PREPARATION AND EVALUATION OF IMMOBILIZED SINGLE AND MULTIPLE ENZYME SYSTEMS.

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Chemical composition, physical and functional properties of milk and milk ingredients

Milk is one of the few foodstuffs consumed without further processing, and it is generally regarded as the most nearly perfect food. Nutritionists worldwide agree that it is of enormous value in promoting growth and development of children and young animals. Although it is important for infant and childhood feeding, milk (and milk products) continues to be important in our diets right throughout our adult life

Studies on Whey Protein Concentrates. 1. Compositional and Thermal Properties

Cheddar-cheese-type whey protein concentrates were studied for their compositional and thermal attributes. The samples were prepared from three milk systems, namely, skim milk, whole milk, and skim milk enriched with buttermilk. The concentrates from skim milk were lower in all fat components and higher in proteins, except for the membrane-associated protein. The buttermilk-enriched samples had the most membrane-associated components. The concentrates from whole milk and buttermilk-enriched, skim milk were similar in protein composition, except for membrane-associated protein. The whole milk samples had the highest concentrations of total and free fat components. Lactose content and mineral composition were similar for the three types of concentrates. Thermal properties and denaturation kinetics were examined by differential scanning calorimetry. The samples exhibited a single broad endothermic peak with the denaturation temperature near 76°C and the enthalpy ranging from 1.86 to 2.16 cal/g. The concentrates from skim milk had higher denaturation enthalpy, whereas the concentrates from buttermilk-enriched, skim milk had slightly higher thermal stability. The overall denaturation process for whey proteins followed the reaction order n = 1.5 with an activation energy ranging from 217 to 251 kJ/mol. The thermal properties were observed to be related to a number of compositional factors. The denaturation enthalpy was positively correlated with β-lactoglobulin and protein content, and negatively correlated with bound fat, membrane protein, and membrane-associated lipid components. The denaturation temperature correlated positively with phospholipid content, and the onset denaturation temperature correlated positively with iron content

Studies on Whey Protein Concentrates. 1. Compositional and Thermal Properties

Cheddar-cheese-type whey protein concentrates were studied for their compositional and thermal attributes. The samples were prepared from three milk systems, namely, skim milk, whole milk, and skim milk enriched with buttermilk. The concentrates from skim milk were lower in all fat components and higher in proteins, except for the membrane-associated protein. The buttermilk-enriched samples had the most membrane-associated components. The concentrates from whole milk and buttermilk-enriched, skim milk were similar in protein composition, except for membrane-associated protein. The whole milk samples had the highest concentrations of total and free fat components. Lactose content and mineral composition were similar for the three types of concentrates. Thermal properties and denaturation kinetics were examined by differential scanning calorimetry. The samples exhibited a single broad endothermic peak with the denaturation temperature near 76°C and the enthalpy ranging from 1.86 to 2.16 cal/g. The concentrates from skim milk had higher denaturation enthalpy, whereas the concentrates from buttermilk-enriched, skim milk had slightly higher thermal stability. The overall denaturation process for whey proteins followed the reaction order n = 1.5 with an activation energy ranging from 217 to 251 kJ/mol. The thermal properties were observed to be related to a number of compositional factors. The denaturation enthalpy was positively correlated with β-lactoglobulin and protein content, and negatively correlated with bound fat, membrane protein, and membrane-associated lipid components. The denaturation temperature correlated positively with phospholipid content, and the onset denaturation temperature correlated positively with iron content