The Influence Of Fat On The Quality Of Western Bacon And The Formation Of N-nitrosoamines And Its Control

Bacon will add salt preparation in the manufacturing process of nitrate or nitrite,breeds into carcinogens in meat products of acid conditions of N-nitrosamines(N-nitrosoamines,NAs),among them,the fat is an important factor of the nitrosation reaction,and bacon make the ribs abdominal fat content is higher in meat,usually in30?40%,even more than 50%.However,there are few reports on the influence of fat addition ratio and fat oxidation degree on the formation of NAs in bacon.Of this study was to explore the adding proportion and fat fat oxidation processing of bacon in NAs formation and the related degree of the influence of the quality,further study of fat to participate in the mechanism of action of nitrosation reaction,and finally to the lab research of compound natural antioxidant in western bacon processing the application,in order to produce a fat percentage is appropriate,good flavor and high safety of bacon products,guide the practical production.The main contents of this paper are as follows:1.For the understanding of the different proportion of fat content in the raw meat of bacon,the influence of safety quality in the process of taking fat accounted for the proportion of the total amount of meat were 0(F0),10%(F10),20%(F20 group),30%(F30 group)as raw material,through the ground,pickling,molding,cooking,drying,smoking,and baked process bacon products,The p H,nitrite residue,thioburic acid(TBARS),bioamine and NAs of the samples were measured in the cooking,fumigation,fumigation for 3 h,fumigation for 7 h and frying for 7h,respectively,to analyze the influence of different fat proportions on the changes of various physical and chemical indexes in the processing of bacon.The results showed that with the increase of fat proportion in raw meat,the p H,nitrite residue,TBARS and NAs in bacon showed a significant increase trend,and their values from high to low were F30>,F20>F10>F0.In the process of cooking and smoking,nitrite residues and TBARS in the four groups showed a decreasing trend,while biological amines and NAs showed an increasing trend.Among the total amount of NAs,the most significant change was n-nitrosodimethylamine(NDMA).The samples in the four groups all reached the maximum value at 7 hours of smoking.After frying,the content of n-nitrosopyrrolidine(NPYR)still increased,especially the content of NPYR in F20 and F30 groups with higher fat ratio reached the highest value(1.27 and1.85 respectively).The correlation analysis showed that the correlation coefficient between the fat proportion of the raw meat and the amount of NAs formation was higher after smoking for 7 h and frying and roasting.2.To understand the influence of the degree of fat oxidation in raw meat on the safety and quality of bacon.This section in the form of repeated freezing and thawing preparation of three groups of different degree of oxidation of fat,F0 group(TBARS value of 0.04 mg/kg),F1 group(TBARS value of 0.09 mg/kg),F2 group(TBARS value of 0.30 mg/kg),the three groups of fat mixed with ground fresh pig lean meat processing into three groups of bacon products,finished products and finished products after baked samples by nitrite residue,biogenic amines,NAs,and other related indicators of change.The results showed that the p H value,reddening value,total sulfhydryl group content and polyunsaturated fatty acid content(PUFA)of bacon decreased gradually with the increase of oxidation degree of raw fat.With the increase of the oxidation degree of the raw material fat,the contents of thiobarbital value TBARS,carbonyl group,total biological amine and NDMA of western bacon tended to increase,especially the contents of NPYR,n-nitrosopiperidine(NPIP)and histamine after frying and roasting.In the fat-protein mixing system of bacon,the oxidation of fat will promote the oxidation of proteins,promote the generation of NAs,bioamines and NDMA,and ultimately affect the safety and quality of products.Therefore,the freshness of raw fat should be strictly controlled in the actual production to improve the quality and safety of bacon products.3.In order to understand the mechanism of fatty acids participating in nitrosation,this chapter uses GC-IMS to monitor the changes of volatile substances during fatty acids participating in nitrosation by reacting fatty acids with NDMA and NPYR at different levels of saturation,identify the intermediate products that may promote the formation of NAs,and explore the possible mechanism of fat promoting the formation of NAs.The results showed that the fatty acids did have a significant promoting effect on nitrosation,and the higher the degree of unsaturated fatty acids,the more obvious the promoting effect was.Therefore,the fatty acids that promoted the formation of NDMA and NPYR were the most obvious ones,namely,alpha linolenic acid,followed by linoleic acid and oleic acid.In vitro nitrosation reaction system(80?,p H6.2,1 h),as the fatty acids,with the increase of adding ratio(0?25%)of the formation of NDMA and NPYR amount showed a trend of lower after the first rise in the GC-IMS analysis results show that the alpha linolenic acid and sodium nitrite after heat reaction does have some new material,new generation of material concentration and types and reaction time and dosage of alpha linolenic acid is added.The newly generated substances include alkenes,esters,furans,etc.Some of these substances may have an effect on the nitrification reaction.However,the nitrification reaction process is very complex,and further experiments are needed to confirm which substances are involved in the reaction.4.To understand complex natural antioxidants of bacon,the influence of quality and safety of this chapter to pig lean meat(ground),and 70%and 30%of pig back fat fat(slice)as raw material,after curing,molding,cooking and baking,smoked processed into western bacon,in curing processing link,add a different combination of compound natural antioxidant form four groups of different curing liquid:(1)CK groups:blank control group(the control the check),by salt,compound phosphate,sugar,soy protein isolate powder,sodium nitrite based curing liquid mixture,such as curing liquid adding proportion 20%of the heavy raw meat.TCER group:adding0.05%Tea polyphenols,0.05%V_C,0.05%V_E and 0.05%Rosemary of the raw meat weight on the basis of the basic curing solution to combine with natural antioxidants;(3)TCNCS group:0.25%tea polyphenol,0.25%Chitosan(Chitosan),0.05%1.25%lactic streptococcus element(Nisin)and spices(clove and cinnamon);TE group:0.06%tea polyphenols and 0.08%V_E.The p H,chroma,nitrite residue,TBARS,peroxide value(POV),bioamine and NAs of 4 groups of western bacon final products were determined,and the sensory evaluation was conducted.The results showed that the addition of 3 sets of composite natural antioxidants does not affect the sensory quality of bacon(P>0.05),it can significantly reduce the p H and nitrite residue of the product,delay the lipid oxidation of the product(P<0.05),and control the formation of NDMA.The TCER group and TE group can significantly reduce the total amount of biogenic amine in the product(P<0.05).It can be seen that the compound natural antioxidant has a significant improvement effect on the quality and safety of bacon.