In this study, the effect of solvent type and solvent concentration on the ultrasound assisted extraction (UAE) of polyphenols from popular tea samples (black, green, mate, blackberry and black mulberry) which have high antioxidant activities were investigated by chemometric approaches. For this purpose, green extraction method was preferred and hydroalcoholic solvents for applied this system in industry. Water, MeOH 100%, MeOH 75%, MeOH 50%, EtOH 100%, EtOH 75%, EtOH 50% were used as extraction solvent. Multivariate calibration analytical technique preferred for quantification of individual phenolic compounds in tea samples and the relationship between total phenolic content (TPC), total flavonoid content (TFC) and total antioxidant activity (TAA) and individual phenolics was determined by chemometric approaches. The results of the study suggest that only spectroscopic comparisons based on TPC, TFC and TAA correlations are insufficient or even incorrect, and this is due to the fact that in tea samples different molecules besides different flavonoid structures are sensitive to spectroscopic techniques. The determination of the appropriate type and the concentration of solvent would contribute the usage of the herbal plants as a source of natural antioxidants in foods and pharmacology in large-scale industrial applications.

中文翻译：

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化学计量法测定各种提取溶剂对茶样品中多酚谱和抗氧化活性的影响

在这项研究中，通过化学计量方法研究了溶剂类型和溶剂浓度对超声波辅助提取具有高抗氧化活性的流行茶样品（黑茶，绿茶，马黛茶，黑莓和黑桑树）中多酚的影响。为此，首选绿色萃取方法，并将水醇溶剂用于该系统的工业应用。将水，100％MeOH，75％MeOH，50％MeOH，100％EtOH，75％EtOH，50％EtOH用作萃取溶剂。多变量校准分析技术可用于定量茶叶样品中的单个酚类化合物，并通过化学计量学方法确定总酚含量（TPC），总黄酮含量（TFC）和总抗氧化剂活性（TAA）与单个酚之间的关系。研究结果表明，仅基于TPC，TFC和TAA相关性的光谱比较是不充分的，甚至是不正确的，这是由于以下事实：在茶样品中，除了不同的类黄酮结构以外，其他分子对光谱技术也很敏感。确定合适的类型和溶剂浓度将有助于在大规模工业应用中将草药植物用作食品和药理学中天然抗氧化剂的来源。