King AbdulAziz University Faculty of Applied Medical Science

King Abdul-Aziz University Faculty of Applied Medical Science Clinical Nutrition Department – Third Year Dr. Sahar Abd El-Hakeem

Dr. Sahar Abd El-Hakeem

Processing Methods Ø amino acid sequence Ø regular folding of protein conformation Ø subunit composition Ø molecular mass Physicochemical Properties Ø surface charge hydrophobicity Ø thermal stability flexibility Ø association / dissociation behavior Functional Properties Environmental ØConditions ph Ø Ionic structure Ø Type of salts Ø moisture content Ø oxidationreduction potential Dr. Sahar Abd El-Hakeem Ø heating Ø freezing Ø drying Ø shearing or mixing Ø pressure Protein Structure Ø amino acid composition

◘ Consumer says: ♦ Inverse association between protein and fats, ♦ More protein means higher quality and higher price. Dr. Sahar Abd El-Hakeem ♦ Protein is associated with nutritional quality, ◘ Processor says: ♦ Protein means functionality (foaming, texture, emulsification, browning color, and

◘ The term “functional foods” has come to have a separate meaning in today’s pop-culture in reference to nutraceuticals. Dr. Sahar Abd El-Hakeem ◘ Functionality as applied to foods and food ingredients in generally ANY property aside from nutritional attributes, that influences the usefulness in a food.

◘ Protein-Protein Interactions ▪Gel formations ▪Precipitation ◘ Surface Properties ▪Emulsifiers ▪Foaming Dr. Sahar Abd El-Hakeem ◘ Hydration properties ▪Water-holding capacity ▪Viscosity modifiers ▪Solubility

Dr. Sahar Abd El-Hakeem ◘Consumer says: q. Differences in nutrition, q. Some amino acids are good for me, q. Some give me allergies (milk, wheat, or peanuts) ◘Processors says: q. Costly little critters, q. Allergies, q. Amino acid content (labeling), and q. Digestibility issues.

Dr. Sahar Abd El-Hakeem ◘ Will “functionality” and nutritional quality change? If so, is this a good thing to happen ? ◘ Heating may denature a protein, (but gives a larger loaf volume for breads) ◘ Decrease in nutritional quality, ◘ Loss in emulsification/foaming ability.

22 -25 Milk (skim) 3. 2 Wheat flour Egg (dry) 35 Walnuts 15 -21 Potato 10 -13 Beef (dry) 81 -90 Rice 7. 5 -9 9. 8 -13. 5 Dr. Sahar Abd El-Hakeem Milk (dry)