Tea from organic production has higher functional quality characteristics compared with tea from conventional management systems in China

Abstract

Organic tea production has increased in China over the past decade because of the perceived higher quality of the tea as well as the benefits for environmental and human wellbeing. The present study compared the functional quality components of tea harvested from organic and conventional management systems in adjacent fields within the same farms at six sites in eastern China. Findings demonstrated that water extracts of organic tea had significantly higher concentrations of key catechins linked to tea quality, including epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG) and epicatechin (EC), compared to that of conventional tea. Concentrations of proline and γ-aminobutyric acid were also statistically higher in organic tea from some sites. However, most of free amino acids, particularly theanine, were lower in organic tea. The findings indicated that the tea in organic systems were under greater environmental stress than the tea in the conventional system, as accumulation of catechins and proline in plants is associated with environmental stress. The lower concentrations of amino acids in organic tea indicated potential nitrogen deficiencies and the need for managing soil nitrogen to increase overall amino acid levels while still managing for high levels of polyphenols. The higher concentrations of antioxidant compounds in organic tea suggested potentially greater health benefits, as these compounds are linked to disease mitigation and health promotion in human consumers. Overall, this study showed improved quality characteristics of organically produced tea whilst also highlighting agro-ecosystem techniques to further enhance the functional quality characteristics of organic tea on the basis of amino acid profiles.