Ch. 14 Milk and Milk products
True/False: Acid may be used to coagulate milk proteins and form cheese.
True
True/False: Evaporated milk that is homogenized Promote emulsification of fat (stable during evaporation)
True
True/False: Lipoproteins have hydrophilic and hydrophobic ends
True
True/False: Majority of milk in the market have been processed to ensure their safe use in foods and as beverages.
True
True/False: Pasteurization has little or no impact on the quality of the product.
True
Rennin is obtained from milk-fed calves, specifically which stomach?
fourth stomach.
Whey proteins are not affected by acid or rennin, but are coagulated by what?
heat.
Increases viscosity, tends to be whiter and has creamy appearance, Less stable to heat and more sensitive to oxidation by light, Does not form curds readily (when curds are formed, they tend to be very soft).
homogenization
Dehydrated whole milk is lumpy and sticky because of what?
hygroscopicity nature of the lactose.
"Certification" of milk implies that milk was produced where and why?
in an environment clean enough to keep the microorganism count sufficiently low.
What are some of the positive effects of Homogenization?
it increases the total surface area, stabilizes milk emulsion, and prevents coalescence of fat particles.
Milk is a medium for what type of activities?
microorganism activities.
Evaporated milk is sterilized (116°C for 15 minutes) to destroy the what in milk?
microorganisms.
The goal of fermented milk products is to produce lactic acid through lactose fermentation through the action of what?
microorganisms.
Evaporated milk is homogenized To prevent the separation of to what and to prevent what?
milk fat and prevent textural problem.
The enzyme most commonly used to coagulate milk in cheese-making is what?
rennin.
Milk is a very rich source of nutrients including.....
riboflavin, calcium and phosphorus, except vitamin C and iron.
CLA is a product of microbial action in the....
rumen.
Careful handling at every stage of milk production is important to ensure
safety.
Regardless of the milk used, milk is dried by what 3 processes?
spray, foam-spray, or roller drying processes.
Though pasteurized milk is save to drink, pasteurization does not imply what?
sterilization
Milk is heated very fast to 138°C (280°F), for 2 sec. then, aseptically packaged and sealed in sterile containers. The intensity of heat treatment kills all the microorganisms.This pasteurized milk can be stored at room temperature for up to 3 months or opened.
Ultrahigh-temperature (UHT) Pasteurization:
About how much of the water from sweetened condensed milk is evaporated and heat treated to kill harmful microorganisms before canning.
About half the water content
Major enzyme in milk include...
Alkaline phosphatase, Lipases, Proteases, Xanthine oxidase.
Lypolysis Activities of milk fat result in undesirable....
chemical changes in milk.
Commercial rennet used in the U.S. includes what enzymes?
chymosin, bovine pepsin, porcine pepsin, and microbial proteases
Rennin is also called what? But is sold commercially by what name?
chymosin, is sold commercially as rennet.
Other sources of available rennin includes what animal or specimen?
cows, pigs, plant sources, and genetically engineered bacteria
A trans fatty acid naturally abundant in milk fat and consists of double bonds on alternate carbon atoms, with one in the cis and another in the trans form.
Conjugated linoleic acid (CLA),
An example of acid coagulated cheese is what?
Cottage Cheese.
Milk that is inoculated with Streptococcus lactis and Leuconostoc bulgaricus and incubated for several hours (approx. 20-hrs) to produce 0.9% lactic acid.
Cultured Buttermilk
This Cream is first pasteurized and then, incubated under a control environment to produced the appropriate level of lactic acid to a desirable clot.
Cultured sour cream
Fermented products currently available in the market include....
cultured buttermilk, sweet acidophilus milk, yogurt, Kefir, sour cream and Lactaid®.
bST milk is the same as milk produced without hormone meaning that there is no
difference in milk quality.
The mixture of acid coagulation is separated into curd and whey by what process?
draining.
Lipoproteins serve as what type of agents; forming a protective layer around triglyceride molecules.
emulsifying agents
Majority are even or odd number carbon chains.
even
True/False: A variety of microorganism fermented products have become part of American diet.
False
Milk lipids consist of....
Triglyceride (more abundant and subject of health related controversy), Phospholipids, Carotenoid pigments, Sterols, Fat-soluble vitamin
Dry/powdered milk can be made from what types of milk?
whole, reduced fat (2%), low fat (1%) or fat-free (nonfat) milks.
Milk Processing involve....
Pasteurization, Homogenization, Evaporation, Fermentation
What bacteria initiates the fermentation process?
Streptococcus lactis
What is the liquid portion of milk that drains from the curd of clotted milk.
Whey
This enzyme catalyze the conversion of flavin-adenine dinucleotids (FAD) to yield riboflavin.
Xanthine oxidase
This enzyme is used as indicator of milk wholesomeness.
alkaline phospate
Triglycerides containing the different fatty acids are dispersed in form of tiny fat globules, surrounded by membrane containing...
phospholipids and protein.
