Sustainable Methods and Nutritional Evaluation of High Protein Fish Meats via Kjeldahl and Sensory Analyses: A Case Study in Southwest El Salvador

Abstract

This study investigates the nutritional composition, chemical analytical methodologies, and functional potential of three underutilized aquatic species — thornback ray (Raja clavata Linnaeus, 1758), eel (Synbranchus marmoratus Bloch, 1795), and tilapia (Oreochromis mossambicus). These species are explored as sustainable, high protein ingredients for the formulation of functional burger-type products designed to mitigate protein deficiency in vulnerable populations. All species are non-endangered and suitable for cultivation in controlled aquaculture systems, supporting environmentally responsible production. Three formulations were developed and subjected to proximate analysis, including moisture (oven drying), crude fat (Soxtec extraction), and total protein (Micro-Kjeldahl), alongside a sensory evaluation using a 9-point hedonic scale. Formulation A demonstrated the most favorable nutritional profile, exhibiting higher protein content (15.6 g/100 g) and substantially lower fat levels (18.4 g/100 g) compared to conventional beef patties (12.8 g/100 g protein; 29.1 g/100 g fat). Its elevated moisture content (60.5 g/100 g) contributed to improved juiciness, though potentially at the expense of shelf stability. Sensory results indicated strong consumer acceptance, with Formulation A achieving an average score of 8.06, closely approximating the beef control (8.37). Panelists expressed high preference for color and texture, while odor and flavor acceptance were moderate but positive, reflecting minimal fishy notes and a balanced flavor profile. These findings highlight the viability of seafood-based burgers derived from non-threatened species as nutritionally enhanced and sensorially acceptable alternatives to traditional meat products. Their adoption could strengthen nutritional security while promoting the valorization of underutilized hydro-biological resources. Future investigations should examine raw-material availability and develop robust preservation strategies to ensure feasibility and scalability for commercial production.