Effects Of Autoclaving Combined With Fermentation By Bacillus Natto On The Allergenicity,Physical And Chemical Properties Of Peanut

Food allergy is the abnormal immune response caused by the intake of food or some components in food,which is generally divided into immunoglobulin(IgE)mediated type,non-ige mediated type and mixed reaction type.And it affects 1-2% of adults and 3-6% of children in developed countries.Therefore,food allergy is a public health problem that needs to be solved urgently,and it is extremely urgent to find processing technology to reduce food allergy.This study assessed peanut allergen by the ELISA,scanning electron microscopy,ultraviolet absorption spectrum,round two chromatography,infrared spectrum,grain size analysis and DSC etc,which was to explore the effect of autoclaving and fermentation with Bacillus natto on the allergenicity of RPP or autoclaving and fermentation with mixed bacteria(Bacillus natto and Lactobacillus plantarum)on the allergenicity of RCP and the structure of peanut protein,resulting in researching the mechanism of reducing peanut allergy.Meanwhile,physical and chemical properties of fermented peanut was evaluated,and a hypoallergenic and high nutrition of peanut products was developed.The main conclusions are as follows:(1)After RPP and RCP were autoclaved,the IgE binding capacity to serum of peanut allergy patients was used to evaluate the changes in the allergenicity of PRR and RCP,and the changes in the protein structure were analyzed by spectroscopic method.Results showed that autoclaving reduced the allergenicity of RPP(reduction rate was 66.6%)and RCP(reduction rate was 11.3%)mainly by reducing the protein molecular weight,increasing protein ultraviolet absorption intensity at 210 nm and280 nm,reducing the protein surface hydrophobicity,reducing the protein content of free sulfhydryl.Thus,the protein primary and tertiary structure were affected by autoclaving,resulting in RPP protein folding,RCP protein aggregation,structure being compact,which caused allergic epitopes were destroyed or hidden and the allergenicity of PRR and RCP were decreased.In addition,the physical and chemical properties of RPP and ACP can be changed by autoclaving.(2)After RPP was treated with autoclaving combined with fermentation byBacillus natto,RPP protein extract was detected by immunological and spectroscopic methods.The results showed that autoclaving combined with fermentation by Bacillus natto reduced the allergenicity of RPP(maximum reduction rate was mainly by affecting the primary,secondary and tertiary structure of RPP protein,among which the secondary structure of protein was mainly affected by protease produced by Bacillus natto.Compared with RPP protein,FAPP-B protein unfolded,structure became loose,allergic epitopes were exposed,and allergic epitopes were then destroyed or hidden due to the degradation of protease produced by Bacillus natto.During autoclaving combined with fermentation by Bacillus natto for 12-48 h,the protein allergenicity decreased with the prolongation of the fermentation time,and the protein allergenicity was positively correlated with the content of free sulfhydryl,negatively correlated with the absorption intensity at 210 nm of ultraviolet absorption,positively correlated with the surface hydrophobicity,and positively correlated with the hydrolysis degree of the sample.(3)After RPP was treated with autoclaving combined with fermentation by Bacillus natto,its(FAPP-B)lyophilized products were analyzed and detected.The result showed that autoclaving combined with liquid fermentation by bacillus natto had a significant effect on the physical and chemical indexes of RPP,and FAPP-B-36 were better peanut products with high nutritional value and low allergenicity after comprehensive consideration of allergy,sensory and other factors.(4)SDS-PAGE and immunological methods were used to study the changes of digestibility and allergenicity of protein extracted from RPP,APP and FAPP-B in simulated gastrointestinal digestion in vitro.The result showed that 1)After RPP was treated with autoclaving combined with fermentation by Bacillus natto,the digestibility of RPP protein increased,and the digestibility of FAPP-B protein was much higher than that of APP,among which FAPP-B-60 had the highest digestibility;2)The protein extracted from RPP,APP and FAPP-B was treated with gastric juice and intestinal juice,gastric intestinal juice,their allergenicity was reduced with the prolonging of digestion In addition,the reduction of allergenicity of FAPP-B was biggest and the allergenicity of FAPP-B-60 was lowest after FAPP-B-60 protein was treated with same time of gastric juice and intestinal juice,gastric intestinal juicecompared with other samples;3)Gastric juice and intestinal juice treatment reduced the allergenicity of peanut,and the effect of gastric juice treatment is better,and the continuous effect of gastric and intestinal juice treatment is better than that of gastric and intestinal juice treatment.(5)After RCP was treated with autoclaving combined with solid-state fermentation by Bacillus natto and Lactobacillus plantarum,immunological and spectroscopic methods were used to detect the protein extracts of RCP to explore the influence of autoclaving combined with solid-state fermentation by Bacillus natto and Lactobacillus plantarum on the allergenicity and structure of the proteins.Results showed that the reduction of allergenicity of RCP was best(reduction rate was 90.2%)when RCP was treated with autoclaving combined with solid-state fermentation by Bacillus natto and Lactobacillus plantarum for 36 h.The treatment mainly reduced molecular weight of RCP protein,made its protein structure unfold,having influence on the primary,secondary and tertiary structure of RCP protein.The protein secondary structure is mainly affected by Bacillus natto and Lactobacillus plantarum,and the influence of degradation of protease produced by Bacillus natto was better compared with the effect of acidification of lactic acid produced by Lactobacillus plantarum,and both influence existed the inhibition of relationship.The acidification of lactic acid lead to the exposure of tryptophan and tyrosine,while the degradation of protease lead to the hiding of tryptophan and tyrosine.The degradation of protease lead to the hiding of free sulfhydryl,which was stronger than the acid denaturation of lactic acid.The degradation of protease lead to the exposure of hydrophobic groups,which was stronger than the acid denaturation of lactic acid.(6)After RCP was treated with autoclaving combined with solid-state fermentation by Bacillus natto and Lactobacillus plantarum,the fermentation products were analyzed and detected.The results showed that autoclaving combined with solid-state fermentation by Bacillus natto and Lactobacillus plantarum changed the physicochemical indexes of RCP and FACP-LB-36 was the best peanut product with low allergenicity,high nutritional value and good sensory evaluation.