Fish Gelatin Hydrolysates Research Articles

Gelatinolytic enzymes from Bacillus amyloliquefaciens isolated from fish docks: Characteristics and hydrolytic activity

Fifty-five bacteria with gelatinolytic activity were screened from over 500 isolates obtained from fishing docks in Songkhla, Thailand. Based on 16S rRNA gene sequence analysis, 3 selected strains (K12, O02, and S13) were identified as Bacillus cereus with 99.8% similarity. Three other stains (D10, G02, and H11) were identified as Bacillus amyloliquefaciens with 99.7% similarity. Gelatinolytic enzymes of the D10, G02, and H11 strains were precipitated using ammonium sulfate precipitation, followed by dialysis with an increase in purity between 19-34-fold. Maximal gelatinolytic activities towards fish gelatin were attained at 50°C and pH 7.5. Metallo- and serine-gelatinolytic enzymes were dominant for all 3 strains. All gelatinolytic enzymes showed similar hydrolysis towards fish gelatin to commercial Alcalase, but higher hydrolysis was found in the formers within the first 60 min. Therefore, gelatinolytic enzymes from selected B. amyloliquefaciens strains can be used for production of fish gelatin hydrolysate.

Glycation and transglutaminase mediated glycosylation of fish gelatin peptides with glucosamine enhance bioactivity

A mixture of novel glycopeptides from glycosylation between cold water fish skin gelatin hydrolysates and glucosamine (GlcN) via transglutaminase (TGase), as well as glycation between fish gelatin hydrolysate and GlcN were identified by their pattern of molecular distribution using MALDI-TOF-MS. Glycated/glycosylated hydrolysates showed superior bioactivity to their original hydrolysates. Alcalase-derived fish skin gelatin hydrolysate glycosylated with GlcN in the presence of TGase at 25°C (FAT25) possessed antioxidant activity when tested in a linoleic acid oxidation system, when measured according to its 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and when tested at the cellular level with human hepatocarcinoma (HepG2) cells as target cells. In addition, Alcalase-derived glycosylated hydrolysates showed specificity toward the inhibition of Escherichia coli (E. coli). The Flavourzyme-derived glycopeptides prepared at 37°C (FFC37 and FFT37) showed better DPPH scavenging activity than their native hydrolysates. The glycated Flavourzyme-derived hydrolysates were found to act as potential antimicrobial agents when incubated with E. coli and Bacillus subtilis.