| The quantity of squid processing wastes was increased with years and there was not good method of utilizing squid processing wastes effectively at present. The concentration of salt was bigger in traditional fish sauce and the fermentation period was longer. The research was done for solving the above questions. The accelerated fermentation technology was studied for low salt fish sauce from squid processing wastes. The changes of biochemistry characteristics were also investigated during production. The details of the paper were as follows.1. The technology of autohydrolysis was investigated about squid processing wastes. The mathematical model was eastablished for autohydrolysis of squid processing squid. The results of single factor experiment suggested that 48 hours was optimum hydrolysis time. The result of the orthogonal experiment suggested that the effect from three factors (temperature, initial pH and water addition ratio) was prominent on the content ofα-amino nitrogen in supernatant. The process of autohydrolysis could be predicated well and truly by the mathematical model. The optimum conditions on autohydrolysis were as follows, temperature (45.49oC), water addition ratio (0.277:1), initial pH (6.42). The results of analyzing the response surfaces showed that the effect from three factors (temperature, initial pH and water addition ratio) had interaction on response value each other. The result of verification test demonstrated that the content ofα-amino nitrogen in autohydrolysis supernatant attained to 0.42±0.02g/100ml. The predicted value of the equation was 0.43g/100ml. The good coherence lied in between them. The result of autohydrolysis could be predicted well and truly by the mathematical model.The result on the change of biochemistry index proveded thatα-amino nitrogen content, solubility total nitrogen content, free amino acid content, etc. in supernatant and the degree of protein hydrolyze were increased gradually during the course of hydrolyzation. The final value of TVB-N content was 63.68±2.39mg/100g and showed that the obvious rotten phenomenon did not happen in 48 hours hydrolysis.2. The changes of important indexes, which consitist ofα-amino nitrogen content, total solutable nitrogen content, pH, TVB-N content, the recovery rate of protein, the content of free amino acids and the total number of bacteria in fish sauce, were explored in three processes. The sense quality of fish sauces was scored by the sense estimate group. The optimum technology for low salt fish sauce was found by virtue of comparison between them. The best technology was as follows, the hydrolyte was fermented by adding salt and koji after squid processing wastes was hydrolyzed by endogenesis proteases.The main factors of fermentation were investigated by single factor test and the quadratic regression orthogonal rotational combing design. The mathematical model was eastablished for predicting the result of fermentation by regressional analysis methods.The result of single factor experiment showed that 30 days was the optimum fermentation time. The result from quadratic regression orthogonal rotational combing design and response surface analysis demonstrated that the effect on response value from four factors (temperature, quantity of salt, quantity of koji, water addition ratio) was prominent. The optimum conditions on the fermentation were as follows, temperature (50.99oC), quantity of salt (9.32%), quantity of koji (30%), water addition ratio (0.20:1) and initial pH (7.28). The result of F-test suggested that the significance effect factors on response value were linearity coefficient: X1 (temperature), X2(quantity of koji), X3(quantity of salt) and X4 (water addition ratio), cross factors coefficient X25(quantity of koji and initial pH), quadratic factors coefficient X11(temperature), X33(quantity of salt), X44(water addition ratio), X55(initial pH). The result from ANOVA showed that the F-value was higher in regression equation. The result of verification test demonstrated that the content ofα-amino nitrogen in fish sauce attained to 1.36±0.04g/100ml. The predicted value of the equation was 1.40g/100ml. The good coherence was present in them. Theα-amino nitrogen content in fish sauce could be predicted well and truly during fermentation.3. The changes of main indexes of quality and microorganism were studied under optimum fermentation condition of fish sauce from squid processing wastes. The results of quality indexes demonstrated thatα-amino nitrogen content, soluble total nitrogen content, TVB-N content, water-soluble solid without salt, salt content in fish sauce were increased gradually with fermentation and were 1.37±0.04g/100ml, 2.24±0.04g/100ml, 157.18±4.02mg/100ml, 19.35±0.57g/100ml, 10.16±0.23g/100ml separately at the end of 30 days fermentation. These index values were superior to the ones in the nation standard of fish sauce. And the recovery of protein was higher under optimum technological condition. The analysis result of biogenic amine suggested that the content of tyramine, putrescine, histamine increased much and other biogenic amine increased little. The content of tyramine, putrescine, cadaverine, histamine, spermine, spermidine, agmatine were 20.753±0.838mg/L, 8.946±0.547mg/L, 0.321±0.072mg/L, 3.366±0.268mg/L, 0.143±0.014mg/L, 0.674±0.016mg/L, 0.689±0.034mg/L separately and was low relative to the ones of fish sauce on sale. The result of microbial classify analyze indicated that the main microorganism was include in bacterium, lactobacillus yeast and mould and these microorganism come from koji. The number of all microprganism decreased gradually with the development of fermentation. The result of sense score suggested that fish sauce from squid processing wastes had better acceptability in umami, salty, fishy, bitter and so on.4. The method was investigated by ion chromatography for analyzing organic acids in fish sauce and the content of organic acids were detected in different fish sauce. The result of experiment suggested that different organic acids were separated well in fish sauce and the recovery of standard addition ranged from 93.6% to 104.33%. The content of L-lactate, acetate, formate, pyruvate, malate, tartrate,α-ketoglutarate, oxalate, fumarate, citrate in low salt fish sauce from squid processing wastes were 14.480±0.151g/l, 0.794±0.017g/l, 0.035±0.001g/l, 0.002±0.001g/l, 1.598±0.015g/l, 0.280±0.003g/l, 0.594±0.005g/l, 0.367±0.005g/l, 1.071±0.018g/l separately. The total content of organic acid in low salt fish sauce was 19.274±0.202g/l, which was higher than traditional fish sauces in Japan, korea, China. And L-lactate was the main organic acid in low salt fish sauce. The volatile flavor compounds were extracted by SPME and were detected by GC-MS in low salt fish sauce from squid processing wastes. The detection results demonstrated that main volatile compounds were 95 compounds and consist of 7 acid compounds, 5 alcohol compounds, 26 carbonyl compounds, 4 ester compounds, 18 nitrogen compounds, 14 sulphocompounds, 5 furan compounds, 5 phenol compounds, 7 hydrocarbons and undetermined compounds. These compounds are thought to be major contributors to low salt fish sauce odor. The major volatile compounds involved of phenylethyl alcohol, 2-methyl-butanal, benzaldehyde, benzeneacetaldehyde, benzoic acid ethyl ester, 2-methoxy-4-vinylphenol, 2-methoxy-phenol, 2-ethyl-furan, dimethyl trisulfide, dimethyl disulfide, 3-phenyl-furan, 2-ethyl-5-methyl-pyrazine and so on.
|
PDF Full Text Request