Goat milk is a type of milk obtained from domestic goats (Capra aegagrus hircus). Produced and consumed worldwide, goat milk attracts attention due to its nutritional properties and some differences compared to cow's milk. It is also used in the production of various dairy products.

^{Goat Milk (Generated by Artificial Intelligence)}

Production

Globally, there are millions of goats, and goat milk production is widespread, especially in the Mediterranean, Middle Eastern countries, and some parts of Asia. Countries such as India, Bangladesh, Sudan, and Pakistan are among the important producers. Goat breeding is also carried out in Turkey, with local breeds such as the Hair Goat being common, and goat milk has a share in the country's total milk production. Goat milk production can vary depending on many factors such as the animal's breed, feeding conditions, age, lactation period, and geographical region where it is raised.

Composition

The chemical composition of goat milk differs from that of cow and sheep milk. Generally, sheep milk has a higher dry matter content than goat and cow milk. The average components and physicochemical properties of goat milk are as follows:

Macronutrients

• Fat: The fat content in goat milk is around 3.8% on average. The diameter of fat globules is smaller than in cow's milk, which contributes to the milk's more homogeneous structure and easier digestion. Goat milk is richer in short and medium-chain fatty acids such as caproic (C6:0), caprylic (C8:0), and capric (C10:0) than cow's milk; these fatty acids also contribute to the characteristic odor of goat milk. It also contains branched-chain free fatty acids with less than 11 carbons, which give goat milk products their distinctive taste and smell. Trans fatty acid content is relatively low. Cholesterol content has been reported to be lower than in cow and human milk.

• Protein: The average protein content is around 3.4%. It is divided into two main groups: caseins ($\alpha_{s_1}$​-casein, $\alpha_{s_2}$​-casein, $\beta$-casein, $\kappa$-casein) and serum (whey) proteins. In goat milk, β-casein is the dominant casein type compared to α-caseins in cow's milk. $\alpha_{s_1}$​-casein content is generally lower than in cow's milk, which can lead to the formation of a softer curd and potentially easier digestion. It has been noted that in some goat breeds, $\alpha_{s_1}$​-casein is absent or present at very low levels, which suggests a hypoallergenic potential. The non-protein nitrogen (NPN) content is higher than in cow's milk, close to human milk. These NPN compounds also include bioactive substances like carnitine; goat milk is richer in carnitine than human milk.

• Carbohydrate: The main carbohydrate is lactose, at a concentration of approximately 4.1%, which is slightly lower than in cow's milk. Goat milk contains a higher amount and variety of oligosaccharides compared to cow's milk; with these properties, it is closer to breast milk. Nucleotide sugar content is also higher than in cow and sheep milk. Sialic acid concentration is approximately four times higher than in cow's milk.

Micronutrients (Vitamins and Minerals)

• Vitamins: Goat milk is richer in vitamin A and niacin than cow's milk. Due to the complete conversion of β-carotene to vitamin A, its color is whiter than cow's milk. It is also a good source of thiamine, riboflavin, and pantothenic acid. However, it is significantly poorer in folic acid and vitamin B12 compared to cow's milk; this can lead to megaloblastic anemia, known as "goat milk anemia," especially in unsupplemented infants. It is also deficient in pyridoxine (vitamin B6), vitamin C, and vitamin D.

• Minerals: Goat milk is generally richer in minerals such as calcium, phosphorus, potassium, magnesium, and chloride than cow's milk. Sodium, iron, sulfur, and zinc content, however, may be lower. It is particularly distinguished from other milks by its high chloride and phosphorus content. Selenium content is higher than in cow's milk and close to human milk. The bioavailability of iron in goat milk has been reported to be higher than in cow's milk. High total mineral and electrolyte content can lead to problems, especially for infants, if consumed in an unbalanced manner.

Physical and Chemical Properties

The density of goat milk (1.029−1.039 g/cm3) is close to that of cow's milk. Its viscosity may be slightly higher than that of cow's milk. Goat milk casein micelles show differences from those in cow's milk in terms of mineralization, hydration, and average diameter; some sources state that goat milk micelle size is larger, while others state it is smaller. Its thermal stability is generally lower than in cow's milk and is affected by factors such as pH, salt balance, and NPN content. The buffering capacity of goat milk is high due to its high protein, NPN, and phosphate content, which can help maintain gastrointestinal health.

Derived Products

Various food products such as cheese, yogurt, butter, kefir, cream, ice cream, milk powder, and infant formula are obtained from goat milk. It is also used in the production of soap and cosmetic products. In Turkey, goat milk is used in the production of some geographically indicated products such as Maraş ice cream and Ezine cheese, as well as various local cheeses and yogurts.

Health and Nutritional Considerations

• Digestibility: Due to the small diameter of goat milk fat globules and the difference in its casein profile (low $\alpha_{s_1}$​-casein), it is thought to be more easily digested than cow's milk.

• Allergenicity: Although goat milk is considered an alternative for some individuals with cow's milk allergy (CMA), there is a high risk of cross-reactivity between the two milks. $\alpha_{s_1}$​-casein and β-lactoglobulin, which are major allergens in cow's milk, are also found in goat milk, and due to structural similarities, a significant portion of individuals with CMA may also react to goat milk. Serious anaphylactic reactions have been reported after goat milk consumption in infants with CMA. Therefore, in cases of CMA, the use of goat milk should only be considered under medical supervision and if found safe after testing.

• Infant Nutrition: Breast milk is the most suitable food for infants. In situations where breast milk is insufficient or cannot be provided, goat milk-based formulas may be an option. However, unprocessed (raw or pasteurized) goat milk is deficient in some important nutrients, such as folic acid, vitamin B12, vitamin C, vitamin D, and iron, and its high electrolyte load is not suitable for infants. Therefore, if it is to be used in infant nutrition, it must be in a technologically processed and fortified form to address these deficiencies and adjust the electrolyte balance.

• Risks: Consumption of raw goat milk carries the risk of transmitting pathogenic microorganisms such as Q fever, toxoplasmosis, brucellosis, and E. coli O157:H7. Therefore, it is important to consume pasteurized goat milk. Furthermore, giving unprocessed goat milk to infants can lead to serious health problems such as electrolyte imbalances, renal dysfunction, and metabolic acidosis.

Bioactive Components

Goat milk may contain various bioactive peptides such as antihypertensive, antimicrobial, antithrombotic, opioid, and mineral-binding peptides, which can emerge during digestion or fermentation. It also contains bioactive lipids such as sphingolipids and conjugated linoleic acid (CLA).