Research On Quality Variation Of Fishmeal During Processing

Based on the samples during the process of fish meal processing stages as the research object, the study is intended to explore the quality relationship between raw fish and fish meal, as well as processing process impact on the quality of fishmeal.This paper has set up two parts:Part one:the quality relationship between raw fish and fish mealTaking fish meal production months March, September and November as the sampling time, Shipu Zhejiang Province, and Rongcheng Shandong Province as the sampling place, we collected the samples of raw fish and fishmeal in factories A and B which are typical of the defatted and semi-skimmed fish meal respectively in Shandong Province and factory D which is typical of the semi-skimmed fish meal in Zhejiang Province. Taking raw materials and fish mealas the research object, we study the relationship of general, safety and nutritional indices between raw fish and fish meal are analyzed using the correlation analysis. The result shows as follows:①there are significant differences in the genaral indices (except pepsin digestibility), safety indices and nutrition index (PUFA) between different seasons of the raw fish in factory A (P<0.05), also there are significant differences in general indices, security indices (except TVBN and putrescine contents), nutritional index (PUFA) between different seasons of the fishmeal in factory A (P< 0.05);②here are significant differences in the genaral indices, safety indices (except MDA content) and nutrition index (PUFA) between different seasons of the raw fish in factory B(P<0.05), also there are significant differences in general indices, security indices (except putrescine content) and nutritional indices (except SFA) between different seasons of the fishmeal in factory B (P<0.05);③there are significant differences in the genaral indices, safety indices and nutrition indices among different seasons of the raw fish in factory D(P<0.05), also there are significant differences in general indices, security indices and nutritional indices among different seasons of the fishmeal in factory D (P<0.05); @In factory A, there are correlations on general indices (contents of crude protein, crude fat, ash and phosphorus) between fish meal and raw fish (r>0.8). The regression analysis is carried on and the regression equations are y=0.3917+43.046x, y=43.046+5.5552x, y 0.4684+9.4832x,1.2617x+y=1.2617, respectively; there are correlations on safety indices (contents of TVBN, MDA, histamine, cadaverine, AV and POV) between fish meal and raw fish (r>0.8). The regression analysis is carried on and the regression equations are y=0.0669x+40.768, y=-0.0371x + 17.031, y= 0.1829x + 1.625, y = 0.0297x+36.38、y=0.1693x+168.41、y=0.0386x+992.64, respectively; there are correlations on nutritional indices (∑FEAA,∑HAA,∑HEAA, SFA, MUFA, PUFA) between fish meal and raw fish (r>0.8). The regression analysis is carried on and the regression equations are y=-1.0306x+2.8123, y=1.4771x-13.655, y=1.3817x-3.4421, y=0.3158x+22.077, y=0.7148x + 22.677, respectively; @In factory B, there are correlations on general indices (contents of crude protein, crude fat, ash, phosphorus and pepsin digestibility) between fish meal and raw fish (r>0.8). The regression analysis is carried on and the regression equations are y=0.5554x+32.198, y= 0.3222x+4.0749, y=1.081x+5.7727, y=0.6905x+0.4483, y=1.7281x-67.962, respectively; there are correlations on safety indices (contents of TVBN, histamine, cadaverine, AV and POV) between fish meal and raw fish (r>0.8). The regression analysis is carried on and the regression equations are y = 0.8589x - 81.979, y = 0.6841x-3.8712, y=-0.0845x+104.93, y=0.3653x+356.36, y=-0.0631x+3086.6, respectively; there are correlations on nutritional indices (∑FAA, ∑FEAA, ∑HAA, ∑HEAA, SFA, MUFA, PUFA) between fish meal and raw fish (r>0.8). The regression analysis is carried on and the regression equations are y = 2.3037x - 4.4899, y 2.1877x-2.2468, y=0.6901x+20.273, y=0.6823x+10.732, y=0.5882x+4.4286, y=1.4424x-10.769、y=1.1161x+19.046, respectively; ④In factory D, there are correlations on general indices (contents of crude protein, crude fat and pepsin digestibility) between fish meal and raw fish (r> 0.8). The regression analysis is carried on and the regression equations are y= 0.2886x+39.647, y= 2.9989x-3.0579, y= 0.2719x+66.615, respectively; there are correlations on safety indices (contents of TVBN, MDA and putrescine) between fish meal and raw fish (r> 0.8). The regression analysis is carried on and the regression equations are y= 0.4097x+22.457, y=-0.1801x+40.716, y= 0.6019x+545.83, respectively; All these show that:①The quality of the raw fish affected significantly by fishing season, species, region. There are significant differences on the general indices, safety indices and nutritional indices of the raw fish among different species, seasons and areas.