continue to increase
during storage, causing the product to deteriorate. Besides, quality of a food item depends
very much on their water content. The feature of food, either it is the texture, taste,
appearance or the stability varies with different amount of moisture in it. Additionally, in
the production of processed food items, they go through a few stages of processes in
which some chemicals changes might take place depending on the moisture contained
within the food item. For this reason, comprehension of the moisture content is crucial to
predict the behavior of foods during the processing operations.




                                                                                         14
In food products, water exists in free and bound form. Bound water is water that is bound
to other substances and no longer exhibits the flow properties and solvent capability
commonly associated with water, whereas free water is present in the intergranular
spaces and within the pores of the food material. Since it is not bounded to any
component in food, it is available for the chemical and biological reaction that may take
place in food.

Since moisture determination is very essential, many techniques have been established to
ease the verification of moisture content in various samples. Among the methods are the
oven, chemical, Karl Fisher and dielectric constant method.

        In an oven method, the sample will be placed in the oven at a particular
        temperature and time. The moisture will be determined once the sample is dried.
        The oven method is known as the standard for testing moisture. However, the
        disadvantage of this method is that it takes up to 24 hours for precise and
        consistent results.
        Samples with large amounts of carbohydrates may undergo chemical changes if
        dried in an oven. In such cases, a vacuum oven can be used. Vacuum ovens works
        with reduced pressure which permit faster drying. A vacuum oven is complete
        with an air inlet and outlet which helps to carry the moisture lost from the sample
        out of the oven, therefore disallow the accumulation of moisture in the oven. The
        boiling point of water in a vacuum oven is lower due to the low pressure. So,
        degradation of heat sensitive substances can be avoided. This method takes
        between 3-6 hours to be completed and is quite costly.
        Chemical reaction methods do not usually involve the application of heat and so
        they are suitable for heat sensitive items including food containing high sugar
        concentrations or foods that contain volatile components that might be lost by
        heating. The Karl-Fisher method is used to determine the moisture content of
        foods that have low water content.
        The dielectric method is used to determine the moisture in food sample when
        accuracy is needed. This method can be used with a wide range of moisture
        contents and it is nondestructive.

Water activity (aw) is a comparison of the vapor pressure of water in a food sample with
vapor pressure of pure water. Water activity is one of the most critical factors in
determining quality and safety of the goods we consume every day. Water activity affects
the shelf life, safety, texture, flavor, and smell of foods. It is also important to the stability
of food. While temperature, pH and several other factors can influence if and how fast
organisms will grow in a product, water activity may be the most important factor in
controlling spoilage. By measuring water activity, it is possible to predict which
microorganisms will and will not be potential sources of spoilage. Water activity
determines the lower limit of available water for microbial growth. In addition to
influencing microbial spoilage, water activity can play a significant role in determining
the activity of enzymes and vitamins in foods and can have a major impact their color,
taste, and aroma.



                                                                                               15
In this experiment, we will be concerned with applying the oven method in determination
of moisture content in different types of food samples. Water activity will also be
determined using AquaLab.


MATERIALS AND PROCEDURES:

MATERIALS

Tofu, sponge cake, flour, jam, raisin

APPARATUS

Aqualab, crucibles, tong, spatula, oven

PROCEDURES

   a) Moisture content (Oven drying method).
      1. Grind sample.
      2. Dry crucibles in the oven at 150 C for 30 minutes. Cool the crucibles in a
         desiccator.
      3. Weigh 10g sample (W) in the pre-weighed crucibles (W1).
      4. Dry in the oven at 105 C for 8 hours.
      5. Cool in the desiccator. Weigh sample.
      6. Repeat drying until stable weight is obtained (W2).

               Moisture content = (W + W1) – W2 x 100
                                       W

   b) Water activity.
      1. Determine the water activity of each sample (tofu, sponge cake, flour, jam,
         raisin) using AquaLab.

   c) Shelf life.
      1. Store each sample in different beaker at room temperature.
      2. Look for sign of spoilage (mold growth, etc.) every two days for two weeks.
      3. Plot a graph of shelf life (days) against water activity (aw) of samples.
      4. Plot a graph of moisture content (%) against water activity (aw).




                                                                                    16
QUESTIONS:

  1. What is the difference between moisture content and water activity?
  2. Using graph, illustrate the relationship of shelf life and:
         a)     Moisture content
         b)     Water activity (aw)
  3. What is the relationship between moisture content and water activity? Describe
     the shape of the curve.
  4. Suggest ways to reduce water activity and prolong shelf life of foods.




                                                                                17
                                       EXPERIMENT 2


TITLE: BOILING PROCESS AND THE EFFECT OF ADDED INGREDIENTS


PURPOSE: The purpose of this experiment is to understand boiling process as well as the
factors that affects this property.


