The effect of type and concentration of acid on the characteristics of gelatine from bones of milkfish (Chanos chanos)

Abstract

Gelatin is derived from the hydrolysis of the animal collagen contained in the bones and skin. Milkfish bones have the potential to be used as raw materials for gelatine production because it is estimated to be 15–20% of the total body weight of the fish. The extraction of gelatine from fish bones is a solution in utilizing the waste of the fish processing industry. Hydrolysis or soaking in an acidic solution against collagen is aimed to eliminate the salt of calcium and other minerals in the cartilage. This research was conducted to determine the influence of acid types and concentration on the milkfish bones gelatine production. This study used a completely randomized factorial design with two factors. The first factor was the type of acid (citric acid, acetic acid, and a mixture of citric and acetic acids), while the second factor was the concentration of acid (5%, 9%, and 13%). The data obtained were analysed using Analysis of Variance (ANOVA) and Duncan Multiple Range Test (DMRT) Advanced test. The results showed that the type and concentration of acid affected the yield, gel strength, viscosity, melting point, and gelling point. The best treatment in this study was extraction using a 9% concentration of citric acid to produce gelatine with a yield of 10.48%, gel strength 283.1 g bloom, viscosity 4.35 cP, melting point 60.1°C, gel point 16.9°C. Identification of gelatine functional groups was carried out on gelatine from the best treatment using FT-IR Spectrophotometer. From the results of FT-IR spectra analysis, it is known that the functional groups present in the sample are – OH, C-O, N-H, C-H, C-N, C=O which are the main functional groups of gelatine. This study showed that the type and concentration of acid affected the characteristics of milkfish bone gelatine