TÜBİTAK Marmara Research Center, Food Institute , Gebze-Kocaeli, Turkey.
J Agric Food Chem. 2013 Aug 7;61(31):7529-36. doi: 10.1021/jf4015137. Epub 2013 Jul 23.
Two types of instant teas produced from low- and high-quality black teas were examined for their proximate composition, dietary fiber, minerals, water-soluble vitamins, total phenolic content, various antioxidant assays, phenolics (flavanols, condensed phenolics, and phenolic acids), alkaloids, and carotenoids as well as taste-active compounds (sugars, organic acids, and free amino acids). Some variations, albeit to different extents, were observed (p < 0.05) among these parameters between instant teas produced from low- and high-quality black teas. With respect to proximate composition, carbohydrate was the predominant component (56.68-59.84 g/100 g), followed by protein (19.31-19.86 g/100 g). Ash, moisture, and, to a lesser extent, dietary fiber and fat were also present in both instant teas. Thirteen minerals, four water-soluble vitamins, six flavanols, two alkaloids, three condensed phenolics, one phenolic acid, and one carotenoid were identified. Total phenolic content varied between 17.35 and 17.82 g of gallic acid equivalents (GAE)/100 g instant tea. With regard to antioxidant activities, three different assays such as oxygen radical absorbance capacity (ORAC), trolox equivalent antioxidant capacity (TEAC), and cupric ion reducing antioxidant capacity (CUPRAC) were measured. No significant differences (p > 0.05) in total phenolic, ORAC, TEAC, and CUPRAC contents between low- and high-quality instant teas were observed. With regard to taste-active compounds, 3 sugars, 5 organic acids, and 18 free amino acids were positively identified, of which fructose, tannic acid, and theanine predominated, respectively. The present work suggests that despite some differences, instant teas produced from low- and high-quality black teas should not be distinguished on the basis of their compositional, nutritional, and functional characteristics as well as taste-active compounds.
两种由低质和高质红茶制成的速溶茶，其成分分析如下：包括其近似成分、膳食纤维、矿物质、水溶性维生素、总酚含量、各种抗氧化测定、酚类（黄烷醇、缩合酚和酚酸）、生物碱和类胡萝卜素以及呈味活性化合物（糖、有机酸和游离氨基酸）。尽管程度不同，但在这些参数中，低质和高质红茶制成的速溶茶之间存在一些差异（p < 0.05）。就近似成分而言，碳水化合物是主要成分（56.68-59.84 g/100 g），其次是蛋白质（19.31-19.86 g/100 g）。灰分、水分，以及膳食纤维和脂肪也存在于两种速溶茶中。鉴定出 13 种矿物质、4 种水溶性维生素、6 种黄烷醇、2 种生物碱、3 种缩合酚、1 种酚酸和 1 种类胡萝卜素。总酚含量在 17.35 至 17.82 g 没食子酸当量（GAE）/100 g 速溶茶之间变化。关于抗氧化活性，使用了三种不同的测定方法，如氧自由基吸收能力（ORAC）、Trolox 当量抗氧化能力（TEAC）和铜离子还原抗氧化能力（CUPRAC）。在低质和高质速溶茶之间，总酚、ORAC、TEAC 和 CUPRAC 含量没有显著差异（p > 0.05）。关于呈味活性化合物，共鉴定出 3 种糖、5 种有机酸和 18 种游离氨基酸，其中果糖、鞣酸和茶氨酸分别占主导地位。本研究表明，尽管存在一些差异，但低质和高质红茶制成的速溶茶不应该因其组成、营养和功能特性以及呈味活性化合物而有所区别。
