Optimization of novel single-step gelatin extraction method using RSM model for valorization of surimi industry by-products
Abstract Surimi industry produces large quantity of by-products as a combination of skin, bones, and scale, which due to technical difficulty in separation, are being currently utilized for production of low- value products such as biofertilizers and fish feed. Present paper focuses on utilization of combined skin, bones, and scale from Pink Perch (Nemipterus japonicus) obtained from surimi industry for gelatin extraction using single step process. Single step extraction method with acetic acid and water was optimized using Response Surface Methodology (RSM) to maximize yield and gel strength so that the process can be applied for sustainable utilization. Parameters such as pH (A), extraction temperature (B) and extraction time (C) with respect to yield and L-hydroxyproline content were optimized. Highest gelatin yield was obtained at pH 3, 75°C extraction temperature, and 30 min extraction time. Gelatin yield and L-hydroxyproline content under optimum condition were 16.2% and 41.62 mg.g−1. The chemical composition, functional, rheological, and structural properties of gelatin were examined and compared with commercial bovine gelatin. Gelatin thus obtained at optimized condition exhibited high gel strength (793g) and higher imino acid content (18.1%) than bovine gelatin. FTIR spectra depicted high similarities between both gelatin sample. Thus, the optimized method can be utilized for gelatin extraction from Pink Perch by-products for development of high value products such as food application.