Chapter 10 Flashcards
Whole milk composition
87% water an 13% fat
What aspects of cow can change fat content and protein of milk ?
Breed of cow , intake of fiber and non fiber carbs
Milk is a solution , oil in water emulsion and a colloidal dispersion , why ?
Oil droplets , casein Micelles, lactose and whey protein
Lactose is what type of carbohydrate ?
Disaccharide
Relative sweetness of lactose
0.35
How common is lactose intolerance in the world ?
~70 % of adults lack enzyme
Why does casein form micelles ?
Uneven distribution of charged amino acids
What 2 things can cause casein micelles to aggregate and precipitate ?
Lower ph and enzyme chymosin/rennet
How is casein coagulation implicated in yogurt and cheese ?
Casein micelles aggregate to
form gel strands
Rough fatty acid composition of milk
2.7 percent trans fat, 69.4 sat fat , 8 percent scfa
What is the MFGM, and why is it significant to the properties of milk? How does it play a role in whipped cream and butter?
Milk fat globule membrane. It helps the milk to remain a stable emulsion for days. Allows cream and butter not to fall apart
What are the primary 3 mechanism through which milk spoils
Microbial growth, lipid hydrolysis , lipid oxidation
The mechanisms that milk spoils, and the chemicals produced that are so off-putting, are also important parts of the fermentation process to produce things like yogurt and cheese, which are generally well-liked. How can this be?
Both are fermented foods that use microbial growth to create new flavors within the food. Balance and context is key
What types of microbes are generally used to make yogurt ?
Lactic acid bacteria
What chemical/physical changes occur (basic level - no need to know specific chemicals) in yogurt and cheese that gives it its key properties, texture or flavor?
Lactose hydrolyzed
• Increase in digestibility
Fermentation of sugars
• Flavor compounds produced
pH reduction
• Precipitation/coagulation of casein
Lipid hydrolysis
• Free fatty acids released
Cheeses can be so different from one another, what are the main factors that affect the final product of cheese?
Flavors of each cheese comes from unique microbes
What is the process of homogenization? What is the purpose of doing it?
Fluid milk forced through small holes at high pressure
Reduces fat globule size and allows it to not separate
What is the process of pasteurization? What is the purpose of doing it? Does pasteurization kill all microbes?
Controlled heat treatment that does not kill all microbes and destroys pathogens as well as increases chela life
How is ultra-pasteurization, UHT, and sterilization different from regular pasteurization? How do they affect shelf life? What products are they used for?
They are both at higher temperatures 138 c and allow for more months of shelf life. Used for creamer and creams
Why is there some controversy surrounding dairy production? What are some of the ethical and sustainability concerns that may be valid?
Environmental water and land use as well as green house gas emissions. Artificial insemination
What are some common plant-based substitutes for fluid milk?
Soy milk, ripple