LEARNING OUTCOMES:

   1. Describe the appearance and temperature range of water that is lukewarm,
      scalding, simmering, and boiling.
   2. Explain the factors that determine the boiling temperature of water alone and with
      various ingredients added.
   3. Explain why is it possible to cook at a higher temperature when oil is the cooking
      medium than when water is the medium.
   4. To collect, analyze and evaluate obtained experimental data.
   5. To collaborate with other students in the experiment as well as in documentation
      of the experiments.


INTRODUCTION:

Water is important in food and its preparation. Its roles are based on its ability to dissolve
and participate in dispersions, change state (solid, liquid, or gas, depending on
temperature), and serve as a cooking medium. Boiling point of water is very much
influenced by a few factors. The boiling point of a liquid is lowered if the pressure of the
surrounding gases is decreased. For example, water will boil at a lower temperature at the
top of a mountain, where the atmospheric pressure on the water is less, than it will at sea
level, where the pressure is greater. In the laboratory, liquids can be made to boil at
temperatures far below their normal boiling points by heating them in vacuum flasks
under greatly reduced pressure. Besides that, boiling temperature of water is also affected
by the addition of ingredients. Boiling point elevation is the law that says adding solutes
to solvent increases its boiling point. The boiling point elevation is a colligative property,
which means that it is dependent on the presence of dissolved particles and their number,
but not their identity. It is an effect of the dilution of the solvent in the presence of a
solute.

In this experiment, the appearance and temperature range of water during heating process
will be examined. Various amounts of different solutes will be added to water and the
change in boiling point will be observed. The data will then be examined for the study of
the pattern of this change. In addition, we will also study the appearance of oil when
heated.



                                                                                           18
MATERIALS AND PROCEDURES:

MATERIALS

Water, sugar, salt, cornmeal, gelatin, oil

APPARATUS

Saucepan, heating element, ring stand, thermometer, tablespoon

PROCEDURES

   a) Appearance of water during heating to boiling.
      1. Place a 1-quart saucepan containing 450 ml water on a heating element and
         use a ring stand to suspend a laboratory thermometer near the middle of the
         pan so that the bulb is immersed completely but not touching the bottom.
      2. Begin heating the water. When the temperature reaches 400C, record the
         appearance of the water (lukewarm).
      3. Continue heating to 650C and record the appearance of the water (scalding).
      4. Continue heating to 820C and note the appearance from that point to 990C.
         Record the changes in the appearance over this range (simmering).
      5. Continue heating to 1000C. Record the appearance of the water (boiling).

   b) Effect of added ingredients.
      1. Place 450 ml water in a 1-quart saucepan with the thermometer suspended as
          in above. Add 15 ml (1 tablespoon) of sugar and heat to boiling. Record the
          temperature when the water boils.
      2. Add 15 more ml sugar and continue heating. Record the temperature when the
          water resumes boiling.
      3. Add another 15 ml of sugar and record the temperature when the water
          resumes boiling.
      4. Again add 15 ml of sugar and record temperature when the water resumes
          boiling.
      5. Repeat step 1-4 with salt, cornmeal and gelatin. As for gelatin, hydrate 1
          envelope of gelatin in 60 ml water. Follow the procedure but use hydrated
          gelatin.

   c) Appearance of oil
      1. Place 1-quart saucepan containing 236 ml oil on a heating element and use a
         ring stand to suspend a laboratory thermometer near the middle of the pan so
         that the bulb is immersed completely but not touching the bottom.
      2. Heat the oil to 1000C and record the appearance of the oil.
      3. Continue heating the oil to 1900C and record the appearance of the oil.




                                                                                  19
QUESTIONS:

  1. Will carrots be done more quickly in vigorously boiling water than in water that is
     gently boiling? Explain your answer.
  2. Did salt and sugar affect the boiling temperature of water exactly the same? If not,
     explain any difference.
  3. Did cornmeal affect the boiling temperature of water the same as sugar? If not,
     explain your answer.
  4. Did gelatin affect the boiling temperature of water the same as sugar? If not,
     explain your answer.
  5. What kind of dispersion is created when each of the following is added to water
     (a) sugar, (b) gelatin, (c) cornmeal?
  6. Why can oil be heated to higher temperatures than water?




                                                                                      20
                                    EXPERIMENT 3


TITLE: EFFECT OF             DIFFERENT        STARCHES         ON    FOOD       PRODUCT
CHARACTERISTICS.


PURPOSE: The purpose of this experiment is to assess the thickening and gelling
capability of starch from different sources.


LEARNING OUTCOMES:

   1. Demonstrate the ability to examine the thickening and gelling capability of
      different starches.
   2. Demonstrate the ability to predict the effect of using different starches on the
      characteristics of a particular food product.
   3. To collect, tabulate, analyze and evaluate obtained experimental data.
   4. To collaborate with other students in the experiment as well as in documentation
      of the experiments.


INTRODUCTION:

Starch occurs in most green-leafed plants in the seed (cereal grains), in the root and tuber
(tapioca and potato), in the stem-pith (sago), and in the fruit (banana). Starches are used
in foods as thickening agents (sauces, cream soups, pie fillings), as colloidal stabilizers
(salad dressings), for moisture retention (cake toppings), as gel-forming agents (gum
confections), as binders (wafers, ice cream cones), and as coating and glazing agents
(candies).

