[4-1330-D] Food Quality (2)

[4-1330-D-01] Reducing Allergenicity of Soy Protein Isolate from Local Varieties of Soybean through Glycation with Lactose

*Nurheni Sri PALUPI^1,2, Endang Prangdimurti^1,2, Didah Nur Faridah^1,2, Muhammad Hasriandy Asyhari³ (1. Department of Food Science and Technology, Faculty of Agricultural Engineering and Technology, Bogor Agricultural University(Indonesia), 2. Southeast Asian Food and Agricultural Science and Technology (SEAFAST) Center, Bogor Agricultural University(Indonesia), 3. Food Science Graduate Program, Graduate School, Bogor Agricultural University(Indonesia))

Keywords:Allergenicity, Enzyme-Linked Immunosorbent Assay (ELISA), Glycation degree, Soy protein isolate (SPI), SPI-lactose conjugate

Food allergy is a specific immunological response caused by allergens contained in food. Soybean is one of the eight type of food products that often cause allergies that can reduce its quality in term of safety aspect. The soybean processing can reduce the risk of allergies by modifying the structure of the soy protein so as to produce hypoallergenic food. Processing involving the Maillard reaction by conjugating proteins with reducing sugars has the potential to reduce allergenicity. This research aims to: (1) determine the degree of glycation based on the formation of soy protein isolates (SPI)-lactose conjugate and free amino acid; (2) determine the molecular weight profile of SPI and SPI-lactose conjugate: and (3) analyze the allergenicity of SPI-lactose conjugate compared to SPI. Protein isolation was carried out by precipitation of soybean protein of Anjasmoro and Grobogan varieties at their isoelectric point by pH arrangement. Then the SPI was reacted with lactose under pH 9.5 and 95°C for 60 minutes. Determination of glycation degree of SPI-lactose conjugate was carried out using two methods, namely thiobarbituric acid reactive substances (TBARS) method and Bradford method for free amino acid. The protein molecular weight profile was analyzed using the SDS-PAGE electrophoresis method. Alergenicity of SPI and SPI-lactose conjugate were analyzed quantitatively using the Enzyme-Linked Immunosorbent Assay (ELISA) method. The results showed that the higher protein content in SPI cause higher glycation degree of the SPI-lactose conjugate. SDS-PAGE electrophoresis results showed that the molecular weight profiles of Anjasmoro and Grobogan SPI were 11.3-144.2 kDa and 10.7-159.0 kDa. The glycation process can eliminate or reduce the intensity of protein bands that are suspected to be the major allergen proteins in soybeans, namely Gly m Bd 60K, Gly m Bd 30K or P34, and Gly m Bd 28K. The glycation reaction can reduce allergenicity in local varieties soybeans (Anjasmoro and Grobogan) by 43.12% and 29.85%.