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Fish mince from Pink perch (Nemipterus japonicus) in the concentration of 15% along with 85% refined wheat flour was used for the production of noodles. Optimisation of thermal process parameters were carried out and it was found Fo value of 7 min, cook value of 74.78 min and total process time of 36.04 min to be optimum for processing fish noodles in HIPP trays. Storage studies of ready-to-eat noodles at ambient temperature indicated a decrease in lightness. Yellowness and redness increased during the storage period. The instrumental texture analysis showed an increasing trend for hardness. Sensory analysis revealed that during storage, appearance, color and texture were mostly affected. Odor, flavor and taste were well accepted even at the end of storage period. Biochemical parameters were well within the limit of acceptability. Thermally processed ready-to-eat fish noodles had a shelf life of 90 days at ambient temperature (28 ± 2 °C).

Increasing environmental pollution and limited biological resources has emphasized the need for better utilization of fish processing waste. In the present study, visceral proteases from little tuna (Euthynnus affinis), catla (Catla catla) and tilapia (Oreochromis mossambicus) belonging to different habitats using acetone, ethanol and ammonium sulfate fractional precipitation were isolated and characterized. Enzymes precipitated from little tuna and tilapia exhibited higher specific activity at 40% saturation for ammonium sulfate fractional precipitation and the specific activities were 18.19 and 13.67 U/mg for little tuna and tilapia enzymes, respectively. Enzymes precipitated from catla reported higher specific activity of 8.32 U/mg at 60% saturation for ammonium sulfate fractional precipitation. Acetone precipitated fraction exhibited higher recovery for all crude enzymes studied. The effect of different combinations of crude tuna visceral waste enzyme and papain enzyme on hydrolysate properties was optimized using response surface methodology. Second order response surface regression model was used to explain the total variability in terms of quadratic and interaction effects of combination enzyme concentration on the properties of croaker protein hydrolysate with a significant R2 value for protein content (0.92), tyrosine content (0.99), degree of hydrolysis (0.99), DPPH free radical scavenging activity (0.97), ferric reducing antioxidant power (0.93), metal chelating activity (0.88), foaming capacity (0.92) and foam stability (0.88). Based on the desirability score, papain at 0.81% concentration and crude tuna visceral protease at 4.36% was found to be optimal for achieving desired properties of croaker protein hydrolysate.

In this study, the gelation and thermal characteristics of microwave extracted fish scale gelatin blended with natural gums such as gum arabic (AG), xanthan gum (XG), guar gum (GG), and tragacanth gum (TG) was evaluated. The nature of interaction and behavior of gelatin in presence of various gums was confirmed by particle size analysis, viscosity profile, FT-IR analysis and turbidity measurements. DSC data revealed that addition of AG, TG and GG remarkably improved the thermal stability of fish gelatin gel. The composite gels of TG, AG, and XG exhibited higher hardness and bloom strength values as compared to pure fish gelatin implying its textural synergy. Based on qualitative descriptive analysis, TG was found to be superior in improving the stability of fish gelatin gel, closely followed by AG. The results suggest that addition of these gums can reduce syneresis and retard melting of gelatin gels at ambient temperature, which are otherwise soft and thermally unstable.

A liquid smoke flavoured sausages were prepared from yellowfin tuna using a commercial liquid smoke flavouring. Physico-chemical changes in the sausages during chilled storage at 3 ± 1 °C were analysed and compared with that of a control. Total plate count was estimated at every 15th day of storage. Liquid-smoked sausages were were found to have higher moisture content but recorded lower values for total volatile base-nitrogen, trimethylamine and thiobarbituric acid (P 0.01). Instrumental colour measurements showed lower L* (lightness), a* (redness) and b* (yellowness) values for liquid smoke flavoured sausages (P < 0.01). The liquid-smoked sausages showed lower hardness values (P < 0.01). Both liquid-smoked and control sausages were found to be sensory wise acceptable up to 55th days of storage and subsequently rejected on the 60th day. The microbial count in both the types of sausages was within the acceptable limit during this period.