Starch is the most abundant storage form of carbohydrate in higher plants. Starch is a
polysaccharide, composed of two polymers, amylose and amylopectin with α-D-glucose
as their basic building block. Amylose is a linear chain polymer of glucose units linked
via α-1-4 glycosidic bonds. The repeating units are maltose. Amylopectin, on the other
hand, is a branched chain molecule linked by α-1,4-glycosidic bonds (linear backbone)
and α-1,6-glycosidic bonds (at branch points). Their repeating units are maltose and
isomaltose. A starch granule normally contains both amylose and amylopectin. The
average proportion of amylose is 15-30%, although there are exceptions: waxy corn,
sorghum (sekoi) and glutinous rice which contains almost 100% amylopectin. There are
also varieties with high amounts of amylose. The two fractions occur together in starch
from most sources; therefore the overall behavior of a starch depends on the relative
amount of amylose and amylopectin. Each of the fractions has unique properties that
contribute to the functionality of starch from various sources. Figure 1 illustrates amylose
and amylopectin structure.



                                                                                         21
Figure 1: Amylose and amylopectin structure.


In this experiment, we will be concerned with determining the water absorption, oil
absorption and puffing characteristics, crunchiness, adhesiveness and freeze-thaw
stability of different starches.


MATERIALS AND PROCEDURES:

MATERIALS

Rice, wheat, barley, corn starch, glutinous rice (pulut) starch, cooking oil, distilled water

APPARATUS

Ruler, balance, beaker, heating element, spoon, paper, coin (one cent), freezer, chiller


PROCEDURES

   a) Water absorption.
      1. Measure weight, length, and width of five grains from each sample and take
         the average.
      2. Soak the grains in distilled water for about 10 minutes.
      3. Remove the grains from the soaking water and repeat step 1. Record the
         readings.

   b) Oil absorption and puffing characteristics.
      1. Heat cooking oil in a 100 ml beaker.




                                                                                           22
     2. Fry the soaked grains in the oil at 150 C until they puff. Record the time taken
        for the grain to puff.
     3. Remove the puffed grain from the oil, and measure the weight of the grains
        after frying. Take average of five grains.
     4. Calculate percentage of oil absorption of each sample:

     % Oil absorption = Weight after frying (g) – Weight before frying (g) x 100%
                                      Weight before frying (g)

  c) Crunchiness.
     1. Evaluate the puffed grains for crunchiness. Rate on a scale of 1 to 5. (1 for
        very soft and 5 for very crunchy).

  d) Adhesiveness.
     1. Measure weight, length, and width of five grains from each sample and take
        the average.
     2. Boil sample in water for about 10 minutes.
     3. Take sample out of the boiling water and measure weight, length, and width of
        five grains from each sample and take the average.
     3. Cut two pieces of paper (2 cm x 6 cm). Paste the end of the two pieces near
        the top of a beaker, facing one another.
     4. Put three grains from each sample lot on the spot that bridge the two pieces of
        paper, and try to make the paper stick to each other using the grain.
     5. Test the strength of the grain as an adhesive by putting one-cent coin on the
        paper bridge. Record the number of coin needed to break the bridge.

  e) Freeze-thaw stability.
     1. Store boiled sample for one week at 0 C in a freezer. Store another lot of the
        sample for one week at 5 C in a chiller.
     2. After a week, thaw sample at room temperature.
     3. Measure length and width of five grains from each sample and take the
        average.
     5. Measure also hardness of the grains. Rate on a scale of 1 to 5 (1 for very soft
        and 5 for very hard).


QUESTIONS:

  1. What is the difference in the observed properties of the different starch?
  2. Why do these different starches exhibit different properties?




                                                                                     23
                                    EXPERIMENT 4


TITLE: EFFECT OF FIBER ON FOOD PRODUCT CHARACTERISTICS.


PURPOSE: The purpose of this experiment is to assess and understand the effect of
different fibers on the rheological and organoleptic properties of pudding.


LEARNING OUTCOMES:

   1. Demonstrate the ability to describe the appearance of food product resulting from
      the use of different fiber.
   2. To collect, analyze and evaluate obtained experimental observations.
   3. To collaborate with other students in the experiment as well as in documentation
      of the experiments.


