Anti-browning potential in the vineyard

In agro-food industry, the enzymatic browning of plant products represents an important voice of loss not only for the quality point of view but also for the economic value. The main responsible of this problem is polyphenol oxidase or tyrosinase (PPO; EC 1.10.3.1), a copper-containing oxidoreductase that catalyses two different reactions involving phenolic compounds and oxygen and producing brown- or black-coloured compounds. Recently the research of PPO inhibitors from natural sources represents a valid alternative to thermal treatments and traditional additives, such as ascorbic acid and sulfites, that have critical points related not only to organoleptic quality but also to nutrition and health claims. The goal of this study is to test the anti-browning potential of some natural extracts obtained from the vineyard of two grape cultivars (Vitis vinifera cv. Barbera and Merlot) using in vitro and in vivo trials. The Merlot extracts showed the best anti-browning performance as detected by in vitro assays. Moreover, the in vivo trials carried out on fresh-cut Golden delicious apples confirmed a significant reduction in the color change. In brief also vineyard could represent a natural source of anti-browning compounds which are safe, easy to achieve and inexpensive.