| Channel Catfish(Ictalurus Punctatus) is a delicious, nutritious freshwater fish without intermuscular bones, which production increased from year to year. But the main processing form is frozen channel catfish fillets, which is monotonic and most of the products are exported abroad to make profit. This trade pattern lead to domestic channel catfish industry is vulnerable to the impact by the international market, resulting in great price volatility and serious economic loss to farmer and processer. Through develop new ready-to-eat and suitable channel catfish product to expand consumer market demand has important practical significance to promote the development of channel catfish industry rapidly and healthily. Nowadays, inebriated fish is one of the most characteristics freshwater fish processing products, which is very popular to the consumer and its market foreground is very vast. For all the above reasons, this article focus on the research of solving the manufacturing problem of high fat content, serious muddy flavor and difficulty to dehydration, which provide a theoretical foundation for the initial development of ready-to-eat inebriated channel catfish products. The main research results were as below:Firstly, five degreasing processes including rinsing with distilled water( Ⅰ), saponification with 1% Na HCO3(Ⅱ), soaking with 8% Na Cl(Ⅲ), lipase(Ⅳ)(p H 9.2, 40 U/m L) and extraction with anhydrous ethanol(Ⅴ) were used for comparing the degreasing and protein loss rate during degreasing experiments. The results showed that: the degreasing rate was Ⅳ>Ⅱ>Ⅴ>Ⅲ>Ⅰ, and the protein loss rate was Ⅱ>Ⅲ>Ⅳ>Ⅰ>Ⅴ. The method of Ⅳ got the highest degreasing rate with relatively low protein loss rate, which showed better degreasing effect.Secondly, the optimum degreasing processing parameters of lipase method was chosen by single factor experiment and response surface methodology as follows: activity of lipase 41 U/m L, soaking time 59 min, temperature 36℃, p H 9.0 and fish/liquid ratio 1/3(w/v),and in this situation the degreasing rate was about 56.55±0.85%.After that, microwave distillation combined with headspace solid phase micro-extract and GC-MS analysis(MD-HS-SPME-GC-MS) and sensory evaluation were used to study the effect of degreasing on channel catfish muscles. Results showed that muddy components(geosmin and 2-MIB) content and sensory score of muddy odor decreased significantly(p<0.05) with the increase of degreasing rate. When degreasing rate came to 55%, geosmin and 2-MIB content decreased 71.5% and 63.6% respectively.And then, the drying properties after degreasing treatment of channel catfish was studied through drying time, drying efficiency, TBARS, color and texture analysis. The results exhibited that after degreasing process(degreasing rate 55%) the drying properties of channel catfish changed significantly. For the samples dried under the same conditions, the decrease of fat content could contribute to shorter drying time, higher drying rate, better oxidation stability, lower surface hardness and better color.Finally, based on the above studies, the process technology of inebriated channel catfish was studied. Results showed that after degreasing and salting process, drying channel catfish fillets at 40℃, air speed 1.2 m/s to final water content 50%, then adding 30%(w/v) inebriated liquid, following vaccum packing and sterilization the self-made inebriated channel catfish were acquired, which quality were close to commercial inebriated products on texture, color and sensory indicators in this study. The formula of inebriated liquid were as follows: spices liquid 30%(v/v), white wine 10%, yellow wine 60% mixed uniformly, then added MSG 3%(w/v), sugar 35%, vinegar 1%, ethyl maltol 0.03‰. |
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