Chapter 8 Milk and Milk Products
Chapter 8 Milk and Milk Products
Milk • Milk should contain • 8.25% milk-solid-not-fat • 3.25% milk fat • Milk is . − a true solution for salts, lactose, watersoluble vitamins − milk is a colloidal dispersion for proteins and some Ca phosphate − a dilute emulsion for fat globules
Milk • Milk should contain • 8.25% milk-solid-not-fat • 3.25% milk fat • Milk is . − a true solution for salts, lactose, watersoluble vitamins − milk is a colloidal dispersion for proteins and some Ca phosphate − a dilute emulsion for fat globules
Milk ◼ pH of milk: 6.6 at 25oC ◼ when heated, pH decreases, H+ are liberated when Ca phosphate precipitates ◼ Freezing Point: slightly lower than water ◼ Lower surface tension than water due to presence of milk fat, protein, free fatty acids, & phospholipids: easy to foam ◼ Components of milk varies with the feed, breed, nutrition & the physiological condition of the cow
Milk ◼ pH of milk: 6.6 at 25oC ◼ when heated, pH decreases, H+ are liberated when Ca phosphate precipitates ◼ Freezing Point: slightly lower than water ◼ Lower surface tension than water due to presence of milk fat, protein, free fatty acids, & phospholipids: easy to foam ◼ Components of milk varies with the feed, breed, nutrition & the physiological condition of the cow
Nutritional Components of Milk ◼ Water: 87%, aw = 0.993 ◼ Proteins: caseins, whey proteins, enzymes ◼ Lipids: mainly triglycerides ◼ Carbohydrates: mainly lactose, also glucose, galactose, & other saccharides ◼ Salts (<1%), ◼ Trace elements, ◼ Vitamins
Nutritional Components of Milk ◼ Water: 87%, aw = 0.993 ◼ Proteins: caseins, whey proteins, enzymes ◼ Lipids: mainly triglycerides ◼ Carbohydrates: mainly lactose, also glucose, galactose, & other saccharides ◼ Salts (<1%), ◼ Trace elements, ◼ Vitamins
Milk Proteins - Caseins ◼ Phosphoproteins, account for 80% of total milk proteins ◼ Four groups: alfas1-, alfas1, Beta-, & Kappa-caseins ◼ Present in milk as micelles, stabilized by Kappa-caseins & Ca phosphate ◼ Easily precipitated by adding acid to pH 5.2-4.6
Milk Proteins - Caseins ◼ Phosphoproteins, account for 80% of total milk proteins ◼ Four groups: alfas1-, alfas1, Beta-, & Kappa-caseins ◼ Present in milk as micelles, stabilized by Kappa-caseins & Ca phosphate ◼ Easily precipitated by adding acid to pH 5.2-4.6