Gelatin Extraction of Alaska Pollock (<i>Theragra chalcogramma</i>) Dry Skin

Alaska Pollock is rich in resource. And during its processing, skin is peeled as byproducts. The skin of Alaska Pollock contains lots of collagen or gelatin, promising materials, which can be used in food, cosmetics, biomedical and pharmaceutical industries. Extracting collagen from the dry skin of Alaska Pollock is studied in this study to provide a better basement for fully using this renewable resource. Three kinds of gelatin were extracted by using acid, pepsin-assisted acid and hot water, respectively. The productivity of Acid Soluble Gelatin (ASG), Pepsin Soluble Gelatin (PSG) and hot Water Soluble Gelatin (WSG) were 7.33, 30.89 and 12.67%, respectively. Their UV absorption spectrum were similar and match with the absorption of dilute protein solution. The protein contents of ASG, PSG and WSG were 84-90%, with no significantly difference between them. The characters of SDS-PAGE and the circular dichroism spectrum shown that the PSG is broken into small fragment and has less secondary structure. In conclusion, the hot water extraction is the best way to extract the gelatin from the dry skin of Alaska Pollock.