INTRODUCTION:

Fiber is the combination of materials in foods that cannot be digested readily. Plant foods
are valued in diet as potentially outstanding sources of fiber. Fiber is categorized into
soluble and insoluble fibers:

       Soluble fibers appear to be digested to a limited extent to provide calories to the
       body whilst insoluble fibers are excreted undigested, thus providing stool bulk,
       but not energy. Examples of soluble fibers include gums (guar, locust bean, gum
       Arabic, gum tragacanth, gum karaya, alginates, agar, carrageenan, xanthan,
       gellan, and cellulose gums) and pectic substances. When eaten regularly as part of
       a diet low in saturated fat, trans fat and cholesterol, soluble fiber has been
       associated with increased diet quality and decreased risk of cardiovascular
       disease. Soluble or viscous fibers modestly reduce LDL cholesterol beyond levels
       achieved by a diet low in saturated and trans fatty acids and cholesterol alone.
       Oats have the highest proportion of soluble fiber of any grain. Foods high in
       soluble fiber include oat bran, oatmeal, beans, peas, rice bran, barley, citrus fruits,
       strawberries and apple pulp.
       Insoluble fibers include cellulose, hemicellulose, and lignin. Insoluble fiber has
       been associated with decreased cardiovascular risk and slower progression of
       cardiovascular disease in high-risk individuals. Dietary fiber may promote satiety
       by slowing gastric emptying, leading to an overall decrease in calorie intake.
       Foods high in insoluble fiber include whole-wheat breads, wheat cereals, wheat
       bran, rye, rice, barley, most other grains, cabbage, beets, carrots, Brussels sprouts,
       turnips, cauliflower and apple skin.




                                                                                           24
Functional properties of fibers in foods affect water-binding capacity, rheological
properties, capacity to form films or gels, capacity to bind flavor compounds, osmotic
pressure, hygroscopicity, chemical reactivity, sweetening and taste enhancement, and
resorption. These properties have been applied in food processing and preparation that
include thickening, emulsification, stabilization of emulsions and foams, flow properties,
texture, softness retention, browning, fermentability, control of microbial and enzymatic
modifications, and stabilization of taste and flavor.

In this experiment, we will be concerned with determining the effect of fiber on food
product characteristics including taste/ flavor, texture/ mouthfeel, and overall appearance.


MATERIALS AND PROCEDURES:

MATERIALS

Agar, carragenan, pectin, oats ( -glucan), guar gum, sugar, milk

APPARATUS

Petri dish, beaker, spatula, Bunsen burner

PROCEDURE

   1. Add 5% sugar and 0.4 g of fiber to 10 ml of milk in a beaker. Stir the mixture
      continuously throughout heating process of 20 minutes.
   2. Pour the solution into petri dish, and then cool in ice bath.
   3. Measure the height and diameter of the liquid pudding in the petri dish.
   4. Remove the pudding from the petri dish. After 30 minutes, measure the height
      and diameter of the pudding.
   5. Conduct simple sensory evaluation on the pudding produced. Evaluate the quality
      of the pudding in terms of the taste/ flavor, texture/ mouthfeel, and overall
      appearance on a scale of 1 to 5.


QUESTIONS:

   1. Illustrate the effect of using different fibers on the rheological properties and
      sensory characteristics of pudding.
   2. Discuss the chemical reactions that may involve which lead to the different
      characteristics as observed by using the different fibers.




                                                                                         25
                                   EXPERIMENT 5


TITLE: EFFECT OF             DIFFERENT       FATS/OILS       ON     FOOD      PRODUCT
CHARACTERISTICS.


PURPOSE: The purpose of this experiment is to assess the effect of different fat/oil on
characteristics of food product.


LEARNING OUTCOMES:

   1. Demonstrate the ability to predict and describe the effect of different fats/oils on
      the characteristics of food product.
   2. To collect, analyze and evaluate obtained experimental data.
   3. To collaborate with other students in the experiment as well as in documentation
      of the experiments.


INTRODUCTION:

The term „lipid‟ is used to cover a variety of chemical substances such as food fats and
oils, or mono-, di-, and triglycerides, phosphatides, sterols, fatty acids, fat-soluble
vitamins, and other substances. Lipid can be classified into simple lipids and compound
lipids. Fats and waxes are part of simple lipids. Compound lipids conversely, consist of
phospholipids, cerebrocides and sphingolipids. Different foods have different content of
lipid. Foods may contain any or all lipid compounds, but those of greatest importance are
the triacylglycerols and the phospholipids. Figure 2 shows the structures of some
common lipids.




                                                                                       26
Figure 2: Structures of some common lipids. At the top are oleic acid and cholesterol.
The middle structure is a triglyceride composed of oleoyl, stearoyl, and palmitoyl chains
attached to a glycerol backbone. At the bottom is the common phospholipid,
phosphatidylcholine.


The term „fat‟ is generally used in reference to materials which are solid or semisolid at
room temperature, whereas the term „oil‟ is used for materials which exist as liquid under
the same conditions. Examples of fats are: vegetable shortenings, butter, and lard.
Examples of oils include corn oil, sunflower oil, and palm oil. Fats consist of a group of
compounds in food that is soluble in organic solvents and normally insoluble in water.
Fats and oils are important sources of food energy and contribute greatly to the feeling of
satiety to any meal.

