milk proteins- Week 8 Flashcards
what are the 3 different phases of milk & what do each contain
1)stable emulsion (containing fat)
2)Colloidal suspension (containing all proteins: whey & casein)
3)true solution(contanning rest of the nutrients, e.g. lactose, minerals, water)
what is casein
casein is composed of alpha, beta (are phosphoproteins) and k-casein proteins (are glycoproteins which are more hydrophobic)
explain what casein micelles is
what is the name of when casein self-assemble into protein packets
what gives milk its white colour
alpha and beta caseins are held together by hydrophobic interactions & k-caseins remain at the surface- this provides a REPULSIVE STERIC FORCE between individual micelles
what are the importance of caseins in the food industry
-it dispenses in water & carries a large amount of calcium
-dairy industry has the capability of separating these proteins which gives us other ingredients
what are the casein-based ingredients (6)
-Skimmed milk powder
-Acid casein
-Rennet casein
-Caseinate
-Milk protein concentrates
-Phosphocasein
(All products are obtained as powder)
what is the benefit of all the casein-based ingredients being powder
-they are dry so will be preserved for a longer time
what is skimmed milk powder (SMP) uses and applications
SMP is soluble following reconstitution (with water they reconstitute and can be used for any other product) & can be used for further processing like UHT
-RECOMBNED MILK PRODUCTS- due to stability at high temp
-CHOCOLATE- milk chocolate may be composed of SMP and whey proteins
-BAKERY- SMP and whole milk powders are used
what is Acid casein uses and applications
it’s the preliminary step in the production of yogurt
-acid gels (yogurts and cream cheese)
what is the difference between skimmed milk powder and acidic casein
SMP has the whey proteins and casein whereas acid casein only has casein proteins
what is the uses/applications of Rennet casein
-preliminary step in production of cheese
-CHEESE ANALOUGE
what is the method to obtain phosphocasein as a caseinate-based ingredient
its the concentration of casein by using microfiltration
what is the method to obtain Milk protein concentrates (MPC) as a caseinate-based ingredient
concentration of casein by membrane technology
what is the method to obtain Caseinate as a caseinate based ingredient
neutralisation of acid/rennet casein through addition of alkali
what are the uses/applications of caseinate
for sodium and calcium caseinate the use/application is ACID GELS
-FOOD EMULSIONS (both types of emulsions, oil-in-water emulsions like mayonnaise and ice-cream & water-in-oil emulsions like table spreads)
what are the uses/applications of Phosphocasein
ACID GELS(like cream cheese and yogurt)
what is whey
its a by-product of the manufacture of dairy products, particularly cheese
what are the 3 most important whey proteins
Beta-lactoglobulin
alpha-lactalbumin
Glycomacropeptides
what are the whey protein-based ingredients
-whey protein concentrates
-whey protein isolates
-whey hydrolysis
how are whey protein concentrates obtained
ULTRAFILTRATION to remove water, lactose and minerals
how are whey protein isolated obtained
ION EXCHANGE SEPARATION- washes out the lactose, minerals & caseinomacropeptide
how are whey proteins hydrolysed
proteins are exposed to hydrolysis by incubating proteolytic enzymes at elevated temperatures
what are the functional properties of the whey protein ingredients (4)
1)SOLUBILIZERS
2)GELATION: formation of gels when heated at conc above 10%
3)FOAMING; formation of aerated foods
4)EMULSIFICATION: oil-in-water emulsions
what are the nutritional properties of whey proteins & explain each one (2)
1)INFANT FORMULATIONS: hydrolysis breaks down possible allergenic proteins
2)SPORTS NUTRION: high levels of branches amino acid chains which are preferably metabolised by muscle rather than liver & sport drinks & nutrition bars
