topic 10 Milk and cheese Flashcards
Types of Frozen Desserts
- Ice creams
- Sherbets
- Water Ices
Ice creams classification
Superpremium – Ben & Jerry’s(higher fat content —>higher quality)
Premium – Kawartha Dairy
Standard or economy – Breyers, Chapman’s
why theres Fat in ice cream
as a emulsion
Homogenization
均化作用
what is homogenization?
the Division of fat globules into small particles
why do we need homogenization?
Prevents separation into a “cream” layer
what is the difference between homogenized milk and standard milk?
Because of increased dispersion of fat, homogenized milk:
Has richer flavor
increased viscosity
whiter
commercial preparation of ice cream
- Blending of Ingredients
- Pasteurization
- Homogenization
- Freezing, Aging and Hardening(skip for soft serving ice cream)
Homemade ice cream maker
Rock salt and Ice
u 1:6 ratio by weight (rock salt : ice)
u 1:12 ratio by measure (rock salt : ice)
why we use rock salt rather than the table salt?
rock salt wouldn’t clump togethger
agitation
搅动
antibiotics and milk in canada
Canada dosen;t allow antibiotics in milk supply
hormones anmd milk
artifical hormones and prohibited in Canada for cow but yes for meat cow
protein in milk
80% in casein, 20% of whey
casein is a kind of phosphoprotein, true or false?
true
curd in milk组成与形成条件
form of casein,Precipitates to form curds if:
u Acidic
u Rennet 凝乳酶 added
u When age gelation occurs(变质)
2 kinds of whey protein
Lactalbumin and lactoglobulin
Coagulated conditions of whey proetin and casein?
whey: heat
casein: acid or rennet
Fat in milk is called
Milkfat
Butterfat
Cream
milk is an emulsion, true or false??
true,milk fat droplets are dispersed in the milk
composition of milk fat
Triglycerides – primary type
Phospholipids
Sterols – cholesterol
Carbohydrate in milk
lactose, a disaccharide=glucose+galactose
why would lactose intolerance happen?
ppl don’t have lactase in their small intestine, lactose will go through bacterial fermentation, producing gas and acids, which would cause flatulence肠胃气胀 and abdominal pain
minerals in milk
Calcium, phosphorus, magnesium, potassium and sodium
Vitamins in milk
fat soluble: ADEK
water soluble: B vitamins
enzymes in milk
Lipoprotein lipase (LPL)
Plasmin血浆酶
Alkaline phosphatase (ALP)
LPL in milk
Associated with casein micelles
plasmin in milk
A proteolytic enzyme that splits proteins
分解蛋白质的一种蛋白质水解酶
Heat stable and responsible for bitter flavour in pasteurized milk
bitter taste of pasteurized milk
plasmin Heat stable and responsible for bitter flavour in pasteurized milk
ALP Alkaline phosphatase碱性磷酸酶
Found in all raw milk
More heat stable then pathogens therefore pasteurization destroys pathogens and the enzyme
why is milk white?
Colloidally dispersed casein micelles
Calcium phosphate salts
yellow pigments in milk?
Carotenes
Greenish-yellow fluorescent color in liquid whey
Riboflavin
natural pH of milk
6.6
natural change of pH
pH increase on standing with loss of carbon dioxide
pH decrease by action of lactic acid producing bacteria
a1 and a2 proteins
2 different types of β-casein
a1 protein have more histetin
a2 protein have more proline
types of milk
- fluid milk whole milk, fat reduced milk flavored milk
- concentrated fluid milk
- dry milk
type of milk milk products
yogurt buttermilk Acidophilus milk, Kefir
Acidophilus milk乳酸菌乳饮料
Lactobacillus乳酸菌
what is filled milk?三花淡奶
Substitute produced from
Non-milk fat such as soybean oil combined with water
u Non-fat milk solids
u Emulsifier, color, flavoring
Imitation milk
Imitation milk
u Usually contains no milk
u Ingredients: water, corn syrup, sugar, vegetable fats, protein source
u May contain casein, whey (milk proteins)
Types of Cream Products
Fluid Cream
Sour Cream
Dried cream
Nondairy products
fat content in fluid cream
Heavy (not less than 36% fat)
Light cream or coffee cream (18 to 30% fat)
Light whipping cream (30 to 36% fat)
Half and half (10.5 to 18% fat)
Sour Cream
Use a culture of Lactobacillus lactis organisms(奶油经过乳酸菌发酵)
“acidified sour cream” when manufacturers use food grade acid instead of bacteria
heat and food preparation
Proteins coagulate-whey-lactoalbumin-66度
Calcium is less dispersed
Fat globules coalesce脂肪球凝聚
Surface films may form
Sugars and protein may brown à Maillard Reaction of lactose
coagulation of milk
- Acid
- Enzyme
- Phenolic compounds
- Salts
Curdling In Cooking
- Higher fat milk is more stable than low fat milk
- Fresh milk is less likely to curdle than “older milk”
Freezing
Protein film is weakened
Fat globules coalesce
Dispersion of protein and calcium phosphate affected
nutritive value of cheese
Protein
Fat
Calcium and phosphorus
Vitamin A
Sodium
ingredients of cheese
Milk
Cultures:(fermentation)specific strains of bacteria, molds, or yeast that are added to milk to initiate the fermentation process.
Rennet (rennin)
Salt
why is cheddar cheese yellow?
Annatto is a natural yellow colouring derived from annatto seed extracts红木籽提取物
composition of cheese
Ripened —> ‘aged’ such as cheddar
Unripened—> consumed right after processing such as cottage cheese
Natural —>made directly from milk
Processed —-> uses natural cheese and other ingredients to change texture/melting point such as cheese spread
different groups of cheese
1.Amount of moisture in the finished cheese
2.Kind and extent of ripening
examples of soft cheese?
Brie布里干酪, Camembert卡芒贝尔奶酪
examples of semi-hard cheese?
Blue Cheese, Havarti哈瓦蒂干酪（一种多孔、味淡的干酪）, Monterey Jack蒙特里杰克乳酪
examples of hard cheese?
Gouda, Cheddar, Parmesan
examples of unripened cheese
Feta, Cottage Cheese
examples of Mold ripened
blue cheese
examples of Bacteria ripened
Cheddar, Swiss
objective of cheese production
- Optimal(最佳) moisture, pH (acidity), fat protein ratio, and calcium
- High-quality texture and structure
- Ripened for optimal aroma, flavour, taste and physical characteristics
procedure of cheese production
Most cheese production begins with pasteurized milk:
1. Promoting curd formation with acid produced by lactic acid bacteria (starter culture) and/or a coagulating enzyme
2. Cutting the curd into small pieces to allow the whey to escape
3. Heating the curd helps separate it from the whey
4. Draining, knitting or stretching, salting and pressing the curd
5. Curing or ripening (cheese such as cottage cheese, cream cheese,mozzarella are not ripened)
ripening of teh cheese
Changes in flavor, aroma, texture, and composition
Flavor varies with type of organism
Swiss cheese develops holes (CO2 gas)
Lactose converted to other compounds
how to storage cheese?
Store cold
Wrap to prevent drying
Mold
Freezing
what causes ripening?
proteolysis蛋白水解作用
glycolysis
lipolysis