Lipids have three important functions in foods: culinary, physiological, and nutritional.
Their ability to carry odors and flavors and their contribution to palatability of meats,
tenderness of baked products, and richness and texture of ice cream are examples of
culinary functions. Because lipids serve as a convenient means of rapid heat transfer, they
have found increasing use in commercial frying operations. Dietary lipids represent the
most compact chemical energy available to humans. They contain twice the caloric value
of an equivalent weight of sugars.
Analysis of fat in food is important for food labeling and quality control. An accurate and
precise quantitative analysis of lipids in foods is important for nutritional labeling, to
determine whether the food meets the standard of identity and is uniform, and to
understand the effects of fats and oils on the functional and nutritional properties of
foods.

In this experiment, we will be concerned with observing and understanding the effect of
different fats/oils on the characteristics of food product.


                                                                                        27
MATERIALS AND PROCEDURES:

MATERIALS

Shortening, butter, palm oil (cooking oil), margarine (buttercup, daisy planta), corn oil/
mazola, wheat flour, sugar

APPARATUS

Oven, disposable glove, tray, basin/bowl, chromometer

PROCEDURE

   1. Mix 10g of sugar with 30g of butter in a basin/ bowl. After the two ingredients are
      thoroughly mixed, add 50g of wheat flour. Mix thoroughly.
   2. Flatten the mixture on flat surface and cut into pieces of 2 cm square. Measure the
      color of the pieces using chromometer.
   3. Measure the height the pieces (take average of three pieces). Transfer the pieces
      onto a tray.
   4. Repeat steps 1 to 3 for buttercup, palm oil, margarine, and corn oil.
   5. Bake in an oven at 160 C for 15-20 minutes.
   6. Cool the cookies at room temperature.
   7. Measure the height and diameter of the cookies. Measure the color of baked
      cookies using chromometer.
   8. Evaluate the crunchiness of the cookies from the different formulation on a scale
      of 5 (1 for soft and 5 for very crunchy).
   9. Evaluate the sensory properties of the cookies using Hedonic scale.


QUESTIONS:

   1. Which oil is the most suitable for making this type of cookies? Discuss why.
   2. Discuss why the different oil/ fat give different effect on the sensory and
      mechanical characteristics on the cookies?
   3. What are the factors that should be taken into consideration when choosing the
      suitable fat/oil for a specific product?




                                                                                       28
                                   EXPERIMENT 6


TITLE: EFFECT OF LIPID OXIDATION ON THE ORGANOLEPTIC PROPERTIES
OF FOOD.


PURPOSE: The purpose of this experiment is to determine, as well as to comprehend the
effect of lipid oxidation on the organoleptic properties of cookies.


LEARNING OUTCOMES:

   1. Demonstrate the ability to describe and examine the presence of the lipid
      oxidation in food systems, and their effect on the quality of food product.
   2. Explain the chain of reactions causing lipid oxidation, as well as the conditions
      that facilitate lipid oxidation in food system.
   3. To collect, analyze and evaluate obtained experimental data.
   4. To collaborate with other students in the experiment as well as in documentation
      of the experiments.


INTRODUCTION:

Oxidation of lipids is a major cause of deterioration in the quality of food products as it
affects many characteristics such as flavor, color, texture and nutritive value. Rapid
development of rancid flavors during storage is a major problem facing the food industry.
Because of their chemical structure, unsaturated fats and oils are subject to oxidative
breakdown or oxidative rancidity. Oxidative rancidity is the chemical deterioration of the
quality of a fat by either oxidative or hydrolytic chemical reactions:

       Oxidative rancidity is a chemical change that results in unpleasant odors and taste
       in a fat. The overall action of oxidative rancidity involves the uptake of oxygen at
       a double bond in an unsaturated fatty acid in a fat. When fats are exposed to
       oxygen, the double bond can be broken so that oxygen can then become a part of
       the molecule. Oxygen attacks the double bond in fatty acids to form peroxide
       linkages - therefore, phospholipids which contain a high content of unsaturated
       fatty acids, are more susceptible to oxidation. Unless mediated by other oxidants
       or enzyme systems, oxidation proceeds through a free-radical chain reaction
       mechanism involving three stages:

                    1. Initiation - formation of free radicals
                    2. Propagation - free-radical chain reaction
                    3. Termination - formation of nonradical products




                                                                                        29
       Hydrolytic rancidity takes place where free fatty acids are split from the glycerol
       in fat molecules, which involves the uptake of water in a process called lipolysis.
       The reactions usually is promoted either by the action of lipase or by heat and will
       eventually yield free fatty acids that may seriously alter the aroma and flavor of
       food containing oil and fat. Figure 3: oxidative rancidity of triaclyglycerol by
       hydrolytic chemical reactions to produce free fatty acids and glycerol which
       causes food rancidity. Figure 3 shows the oxidative rancidity of triaclyglycerol by
       hydrolytic chemical reactions to produce free fatty acids and glycerol which
       causes food rancidity.




Figure 3: Oxidative rancidity of triaclyglycerol by hydrolytic chemical reactions to
produce free fatty acids and glycerol.


In this experiment, we will be concerned with observing and understanding the effect of
different conditions on the oxidative rancidity of food product. We will also assess the
characteristics of these food products to evaluate the presence or absence of oxidative
rancidity.