PUSF is very limited and consist of...
primarily Linoleic (18:2 C)
Milk that is a non-dairy product, but used as a beverage by those who are allergic to milk or who are seeking to increase their isoflavones consumption.
Soymilk
Alternatively, enzymes may be derived from what bacterial starters from certain molds, or other microorganisms.
Streptococci and Lactobacilli
What is Susceptible to nonenzymatic browning during storage and heating because of the high level of sugar.
Sweetened condense milk
What is the Most abundant MUSF?
Oleic acid (18 C fatty acid)
This milk process involves Milk being heated to treat and destroy problematic microorganism population such as Salmonella and campylobacteria.
Pasteurization
True/False: UHT pasteurized milk needs to be chilled before serving and must be refrigerated like fresh milk once opened.
True
Fermentation by microorganism results in the production of what from lactose?
acid
The double drying helps instant milk to achieve the ability to do what?
agglomerate and is instantly dissolved in cold water.
To ensure sufficient pasteurization, milk processors measure the activity of.....
alkaline phosphatase
The high sugar content of sweetened condensed milk also serves as what type of agent?
an effective antimicrobial agent
Chocolate or coffee is added to mask/offset what flavor of soy?
beany natural
Introduced in 1994 a Recombinant bovine somatotropin. it is also known as what type of hormone or what name?
bovine hormone - bST or BST
In cheese making, As the curds form, whey separates, but most of what nutrient in the milk remains in the curd.
calcium
Coagulant from acid coagulation of cheese contain what nutrients?
casein and fat
Milk is a unique beverage that provides what type of vitamins and nutrients?
complete protein, many B vitamins, vitamins A & D, and calcium
A child whose sole source of daily intake from calorie is milk in exclusion of others foods, may be affected by what deficiency
iron deficiency anemia.
Yogurt and other fermented milk products are sources of what type of biotics?
probiotics
Milk as it comes from the animal is designated as what type of milk?
raw milk (certified raw milk is available in some places.)
Milk is a store house for many important nutrients in American diet EXCEPT what micronutrients?
vitamin C and iron.
Which isomer tends to precipitate and form insoluble crystals, which impacts the sandy texture of some ice cream?
α-lactose
Which isomer is the least soluble in milk and the major contributor of undesirable mouhtfeel in reduced fat frozen desert?
α-lactose is the least soluble of the 2 isomers
Nonfat milk contains what percent fat?
≤0.1%
Fat content of this product varies from what percent to which other percent?
10.5% (half-and-half) to 36% (heavy whipping cream).
Milk is heated in large vats to what temperatures to provide optimal environment for enzymes and bacterial activity, which contributes to the formation of curd.
72° - 95°F (22° to 35°C)
Besides enzyme coagulation, what other type of coagulation is used to form cheese?
Acid Coagulation
Milk flavor are contributed by volatile organic compounds such as...
Aldehydes, Ketones, Acid
Fatty acid carbon chains length range from...
4- 26.
Casein can be precipitated by acid and/or enzyme (rennin) at pH of what?
4.6
What are the negative effects of homogenization?
Causes milk to lose its creaming ability, More prone to rancidity and off-flavors unless it was pasteurized before homogenization
1 cup of milk contains on average of how many mg of calcium?
300 mg of calcium.
In most cases, milk is fortified with what vitamins?
vitamin D & A.
Whole milk contains what percent fat?
3.25% fat
What is a draw back of using UHT pasteurization?
"Cooked" flavor develops because of the high temperature used.
Sweetened condensed milk is canned milk to which substantial amount of sugar have been added. What is the substantial amount of sugar and what is the approximate break down of the mixed sugars within the total amount?
(>54%) -approximately 42% sucrose or glucose and 12% lactose
Acid coagulated cheese is not aged because its high acidity inhibits what type of growth, which characterizes the aging process.
...
Lactose is present in what type of isomersα-lactose and β-lactose isomers.
...
Nearly what percent of nonpathogenic bacterial, which are capable of converting lactose to lactic acid (creating milk spoilage) remain.
1 to 5%
Low-fat milk contains what percent fat?:
1.0%
A cup of milk contains between how many grams of carbohydrate and what is the primary sugar?
11 - 12 grams of carbohydrate - primarily lactose.
Purposely - to increase milk production, the bovine hormone increases average milk production per cow by about how many pounds?
1800 pound (from approximately 14,841/cow to 16,641) annually.
Reduced fat milk contains what percent fat?
2% fat
Soymilk contains calcium that is added and approximately what percent of protein?
3.2% protein
Between what % of original volume of fluid in milk is removed under a partial vacuum during the evaporating process, and then the milk is packaged aseptically.
Between 50 - 60%
This product is a water-in-oil emulsion dairy product containing 15% water and at least 80% fat.
