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Allergenicity Assessment of Genetically Engineered (GE) Crops, GE Food Ingredients, and Non-Thermal Processed Soy Products
Abstract
A new food crop or food ingredient derived from a genetically engineered (GE) organism must undergo safety assessment including allergenicity assessment prior to its release into the market. This thesis included two studies using bioinformatics methodology combined with literature review of the history of safe use of transgenic proteins, the gene donor, and the gene recipient. One study evaluated the risk of a GE banana inserted with two genes from Capsicum annuum, and the other evaluated the risk of soybean hemoglobin (LegHb) expressed in Pichia Pastoris. The LegHb also underwent in vitro pepsin digestion to evaluate its stability. There were 17 Pichia proteins existing in the product that also went through the bioinformatics analysis and the digestion assay. A third study included comparison of IgE binding from soybean allergic patients to proteins in a GE soybean line, a control near isogenic soybean line, and four other non-genetically modified commercial soybean lines. All three studies demonstrated that the GE crops and GE ingredients did not pose any additional allergenic risk compared to each non-GE counterparts. Soybean allergy affects less than 0.5% of general population worldwide. A number of soybean proteins have been proposed as allergens with or without clinical evidence. Among them, Gly m 5 and Gly m 6 are the two most important allergens in soybean. We investigated the effect of several non-thermal processing methods on the allergenicity of soybean proteins. The potential allergencity of fermented soybean (natto) and soymilk (soy yogurt) was decreased as supported by reduction in both IgE reactivity and mediator release capacity using sera from soybean allergic patients. High pressure processed (HPP) soybean did not bind less IgE or cause lower mediator release in all soy-allergic patients. A HPP treatment applied to germinated soybean rendered proteins that bound less IgE for some patients, but showed higher amount of IgE binding in some others. In addition, our work demonstrated that HPP changed the digestive stability of the β subunit of Gly m 5, the only pepsin-stable subunit of Gly m 5 and Gly m 6, and made the major soy allergens rapidly digested upon exposure to pepsin.
Subject Area
Food Science
Recommended Citation
Jin, Yuan, "Allergenicity Assessment of Genetically Engineered (GE) Crops, GE Food Ingredients, and Non-Thermal Processed Soy Products" (2017). ETD collection for University of Nebraska-Lincoln. AAI10683589.
https://digitalcommons.unl.edu/dissertations/AAI10683589