Effects of acid pretreatment and extraction temperature on the properties of gelatin from striped snakehead (Channa striata) scales

Abstract

The gelatin properties can be influenced by the source materials and the way it is extracted. Acid pretreatment can increase the production of gelatin from raw material by disrupting the collagens helical structure. The purpose of this research was to study how acid pretreatment and extraction temperature can influence the gelatin properties from striped snakehead (Channa striata) scales. C. striata scales were pretreated with 0.05 M acetic acid and elicited at 60, 70, and 80oC for 12 h. Experiments were based on a completely randomized design and data were analyzed with Duncan’s multiple range test. The measurements were triplicated. The results showed that pretreatment with acetic acid had produced a higher yield of gelatin compared to no acid pretreatment. Rising extraction temperature increased the extraction yield, although at 70 and 80oC the yields were not significantly different (p>0.05) anymore. The SDS-PAGE electrophoresis banding pattern indicated that all gelatins consist of α- and β-chain components. Increased extraction temperature resulted in degraded peptides with smaller molecular weights. The degradation of protein occured at a higher temperature, reducing the gel strength and viscosity of C. striata scales gelatin. The spectra in FTIR spectrometer displayed a significant degree of gelatins’ triple helical structure loss, due to the high temperatures of the protein degradation, which indicates that, in this state, collagen is transformed into soluble gelatins. This research concluded that C. striata scales could be a source of gelatin, even though the gelatins' attributes can easily be affected by the extraction process.