Ricci Arianna, Olejar Kenneth J, Parpinello Giuseppina P, Mattioli Alessia U, Teslić Nemanja, Kilmartin Paul A, Versari Andrea
a Department of Agricultural and Food Sciences , University of Bologna , Cesena , Italy.
b School of Chemical Sciences , The University of Auckland , Auckland , New Zealand.
Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2016 Dec;33(12):1761-1774. doi: 10.1080/19440049.2016.1241901. Epub 2016 Oct 24.
Although commercial tannins are widely used in foods and beverages, an improved understanding of the structure and composition of vegetable tannins is needed to promote the exploitation of agri-food by-products and waste and their valorisation in more sustainable industrial applications. This study aims to characterise the phytochemical composition and antioxidant activity of 13 food grade tannins using multiple analytical approaches, including spectrophotometry and HPLC-ECD to determine the amount of targeted polyphenolic compounds. Moreover, the antioxidant activity of tannins was assessed in terms of radical scavenging activity (DPPH• assay), reducing power (FRAP assay), and redox properties (cyclic voltammetry, CV). A statistical univariate and multivariate correlation analysis was performed on 17 parameters including tannin content (range: 0.71-1.62 mM), gallic acid, (+)-catechin, syringic acid and (‒)-epicatechin. The compositional profile of tannins was related to their chemical moiety, antioxidant activity and the botanical origin of the extracts. In particular, the CV signal at 500 mV was highly correlated with DPPH• value due to the catechol ring of flavonoids and trigalloyl moieties of gallic acid-based compounds. Practical examples of tannins application in winemaking are discussed.
尽管商业单宁广泛应用于食品和饮料中，但为了促进农业食品副产品和废弃物的开发利用以及它们在更可持续工业应用中的价值提升，仍需要对植物单宁的结构和组成有更深入的了解。本研究旨在使用多种分析方法，包括分光光度法和高效液相色谱 - 电化学检测法（HPLC - ECD）来测定目标多酚化合物的含量，从而对13种食品级单宁的植物化学成分和抗氧化活性进行表征。此外，还通过自由基清除活性（DPPH• 测定法）、还原能力（FRAP测定法）和氧化还原性质（循环伏安法，CV）来评估单宁的抗氧化活性。对包括单宁含量（范围：0.71 - 1.62 mM）、没食子酸、（+） - 儿茶素、丁香酸和（ - ） - 表儿茶素在内的17个参数进行了统计单变量和多变量相关性分析。单宁的组成特征与其化学部分、抗氧化活性以及提取物的植物来源有关。特别是，由于黄酮类化合物的儿茶酚环和基于没食子酸的化合物的三没食子酰基部分，500 mV处的CV信号与DPPH• 值高度相关。文中还讨论了单宁在酿酒中的实际应用实例。
