Hsiao Yu-Hsuan, Hsia Sheng-Yang, Chan Yin-Ching, Hsieh Jung-Feng
Ph.D. Program in Nutrition & Food Science, Fu Jen Catholic University, Taipei 24205, Taiwan.
Department of Food Science, Fu Jen Catholic University, Taipei 24205, Taiwan.
Molecules. 2017 Jun 20;22(6):1022. doi: 10.3390/molecules22061022.
In this study, the chitosan-induced coacervation of soy protein-isoflavone complexes in soymilk was investigated. Most of the soymilk proteins, including β-conglycinin (7S), glycinin (11S), and isoflavones, were found to coacervate into the soymilk pellet fraction (SPF) following the addition of 0.5% chitosan. The total protein in the soymilk supernatant fraction (SSF) decreased from 18.1 ± 0.3 mg/mL to 1.6 ± 0.1 mg/mL, and the pH values decreased slightly, from 6.6 ± 0.0 to 6.0 ± 0.0. The results of SDS-PAGE revealed that the 7S α', 7S α, 7S β, 11S A3, and 11S acidic subunits, as well as the 11S basic proteins in the SSF, decreased to 0.7 ± 0.5%, 0.2 ± 0.1%, 0.1 ± 0.0%, 0.2 ± 0.2%, 0.2 ± 0.2% and 0.3 ± 0.2%, respectively. We also found that isoflavones in the SSF, including daidzein, glycitein, and genistein, decreased to 9.6 ± 2.3%, 5.7 ± 0.9% and 5.9 ± 1.5%, respectively. HPLC analysis indicated that isoflavones mixed with soy proteins formed soy protein-isoflavone complexes and were precipitated into the SPF by 0.5% chitosan.
在本研究中，对壳聚糖诱导豆浆中大豆蛋白 - 异黄酮复合物的凝聚进行了研究。发现加入0.5%壳聚糖后，豆浆中的大部分蛋白质，包括β-伴大豆球蛋白（7S）、大豆球蛋白（11S）和异黄酮，凝聚到豆浆沉淀部分（SPF）中。豆浆上清部分（SSF）中的总蛋白从18.1±0.3 mg/mL降至1.6±0.1 mg/mL，pH值略有下降，从6.6±0.0降至6.0±0.0。SDS - PAGE结果显示，SSF中的7Sα'、7Sα、7Sβ、11S A3和11S酸性亚基以及11S碱性蛋白分别降至0.7±0.5%、0.2±0.1%、0.1±0.0%、0.2±0.2%、0.2±0.2%和0.3±0.2%。我们还发现，SSF中的异黄酮，包括大豆苷元、染料木素和黄豆黄素，分别降至9.6±2.3%、5.7±0.9%和5.9±1.5%。HPLC分析表明，与大豆蛋白混合的异黄酮形成了大豆蛋白 - 异黄酮复合物，并被0.5%的壳聚糖沉淀到SPF中。
