Department of Agricultural Technology, Faculty of Science and Arts, Burapha University, Chanthaburi Campus, Chanthaburi, Thailand.
Department of Food Science and Technology, Faculty of Agricultural Innovation and Technology, Rajamangala University of Technology Isan, Nakhon Ratchasima, Thailand.
PeerJ. 2024 Sep 26;12:e18116. doi: 10.7717/peerj.18116. eCollection 2024.
Kombucha is traditionally a non-alcoholic beverage whose production is dependent on culture and the various ingredients used as substrates for fermentation. The goal of our study was to apply hemp leaf and milky mushroom () flour as functional ingredients to enhance phytonutrient quality, along with using a microbial consortium highly symbiotic with these ingredients. The study determined the content of phytonutrients (phenolic and flavonoids content), antioxidant activity through percentage inhibition of DPPH radical scavenging activity (%), and microbial communities changes during fermentation. The microbial changes were evaluated by cell viable count (total bacteria, Lactic Acid Bacteria, and Yeast & Mold) and ITS in prepared kombucha (using red tea leaves, pandan leaves, and sucrose) supplemented with functional ingredients: T1 (hemp leaves (control)) and T2 (hemp leaves with milky mushroom flour). The results indicated that microbial consortium changed during fermentation. In the first 7 days, the levels of yeast and mold increased to 6.17 and 6.18 log CFU/mL, respectively. By day 21, the levels of both T1 and T2 continued to rise, reaching 7.78 and 7.82 log CFU/mL, respectively. The viable count of lactic acid bacteria in T1 and T2 gradually increased to 6.79 and 6.70 log CFU/mL, respectively, by day 14. These changes resulted in a marked decrease in pH value, reaching 3.63 and 3.23 in T1 and T2, respectively, by the end of the process (21 days). The total bacterial viable count decreased with an increase in the fermentation time. During fermentation, unique genera of tea fungus observed in T1 and T2 were 64% and 19%, respectively. At the beginning (0 days), the top five genera found in T1 were: (25.91%), (14.88%), (7.81%), (7.12%), (6.63%), while the top five genera in T2 were (94.55%), (1.87%), (0.77%), (0.40%), (0.38%). However, on day 21 (end of the process), it was found that had the highest relative abundance in both T1 and T2. In addition, the supplementation of the two ingredients affected the total phenolic and total flavonoid content of the treatments. At the end of the process, T2 showed values of 155.91 mg GAE/mL for total phenolics and 1.01 mg CE/mL for total flavonoids, compared to T1, which had 129.52 mg GAE/mL and 0.69 mg CE/mL, respectively. Additionally, the DPPH inhibition was higher in T1 (91.95%) compared to T2 (91.03%). The findings suggest that kombucha fermented with these innovative ingredients exhibited enhanced phytonutrients, and served as substrate for LAB and tea fungus fermentation, while limiting the growth of fungal genera and diversity of microbial consortium.
康普茶传统上是一种无酒精饮料，其生产依赖于文化和用作发酵基质的各种成分。我们的研究目的是应用大麻叶和牛奶蘑菇（）粉作为功能性成分，以提高植物营养素的质量，并使用与这些成分高度共生的微生物联合体。该研究测定了植物营养素（酚类和类黄酮含量）的含量、通过 DPPH 自由基清除活性抑制百分比（%）测定的抗氧化活性，以及发酵过程中微生物群落的变化。微生物变化通过细胞活菌计数（总细菌、乳酸菌和酵母和霉菌）和制备康普茶中的 ITS 进行评估（使用红茶、斑兰叶和蔗糖），补充功能性成分：T1（大麻叶（对照））和 T2（大麻叶与牛奶蘑菇粉）。结果表明，微生物联合体在发酵过程中发生了变化。在第 7 天之前，酵母和霉菌的水平分别增加到 6.17 和 6.18 log CFU/mL。到第 21 天，T1 和 T2 的水平继续上升，分别达到 7.78 和 7.82 log CFU/mL。T1 和 T2 中的乳酸菌活菌计数分别在第 14 天逐渐增加到 6.79 和 6.70 log CFU/mL。这些变化导致 pH 值明显下降，T1 和 T2 分别达到 3.63 和 3.23，在过程结束（第 21 天）时。总细菌活菌计数随着发酵时间的增加而减少。在发酵过程中，在 T1 和 T2 中观察到的茶菌特有属分别为 64%和 19%。在开始（0 天）时，T1 中发现的前 5 个属是：（25.91%）、（14.88%）、（7.81%）、（7.12%）、（6.63%），而 T2 中的前 5 个属是（94.55%）、（1.87%）、（0.77%）、（0.40%）、（0.38%）。然而，在第 21 天（过程结束时），发现两种处理中都以属的相对丰度最高。此外，两种成分的补充影响了处理的总酚和总类黄酮含量。在过程结束时，T2 显示总酚含量为 155.91 mg GAE/mL，总类黄酮含量为 1.01 mg CE/mL，而 T1 分别为 129.52 mg GAE/mL 和 0.69 mg CE/mL。此外，T1 的 DPPH 抑制率（91.95%）高于 T2（91.03%）。研究结果表明，用这些创新成分发酵的康普茶表现出增强的植物营养素，并作为 LAB 和茶菌发酵的基质，同时限制真菌属的生长和微生物联合体的多样性。
