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					           Food Lipids


         Professor David B. Min
Department of Food Science and Technology
        The Ohio State University
         Columbus, Ohio 43210

               Min.2@osu.edu
    http://class.fst.ohio-state.edu/fst821
DESCRIPTION



        This course will cover an in-depth study of chemical and
physical properties of edible fats and oils and the roles of their
functional properties in food systems. Major topics covered will
be chemistry of triglycerides, auto and thermal oxidation,
antioxidants, chemical reactions in deep-fat frying, principles
and application of polymorphism, interesterification and
hydrogenation, fractionation of fats and oils, current
instrumental analyses of lipids and biotechnology of fats and
oils.
OBJECTIVES




 • To describe the relationship between the composition of
 tryglycerides and their chemical and physical properties.

 • To describe the chemical reactions of auto and thermal
 oxidation of oil and the mechanisms of antioxidants.

 • To describe the chemical mechanisms of hydrogenation and
 interesterification and their applications in fats and oils.
OBJECTIVES



• To apply the physical and chemical methods to convert readily-
available fats into tailor-made fats, that may be in greater demand or
more desirable economically or nutritionally than the original fats.

• To describe the current instrumental and analytical methods as
research tools in the fats and oils area.

• To describe the application of biotechnology to the modification
and production of fats and oils.
GRADING




      Exams (3)              60%
      Final Exam             30%
      Homework Assignments   10%
Course Schedule

   Class                 Topics

   1.      Introduction and Classification of Lipid
   2.      Chemistry of Fatty Acids
   3.      Chemistry of Triglycerides
   4.      Chromatographic Analyses of Lipids
   5.      UV & IR Spectrometric Analyses
   6.      NMR Spectrometric Analyses
   7.      NMR Spectrometric Analyses
   8.      NMR and Mass Spectrometric Analyses
   9.      Mass Spectrometry
   10.     Mass Spectrometry
Course Schedule

  Class                Topics

  11.     Identification of Lipid Compounds by IR, NMR, MS
  12.     Examination
  13.     Lipid Oxidation - Chemistry of Oxygen
  14.     Free Radical Lipid Oxidation
  15.     Free Radical Lipid Oxidation
  16.     Singlet Oxygen Lipid Oxidation
  17.     Singlet Oxygen Lipid Oxidation
  18.     Singlet Oxygen Oxidation in Milk Products
  19.     Enzymatic Lipid Oxidation
  20.     Evaluation of Flavor Quality and Stability
Course Schedule

    Class                 Topics

    21.     Chemical Reactions in Deep-Fat Frying Oils
    22.     Examination
    23.     Polymorphism
    24.     Application of Polymorphism in Foods
    25.     Interesterification
    26.     Interesterification
    27.     Hydrogenation
    28.     Hydrogenation
    29.     Examination
Reference Books
   1.   Flavor Chemistry of Fats and Oils by David B. Min and Thomas
        H. Smouse. American Oil Chemists' Society, Champaign, IL. 1985

   2.   Flavor Chemistry of Lipid Foods by David B. Min and Thomas H.
        Smouse. American Oil Chemists' Society, Champaign, IL. 1989

   3.   Food Lipids and Health by Richard E. McDonald and David B. Min.
        Marcel Dekker, Inc. New York, NY. 1996

   4.   Food Lipids by Casimir C. Akoh and David B. Min, Marcel
        Dekker, Inc. New York, NY.1998

   5.   Bailey's Industrial Oils and Fat Products by Y.H. Hui Wiley
        Interscience. New York, NY. 1996

   6.   Food Chemistry, 3rd Edition by O. Fennema, Marcel Dekker, Inc.
        New York, NY.1998
CLASSIFICATION OF LIPIDS
Triacylglycerol
Simple Lipids


               A. Neutral fats - Triglycerides

                                                 O
                       O
                                         H2 C O C R
 H2 C OH          HO C R
                                                O
                     O
 HC OH     +                              HC O C R    + 3 H2O
                  HO C R
 H2 C OH                                       O
                     O
                  HO C R                 H2 C O C R
Simple Lipids


     B. Waxes

        Fatty acids + Long chain alcohol

        Beeswax (myricyl palmitate)
                    O
         C30 H61 O C C15 H31

       Spermaceti (cetyl palmitate)
                      O
        C16 H33 O C C15 H31
Simple Lipids


      Cholesterol and Esters

                                  CH3               CH3
                                  CH CH2 CH2 CH2 CH
                               17                   CH3