MATERIALS AND PROCEDURES:

MATERIALS

Cookies prepared in Experiment 4.

APPARATUS

Oven, beaker



                                                                                        30
PROCEDURE

  1. Place 5 pieces of cookies prepared in Experiment 4 in 4 different beakers.
  2. Store for the cookies for 1 week:
     Beaker A: Cover the beaker and store in the dark at room temperature.
     Beaker B: Cover the beaker and left exposed to light at room temperature
     Beaker C: Cover the beaker and store in refrigerator.
     Beaker D: Cover the beaker and store in oven at 60 .
  3. After a week, conduct sensory evaluation on the cookies. Assess the aroma and
     flavor/taste characteristics of the cookies using Hedonic scale.


QUESTIONS:

  1. Describe the characteristics of flavor and aroma perceived. Is there any difference
     in the sensory characteristics of the cookies stored under different condition?
  2. Discuss the chain of reactions that took place that lead to the undesirable sensory
     perception.
  3. What can be done to eliminate the problems of rancidity?




                                                                                     31
                                   EXPERIMENT 7


TITLE: MELTING POINT AND COMPOSITION OF OILS.


PURPOSE: The purpose of this experiment is to determine and rationalize the various
meting points of different oils.


LEARNING OUTCOMES:

   1.   Identify the differences in content of the various fat products in the market.
   2.   Differentiate between the use of whipped, soft and regular margarines.
   3.   Evaluate the plastic range of the various fats tested.
   4.   Select the best fat product for specific use.
   5.   To collect, analyze and evaluate obtained experimental data.
   6.   To collaborate with other students in the experiment as well as in documentation
        of the experiments.


INTRODUCTION:

Fatty acids are merely carboxylic acids with long hydrocarbon chains. The hydrocarbon
chain length may vary from 10-30 carbons (most usual is 12-18). The non-polar
hydrocarbon alkane chain is an important counter balance to the polar acid functional
group. In acids with only a few carbons, the acid functional group dominates and gives
the whole molecule a polar character. However, in fatty acids, the non-polar hydrocarbon
chain gives the molecule a non- polar character.

There are two groups of fatty acids: saturated and unsaturated. The term unsaturated
refers to the presence of one or more double bonds between carbons as in alkenes. A
saturated fatty acid has all bonding positions between carbons occupied by hydrogens. As
a group, the unsaturated fatty acids have lower melting points than the saturated fatty
acids. The reason for this phenomenon can be found by a careful consideration of
molecular geometries. The tetrahedral bond angles on carbon results in a molecular
geometry for saturated fatty acids that is relatively linear although with zigzags. This
molecular structure allows many fatty acid molecules to be rather closely "stacked"
together. As a result, close intermolecular interactions result in relatively high melting
points. On the other hand, the introduction of one or more double bonds in the
hydrocarbon chain in unsaturated fatty acids results in one or more "bends" in the
molecule. The geometry of the double bond is almost always a cis configuration in
natural fatty acids. These molecules do not "stack" very well. The intermolecular
interactions are much weaker than saturated molecules. As a result, the melting points are
much lower for unsaturated fatty acids.



                                                                                       32
Figure 4: Stearic acid (saturated fatty acid) has a higher melting point because of the
close intermolecular interactions. Therefore, fats which have stearic acid as their major
fatty acid component in them are solid at room temperature. Linoleic acid on the other
hand, is an unsaturated fatty acid with “bends” which causes lower melting point.


The plasticity of fat is its ability to hold its shape but still be molded or shaped under light
pressure. Plasticity determines a fat‟s spreadability. It is an important characteristic to
consider when choosing which fat to use in the preparation of confections, icings,
pastries, and other baked products. Although most fats look solid at room temperature,
they are actually composed of liquid oil with a network of solid fat crystals holding it in
place. This combination allows the fat to be molded into various shapes. Chilled butter
has very little plasticity as compared to hydrogenated vegetable oil, or shortening. The
more unsaturated a fat is, the more plastic it will be. Temperature also influences
plasticity, hard fats such as butter becoming soft and more spreadable when warmed.

In this experiment, we will be concerned with observing and understanding the effect of
different composition of oils on the melting point and also the plasticity of the specific
oils.




