Valorization of Snapper Filleted Frame Waste: Process Optimization and Characterization of a Protein-Enriched Biopolymer Cracker Matrix

Abstract

Background: Fish crackers are traditional starch-based snack foods widely consumed in Southeast Asia and are increasingly recognized as convenient protein-enriched products. Surimi technology has been widely recognized as an effective method for converting mechanically recovered fish meat into functional protein suitable for value-added products. Aims: The present study develops surimi-based fish crackers from snapper filleted frame meat and to evaluate their physicochemical, nutritional, microbiological, sensory, and storage stability characteristics to assess the feasibility of value addition and sustainable utilisation of fish processing waste. Study Design: An experimental laboratory study involving recovery of snapper frame meat, optimisation of surimi through water-washing, development of surimi-based fish crackers, and evaluation of physicochemical, nutritional, microbiological, sensory, and storage stability under ambient and refrigerated conditions. Place and Duration of Study: The experimental work was carried out during the period July 2019 to March 2020 at the Department of Fish Processing Technology, College of Fisheries, Mangaluru, Karnataka Veterinary, Animal and Fisheries Sciences University, India. The laboratory is                 located in the coastal region of Karnataka at approximately 12.87° N latitude and 74.88° E longitude. Methodology: Snapper filleted frame meat recovered by mechanical mincing was evaluated for quality and processed into surimi using standardised chilled water-washing cycles. Fish crackers were developed by blending surimi with tapioca flour, millet flour, and soya chunk powder in different ratios, followed by cooking, drying, and frying. The optimal formulation was selected through sensory evaluation. Dried and fried crackers were analysed for nutritional, biochemical, microbiological, and sensory quality, and storage stability was assessed under ambient and refrigerated conditions. Results: Snapper filleted frames yielded substantial recoverable meat (n = 10), with a mean total length and weight of 660.9 ± 28.4 mm and 2550 ± 506 g, respectively, and an average fillet yield of 1369 ± 264 g. Progressive water-washing significantly increased moisture while reducing lipid content, TVB-N, TMA-N, free fatty acids, TBARS, and microbial load (p < 0.05), improving surimi quality. Among four formulations evaluated by 25 panellists, crackers containing surimi (50%), tapioca flour (25%), millet flour (25%), and soya chunk powder (5%) showed the highest overall acceptability (8.61 ± 0.04; p < 0.01). Dried crackers had higher protein (20.41 ± 0.58%) and lower lipid content (0.95 ± 0.02%) than fried crackers (p < 0.001). Initial microbial counts were low (≤1.84 × 10² cfu/g), with no mould or yeast detected. During 60-day storage, biochemical spoilage indices and microbial counts increased significantly (p < 0.05), with slower deterioration and better sensory retention under refrigerated conditions. Conclusion: The study confirms the feasibility of converting snapper filleted frame waste into nutritionally acceptable, microbiologically safe, and sensory-appealing surimi-based fish crackers, with improved functional quality through controlled washing and superior storage stability under refrigerated conditions, supporting sustainable fish processing and value addition.