Screening And Application Of Lactic Acid Bacteria With Heterocyclic Aromatic Amines Adsorption Capacity

The bacterial strain and Ph IP co-culture technology was used to screen the lactic acid bacteria with high adsorption capacity of Ph IP by High Performance Liquid Chromatography（HPLC）from 53 strains,and the adsorption characteristics and mechanism of strains and its application in fermented lamb jerky（control,lactic acid bacteria and peptidoglycan）were studied in order to provide theoretical basis for the reduction of Ph IP in meat products and the development of lactic acid bacteria.The main research results are as follows:Taking the adsorption capacity as the evaluation index,the ability of adsorbing Ph IP in vitro of the strains was analyzed by investigating the influence of environmental factors and simulated gastrointestinal enviroment.The results show that three strains with high adsorption capacity for Ph IP were screened,there are Pediococcus pentosaceus37X-15,Lactobacillu splantarum 37X-6,and Lactobacillus curvatus X3-1B,the adsorption rates are respectively 83.36%,80.43%,76.96%.The best conditions for Ph IP adsorption of 37x-15 were 1.5 h,37℃,p H 6,the cell concentration was 1×10¹⁰cfu/m L and Ph IP concentration was 50 mg/L.The best conditions for Ph IP adsorption of 37x-6were 24 h,37℃,p H 6,the cell concentration was 1×10¹⁰cfu/m L and Ph IP concentration was 50 mg/L.The best adsorption conditions for Ph IP of X3-1B were 24h,37℃,p H 6,the cell concentration was 1×10¹⁰cfu/m L and Ph IP concentration was 50 mg/L.The stimulation of gastrointestinal environments showed that the maximum adsorption rates of strains 37X-15,37X-6 and X3-1B were respectively 81.05%,75.53%and 74.57%.In conclusion,strain 37X-15 had a higher adsorption rate for Ph IP compared to the other two strains.For clarifying the adsorption mechanism of Ph IP by heat treatment,scanning electron microscope and Fourier infrared spectroscopy.After heat treatment,the adsorption rate of Ph IP was no significant difference compared with untreated strain（P>0.05）,which indicated that the adsorption of Ph IP was physical and had nothing to do with the physiological metabolism of strain.The results of scanning clectron microscope could show that the cell surface was obviously damaged after adsorped Ph IP.The groups that participated in the Ph IP adsorption were the protein amide bandⅡ,C-N,O-H,N-H,C=O,P=O of the amine group,polysaccharide components on the cell wall and methyl,methylene,methylene groups on the cell membrane.The adsorption characteristics and mechanism of Ph IP by peptidoglycan are similar to that of bacteria,which further indicated that peptidoglycan was the main part of Ph IP adsorption by strain 37X-15.In the fermented lamb jerky,the lactic acid bacteria and peptidoglycan with adsorption rates of Ph IP were respectively 69.19%and 49.73%,which explain that the lactic acid bacteria with higher adsorption of Ph IP than that of peptidoglycan.After roasting,the p H value（5.38）,water activity（0.63）and e value（1.01）of the lactic acid bacteria group were significantly lower than those of the control group（P<0.05）,and fat content（8.85%）of the lactic acid bacteria group was significantly higher than that of the other groups（P<0.05）.The protein content of the peptidoglycan group（57.09%）was significantly higher than that of the other groups（P<0.05）.There are more flavors varieties in lactic acid bacteria group were significantly than those in other groups（P<0.05）.