| Soybean has been recognized as one of the important protein sources in the field of food processing because of its nutritional and functional benefits. However, soybean contains allergenic proteins. For patients allergic to soybean, the risk of the soybean-allergic individuals is increasing due to its extended application. The thesis mainly focused on four aspects: the identification of soybean allergens, the influence of processing and Glycan moiety of allergic protein on allergencity, the ways to remove allergen from soybean and the processing properties of soybean protein removed allergens. The research conclusions are as following:It was found that it was possible to produce new allergens on different varieties and the identified bands from different individuals were different. Ten allergic bands including almost all proteins of soybean except acid chain of glycinin were identified in the experiment. Lipoxygenase was the most powerful allergen and 100% individuals reacted with it. The secondary was a-subunit of P-conglycinin, However, a'-subunit β-subunit, 60 kDa, 32.5 kDa 30/28 kDa 18.9kDa and 14 kDa had the same probability to induce allergy. After studying the commercial soybean products, it was found that ferment ed soybean products did not induce allergy, the a-subunit of p-conglycinin in non-ferment soybean products was easy to be identified and 18.9 kDa allergic protein of texturized soybean products would lose the allergic activity.After studing the influence of treatment to the allegic protein based on the variety of Kefeng 6, the conclusions were: lipoxygenase, a-subunit of p-conglycinin was instable with heat and ethanol, 32.5 kDa was stable with heat and ethanol and 28 kDa was only instable with ethanol. Thermal denature could decrease 14.2% allergencity and ethanol denautre could decrease 25.3% allergencity; while high voltage electrostatic field only decreased 3.2%. Saline extraction with adjusting pH could be effective to eliminate 32.5 kDa and 28 kDa, but the allergencity only decreased 25% due to a-subunit remained in 3-conglycinin, whose effect was identical to ethanol treatment. The allergencity could decrease 80% when 0.5% (E/S, WAV) pepsin on 10% (WAV) soybean protein 1 hr at 37°C, and the hydrolyzed protein could not binding to IgE from soybean sensitive patients.There was no difference on allergencity before and after deglycosylating 7S globulin. Thus Glycanmoiety is not a critical group to allergy.The method to separate 7S and 11S, and then a-subunit of P-conglycinin be hydrolyzed was established according to the protein hydrolysis characteristic. 0.03 M phosphate buffer was used to separate 7S from IIS and pH was adjusted to 6.3-6.4. The allergencity of the 1 IS was much lower. Taking 5% 7S globulin as substrate, adding 0.5% (E/S, WAV) pepsin at 37°C for 2 hr, a-subunit of P-conglycinin could be eliminated efficiently and the antigen titer was decreased to 86.4%.Experiments of processing properties showed the solubility of 7S increased after removal of allergen from 7S, emulsifying activity and emulsifying stability were the same as SPI, but foam formation capacity and foaming stability were decreased. Hardness experiment of GDL gel showed that peptide (removal of a-subunit by enzyme hydrolysis 7S) had a special effect during the processing. The gel hardness had no linear relationship with the ratio of 11S/7S. The gel hardness was the highest when adding 8% 7S peptide to US, but decreased dramatically after exceeding this concentration. Compared with SPI, the gel hardness was also higher than SPI even adding 15% 7S peptide to US. It could be concluded that 1 IS was the critical factor to cohesiveness. Chew experiment showed that chewiness was almost the same as 11S when adding 8% 7S peptide to US, and chewiness was higher than SPI when adding 15% 7S peptide to 11S.
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