Study On The Degradation Of Soybean Allergens By Fermentation

Soybean, as one of the main plant protein sources, is widely used in food industry fromnutritional and economical standpoints. However, with the food diversity and complexitybecoming increasingly great, the number of allergenic sufferers grows rapidly. So searchingfor methods of reducing or even eliminating the soybean allergens is on the agenda of foodsafety. This paper is mainly focused on the following aspects: preparing and measuring theanti-soybean allergens polyclonal antibodys by immunizing rabbits with total soybean protein,purified β-conglycinin and glycinin; comparing the efficacy of reducing the soybean allergensby different microorganisms both in liquid state fermentation and solid state fermentation,optimizing the conditions for the better microorganism of solid liquid fermentation or statestate fermentation to get the best soybean allergens reducing rate and finally accessing aminoacids of the fermented soybean meal under optimized conditions. The conclutions of thisresearch are as follows:(1) Using conventional immune to prepare for the anti-soybean allergens polyclonalantibodys by immunizing rabbits with total soybean protein, purified β-conglycinin andglycinin. After purification of polyclonal antibodys by ammonium sulfate, The antibody titeris1:80000of total soybean allergens,1:120000of β-conglycinin,1:240000of glycinin, whenantigen coating concentration is1μg/mL, was determined by indirect ELISA; the crossreacti-vity of antiserum of total soybean protein、β-conglycinin and glycinin to peanut and riceproteins measured by competitive indirect ELISA is low, which revealed that the preparedpolyclonal antibodys are of great specificity.(2) Bacillus subtilis, Bacillus subtilis natto, Lactobacillus casei, Lactobacillus plantarum,Saccharomyces cerevisiae and Aspergillus oryzae M1/M2have significant differences on thedegradation of soybean allergens by liquid fermentation or solid fermentation. SDS-PAGE,Western Blot and ELISA showed that Lactobacillus plantarum can achieve the bestdegradation rate of80.94%for total soybean allergens,91.43%for β-conglycinin and75%forglycinin by liquid fermentation and Aspergillus oryzae M1was the best under solidfermentation, with the degradation rate of87.39%for total soybean allergens,97.41%forβ-conglycinin and80.69%for glycinin.(3) The best liquid fermentation condition of Lactobacillus plantarum was determined bysingle fator experiment and response surface method. The results showed that under thecondition of initial pH6.42,12%soybean meal, fermentation temperature37.2℃, time55.1h，speed80r/min,inocula amount2×108CFU in every50mL system with four layers ofgauze sealing the bottle, the lowest allergens degradation rate of95.22%measured by ELISAcan be achieved. At the same time, the degradation rate of99.41%can be reached forβ-conglycinin and90.73%for glycinin. The total amino acids and free amino acids offermented products were5.8%and6.18times higher than its original.(4) The best solid fermentation condition of Aspergillus oryzae M1was also determinedby single fator experiment and response surface method. The results showed that under thecondition of ratio of material to water1:1, fermentation temperature29.8℃, initial pH6.63,time120h, inocula amount1×108CFU in every10g soybean meal in250mLtriangular flask, the lowest allergens degradation rate of99.02%measured by ELISA can be achieved. At thesame time, the degradation rate of99.01%can be reached for β-conglycinin and99.23%forglycinin. The total amino acids and free amino acids fermented products were7.1%and9.22times higher than its original.