Extraction of Soybean Protein Isolate Using Multi-stage Countercurrent Solid-Liquid Extraction Method

Release behavior of proteins in soybean meal during their extraction process using high performance liquid chromatography-mass spectrometry was investigated.The possibility for extraction of soybean protein isolate using multi-stage countercurrent solid-liquid extraction(MSCSLE) was also studied.The result indicated that 2S protein showed a higher release rate and more than 80% of total 2S proteins were released after extraction in two times.The total release rate of 7S and 11S proteins reached 69% after three times of extraction,indicating that 7S and 11S fractions had a lower release rate during extraction process.Increasing the concentration gradient between the solid and liquid or extending the extraction time enhanced the release of 7S and 11S fractions.The concentration of total proteins obtained using MSCSLE was higher than that obtained by multi-time extraction,resulting in higher 7S and 11S recovery rate.Under the same recovery rate of soybean protein isolate,11% of water could be saved.During precipitation,8% of total 7S and 11S protein could be recovered.