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Components and Compositions

VIEWS: 13 PAGES: 33

									Colloid and surface phenomena
aspects of Chocolate



CE 457/527            Chin Kok Ooi
                       Teck Yu Sia
                      Anshu Verma
                    Shushan Munshi
Introduction
   Chocolates has a wide variety and found in
    common places
   Has to meet consumer need
   Types of chocolates
   Good for health
Marketing
   Designing chocolates
       Energy
       Size
       Price
       Efficiency
       Legal requirements
   Advertisement
Components and Compositions

   The   ingredients of chocolate
     Cocoa,   cocoa butter, milk and sugar
   Additional   ingredients
     Lecithin(emulsifier)   and flavoring
     agents
Cocoa and Cocoa butter
   Both are obtained from the seeds of
    „Theobroma Cocoa‟.
   „Cocoa beans‟ grow in pods.
Cocoa and Cocoa butter
     General compositions of cocoa bean
Composition   Per cent     Composition          Per cent

Moisture       6.3- 8.5    Cocoa Red            2.5- 5.0

Fat           46.9- 52.1   Ash                  2.9- 4.8

Albuminoids   11.6- 21.1   Astringent matters   7.2- 8.6

Cellulose      3.3- 6.6    Cane sugar

Alkaloids      0.3- 0.5    Starch               8.7- 12.6
Cocoa and Cocoa butter
   Alkaloids
       Theobromine and caffeine
         Theobromine – 3,7-dimethyl-xanthine
         Caffeine – 1,3,7-trimethyl-xanthine

   „Cocoa red‟– is formed during the drying
    of the beans by the action of enzymes on
    the glucosides.
Cocoa and Cocoa butter
   Special characteristics of cocoa butter:
       The melting point of cocoa butter is between
        32°C and 36°C.
       In spite of low melting point, cocoa butter is
        hard and brittle at normal room temperature.
       Help to prevent „fat bloom‟
Milk
      Compositions of cow milk
    Component                               Content (% w/w)

    Water                                        87.3

    Proteins (caseins & whey proteins)            3.3

    Fat                                           3.9

    Lactose                                       4.6

    Minerals                                     0.65

    Others (vitamins, organic acids, etc)        0.32
Milk
   Compositions of lipids in milk
Component          Content (% of total fat)

Triglycerides               96-99

Diglycerides               0.3-1.6

Monoglycerides            0.02-0.1

Free fatty acids           0.1-0.4

Phospholipids              0.2-1.0

Sterols                    0.2-0.4

Cerebosides               0.01-0.07
Sugar
   Sucrose
       Combination of „glucose‟ and „fructose‟
   Sugar bloom
Chocolate manufacturing process                             Fermented and Dried Beans

                                                                    Cleaning

                                                                    Roasting

                                                            Breaking and Winnowing

                                      Nib-Shell Mixtures              Nib                      Shell

                                                                                                             Germ Separation
                                                                 Germ-free Nib

                                                                    Milling

                                                                 Cacoa-Mass
                                                               (Chocolate liquor)
                     Cocoa manufacture                                                           Chocolate manufacture

                     Alkalization                                                        Addition of Sugar, Flavor, Milk etc. and
                                                                                         Cocoa Butter
                Removal of excess moisture
                                                                                                          Mixing
                       Fat Pressing
                                                                                                         Refining

    Press Cake                               Cocoa Butter                                               Conching

    Breaking                                                                                            Tempering

    Grinding
                                                                                    Molding                                Enrobing
      Sifting
                                                                               Plain or Milk                             Chocolate -coated
                                                                               Chocolate                                 goods
   Cocoa Powder
     Major function of these processes
1.   Fermenting and drying
          Removal of adhering pulp
          Removal of moisture
2.   Roasting
          Critical for flavor development
3.   Winnowing
          Removal of seed coat
          Size selection of nibs
4.   Milling
          Release of fat from cells
     Major function of these processes
5. Cocoa manufacture
        Production of additional fat (cocoa butter)
6. Refining
        Grinding of sugar particles
7. Conching
        Reduction in viscosity
8. Tempering
        Pre-crystallization process
         Chocolate flow properties
Chocolate exhibits non-Newtonian properties
For Newtonian fluid:   D
For Bingham fluid:       pl D

