Division of Basic Medical Sciences, Department of Nursing, Chang Gung University of Science and Technology, Chiayi, Taiwan.
Chang Gung Memorial Hospital, Chiayi, Taiwan.
PLoS One. 2021 May 11;16(5):e0249250. doi: 10.1371/journal.pone.0249250. eCollection 2021.
In this study, different probiotics commonly used to produce fermented dairy products were inoculated independently for Chenopodium formosanum Koidz. fermentation. The strain with the highest level of antioxidant activity was selected and the fermentation process was further optimized via response surface methodology (RSM). Lactobacillus plantarum BCRC 11697 was chosen because, compared to other lactic acid bacteria, it exhibits increased free radical scavenging ability and can produce more phenolic compounds, DPPH (from 72.6% to 93.2%), and ABTS (from 64.2% to 76.9%). Using RSM, we further optimize the fermentation protocol of BCRC 11697 by adjusting the initial fermentation pH, agitation speed, and temperature to reach the highest level of antioxidant activity (73.5% of DPPH and 93.8% of ABTS). The optimal protocol (pH 5.55, 104 rpm, and 24.4°C) resulted in a significant increase in the amount of phenolic compounds as well as the DPPH and ABTS free radical scavenging ability of BCRC 11697 products. The IC50 of the DPPH and ABTS free radical scavenging ability were 0.33 and 2.35 mg/mL, respectively, and both protease and tannase activity increased after RSM. An increase in lower molecular weight (<24 kDa) protein hydrolysates was also observed. Results indicated that djulis fermented by L. plantarum can be a powerful source of natural antioxidants for preventing free radical-initiated diseases.
在这项研究中，不同的益生菌常用于发酵乳制品的生产，独立接种于台湾土荆芥的发酵。选择抗氧化活性最高的菌株，并通过响应面法（RSM）进一步优化发酵工艺。选择植物乳杆菌 BCRC 11697，因为与其他乳酸菌相比，它具有更高的自由基清除能力，并能产生更多的酚类化合物，DPPH（从 72.6%到 93.2%）和 ABTS（从 64.2%到 76.9%）。通过 RSM，我们通过调整初始发酵 pH 值、搅拌速度和温度进一步优化 BCRC 11697 的发酵方案，以达到最高的抗氧化活性水平（DPPH 为 73.5%，ABTS 为 93.8%）。最佳方案（pH 5.55、104 rpm 和 24.4°C）显著增加了酚类化合物的含量，以及 BCRC 11697 产物的 DPPH 和 ABTS 自由基清除能力。DPPH 和 ABTS 自由基清除能力的 IC50 分别为 0.33 和 2.35 mg/mL，并且 RSM 后蛋白酶和单宁酶活性均增加。还观察到低分子量（<24 kDa）蛋白水解产物的增加。结果表明，植物乳杆菌发酵的土荆芥可以成为预防自由基引发疾病的天然抗氧化剂的有力来源。