Butter
In cheese making What nutritional element may be added to speed up coagulation and strengthen the curd's consistency.
Calcium chloride
Milk protein components in milk, includes....
Casein (approx 82% of milk protein), Whey proteins (18% of milk protein).
These are preserved foods made from the curd or solid portion of milk.
Cheeses
In cheese, what process combined with enzymes occurs in less than an hour, and creates a tough, rubbery curd.
Coagulation
Flavor Changes in Milk - Example:
Heat-treated milk tends to have "cooked" flavor because heat promotes chemical reactions, which results in the degradation of lactose (Mallard reaction - interaction with protein).
This is the most common method of pasteurization used in milk processing. Milk is heated at 72°C (161°F) and held for at least 15 seconds, followed by cooling to l0°C (50°F). Milk processed using this method is safe for consumption as beverage. Must be refrigerated. Some deteriorative changes occur overtime.
High-temperature Short-time (HTST) Pasteurization:
Methods used in Pasteurizing Milk are....
Hold Method Pasteurization, High Temperature Short Time Pasteurization, Ultrahigh-temperature Pasteurization (UHT)
Pasteurization where Milk is heated to only 63°C (145°F) and held at this temperature for 30 minutes, followed by cooling to 7°C (45°F).
Hold Pasteurization
Mechanical processing technique by which milk is forced through tiny apertures under a pressure of (2000 to 2500 psi), to break up the fat globules into smaller units, which do not separate in solution.
Homogenization
Milk that is fermented by Lactobacillus kefir, resulting in a product with 3% alcohol, the microorganism also adds CO2.
Kefir
The 2 major proteins in whey are...
Lactalbumin, Lactoglobulin
These milks have Large proportion of the carbohydrate (lactose) is predigested to galactose and glucose by and enzyme lactase.
Lactase-containing Milks
What bacteria continues the fermentation at a lower pH?
Lactobacilli
The primary constituents of whey include....
Lactose, Proteins, Water-soluble vitamins, Minerals
What enzyme promote lipolysis of milk fat?
Lipases
During sterilization, the lactose and milk protein undergo what type of reation?
Maillard reaction ( slightly brown color of pet milk).
This is one of the major sources of riboflavin in American diet.
Milk
What enzymes are resistant to heat of pasteurization?
Proteases
Milk fats vary, what is the range of the amount of milk fats according to some authors?
Range 3.3 - 3.7% and 5%
Raw milk is considered as not safe to use as a beverage and may contain microorganism such as what that are capable of causing illness.
Salmonella Dublin or Listeria Monocytogenes
Unfermented milk that is inoculated with Lactobacillus acidophilus; producing sweet rather than sour milk.
Sweet Acidophilus Milk
What are the steps of acid coagulation?
The first method is adding acid directly to the milk. Followed by inoculating the milk with cultures of bacterial that convert lactose (milk sugar) to lactic acid-(Making the milk medium more acidic.). About one-fourth to one-half of the calcium in milk is lost in whey during processing.
What treatments also contribute flavor associated with milk and milk products?
Treatment by heat, fermentation, and storage
This milk product is a clotted milk inoculated with Streptococcus thermophilus and Lactobacillus Bulgaricus until it is fermented to about the pH 5.5.
Yogurt
The curd produced by acid in cheese making has what type of texture?
a soft and spongy texture.
This is Manufactured by continuous churning, which reverses the colloidal dispersion, transforming water from continuous to the dispersed phase (tiny water droplets is created). When rigidity is established the water is squeezed out to about 15%. Color and salt may be added if so desired.
butter
How is Instant milk manufactured?
by exposing nonfat dried milk to steam to make them sticky, after which it is redried.
What is the Most abundant saturated fatty acids?
palmitic acid (16 carbon fatty acid).
Alkaline phosphatase (alk phos)is destroyed at the heat of what?
pasteurization
The presence or absence of alk phos is used as indicator of adequate pasteurization and destruction of what that is originally in milk?
potentially harmful microorganism in milk.
Vitamins A and D are fat-soluble; therefore, whey is devoid of these nutrients, meaning....
precipitated with casein during curdling BUT whey it is rich in riboflavin.
Whey created from acid coagulation of cheese contain dissolved materials such as what?
proteins (which can be processed to produce other foods) and water soluble vitamins.
Cheese-making starts with the coagulation of what, which is the protein found in milk?
the casein
The different enzymes, bacteria, molds, and/or yeasts added during coagulation influence what characteristics developed during ripening?
the flavor, texture, and color developed during ripening.
The lower the fat content of these beverages, the higher amounts of what?
the other nutrients.
Riboflavin is easily destroyed by what?
ultraviolet light
Beverage milk is packaged in opaque containers to shield riboflavin from what to prevent what?
ultraviolet light and prevent its destruction
Particularly reduced fat milk has what vitamin added?
vitamin A added.
