Milk and Milk Products Study Notes
Introduction
The document elaborates on the art and science of milk and milk products as part of a curriculum at the Hospitality College in collaboration with B.H.M.S., Lucerne, Switzerland.
Milk
Definition
Milk is defined as a white liquid produced by the mammary glands of mammals.
It serves as the primary source of nutrition for young mammals prior to their ability to digest solid food.
Early-lactation milk contains colostrum, which is rich in antibodies from the mother, helping to reduce the risk of diseases in infants and providing essential nutrients.
Uses of Milk
Milk is utilized in various culinary applications including:
As a beverage or in the preparation of hot drinks.
In soups such as cream soups.
In sauces, for example, custard sauce and bread sauce.
For making batters, such as those used for pancakes.
In milk custards and egg custards.
In milk puddings.
In bakery products like cakes.
For glazing pastries, such as brushing over the surface of scones for a smooth, shiny finish.
Composition of Milk
Milk is comprised of the following components:
3-4% Lipids/Fats
87% Water
3-4% Protein
Major milk proteins include:
Lactalbumin
Caseinogens
Lactoglobulin
0.7% Minerals and Vitamins
Includes cations and anions such as:
Calcium
Phosphate
Magnesium
Sodium
Potassium
Citrate
Chlorine
Vitamins present include:
A, B6, B12, C, D, K, E
Thiamine, Niacin, Biotin, Riboflavin, Folates, Pantothenic Acid
4-5% Carbohydrates
Key carbohydrates include:
Lactose
Glucose
Galactose
Factors Affecting Composition of Milk
The exact composition of milk can vary widely due to:
Breed of the animal.
Age of the animal.
Psychological state of the animal during milking.
Stage of lactation and giving birth.
The type of feed provided to the animal.
Seasonal changes, where in rainy seasons, milk may be less nutritionally dense due to increased water content from feed.
Types of Milk
Milk is available in various forms:
Sour Milk (curd): milk that has soured due to bacterial activity, leading to a sharp flavor. Different cultures have various forms.
Powder Milk: also known as dried milk, with moisture removed for longevity.
Ultra Heat Treated (UHT) Milk.
Skimmed Milk: fat reduced to under 0.5%.
Pasteurized Milk.
Whole Milk: raw and unprocessed.
Evaporated Milk: moisture reduced by half through evaporation for concentration.
Condensed Milk: significant moisture removed similar to evaporated milk.
Storage of Fresh Milk
To prevent contamination, fresh milk should be:
Kept in its original delivery container.
Stored in a refrigerator, consumed within 5 days.
Covered to avoid absorbing odors from foods.
Fresh milk should ideally be ordered daily, and for tinned milk, maintained in cool, dry environments.
Dried milk is stored in airtight tins kept in dry storage.
Sterilized milk lasts 2-3 months unopened but must be treated like fresh milk once opened.
Cream
Definition
Cream is the layer of fat skimmed from milk before homogenization, retaining most constituents but in different ratios compared to milk.
It typically contains a higher fat content and lower water content than milk.
Types of Cream
Different types of cream include:
Double Cream: 48% fat, can be whipped easily, good for puddings and desserts.
Clotted Cream: 55% fat, thick and spreadable, often used with scones and in desserts.
Extra Thick Double Cream: 48% fat, heavily homogenized and not suitable for pouring.
Whipping Cream: 35% fat, whips well, used in piping for cakes and pastries.
Whipped Cream: also 35% fat, used as a topping for cupcakes, desserts, etc.
Sterilized Cream: 23% fat and sterilized for preservation.
Single Cream: 18% fat, used in sauces but does not whip.
Half Cream: 12% fat; used primarily as pouring cream.
Soured Cream: 18% fat, has a tangy taste, used in various dishes.
Aerosol Cream: 35% fat, UHT processed; used for toppings but has a short shelf life once opened.
Uses of Cream
Cream can be incorporated into food in various ways:
Diluted when added to hot liquids to prevent separation.
Used in hot drinks, soups, sauces, batters, custards, desserts, bakery products, and ice creams.
Yoghurt
Definition
Yogurt is a curd-like food made from milk that has been fermented using specific bacteria, known as yogurt culture. The fermentation process converts lactose into lactic acid, contributing to yogurt's distinct texture and flavor.
Yogurt may be plain or flavored with fruits, sweeteners, and stabilizers.
Types of Yogurt
Two major types include:
Stirred Yogurt: smooth and fluid consistency.
Set Yogurt: firmer and more solid texture.
Uses of Yogurt
Commonly used as:
A cold beverage.
Dips or accompaniments to curries.
Salads dressings.
Ingredients in marinades.
Desserts mixed with fruits or nuts or in cheesecakes.
A substitute for cream in several applications.
To garnish soups or serve as the base for cold soups.
Production of Yogurt
Procedure for making yogurt involves:
Cooling pasteurized milk, inoculating with rennet or lactic bacteria (e.g., Streptococcus thermophilus and Bacterium bulgaricum),
Fermenting at temperatures of approximately 42-43°C before cooling to halt lactic acid production.
Butter
Definition
Butter is made by churning fresh or fermented cream or milk;
Approximately 1 liter of cream yields around 0.5 kg of butter.
Churning involves shaking milk or cream in a churn, separating butterfat from liquid.
It is produced at temperatures between 16°C and 18°C and can be salted or unsalted.
Ghee, a form of clarified butter, involves heating butter until water evaporates, reaching approximately 120°C.
Uses of Butter
Culinary applications for butter include:
Alternative fat for cooking.
Flavoring agent for other foods.
Used in roux for soups and sauces.
Making pastes except suet pastry.
Decorating cold dishes and savory cocktails.
Important in baking, such as cakes and butter creams.
Clarified butter is also suitable for shallow frying.
Served as a spread.
Cheese
Definition
Cheese is produced through the coagulation of milk, involving removing a significant amount of water. It results from adding enzyme rennet to acidified milk, causing curd formation.
The curds are then separated from whey and pressed into a compact form.
Classification of Cheese
Hard Cheeses: Pressed to eliminate much whey, requiring long ripening for flavor development, hard to cut, suitable for grating.
Semi-Hard Cheeses: Firm texture, varies in ripening period, easy to cut.
Soft Cheeses: Lightly pressed, soft and spreadable, short ripening period.
Blue-Veined Cheeses: Mold spores introduced to grow through the cheese.
External-Mould Cheeses: Molds can develop on the surface; moisture retention encourages specific bacteria or molds that influence taste.
Varieties of Cheese
Some examples include:
British Cheeses: Cheddar, Cheshire, Lancashire, Stilton.
French Cheeses: Roquefort, Camembert.
Italian Cheeses: Mozzarella, Parmesan, Ricotta.
Soft Curd Cheeses: Cottage Cheese, Fromage frais.
Conclusion
The document provides comprehensive information about milk and milk products, including definitions, uses, compositions, storage techniques, and processing methods. It emphasizes their importance in culinary arts and their varied applications in the food industry.