                                                                                             33
MATERIALS AND PROCEDURES:

MATERIALS

Hot water, cold water, assigned fats

APPARATUS

Measuring cup, spatula, frying pan, heating unit, ring stand, thermometer, funnel,
graduated cylinder, penetrometer, refrigerator, freezer


PROCEDURE

   a) Record the label information for each fat being tested.

   b) Melting point and fat content:
   1. Lightly pack the assigned margarine into a ¼-cup metal measure, and leave it
       carefully with the straight edge of a spatula.
   2. Place the measuring cup in a frying pan. Position the frying pan on a heating unit
       on the range, but do not turn on the unit.
   3. Position a ring stand supporting a thermometer so that the bulb of the
       thermometer will be in the center of the fat. The bulb must be covered completely
       by the fat, but not touching the bottom of the cup. The positioning need to be done
       carefully.
   4. Without splattering on the fat, carefully pour cold water into the frying pan to a
       depth of 1/4‟‟. Begin heating very slowly.
   5. Note the temperature when the fat at the edge of the cup melts.
   6. Continue heating very slowly until all of the fat is melted. At precisely the point
       where all the fat melts, note the temperature.
   7. Very carefully remove the cup from the pan, and pour the melted fat into a
       graduated cylinder. If it is necessary to use a funnel to do this, be sure the funnel
       is warm enough to keep the fat from solidifying. Note the volume of the melted
       fat, after the measurement is taken, insert the thermometer and observe changes in
       the fat as it cools.
   8. Note any layering that may appear and the volume of the layers.
   9. At precisely the point that the fat losses its ability to flow when the cylinder is
       tipped, record the temperature and remove the thermometer.
   10. Allow the fat to continue cooling without disturbance. Observe the appearance of
       the modified fat.
   11. To remove the fat, place the cylinder in hot water until the fat melts enough
       around the edges to slide out.
   12. Carry out step 1-11 using the following:
           i.   Butter
          ii. Regular corn oil margarine
         iii. Regular canola oil margarine



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       iv.   Regular safflower oil margarine
        v.   Regular soybean oil margarine
       vi.   Soft margarine (corn oil)
      vii.   Soft margarine (other oil)
     viii.   Whipped butter
       ix.   Shortening

  c) Plasticity
  1. Pack a ¼-cup measuring cup with the assigned fat. Level with a spatula. Allow
     the measured fat to sit at room temperature for 30 minutes.
  2. Using the needle attachment on the penetrometer, test the penetration by releasing
     the needle for precisely 2 seconds
  3. Transfer the margarine to the refrigerator for 30 minutes.
  4. Test again on the penetrometer.
  5. Place the fat in the freezer for 30 minutes.
  6. Again take the penetrometer reading. Be sure to check the temperature of the fat
     immediately following ache penetrometer test. Smooth the surface of the fat with
     a spatula after the thermometer has been removed.

  Evaluation:
  a) Compare not only the initial temperature at which melting begins and the final
     temperature, but also the total temperature span over which the melting occurs for
     the various fats. Review these data carefully for commonalities within the specific
     groups of fats and for other generalizations that may be drawn from the results.
     Compare the total volume of regular butter with its whipped counterpart. Observe
     the amount of water found in the various fats as they cool and separate. Look
     carefully at the crystalline nature of each of the re-solidified fats.
  b) Compare the penetrometer results with the trends in melting points observed.


QUESTIONS:

  1. Which fats used in this experiment contain the largest amount of water? The
     least?
  2. What are the possible reasons for incorporating water into a fat? How does the
     water content influence the ways in which a fat can be used in food preparations?
  3. Does butter have as wide a range between initial and final melting temperature as
     does a regular margarine? How does this difference influence the usefulness of
     butter? Of margarine?
  4. What is done commercially to avoid the coarse crystal structure observed in the
     fats that were heated and then cooled in this experiment? Why is it important to
     have smaller crystals in fats?
  5. Which fats were softest at room temperature, refrigerator temperature and freezer
     temperature? How can this information be applied in food preparations?
  6. Does the order of the ingredients on the label provide clues as to probable
     physical characteristics of fats? Explain your answer.



                                                                                     35
                                    EXPERIMENT 8


TITLE: EMULSIFICATION AND FLAVOR OF OILS.


PURPOSE: The purpose of this experiment is to assess and understand the principles of
emulsification, as well as to evaluate the flavor contributed by different oils.


LEARNING OUTCOMES:

   1. Explain the theory of emulsion formation and the role of various emulsifying
      agents.
   2. Characterize the flavor of the oils tested and evaluate potential uses of these
      substances on the basis of their flavor contributions.
   3. Outline the changes that take place in oil-in-water emulsion with increasing levels
      of oil.
   4. Explain how to re-establish a broken emulsion.
   5. To collect, analyze and evaluate obtained experimental data.
   6. To collaborate with other students in the experiment as well as in documentation
      of the experiments.


INTRODUCTION

Most oils are less dense in water, and if oil and water are mixed then the oil will simply
float to the surface. In emulsions, the oil is dispersed as liquid droplets through the
continuous phase, usually but not necessarily water. This means that an emulsion is
thermodynamically unstable. Those droplets want to combine together again to form a
single blob of oil. To prevent them from doing this, emulsions contain a surfactant which
coats the surface of each drop and prevents the droplets from coalescing. In practice, a
mixture of oil, water and added surfactant are put through a blender, for example, and the
product is an emulsion. However the oil is still less dense than the water. So each drop is
prone to floating upwards. This process is called creaming - the oil droplets will
gradually form a dense layer at the top of the sample. Emulsification is the process of
dispersing one liquid in a second immiscible liquid. The largest group of emulsifying
agents is soaps, detergents, and other compounds, whose basic structure is a paraffin
chain terminating in a polar group.

