Composition of Cow’s Milk: Nature's Complete Nutrient Package

Cow’s milk is a remarkable fluid, consisting predominantly of water at approximately 87%, with the remaining 13% encompassing vital milk solids. These milk solids comprise two major components: butterfat and solids not fat (SNF), collectively contributing to the milk's nutrient richness and versatility.

The fat portion, also known as butterfat, constitutes about 3.7% of cow’s milk. This fat content can slightly vary depending on the breed, with Ayrshire, Brown Swiss, Guernsey, and Jersey cows generally yielding milk with slightly higher fat content compared to Holstein cows. Despite these variations, Holstein cows, renowned for their high milk production, remain a dominant source of milk globally.

The SNF portion, accounting for 8.9% of the milk, is where the essence of milk's nutritional value lies. SNF can be further categorized into lactose (milk sugar), essential minerals (such as calcium, potassium, and phosphorus), and proteins (including casein and whey proteins).

The protein content in milk, constituting approximately 3.3% of its composition, primarily consists of casein and whey proteins. Casein, representing 77% of the total protein content, is unique for its role in forming micelles—complex structures essential for transporting calcium and phosphate. Meanwhile, whey proteins complement the nutritional profile with their high-quality amino acids, crucial for growth and tissue maintenance.

Furthermore, cow’s milk is revered as a nutrient-dense food due to its balanced composition of essential nutrients relative to its caloric content. It stands out as the quintessential complete food, even containing trace amounts of essential vitamins and minerals vital for human health.

However, the suitability of milk can vary across species due to differences in lactose composition. Some young mammals might face lactose intolerance issues when exposed to milk from different species.

In summary, cow’s milk is a nutritional powerhouse, providing an array of vital nutrients essential for growth and development. Its varied composition, influenced by breed and species, underscores its significance in global agriculture and nutrition. Whether it’s for sustenance in infancy or as a staple in adulthood, cow’s milk remains unparalleled as a source of nourishment, offering a comprehensive blend of nature's finest nutrients.
Composition of Cow’s Milk: Nature's Complete Nutrient Package

Whey Protein Concentrates

Whey proteins are commonly commercialized as powdered concentrates (WPC) and isolates (WPI).

Other Name for Whey protein concentrates: Whey proteins, Designer Whey, Milk basic protein, Whey powders (permeate), Sweet whey Acid whey, Demineralized whey products, Bioactive proteins/Whey fractions, Reduced lactose whey.

Whey protein concentrates (WPCs) are considered as fat mimetics and they have found extensive use in reduced-fat foods, either alone or in combination with other mimetics. Fat mimetics are compounds that help replace the mouthfeel of fats by contributing a greater viscosity to the liquid phase in the mouth, but cannot substitute for fats on a gram-for gram basis.

Whey Protein Concentrate is obtained by the removal of sufficient non-protein constituents from whey so that the finished dry product contains ≥ 25% protein. It is produced by physical separation techniques such as membrane filtration.

There is approximately 3.6% protein in liquid bovine milk. This protein fraction is composed of 20% whey 40 and 80% casein. Whey is the liquid substance obtained by separating the coagulum from milk or cream in cheese making.

In its raw liquid form, whey is composed of naturally occurring macronutrients-i.e., water (93%) protein (0.8%), fat (0.3%), lactose (4.8%) and minerals-referred to as ash (0.5 %).

Characteristics of Whey Protein Concentrate
Scorched Particle Content: ≤ 15.0 mg
pH: 6.0 – 6.7
Color: white to cream
Flavor: bland, clean

Their high nutritional quality and unique range of functional properties make them valuable in a wide range of low-fat products including soups, sauces, salad dressings and meats.
Whey Protein Concentrates

Milk fat composition

Milk fat is a source of energy for human being including infants, children and adults. It is the major component for the growth and generation of energy for infants. The fats including cholesterol is necessary for cell membranes especially for brain ones.

Milk fat is one of the most complex of all common fats, composed of about 98% triglycerides. It contains numerous fatty acids, mainly saturated (66%), but also monosaturated (30%) and polyunsaturated (4%).

Phospholipids are about .5 to 1% of total lipids, and· sterols are .2 to .5%. These are mostly located in the globule membrane. Cholesterol is the major sterol at 10 to 20 mg/dl.

