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Carp species forms the bulk of the aquaculture production in India and studies have shown that the filleting waste of these species, particularly skin can be a good source of gelatin. This study is a comparison of the gelatins from these unexploited sources with that of mammalian gelatins to get a better understanding of their physicochemical and functional properties with respect to mammalian gelatins. The study showed that mammalian gelatins had significantly superior physical properties viz., higher viscosity, melting & setting temperature and faster setting time. The odour scores were significantly higher (P<0.05) for bovine and porcine skin gelatins (3.1-3.12), indicating that they had a distinguishable odour and hence can be considered as inferior to fish skin gelatins in organoleptic qualities. The gel strengths of rohu and common carp skin gelatins were significantly lower than mammalian gelatins. Among the carp skin gelatins, grass carp skin gelatin was found to have better compatibility with gelatin from bovine and porcine skins.

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Tilapia (Oreochromis mossambicus) is a relatively abundant, low‐value fish that has wide distribution in India because of its adaptability to different environments. However, the fish has limited scope for consumption in the fresh form. This study is an attempt to explore the possibilities of better utilization of this species by development of mince‐based value‐added products and the evaluation of shelf life during frozen storage. Mince from tilapia was used for the preparation of value‐added products viz., chilly fish, fish cutlets and fish balls. The biochemical and sensory parameters of these products were analyzed to study the quality changes and shelf life of these products in frozen storage at −20C. Fish cutlets and fish balls remained acceptable up to 18 weeks of storage after which loss in flavor and texture was noticed. Chilly fish remained acceptable for 21 weeks in frozen condition. PRACTICAL APPLICATIONS The study aims in value addition of tilapia (Oreochromis mossambicus), a low‐value fish, which at present has only limited scope for consumption in fresh form. Earlier studies showed that the mince yield of this species is 32–36%. The quality of tilapia mince is comparable to that from other marine and freshwater species of commercial importance. Utilization of the mince for the production of cutlets, fish balls and chilly fish are simple and a cost‐effective means of converting tilapia to value‐added convenience products. Shelf life studies indicate that in frozen storage, the products can retain the sensory qualities for 18–21 weeks. Commercialization of these products can contribute to diversification in the fish processing industry through better utilization of a relatively underutilized species.

Films of 0.11 to 0.13 mm thickness were prepared using gelatins from the skins of cultured freshwater carp species and mammalian gelatins viz., porcine and bovine skin gelatin. A comparative study was made on the physical, mechanical, and barrier properties of these films. The amino acid composition, gel strength, clarity, and gel setting point of the gelatins were also determined. Carp skin gelatins had a lower imino acid content (19.16% to 20.86%) than mammalian skin gelatins (22.91% to 23.7%). Grass carp gelatin had gel strength of 230.2 B that is comparable to the reported value for bovine skin gelatin (227.2 B). The bloom values of rohu and common carp skin gelatins were 188.6 B and 181.3 B, respectively, which were significantly lower than mammalian gelatins. Mammalian gels have significantly higher (P < 0.05) setting temperatures (23.7 to 24.2 °C) than carp skin gelatins. Tensile strength (TS) was lowest for films from common carp and rohu skin gelatin (490 and 497 kg/cm(2), respectively) and highest for porcine skin gelatin film. The degree of transparency (L*) was significantly higher for films from grass carp, bovine hide, and pork skin gelatin films. Carp skin gelatin films had significantly lower water vapor permeability (WVP) and oxygen permeability (OP) than mammalian skin gelatin films, which indicated that carp skin gelatin based films have superior barrier properties than mammalian skin gelatin films.