Purification, characterisation, and quantification of the soy allergen profilin (Gly m 3) in soy products

Profilins are pan-allergen proteins present in various plant foods and pollens. The objective was to develop a method for purification and characterisation of profilin from soy protein isolate. Furthermore, profilin was quantified in soy products and the effect of processing evaluated. Profilin was purified using poly-l-proline affinity chromatography, dialysis and ultrafiltration, and its quantification was implemented by indirect ELISA. Profilin in soymilks ranged from 4.37 ± 0.14 to 7.24 ± 0.30 mg/g protein, while in fermented products profilin ranged from 1.67 ± 0.02 to 5.47 ± 0.02 mg/g protein. Pasteurisation of soymilk was an ineffective method to completely eliminate profilin. Food matrix influenced thermal stability; at 100 °C, β-sheet and random coil structures were altered, while the α-helices remained intact. Induced fermentation of soybean meal by Bifidobacterium lactic, Lactobacillus plantarum and Saccharomyces cerevisiae resulted in 68.3% to 72.7% reduction of soy profilin. Heat treatment, fermentation and hydrolysis effectively reduced soy profilin.