| Due to the habit of diet,the consumers prefer the head of the bighead carp to the body.With the rapid pace of modern people’s life,more and more people pay attention to the convenient,nutritional and safe ready-to-eat food,which provide the chance for the prepared bighead carp food.In this study,the Aristichthys nobilis was used as raw materials,on the one hand,the fuzzy mathematics evaluation was carried on the optimization of frying the coated aristichthys nobilis fillets and having a research on the effect of refrigerated and freezing condition on the quality of fried coated aristichthys nobilis fillets,in addition,the effect of cold/hot chain distribution on the flavor and nutritional quality of fried fillets was studied.On the other hand,the study was carried on the effect of the composite of ginger,onion and garlic on lipid oxidation and heterocyclic aromatic amines of fried aristichthys nobilis fillets,and the effect of different cooking methods on the lipid oxidation and heterocyclic aromatic amines of fried aristichthys nobilis fillets was also studied.(1)Fuzzy mathematic evaluation model was introduced to optimize the process of frying Aristichthys nobilis steaks with a view to determine the optimal values of curing time,frying temperature and frying time,at the same time.The correlation coefficients for physicochemical indexes and sensory evaluation were analysed.non-volatile flavor compounds were identified by high performance liquid chromatography(HPLC).The results showed that optimum condition was as follows:curing time 20 min,frying temperature 180 ℃ and frying time 5 min.Under this condition,the content of total free amino acid was 408.53 mg/100g and the content of total flavor nucleotides was 73.06 mg/100g.The water content,a*and b*were the key factors to the sensory evaluation of frying steaks.Compared to the fresh,different frying conditions had significant effects on the content of the free amino acid and flavor nucleotides(p<0.05).Glu,Gly,His and Ala were the highest content in the free amino acid,in addition,Glu and His contributed to the flavor significantly;in most samples,5’-IMP was the most ample in the flavor nucleotides,but the 5’-AMP was not found under all kinds of conditions.Otherwise,5’-IMP and 5’-CMP were more than the threshold and mada contribution to the taste.Therefore,under the codition of curing time 20 min,frying temperature 180℃ and frying time 5 min,the steaks had the optimum quality.(2)Effect of different storage conditions(4 ℃ and-20 ℃)on safety of the fried Aristichthys nobilis fillets was studied.The result showed that the values of pH and water content had no significant change,but they all decreased under 4 0C and they all fluctuated under-20 ℃;with the time growing,the content of T-VBN increased and the rate in 4 ℃was faster than the one in the-20 ℃.The number of microorganism was still lower after frozen for 49 days while the refrigerated,and the advantage of freezing condition was larger than refrigerated condition.(3)Fried Aristichthys nobilis fillets was storaged at hot chain condition(incubator 65 ℃)for 5h and cold chain condition(fridge 4 ℃)for 60h,then reheated by microwaving in order to study changes occurring in the lipid oxidation and volatile flavor compounds.Peroxide value(POV),2-thiobarbituric acid(TBA)were measured to evaluate the lipid oxidation,suggesting that the degree of lipid oxidation significantly increased with the extension of the storage time(p<0.05).Volatile flavor compounds in the fried fillets were investigated by SPME-GC-MS,and the result showed that total 110 compounds were identified from the fish fillets,including 27 kinds of hydrocarbons,18 kinds of the alcohol,11 kinds of kedone,11 kinds of aldehydes,25 kinds of alkenes and 5kinds of others,the fatty hydrocarbon and alcohol take the biggest account in the flavor compounds of fried fillets.However,the aldehydes and pyrazine of the maillard reaction were the characteristic flavor of the fried fillets.(4)The objective of present study was to investigate the effects of different cooking methods(boiling,microwave baking,roasting,and frying)and various fried oils(soybean oil,peanut oil and sunflower oil)on the lipid oxidation and heterocyclic aromatic amines(HAAs)of fish fillets.In all cooked fish fillets,the microwaved fish fillets has the highest peroxide value(POV)of 0.035 meq/kg,but the POV of fried fillets with peanut oil showed the lowest,0.0093 meq/kg.Additionally,among all cooked fish fillets,the thiobarbituric acid value(TBA)of microwaved fillets was also the highest,4.71 MDA/kg,and the fried fillets with peanut oil had the lowest TBA of 1.93 MDA/kg.The type and content of HAAs were related to the cooking methods.9H-pyrido[3,4-b]indole(Norharman),2-amino-3-methulinidazo[4,5-f]quinoline(IQ),1-methyl-9Hpyrido[3,4-b]indole(Harman)and 2-amino-l-methyl-6-phenylimidazo[4,5-b]-pyridine(PhIP)were detected in all the samples.In addition,in all cooked fish fillets,the content of heterocyclic aromatic amines was the highest,up to 203.58 ng/g(microwaved fillets),but the lowest was in the boiled fillets(only 32.35ng/g).Among fried fish fillets,the content of fish fillets with sunflower oil was the lowest,52.20 ng/g,but the highest value was the fish fillets fried with soybean oil(67.90 ng/g).Furthermore,there is no significant correlation between the potential precusors(Leu,Ile,Phe and Tyr)and the aimed HAAs(IQ,PhIP and MelQx).(5)Effects of the dosage of ginger,onion and garlic(OGG)(0%,5%,10%,15%)and fermentation time(30 min,60min,120 min)on lipid oxidation(peroxide value(POV),2-thiobarbituric acid(TBA))and heterocyclic aromatic amines(HAAs)of the fried Aristichthys nobilis fillets were evaluated.With the dosage of the OGG and the fermentation time increasing,the peroxide value(POV)and 2-thiobarbituric acid(TBA)of the fried fillets decreased significantly(P<0.05),it showed that the OGG could have significant inhibitive effects on the lipid oxidation.In addition,Harman,MeA&C,PhIP,Norharman and MelQx were detected in the fried fillets.OGG had the inhibition on the HAAs,ranging from 4%to 56%,especially on the MeA&C,up to 100%.Furthermore,there is no relationship between IQ,PhIP and MeIQx and Leu,Ile,Phe and Tyr. |
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