Study On Process And Technology Of Semi-Dry Silver Carp Fillets

Freshwater fishes which are low in cost can be processed into higher value added snacks. It notonly meets the market, but also promotes the healthy development of China’s aquaculture andaquatic product processing industry. Among the large variety freshwater fishes, the silver carp isrich in nutritiou and substances that are beneficial to the human body. They are minerals,eicosapentaenoic acid, docosahexaenoic acid, and so on. The annual yield of the silver carp is veryhigh. However, majority of the silver carps are sold fresh while the high value silver carp snack arerarely produced and sold. Therefore, the silver carp snack has great market prospects to develop intoa popular snack.In this research, the process and technology of producing delicious, popular and high valuesemi-dry silver carp fillets is studied. The technology contains brine salting, hot drying and frying.Firstly, brine salting and removing the fishy smell were studied. The fillets were cut ino size of3cm×2cm×1cm. The basic processing conditions of brine salting and deodorization weredetermined by single-factor test. The orthogonal experiment was carried out to obtain the optimumconditions of brine and deodorization. The optimal condition are as the following: the brine saltingconcentration3.5%, monosodium glutamate concentration0.5%, deodorization agent concentration（onion, ginger and garlic） concentration1.5%, salting time2h.Secondly, the dehydration technology of silver carp fillets was studied, using hot air drying andfrying. The final moisture content of product was40%（wet basic） which was determined bysensory test. In order to determined the mid-moisture content of fillets between hot air drying andfrying, oil content and sensory test of fillets were studied. Results showed the mid-moisture contentof filltes wsa about65%（wet basic）. Further studies showed that the optimal drying temperatureand frying temperature were50℃and180-200℃respectively. The three key processingparameters （drying temperature, mid-moisture content and drying temperature） were optimized bythe multi-quadric roundabout orthogonal test. The optimal condition are as the folowing: dryingtemperature50℃, mid-moisture content63%, frying temperature191℃. Under these conditions,a better product was obtained.Also, the sterilization technology was studied. The relationship between F-value andsterilization conditions （temperature and time） was determined by measuring the center temperatureof fillets placed in sterilization pot. The critical F-value of sterilization technology was determinedby microbiological and sensory testes of products after sterilization （different F-values）. In order todetermin the optimal sterilization condition, the effects of the different sterilization conditions underthe equal F-value on the quality of product （texture, color） were studied. Results showed that theoptimal sterilization conditions were: sterilization temperature121℃, sterilization time6min.Lastly, the shelf life of product was predicted. It was determined that acid value was the keyfactor during storage, through the relative analysis between the physical, chemical indicators （pH,TVB-N, acid value, peroxide value） and sensory evaluation. The Arrhenius model of product at25℃was established by the acid value and the first-order reaction kinetics model. The model wasA=0.342e^0.0085t. The shelf life prediction was255days by this model.