College of Food Sciecne and Technology, Nanjing Agricultural University, 1 Weigang Road, Nanjing, Jiangsu Province, P. R. China.
Food Funct. 2018 Apr 25;9(4):2270-2281. doi: 10.1039/C7FO01578J.
This study explored a novel strategy to develop solid-state whole-grain oats as a novel carrier of lactic acid bacteria and a nutraceutical supplement rich in ACE inhibitory peptides. Oats were fermented by Lactobacillus plantarum B1-6, Rhizopus oryzae, or a combination of L. plantarum B1-6 and R. oryzae. L. plantarum showed a much better growth performance in oats when it was combined with R. oryzae than when it was cultured alone, as evidenced by an increase in viable cell count to 9.70 log cfu g-1 after 72 h of fermentation. The coinoculated fermented oats (CFO) and the R. oryzae-fermented oats (RFO) were then selected for investigations on protein hydrolysis and on the functional properties of the released bioactive peptides. The results showed that the soluble protein contents changed from 7.05 mg g-1 to 14.43 and 10.21 mg g-1 for CFO and RFO, respectively. However, the degree of hydrolysis and the content of peptides with molecular masses less than 10 000 Da indicated that the CFO proteins can be degraded to a greater degree. As analyzed by electrophoresis and reversed-phase high-performance liquid chromatography, the protein and peptide profiles of CFO and RFO demonstrated that the proteins from CFO were more obviously hydrolyzed and more small peptides were obtained. In addition, both CFO and RFO presented higher ACE inhibitory activities than unfermented oats, whereas the protein extracts from CFO exerted a lower IC50 value of 0.42 mg protein per mL compared with the protein extracts from the other samples. This research has broadened our knowledge on the development of whole-grain oat products as a probiotic carrier and on the difference between mixed solid-state fermentation (SSF) and fungi SSF in terms of protein degradation and the capacity to release ACE inhibitory peptides. Our approach could be used to obtain probiotic food products and probably to develop oats as a potential therapeutic ingredient targeting hypertension.
本研究探索了一种新策略，即将整粒燕麦开发为新型乳酸菌载体和富含 ACE 抑制肽的营养补充剂。通过植物乳杆菌 B1-6、米根霉或植物乳杆菌 B1-6 和米根霉的组合发酵燕麦。与单独培养相比，当植物乳杆菌与米根霉组合时，在燕麦中的生长表现更好，发酵 72 小时后活菌数增加到 9.70 log cfu g-1。然后选择共接种发酵燕麦（CFO）和米根霉发酵燕麦（RFO）进行蛋白质水解和释放生物活性肽的功能特性研究。结果表明，可溶性蛋白含量分别从 7.05 mg g-1增加到 14.43 和 10.21 mg g-1。然而，水解度和分子量小于 10000 Da 的肽含量表明 CFO 蛋白可以被更大程度地降解。电泳和反相高效液相色谱分析表明，CFO 和 RFO 的蛋白质和肽谱表明，CFO 的蛋白质被更明显地水解，得到更多的小肽。此外，CFO 和 RFO 均表现出比未发酵燕麦更高的 ACE 抑制活性，而 CFO 的蛋白质提取物的 IC50 值为 0.42 mg 蛋白质/mL，低于其他样品的蛋白质提取物。本研究拓宽了我们对整粒燕麦产品作为益生菌载体的开发以及混合固态发酵（SSF）和真菌固态发酵在蛋白质降解和释放 ACE 抑制肽能力方面的差异的认识。我们的方法可用于获得益生菌食品产品，并可能开发燕麦作为针对高血压的潜在治疗成分。
