Collagen is a protein that forms the basis of the connective tissues of animals and poultry. It is responsible for the strength and elasticity of skin, bones, cartilage, and tendons. In the food and meat industry, its value lies in the fact that collagen can be used to produce functional ingredients – from gelatin to bioactive peptides – which improve product quality and provide health benefits.
Collagen is obtained from bones, skin, tendons, and chicken feet using different methods. The oldest and simplest method is thermal processing, in which collagen is converted into gelatin during heating. This product is widely used in the food industry for jellies, confectionery, and meat products. Another method is acid and alkaline treatment, which enables the breakdown of protein bonds and the extraction of collagen. However, such methods require long processing times and large amounts of reagents. A more modern and demanded approach is enzymatic hydrolysis. With the help of specific enzymes (such as pepsin or papain), small protein fragments – collagen peptides – are obtained from raw materials. They are easily absorbed by the body, possess antioxidant and functional properties, and are used in the production of dietary supplements, beverages, and functional foods. New technologies – ultrasonic and microwave treatment, as well as hydrothermal hydrolysis – are also being actively studied, as they make the process faster, more environmentally friendly, and increase product yield.
Poultry by-products – feet, skin, and bones – are rich sources of collagen. For example, soluble forms of collagen can be extracted from chicken feet using acid or enzymatic treatment. Studies show that pepsin (an enzyme) allows the extraction of up to 49% of collagen from chicken feet skin, with the resulting product maintaining a stable structure and high thermal resistance. From chicken skin, collagen peptides with a low molecular weight (180–5000 Da) can be obtained after enzymatic hydrolysis. These peptides are easily absorbed and have favorable functional properties for food applications.
Animal bones are another powerful source of collagen. In bovine bones, collagen accounts for up to 98% of the organic matrix, where it forms fibers that provide strength to bone tissue. When heated, collagen undergoes stages of denaturation: first, its spiral structure is disrupted, and then it is converted into simpler compounds. These processes can be applied in technology – for example, to obtain gelatin or collagen hydrolysates.
Such technologies are already being applied in the meat industry. In Russia and Kazakhstan, researchers have proposed including collagen hydrolysates in meat product formulations, such as meat loaf. The addition of collagen hydrolysate reduces fat content and increases protein levels, while the product retains excellent taste qualities . In another study, meat-vegetable canned products based on chicken by-products with an increased collagen content were developed. During thermal processing in the can, collagen is partially hydrolyzed, becoming more bioavailable, which is especially important for preventive nutrition of elderly people .
At the Semey branch of the Kazakh Research Institute of Food and Processing Industry, a patented method for obtaining collagen from chicken feet has been developed. The institute’s specialists clean the raw material, finely grind it, and subject it to enzymatic treatment, after which they obtain a dry protein powder. Such a hydrolysate improves the environmental sustainability of production by recycling poultry processing by-products and can be used to expand the range of meat products.
Thus, the use of collagen from secondary products of poultry and livestock processing not only reduces processing waste but also provides value-added products. These include meat products with improved structure and nutritional value, functional additives for joint and skin health, and specialized products for dietary nutrition.
Dry collagen from chicken feet
Yesimbekov Zh.S., PhD, Associate Professor, Semey Branch of Kazakh Research Institute of Food and Processing Industry