     D
                1   2           3




                                       Different types of rheogram: (1) Newtonian;
                                       (2) Bingham; (3) pseudoplastic
                                       (e.g. chocolate)


           o               
    Steiner‟s model for chocolate - adapted from
       Casson‟s model for printer‟s ink

       1  a    DN 
                          1
                          K1
                                                   
                             1  a    2 K 0 ..........
                                                         ..........        ..........
                                                                  ..........        ..........        .......... 1)
                                                                                             ..........        .(

       a  r / R..........        ..........
                         ..........                 ..........
                                           ..........        ..........
                                                                      ..........
                                                                               ..........        ..........
                                                                                        ..........                 ..(
                                                                                                          .......... 2)
                2
        DN                   ..........
                     ..........                 ..........
                                       ..........        ..........
                                                                  ..........
                                                                           ..........        ..........
                                                                                    ..........                 .....(
                                                                                                      .......... 3)
               1 a2

where r, R are the inner and outer radius of the cylinder respectively,  is the angular
velocity, DN is the shear rate at the inner cylinder.

CA = (1/slope)2 = (1/K1)2 = plastic viscosity according to Casson;

CA = (b/2)2 =K02 = yield value according to Casson
(1  a) DN




             b=2K0                           (1  a ) 



                     Casson rheogram according to OICC
             Factors affecting the flow properties of
             chocolate
                                                      Fat content:
                                                  12




                                                  10
                Casson plastic viscosity (Pa.s)




                                                  8

                                                                1
                                                  6




                                                  4

                                                            2

                                                  2




                                                  0
                                                       28            32     36

                                                                    % fat




Influence of fat content on Casson parameters of two milk chocolates with 0.25% lecithin.(1) Fine chocolate with 5.7% particles >
20m; (2) moderaltely coarse chocolate with 16% particles > 20m.
          Lecithin and other emulsifiers: immediate
           reduction in viscosity
          Moisture content: increases viscosity
          Particle size distribution:
                                             4
                                                                                                                  80


                                                                                                                  70
           Casson plastic viscosity (Pa.s)




                                             3
                                                                                                                  60




                                                                                        Casson yield value (Pa)
                                                          1
                                                                                                                  50


                                             2                                                                    40                  1

                                                                                                                  30
                                                     2                                                                     2
                                             1                                                                    20


                                                                                                                  10


                                             0                                                                     0
                                                 0       10     20     30     40   50                                  0       10    20     30      40   50

                                                              %>20 m icrons                                                         %>20 m icrons



Influence of fineness on Casson parameters of two milk chocolates with 0.25% lecithin. (1) 30% fat; (2) 32% fat
                 Temper: increases viscosity
                 Thixotropy: decreases viscosity
                 Vibration: decreases viscosity
                 Temperature:
                                                      5
                                                                                                                   120
                    Casson plastic viscosity (Pa.s)




                                                      4
                                                                                                                   100
                                                                                                                                                     1

                                                                                         Casson yield value (Pa)   80
                                                      3


                                                                                                                   60

                                                      2            2                                                                                     2
                                                                                                                   40



                                                      1        1                                                   20



                                                                                                                    0
                                                      0                                                                  40   45         50         55       60
                                                          40             50         60
                                                                                                                                   Tem perature C
                                                                   tem perature C


Influence of temperature on Casson parameters of two milk chocolates. (1) 34% fat, without lecithin; (2) 30% fat, 0.15% lecithin
  Surface- active substances in chocolate
  manufacturing
  Lecithin is the chief surfactant used
  The other surfactants are:
       ammonium phosphatides (YN)
       polyglycerol polyricinoleate (PGPR)
  The chief function are:
       reduce viscosity
       Reduce thickening due to moisture and temperature
       Modify the setting behavior of fat phase

  Flow characteristics of plain chocolate with added surface-active lipids
                               Casson plastic               Casson yield
                               viscosity                    value
  Addition                     (poise)                      (dynes/cm2)


0.3% soy lecithin                6.1                           92
0.3% YN                          10.3                          30
0.3% sucrose dipalmitite         8.6                           166
0.3% PGPR                        32.5                          25
0.8% PGPR                        20.3                          0
                                      8                                                                                      80


                                      7                                                                                      70
Casson plastic viscosity (Pa.s)




