Effect of various extraction times on the physicochemical properties, functional groups, and microstructure of snakehead fish Channa striata skin-scale blended gelatin

The physicochemical characteristics of gelatin can be enhanced by altering the production process. Combining two different forms of biowaste is one approach that is addressed. This investigation aims to determine the physicochemical, functional group, and microstructural characteristics of snakehead fish skin-scale blended gelatin at various extraction times. Skin and scales of snakehead fish were combined during the extraction process in a 60 celcius water bath for 12, 15, or 18 h. The physicochemical characteristics of the skin-scale blended gelatin were evaluated, including the yield, gel strength, viscosity, pH, and color as well as other parameters such as functional groups and gelatin micrographs. Skin-scales blended gelatin did not show any characteristic differences between the treatments after different extraction times (P > 0.05), except for color assessment, where the yellowness (b*) of the gelatin tended to decrease after 15 h of extraction (P < 0.05). The secondary structure of the three types of gelatin that underwent different extraction time treatments showed a change in wavenumber as the extraction time increased. Micrographic analysis revealed the surface structure of the gelatin samples. Gelatin after extraction for 12 h showed smaller and denser cavities compared with the those subjected to extraction for 15 and 18 h. However, with increasing extraction time up to 18 h, there was no change in the physicochemical characteristics of the gelatin. Although the confirmatory results based on functional groups and microscopic examination revealed differences, these did not result in changes to the physicochemical properties of the gelatin.