The type of emulsion formed, i.e.: (1) oil-in-water or (2) water-in-oil depends upon the
nature of the emulsifying agent, the nature of the oil, and the effect of electrolytes. With
one emulsifier an oil-in-water emulsion may be formed with specific oil. Sometimes by
the addition of the right substance, usually an electrolyte, the emulsion can be reversed




                                                                                         36
and changed to a water-in-oil emulsion. Other emulsifiers with the same oil will form
water-in-oil emulsions.




Figure 5: Light micrograph of an oil in water emulsion.


Fats contribute their own flavor, while also absorbing fat-soluble flavor compounds from
other foods. Sauteing garlic, onions, and herbs in oil releases their flavorful and aromatic
compounds and also lends them a smooth, rich mouthfeel. One of the most obvious
contributions to flavor foods from fat is found in fried foods such as breaded poultry or
fish, french fries, potato chips, and doughnuts.

Fats also contribute texture. The higher the fat contents in ice cream, the smoother and
creamier the mouthfeel. The tenderizing effect of fats on foods makes them easier to
chew and causes them to feel moister in the mouth. The lubricating action of fat acts to
moisten certain foods such as crackers and chips in which saliva would not be enough.
These dry foods are processed in the mouth much more easily if they are coated with oil
or served with a high-fat dip or spread. In addition to contributing to flavor and texture,
fats also induce a sense of fullness, or satiety, because they take longer to digest than
carbohydrates and proteins.

In this experiment, we will be concerned with determining the stability of various
emulsions formed using different types of oils. The flavor produced by these oils will
also be assessed.




                                                                                         37
MATERIALS AND PROCEDURES:

MATERIALS

17 g egg yolk, 15 ml vinegar, 2 g sugar, 1.5 g salt, 0.6 g dry mustard, 0.6 g paprika, 118
ml oil, red food coloring

APPARATUS
Bowl, rotary beater, centrifuge, tubes, microscope

PROCEDURE

   1. Place the egg yolk, vinegar, and seasonings in a small bowl, and beat with a rotary
      beater.
   2. Begin adding the oil, approximately 3 ml at a time while beating slowly with a
      rotary beater after each addition until no trace of oil shows.
   3. Continue adding in very small additions until approximately 25 ml of oil have
      been added. Then the oil can be added more rapidly. One person can pour the oil
      while another beats the emulsion. Continue in this fashion until all the oil has
      been added.
   4. Carry out step 1-3 using olive oil, soybean oil, corn oil, cottonseed oil, safflower
      oil, sunflower oil, peanut oil, and canola oil.
   5. Stir 1 drop of red food coloring into a teaspoon of the corn oil mayonnaise made
      in the previous step. Continue to stir until the color is uniform throughout the
      sample.
   6. Evaluation:
   a) Objective: Depending on the size of the centrifuge tube, pour equal amounts of all
      mayonnaise samples from step 4 into the tubes. Load the samples into the
      centrifuge and centrifuge at the fastest settings for 15 seconds. Check to see which
      emulsification has broken, and remove them from the centrifuge. Determine the
      amount of oil that has separated in the broken emulsion. Reload the centrifuge to
      keep the balanced with samples opposite each other, and then centrifuge another
      15 seconds. Again remove broken emulsions, measure the volume of separated
      oil, reload the centrifuge, and continue this cycle until all the emulsions have
      broken. Freeze small samples of each mayonnaise and check the stability of the
      emulsion after thawing samples.
   b) Subjective: Subjective evaluation of mayonnaise is a useful means of identifying
      the flavor characteristics of the various oils used in this experiment. If the
      mayonnaises seem too oily to be palatable to sample, the sample can be placed on
      a corner of a soda cracker for evaluation. Evaluation should be directed toward
      appearance, including any suggestion of oiliness on the surface, and the color of
      the sample. Flavor and mouthfeel also are meaningful subjective evaluation
      criteria. Slice the sample with excess oil and observe the cut surface.
   c) Microscopic examination: place a drop of the emulsion containing red dye on a
      slide. View the emulsion under the microscope and sketch the appearance. Since




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     the red food coloring is water soluble, the areas tinted with the dye will be the
     vinegar, and the oil will be untinted.


QUESTIONS:

  1. Define an emulsion. What is the difference between an oil-in-water and water-in-
     oil emulsion?
  2. What type of emulsion is mayonnaise? Does the microscope side confirm your
     classification?
  3. What is the role of dry ingredients in mayonnaise? Of egg yolk?
  4. Is there any difference in the stability of mayonnaise when different oils are used?
     If so, which is the most and least stable? Why is it so?
  5. Describe the flavor of each of the mayonnaise samples. Which oil is in the most
     acceptable mayonnaise? Which oil is in the least acceptable sample?
  6. How to re-establish a broken emulsion?
  7. Does freezing influence stability of mayonnaise? Why?




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