                                                                                                  Casson yield value ( Pa)
                                      6                                                                                      60


                                      5                                                                                      50
                                                                                                                                                                       Influence of soya lecithin addition on
                                                                                                                                                                       Casson parameters of two dark
                                      4                                                                                      40
                                                                                                                                                                       chocolates. (1) 33.5% fat, 1.1% water;
                                      3                                            1                                         30
                                                                                                                                                             1         (2) 39.5% fat, 0.8% water
                                      2                                                                                      20
                                                   2
                                                                                                                                            2
                                      1                                                                                      10

                                      0                                                                                       0
                                           0   0.2         0.4         0.6       0.8        1                                     0   0.2       0.4    0.6   0.8   1
                                                           % lecithin                                                                           % lecithin




                                      10



                                      8                4
          Apparent viscosity (Pa.s)




                                      6
                                                                             3                   Viscosity reduction of dark chocolate by soya lecithin and by synthetic active
                                                                                                 lipids . Apparent viscosity determined at shear rate 15 s-1 and 50oC; initial
                                      4                                                1         apparent viscosity before addition: 19.5 Pa s or 195 poises. (1) Soya lecithin;
                                               2                                                 (2) phospholipid YN; (3) sucrose dipalmitate; (4) polyglyceryl polyricinoleate,
                                      2                                                          PGPR

                                      0
                                           0       0.2           0.4         0.6           0.8
                                                           % addition
 Mechanism of viscosity reduction by
lecithin

1.   a monomolecular film is formed on the surface of the
     non-fatty particles by surfactant molecules.
2.   reduction in internal friction by promoting the coating of
     sugar and cocoa solids by fatty medium.
3.   increase in the amount of „free‟ cocoa butter in the
     dispersion medium by displacement from the surface of
     solids.
4.   prevention of agglomeration of sugar particles and cocoa
     particles by break down of any lattice-type structure
     between them.
5.   absorption of moisture
            Effect of lecithin on the stability of
            emulsions




Lecithin molecule    oil-in-
at interface
                                      water-
                     water            in-oil
between water and
oil
                                                                                    Oil
Types of emulsions




                               Creaming            Sedimentatio     Coalescence   Separatio
                                                   n                              n
                               Creaming of emulsions: four phases
  Chocolate – an emulsion of hydrophilic sugar and lipophilic cocoa
  particles in a continuous fat medium


                                      Molecular structure of main
                                      phospholipids found in
                                      lecithin




Phospholipid structure at
the interface of an
emulsion
PACKAGING AND STORAGE
METHOD OF WRAPPING:         MATERIAL FOR PACKAGING:

   MOLDED CHOCOLATE           ALUMINUM FOIL.
    BLOCKS.
                               REGENERATED
   CHOCOLATE COUNTLINES.       CELLULOSE FILM (RCF).

   BOXED CHOCOLATE.           PLASTIC FILM.

   TWRIST WRAPPING.
MOLDED CHOCOLATE BLOCK




   Protection against dirt, moisture and taint.
   It is more economical .
   Wide surface for labeling.
CHOCOLATE COUNTLINES




   Normally wrap in “pillow pack”
   By heavy-backed foil, waxed paper or
    glassine.
   Protection against moisture vapor and taint.
BOXED CHOCOLATE




   Usually, a thin layer of greaseproof film
    includes at the inner fitment.
   It prevents crushing of sweetness and
    cushioning.
   Protect against handling dirt.
    TWRIST WRAPPING


   In “double end fantail” form.
   By aluminum foil, backed and unbacked plain
    sliver, colored and printed film.
   Protection against dirt and taint.
ALUMINUM FOIL

   Best barrier for water vapor and gas
    transmission.
   Thickness range from 7-12 m for pure
    aluminum.
   Combination with special alloy for extra
    strength.
   Thickness range 7-8 m.
REGENERATED CELLULOSE FLIM (RCF)


   Packaging in flexible form.
   Usually coated or giving other treatments.
   Protection against moisture vapor and taint.
   PVDC for extra protection such as
    electrostatics.
   An advantage for tear strip product.
PLASTIC FILM


   Three different forms: polyethylene,
    polyvinyl chloride and polyester.
   Available in film or coating purposes.
   Protection against moisture, gas and
    ultraviolet.

								
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