Study On Lipid Oxidation And Control Of Quality In Chinese Bacon By Procyanidin Liposomes

Procyanidin(PC),derived from the main active ingredient of grape seed extracts.Because of its strong antioxidant and antibacterial properties,it is known as a "natural,efficient and green" antioxidant.However,the lipid insolubility and chemical instability of PC reduce the bioavailability of PC.The lipid solubility of PC is enhanced by encapsulated-liposome,and the slow-release effect of liposome further expands the application prospect and potential of PC.Chinese bacon(CB),as a kind of food with unique flavor,is distributed all over the world.First,PC was applied to the preservation process of CB,and the effects of liposome-encapsulated PC on the antioxidant and microbial inhibition of CB were studied.Second,the effects of PC liposome(PCL)on the quality of CB were evaluated using color difference,texture analysis and sensory evaluation indicators.Finally,the effect of PCL on hazardous substances(benzopyrene and nitrosamines)during CB processing was investigated.The detailed experimental contents and research results are as follows:(1)Antioxidant and antibacterial effects of PCL on CB during storage: PC and PCL were divided into three concentration levels(20,40,and 60 mg/kg)to generate six main groups of experiments,with storage time lengthened,the dependent variables(thiobarbituric acid value,peroxide value,total number of colonies and p H value)were determined for different groups of experiments.The experimental results showed that PCL had stronger inhibitory effect on the oxidation and bacterial of CB than PC after the storage time reached 40 days,at the same concentration level.And this effect was presented in a dosedependent manner,that is,when the concentration of PCL was higher than 40mg/kg,the delay effect was relatively reduced.The p H of CB in 40 mg/kg PCL group is 5.80.(2)Effects of 40 mg/kg PCL on the quality of CB: after stored at 0,10,20,30 and40 days,color parameters and texture property of CB were determined,and sensory evaluation was also conducted.The results showed that the highest redness value(a*)was found in PCL group after 40-day storage,and PCL was also the most effective to maintain the tenderness of CB(prevent it become harder),the overall acceptability of PCL group was the highest,with the value of 7.34.(1)Different combinations of PC,PCL and tea polyphenol chitosan films(TP)were added in the salting stage of CB to explore the effects of PCL on the physicochemical properties of CB,and the number of colonies(total viable count(TVC)and lactic acid bacteria(LB))was detected during processing.Effects of PCL on hazardous substances(benzopyrenes and nitrosamines)formation were further measured during processing.The experimental results showed that after smoking,the p H of all antioxidant groups was higher than that of the control group(p<0.05),and the p H value of PCL group was 5.34;the addition of antioxidants had little effect on the water activity of CB(p>0.05).In addition,at the end of smoking,the TVC and the number of LB in all groups decreased to the minimum;when stored for 6 days after smoking,the TVC in PCL group was smaller than that in TP group,but the number of LB in PCL group was higher.After smoking,PCL can effectively control the content of benzopyrene.The results of the biogenic amine determination showed that the content of biogenic amines(putrescine,cadaverine,tyramine,spermine,phenethylamine)in all experimental groups increased.However,at different storage points,the increasing trend of biogenic amine content in PCL group was lower than that in other groups,and PCL could effectively reduce the total biogenic amine content.At the same time,by measuring nitrosamines(Ndimethylnitrosamine,N-nitrosopyrrolidine,N-nitrosopiperidine and Nmethylethylnitrosamine)in CB samples.At different storage points,the content of nitrosamines in PCL group was lower than that in the other groups,and PCL could effectively reduce the total content of nitrosamines.