*3.6.1.1 Properties of bovine hides*

**3.6 Collagen sources**

*Biotechnological Applications of Biomass*

*3.6.1 Bovine collagen*

is in the production of collagen.

over the animal (**Figure 6**) [29].

increases with age [30].

**Figure 6.**

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As collagen is one of the most abundant proteins on earth, it can be extracted from various sources. Collagen can be extracted from almost every living animal, including alligators and kangaroos. However, common sources of collagen for the food industry and tissue engineering applications include bovine skin and tendons, porcine skin and rat-tail. Collagen can also be extracted from marine life; it can be extracted from sponges to fish and jellyfish. All collagen sources are worth investigating as each source differs in the collagen type in terms of characteristics.

Collagen is extracted from many different sources; however, bovine collagen is seen to be the most used collagen type in a variety of different applications, such as the food industry, cosmetics, and medical applications. As the name implies, bovine collagen is a by-product of cows, mainly from the hides. It is a naturally occurring substance found in the skin, muscle, bones and tendons of cows. In the 1970s, the research on bovine collagen gained momentum, as researchers developed a system

The natural, unbleached skin and hair of cattle is the bovine hide (skin). Bovine

Animal hide constitutes 60–65% water, 25–30% protein and 5–10% fats. The protein is mainly collagen [28]. Raw hides have four main parts; epidermis (6– 10%), grain (less than 10%), corium (55–65%) and flesh and the thickness vary all

The epidermis and flesh layers are removed during tanning leaving the grain and

corium layers. The grain is made up of collagen and elastin protein fibres. The corium is packed with collagen protein fibres. The thickness of corium also

hides are a by-product of the food industry from cattle. Bovine hides without complex processing can be manufactured into leather, which in turn can be used in the shoes and clothing industry. However further complex processing of the hides can be carried out to obtain the corium section of the hide for a variety of different medical and scientific applications [27]. One of the main applications of the corium

of extracting collagen and processing it in a liquid form [26].

*The approximate composition of bovine hide [28] (used with permission).*

Each section of the animal hide for its properties is discussed further [29] (**Figure 7**) [29]:

