Pihurov Marina, Păcularu-Burada Bogdan, Cotârleț Mihaela, Bahrim Gabriela Elena
Faculty of Food Science and Engineering, Dunarea de Jos University of Galati, Domneasca Street No. 111, 800201 Galati, Romania.
Foods. 2022 Oct 6;11(19):3107. doi: 10.3390/foods11193107.
Kombucha culture (named SCOBY-Symbiotic Culture of Bacteria and Yeasts) and milk kefir grains represent multiple consortia of wild microorganisms that include lactic acid bacteria, acetic acid bacteria and yeasts with valuable functional properties. Their fermentative potential provides a wide range of derivate metabiotics (prebiotics, probiotics, postbiotics and paraprobiotics) with valuable in vitro and in vivo benefits. This study targeted the evaluation of the functionality of a co-culture of SCOBY-based membranes and milk kefir grains, used as freeze-dried starter cultures, for the fermentation of a newly formulated medium based on black tea infusion, supplemented with bovine colostrum and sugar, in order to produce bioactive compounds with functional properties. The design and optimization of the biotechnological process were achieved by using the Plackett-Burman experimental design (six factorial points, three center points) and the response surface methodology and central composite design (three factorial points, six axial points and two center points in axial) tools. The statistical analysis and the mathematical modelling of the responses such as the pH, titratable acidity, antioxidant activity and antimicrobial activity (against , , and ) were investigated. Further, the composition of organic acids, polyphenols and flavonoids of the fermented product obtained under the optimized fermentation conditions was also analyzed. The fermentation of the medium containing 6.27% (/) bovine colostrum powder, 1.64% (/) black tea, 7.5% (/) sugar, pH 6.7, with an inoculum based of 0.36% (/) milk kefir grains powder and 0.5% (/) SCOBY-based membrane (both as freeze-dried culture), at 30 °C, for 5 days, in an aerobic stationary system, revealed an antifungal activity between 80 and 100% against , an antibacterial activity of 8-22 mm against and spp. And a titratable acidity of 445 °Th. The chemical composition of the obtained product had a positive impact on the functional properties of the fermented products in terms of the antimicrobial and antioxidant properties.
康普茶培养物（名为SCOBY——细菌和酵母共生培养物）和牛奶开菲尔粒代表了多种野生微生物群落，其中包括具有宝贵功能特性的乳酸菌、醋酸菌和酵母。它们的发酵潜力产生了多种具有宝贵体外和体内益处的衍生代谢生物（益生元、益生菌、后生元和准益生菌）。本研究旨在评估用作冻干发酵剂的基于SCOBY的膜和牛奶开菲尔粒的共培养物对一种新配制的基于红茶浸液、添加牛初乳和糖的培养基进行发酵的功能，以便生产具有功能特性的生物活性化合物。通过使用Plackett-Burman实验设计（六个因子点、三个中心点）以及响应面方法和中心复合设计（三个因子点、六个轴向点和两个轴向中心点）工具实现了生物技术过程的设计和优化。研究了诸如pH值、可滴定酸度、抗氧化活性和抗菌活性（针对 、 、 和 ）等响应的统计分析和数学建模。此外，还分析了在优化发酵条件下获得的发酵产物中有机酸、多酚和黄酮类化合物的组成。在有氧静态系统中，于30℃下，使用基于0.36%（/）牛奶开菲尔粒粉末和0.5%（/）基于SCOBY的膜（均为冻干培养物）的接种物，对含有6.27%（/）牛初乳粉、1.64%（/）红茶、7.5%（/）糖、pH值为6.7的培养基进行5天发酵，结果显示对 的抗真菌活性在80%至100%之间，对 和 菌的抗菌活性为8 - 22毫米，可滴定酸度为445°Th。就抗菌和抗氧化特性而言，所得产物的化学成分对发酵产物的功能特性产生了积极影响。
