Presentation on theme: "Flavor Chemistry 820 The Ohio State University"— Presentation transcript:
1 Flavor Chemistry 820 The Ohio State University Food Science and TechnologyInstructor : Dr. David B. Min
2 General ObjectiveThe objective of this course is to teach students the role of flavor chemistry in food quality. Chemical structures and formation of flavor compounds, organic, bio, and analytical chemistries involved in flavor research, the effects of processing, packaging and storage conditions on the flavor quality and stability of foods, and current research related to flavor are covered.
3 Upon completion of this course, students should be able to: 1. Understand Chemical reactions involved inflavor compounds formation in natural andprocessed food.2. Comprehend the effects of food components,processing parameters and storage conditions onflavor quality of foods.3. Understand principles, techniques andapplications of analytical instruments involved inflavor analysis.
4 4. Optimize ingredient concentration, processing parameters, packing materials and storageconditions for optimum quality and stability.5. Develop simple research programs of flavor chemistry.6. Specify the flavor qualities of raw ingredients.
5 Evaluation Midterm Examinations (2) 40% Final Examination 30% Home Work and Class Participation 30%
6 1. Introduction I. Definition of Flavor II. Classification of Food FlavorIII. Scope of Flavor Chemistry1.Chemical compounds responsible for food flavor2.Flavor of foods3.Reconstitution of flavor compounds4.Precursors of the flavor compounds5.Mechanism for the formation of flavor compounds and precursors in foods6.Relationship between physical properties and its flavorIV. Objectives of Flavor Chemistry
7 2. Isolation and Separation of Flavor Compounds I. ObjectiveII. PrerequisitesIII. Apparatus for Isolation1.Headspace analysis2.Continuous solvent extraction3.Steam distillation and continuoussolvent extractionIV. Extraction and ConcentrationV. Preliminary and Final FractionationVI. Dynamic Headspace analyzerV. Solid Phase Microextraction Analysis
8 3. Flavor Identification by Spectrometric Methods I. Introduction of Spectrometric AnalysesII. Ultra Violet SpectrometryIII. Infrared SpectrometryIV. Nuclear Magnetic Resonance SpectrometryV. Mass Spectrometry1.Furans2.Pyrroles3.Thiophenes4.Pyridines5.Pyrazines
9 4. Manufacture of Food Flavor I. Natural or Imitation FlavorII. Problems of Using Natural FlavorIII. Disadvantages of Using Imitation FlavorIV. Advantages of Imitation FlavorV Methods in Synthetic Flavor Reconstitution
10 5. Chemistry of Flavor Precursors I. Flavor Compounds from Carbohydrates andProteinsII. Thermal Degradation of Vitamin B1III. Lipid OxidationIV. Flavor Generated from Enzymatic Method, Microbiological Reaction, and Biogenesis
11 6. Dairy Products Flavor Chemistry I. Milk Flavor1.Oxidized flavor2.Rancid flavor3.Heated flavor4.Microbiological flavor5.Absorbed flavor6.Sunlight flavorII. Cheese Flavor1.Isolation, separation and identification of cheese flavor2.Biological pathways of fat in cheese flavor3.Reaction products of methionine4.Biochemical pathways of cheese flavor formation from protein5.2-Butanone and 2-Butanol formation from diacetyl and acetone6.Biochemical pathways of cheese flavor formation from lactose7.Lactone formation8.Mechanisms of methyl ketone formation
12 7. Meat Flavor Chemistry I. Introduction II. Effect of Psychrotropic Bacteria on the Volatile Compounds of Raw Beef1.Introduction2.Volatile compounds of aseptic raw ground beef3.Effects of psychrotropic bacteria on the volatile compounds of aseptic raw ground beefIII. Isolation, Separation, and Identification of Roast Beef Flavor Simulated Meat Flavor Formation
13 8. Interaction of Flavor Compounds with Foods I. Physical and Chemical Stability of Flavor Compounds of Lipid FoodII. Effects and Interactions of Carbohydrates with Flavor CompoundsIII. Interactions of Proteins with Flavor Compounds
14 9. Packaging and Flavor Compounds Interaction I. Effects of Packaging Materials on the Flavor Quality of FoodII. Sorption of Orange Flavor Compounds by Packaging Materials
15 10. Favor Compounds and Solvent Interaction I. Commercial Cherry Flavor and Solvent InteractionII. Acetal Formation
16 1. INTRODUCTION I. Definition of Flavor 1. “Flavor is the sensation produced by a material taken in the mouth, perceived principally by the senses of taste and smell, and also by the general pain, tactile, and temperature receptors in the mouth. Flavor also denotes the sum of the characteristics of the material which produces that sensation.”2. “ Flavor is one of the three main sensory properties which are decisive in the selection, acceptance, and ingestion of a food.”
