Enzymatic Extraction of Gelatin from Threadfin Bream(Nemipterus japonicas) Skin

Abstract

Threadfin bream (Nemipterus japonicus) skin
gelatin was enzymatically extracted for 6 or 12 hrs at 60°C, pH
8 in the presence of alcalase. The gelatin was analyzed for yield,
gel strength, melting point, setting point, setting time, viscosity,
solubility and molecular weight distribution. The gelatin was
also compared with commercial gelatin. The 12 hrs extraction
time yield 7.74% gelatin and the gelatin was more soluble while
6 hrs gelatin resulted in 5.69% yield. Gel strength of the
extracted gelatin decrease with longer extraction time. The 6
hrs gelatin exhibited gel strength of 324.93g which was very
close to the commercial gelatin (342.10g) while 12 hrs gelatin gel
strength was 202.47g. Melting points of threadfin bream gelatin
increased when the extraction time increased ranging from
25.53 to 29.42°C while commercial gelatin melted at 34.03°C.
Threadfin bream gelatins set at lower temperature and longer
time with increase in extraction time compared to commercial
gelatin. The gelatin extracted for 6 hrs resulted in higher gel
strength, viscosity, melting point, setting point and shorter
setting time than the 12 hrs gelatin. This shows that the 6 hrs
extracted gelatin is more suitable to be used in food production
than the 12 hrs gelatin.