②The quality of raw fish affects the fish meal significantly. There was a positive correlation between raw fish and fish meal on general indices (contents of crude protein, crude fat, ash, phosphorus and pepsin digestibility). The correlation coefficient for at least 0.9303,0.9373,0.9928, 0.7294,0.703; There was a positive correlation between raw fish and fish meal on safety indices (contents of TVBN, histamine, putrescine, cadaverine and AV). The correlation coefficient for at least 0.8531、0.9964、0.9774、0.6485、0.995; There was a positive correlation between raw fish and fish meal on nutritional indices ((∑FAA, ∑HAA, ∑HEAA, MUFA and PUFA). The correlation coefficient for at least 0.9976, 0.9985、0.9985、0.8707、0.9356. So feed enterprises is advised to focus on putrescine and cadaverine contents when choosing fish meal, in addition to the fishmeal standard specified in the indices at the same time. Also the quality of the raw fish need to be considered. ③When fishmeal factory chooses raw fish, generally, high content of crude protein, crude fat, low ash content is advised;on safety indices, low content of TVBN, histamine, putrescine, and adaverine is advised; on nutritional indicators, high content of ∑,∑HAA, ∑HEAA, MUFA and PUFA is advised.Part 2:processing technology impact on the quality of fishmealTaking fish meal production months November as the sampling time, Shipu Zhejiang Province, and Rongcheng Shandong Province as the sampling place, we collected the samples of raw fish, press cake samples after each dryers and fishmeal in factories A, B, C and D. Factory A is typical of the defatted while B and C are semi-skimmed fish meal in Shandong Province. Factory D is typical of the semi-skimmed fish meal in Zhejiang Province. Taking all the samples as the research object, we study the impact of processing technics during each stage by Duncan’s multiple comparisons. The result shows as follows:①General, safety and nutritional indices of samples during each process stage attained for the first time, which represent domestic fish meal of different seasons and regions;②Cooking and pressing process is one of the key technology which affects the quality of fishmeal. Cooking and pressing process significantly affects the general and nutritional indices of fish meal:contents of oil oxidation and protein decomposition products decrease significantly after cooking and pressing process. Acid value, peroxide value, contents of volatile base nitrogen, histamine, putrescine and cadaverine decreased over 44.73%,44.73%,37.38%,64.76%, 40.06% and 20.19%, respectively; contents of taurine, ∑FAA, ∑FEAA decreased over 28.73%,29.62% and 21.18%, respectively.③Drying process is one of the key technology which affects the quality of fishmeal. Drying process significantly affects the general, safety and nutritional indices of fish meal:a) The crude protein content and pepsin digestibility under low temperature drying condition (no higher than 80℃) have no significant change, while pepsin digestibility under the high temperature (90～ 110 ℃) drying conditions significantly reduced, with the damping of 1.80%; b) it is high temperature compared with low temperature that can speed up the fat oxidation, acid value and peroxide value of fish meal increase up to 109.4% and 136.34% during the drying process; At the same time, the antioxidant works. A, POV, MDA content of fish meal after adding antioxidants reduced by at most 39.32%,35.18% and 13.71%.3 ‰ BHT/TBHQ or 1‰ ethoxy quinolone is advised to add in drying process; Biogenic amine is produced in the process of drying, high temperature drying can effectively reduce the biogenic amine and volatile base nitrogen content, but might generate gizzerosine. c) free amino acid, taurine, ∑HAA and PUFA are protected under a low drying temperature. In the process of low temperature drying histidine content are negatively correlated with histamine content. So are AV and UFA content, MDA content and UFA content. The correlation coefficient were above 0.801,0.773 and 0.773; High temperature decreases the amount of EFAA ∑FEAA, taurine,∑HEAA, PUFA, EPA and DHA in the fish meal reduced by at least 8.72%,9.32%,6.37%,9.32%,3.58%,66.19% and 3.58%, respectively.