Detection and Quantification of Soy Allergens in Food: Study of Two Commercial Enzyme-Linked Immunosorbent Assays



ABSTRACT:  The objective of this study was to evaluate the efficacy of 2 commercially available soy enzyme-linked immunosorbent assays (ELISA) and use them in detecting soy proteins in selected food commodities. Both ELISA kits exhibited high sensitivity. The determined limits of detection (LOD) (approximately 2 and <1 μg/mL for Tepnel Biosystems and Elisa Systems kits, respectively) were lower than those claimed by the manufacturer. Quantification range for both kits was, however, narrower and in a lower concentration range than defined by the kit providers. Our examination revealed a positive cross-reactivity with chickpea proteins and matrix interferences for both kits. The immunoreactivity of soy proteins, when tested by the Tepnel Biosystems kit, was partially reduced by papain and bromelain hydrolysis; it was significantly decreased by protein glycation (>47%). Nondenatured and nonheated soy protein isolate (SPI) samples were also significantly less antigenic than the treated ones.