P1-34 Development of a Reliable ELISA Kit for the Determination of Soya Protein

Sunday, July 26, 2015
Exhibit Hall (Oregon Convention Center)
Mitsuko Takahashi , Morinaga Institute of Biological Sacience, Inc. , Yokohama , Japan
Yuki Touhata , Morinaga Institute of Biological Sacience , Yokohama , Japan
Masayoshi Tomiki , Morinaga Institute of Biological Science, Inc , Yokohama , Japan
Hirotoshi Doi , Morinaga Institute of Biological Science, Inc , Yokohama , Japan
Masatoshi Sakai , Morinaga Institute of Biological Science, Inc , Yokohama , Japan
Introduction: Soya is widely used in processed foods and it is one of the more common allergic ingredients. For some ELISA kits, it is difficult to evaluate the contamination of soya protein in processed foods.

Purpose: To accurately detect soya protein in processed foods, we developed a reliable ELISA kit and evaluated the performance of this kit.

Methods: A soya protein-specific sandwich ELISA kit was developed using a special extraction solution (patent pending) and polyclonal antibodies against beta-conglycinin. For standard, soya protein was extracted from defatted soya (Enrei) powder with the extraction solution and the protein content was determined by a 2D Quant kit (GE healthcare).

Results: Our kit was able to detect both raw and heat treated soya protein and the recovery was more than 80%. The kit showed no cross-reactivity to other food ingredients such as peanut, wheat, egg, milk, buckwheat and many kinds of nuts (e.g., almond, cashew, pistachio, walnut, pecan, hazelnut), and low cross-reactivity to some kinds of beans. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.156 microgram/g food and 0.31 microgram/g food, respectively. The recovery of soya protein from model processed foods ranged from 77% to 122% and was higher than other commercial kits. The average intra-assay variation (repeatability) was C.V. 1.0% calculated by measuring in three assay on the same day. The inter-assay variation (reproducibility) was C.V. 2.6% calculated by measuring for three days.

Significance: Our ELISA kit is useful and valuable for detecting soya protein in both non-processed and highly processed foods.