                       5
                   3       6
Fatty acids + HO
Simple Lipids

      Retinol (Vitamin A1) and Esters



H3C                  CH       CH
        CH 3              3        3
                                       CH OH   + fatty acids
                                         2

               CH3
Simple Lipids

   Vitamin D and Esters


   R = C8H17 in Vitamin D3
   R = C9H17 in Vitamin D2                          R
                                H2C
                                                8
                                      5
                                          6 7
             fatty acids + HO
CHEMISTRY OF FATTY ACIDS
Classification and Structure-Saturated Fatty Acids


   Common Name        Systematic Name      Formula
                                                 O
   Butyric acid       n-butanoic        CH3(CH2)2C OH
                                                 O
   Caproic acid       n-hexanoic        CH3(CH2)4C OH
                                                 O
   Caprylic acid      n-octanoic        CH3(CH2)6C OH

                                                 O
   Capric acid        n-decanoic        CH3(CH2)8C OH
                                                  O
   Lauric acid        n-dodecanoic      CH3(CH2)10C OH
Common Name       Systematic Name       Formula
                                              O
Myristic acid     n-tetradecanoic   CH3(CH2)12C OH

                                              O
Palmitic acid     n-hexadecanoic    CH3(CH2)14C OH

                                              O
Stearic acid      n-octadecanoic    CH3(CH2)16C OH

                                              O
Arachidic acid    n-eicosanoic      CH3(CH2)18C OH

                                              O
Behenic acid      n-docosanoic      CH3(CH2)20C OH

                                              O
Lignoceric acid   n-tetracosanoic   CH3(CH2)22C OH
Monoethenoic Acid - Cis



              10    9   8   7    6   5     4       3       2       1
                                               g       b       a   O
    1          9
   w C H3(C H2)7 HC CH C H2 CH2 CH2 CH2 C H2 CH2 C H2 C                OH



                   Δ 9, 10 - Octadecenoic acid
                   9 - Octadecenoic acid
Common Name of Fatty Acids


  Common Name    Systematic Name cis

  Myristoleic    9-tetradecenoic acid

  Palmitoleic    9-hexadecenoic acid

  Oleic          9-octadecenoic acid

  Vaccenic       11-octadecenoic acid

  Erucic         13-docosenoic acid
Polyethenoic Acids

 Common Name    Systematic Name


 Linoleic       9,12-octadecadienoic acid(cis,cis) or
                Octadeca-9,12-dienoic acid

 Linolenic      9,12,15-octadecatrienoic acid


 Arachidonic    5,8,11,14-eicosatetraenoic acid
                4,8,12,16-eicosatetraenoic acid
Ethynoic Acids


   Common Name    Systematic Name

   Tariric acid   6-octadecylinic acid
Hydroxy and Keto Acids

  Common Name         Systematic Name

  Dihydroxystrearic   9,10-dihydroxyoctadecanoic

  Lactarinic          6-keto-octadecanoic
Cyclic Acids

Chaulmoogric acid

                                                      O
               4             5         1
               CH            CH        CH    (C H ) 12 C   OH
                    2             2              2

                        CH        CH
                        3         2

     13-(2-cyclopentenyl) tridecanoic acid
Triacylglycerol
Fatty Acid Analysis


 1. Method for oils :

    a. measure 5 - 15 mg oil into small vial.
    b. add 0.4 - 0.8 ml sodium methoxide.
    c. heat 60C for 50 - 60 min.
    d. add 0.4 - 0.8 ml saturated NaCl solution.
    e. extract with 0.4 ml petroleum ether.
    f. check derivertization (TLC-chloroform solvent).
    g. Gas Chromatography analysis
Fatty Acid Analysis

  2. For quantification : the same as above except
     a. add internal standard free fatty acid to oil.
     b. add equal volumes of sodium methoxide and
          BF3-methanol, 0.5 - 1.0 ml of each.
     c. heat 70 - 80C for 50 - 60 min. (if, after 20 min.
         of heating the sample is not dissolved, add more
          sodium methoxide and BF3-methanol).
Disadvantages of Gas Chromatography

  Material has to be volatilized at 250°C without decomposition.

     Fatty Acids            Methylester


         O                                      O
                                  Reflux
      R C OH+ CH3OH + H2SO4                  R C O CH3
                                            Volatile in Gas Chromatography

              O
        CH2 O C R

                O                                           O
                                           CH3 ONa
        CH    O C R    +     CH3OH                    3 R C O CH3
                                                        Volatile in Gas Chromatography
              O
        CH2 O C R
Chromatogram of Fatty Acid Methyl Ester

				
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