Extraction of Fish Gelatin and Influencing Factors

Gelatin is a kind of fat - free, high protein, cholesterol - free natural nutritional food additives. In addition to the wide application of gelatin in the field of food, gelatin in medicine, cosmetics, photography and other fields because of its good gel, film forming, water holding and foaming properties and other characteristics also play a special role.

Although the research on fish gelatin is very common in recent decades, due to the relationship between yield and quality of fish gelatin, it can not completely replace the mammalian gelatin. So improving the yield and quality of fish gelatin is an important research direction to expand its application prospects.

Extraction steps of fish gelatin

1) Remove non-collagen impurities from raw materials;

(2) Pretreatment makes collagen swell and improves extraction efficiency;

(3) Extraction gelatin by thermal hydrolysis;

(4) The gelatin obtained was dried and preserved

Chemical extraction means that the non-covalent bond of fish collagen is destroyed by acid or alkali reagent, and then the three-strand spiral structure of collagen is disorganized by heat shock, resulting in helix-coil structure transformation, breaking hydrogen bond and covalent bond and transforming it into soluble collagen.

Factors affecting the yield and quality

• The growth environment of fish will affect the amino acid distribution and collagen structure in fish, thus affecting the yield and quality of fish gelatin.
• Fish gelatin raw materials are generally preserved by freezing and drying. The temperature of freezing and the way of drying all affect the quality of fish gelatin.
• The increase of temperature and extraction time is beneficial to increase the yield of gelatin.
• In order to prolong the storage time of fish gelatin, ultraviolet sterilization is a common method.

Study on modification by enzyme

Protease hydrolysis has the advantages of short treatment time and less waste generation, such as pepsin digestion of collagen in natural skin up to 80% ~ 90% (depending on the source) under specific enzyme-substrate ratio and temperature conditions. Rational utilization of enzyme has become a new method to extract gelatin.

Enzymes used for modification of fish gelatin can be broadly divided into two categories: exogenous protease and endogenous protease. Exogenous enzyme tyrosine protein has been reported.
Enzyme modification of fish gelatin to improve the functional properties of fish gelatin, but due to the high price of limited use. After much exploration, microbial transglutaminase (MTGase) was found to be a better alternative.