The saturated fatty acid present in higher quantity on milk is the palmitic (C16:0), which represents round 40% of the total saturated fatty acid. Related to the amount of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acid (PUFA), the oleic (C18:1) and the linoleic (C18:2) acids are the most representatives.

Milk fatty acid composition can be influenced by several factors, many of which are interactive. These include stage of lactation, seasonal variation, low milk fat syndrome, feeding, genetic variation, and changes in the energy status of the cow due to administration of bovine somatotropin.
Milk fat composition

Enzymes in milk

Milk contains more than 60 different indigenous enzymes. Indigenous milk enzymes are found in or associated with a virus casein micelles, milk fat globule membrane, milk serum or somatic cells and may originate from blood, somatic ells, the MFGM or the cell cytoplasm.

Many enzymes found commonly in milk are not intrinsic milk enzymes, but are in milk because of the presence of microorganisms.

Pasteurization eliminates most natural enzyme activity in milk.

The two groups of enzymes of major economic importance are proteinases and lipases, including phospholipases, which are produced extracellularly and can act on micellar casein or on milk fat globules.

Besides microbial enzymes, milk also contains a natural proteinase and lipase. The milk lipase is inactivated by pasteurization, while the alkaline milk proteinase is heat stable and survives low-temperature short-time pasteurization conditions.

Other milk enzymes are stable; plasmin, for example, loses only 60% of its activity after 15 sec at 100 °C. Plasmin is the predominant indigenous proteinase in milk. It is part of a complex protease system in milk, consisting of its inactive, precursor, plasminogen, plasminogen activators, which catalyze the conversion of plasminogen to plasmin, plus inhibitors of plasmin and plasminogen activators.

Plasmin and plasminogen originate from the mammal’s blood and are predominantly associated with the casein micelle in milk.
Enzymes in milk

Milk in General

Milk in General
Milk is the first food of young mammal produced by the mammary glands of female mammals.

It is the mixture of fat and high quality protein in water and contains some carbohydrate (lactose), vitamins, and minerals.

Milk and milk products may be obtained from different species such as goats and sheep.

While fluid milk contains a very large percentage of water, it may concentrated to form evaporated milk and cheese, yogurt or in soups and sauces.

By law, milk and milk product must contain a designated percent of total milk solids (all of the component of milk except water) and also the milk solids, not fat (all of the components of milk solids not include fat).

The butterfat component of milk is the most expensive component of milk and its level determines if milk offered for retail sale as whole milk or at some lesser percentage of fat such as 2% milk, ½% or fat free.

Milk may be cultured, dried, fortified, homogenized or pasteurized and used to create products with different taste texture nutritive, value, and shelf life.

It may be processed into products such as buttermilk, cheese, cream, ice milk, ice cream, sour cream and yogurt with different levels of fat content.

Dried milk is added to a multitude of foods. It may be added to foods to increase the protein or calcium value.

High temperatures may curdle milk: therefore care must be taken in the preparations of foods with milk. Milk requires safe handling and old storage.

Milk is not well tolerated by a large portion of the population. The milk sugar, lactose, is not digested by persons lacking the enzyme lactase.
Milk in General

Composition of Milk

Composition of Milk
The average gross composition of cow’s milk is as follows:

• Water – 87%
  
• Fat – 3.7%
  
• Lactose – 4.9%
  
• Proteins – 3.5%
• Ash – 0.7%

However, the composition of milk from individual cows may vary considerably from these average values. Breed differences, the time of year, the time of day, individual differences, the age of the cow, the period of lactation, the portion of any one milking, feeding, etc., are some factors that may contribute to variation in the composition of milk.

Variation in milk composition due to breed are of the greatest magnitude. Jersey, Guernsey and Ayrshire cows gives milk richer in fat than Holstein cows. Usually milk obtained in the fall and early winter is richer than obtained in the spring and the summer. The morning milk usually is richer in fat than evening milk, at times by almost 2%.

The first portion (or fore milk) of milk drawn in the milking process are lower in fat than the last portions (or strippings). Milk obtained the first few days after calving is known as colostrum and differs materially from normal milk. During the final stages of lactation, when the daily production of milk is decreasing, there is some increase in percentages of fat and casein. The differences in milk composition occur mainly in the relative amounts of fat, protein, and water. The percentages of ash and lactose remain fairly constant in normal milk regardless of the amount of other components.
Composition of Milk