Effect of Extraction Temperature of Gelatin from the Skin of Cultured Great Sturgeon (Huso huso) on Molecular Weight Distribution of Peptides, Amino Acid Composition and Antioxidant Activity of Gelatin Hydrolysates

The aim of the present study was to extract gelatin from the skin of farmed great sturgeon at different temperatures, hydrolysis using Alcalase enzyme, and to measure molecular weight distribution of peptides, amino acid composition and antioxidant activity of hydrolysates.

After removing pigments and non‐collagenous proteins, defatting, and swelling of triple‐helix structure, gelatin was extracted at the temperatures of 50, 60, 70, and 80°C for 6h and then hydrolysed using Alcalase (E/S ratio of 1:20w/w) for 3h. Molecular weight distribution of peptides, amino acid composition and antioxidant activity of hydrolysates were determined in different models.

Degree of hydrolysis (DH) reached its maximum within the first 30min in all samples. The highest DH was in the 80°C. There were no significant differences among hydrolysates with regards to amino acid composition and peptide molecular weight distribution. Hydrolysates produced at the extraction temperature of 60°C showed that the content of small peptides (molecular weight<1kDa) and total amino acids (g/100g) were slightly higher compared to other samples. This could influence antioxidant activity. At higher extraction temperature of gelatin, the efficacy of hydrolysates in preventing the loss in total sulfhydryl groups content was decreased (p<0.05) while there was no effect on TBARS and surface hydrophobicity (p<0.05).

Extraction temperature of gelatin did not reveal a considerable effect on properties and antioxidant activities of the resulting hydrolysates and gelatin hydrolysates with antioxidant activity and rich in peptides with molecular weight less than 1kDa could be produced at 50°C.