18 II. Scope of Flavor Chemistry 1. Chemical compounds responsible for food flavor1) Even distribution: Brandy2) Star compound: A star compound can not be identical to the total true flavor but is close and can not produce the true flavor without the star compound.
23 Reversion Rancid Flavor of Soybean Oil: 2-Pentylfuran and 2-Pentenylfuran
24 2. Flavor of Foods 1) Desirable flavor orange juice potato chip roast beef2) Undesirable flavor (off-flavor)oxidizedstalerancidwarmed-over
25 3. Precursors of Flavor Compounds Linoleate 2-pentylfuran
26 1) Non-enzymatic reaction Precursor of beef flavor can be isolated as a white fluffy powder.White fluffy powderOil Waterbroil stew beef brothAmino acid + SugarMaillard reaction
27 2) Enzymatic reactionProcessed banana no fresh banana flavorenzyme extracted from banana peelFresh banana flavor
28 4. Mechanisms for Flavor Compounds Formation and Precursors in Foods 1) Volatile flavors developed in most food plants mainly atthe ripening stage - the result of plant metabolism through enzymatic reaction.2) Raw meat must be heated before it develops anyorganoleptically acceptable flavor.meat flavor (boiled beef)3, 5-Dimethyl-1,2,4-trithiolane
30 Apply the knowledge we gained from the mechanism and precursor studies to processed food. a. Enhance the desirable food flavor.b. Elimination of the undesirable food flavor.c. Application of heated model system to processedfoods.
31 5. Relationship between Physical Properties of Compound and Flavor B.P.(0C) Solubility in Sense of smellH2O g/100 ml (ppm)n-propanoln-butanoln-hexanalCH3-S-CH insoluble
32 Odor Threshold (ppm) in Water 2-t-pentenal 2.32-t-hexanal 10.02-t-heptanal 14.02-t-octenal 7.02-t-nonenal 3.22-t-decenal 33.82-t-undecenalThe series has an increase b.p. and decreased solubility in H2O
33 Effect of Medium on the Vapor Compositions of Flavor Compounds Headspace AnalysisCompound Water Corn oil(200ppm) (peak area) (peak area)acetone2-butanone2-pentanone2-hexanone2-heptanone
34 IV. Objectives of Flavor Chemistry 1. To understand the chemical composition of natural flavors and the mechanism of their formation.2. To retard or prevent the development of the off- flavors in foods.Reversion rancid flavor in soybean oil: hexenal, 2-pentyl furan3. To restore the fresh flavor to a processed food4. To improve the flavor of food by the addition ofsynthetic flavor.5. To produce new foods with special flavor such as potato chip flavor.
35 6. To improve flavor by the acceleration of reactions which produce desirable flavor compound (onion flavor: pH 5~7).7. To assist geneticist to breed food raw material withimproved flavor compounds or flavor precursors.8. To specify raw material and to control quality of food products.The price of tea can be correlated with GLC peak of linalool.Ceylon tea contains cis-hexenol, India tea doesn’t contain cis- hexenol