Antimicrobial and antioxidant effects of phlorotannin coating in spoilage prevention of tomato during storage

Abstract

The microbial flora present on vegetables and fruit is commercially significant as they cause spoilage and potential health risks in consumers. Synthetic chemicals used to combat food microbes posed serious health and environmental hazards leading to the search for natural alternatives. In this study, phlorotannins from three Indian brown seaweeds, Sargassum myriocystum, Turbinariaornata, and Padina tetrastromatica were evaluated for antimicrobial, antioxidant, and fruit spoilage prevention potentials. The crude phlorotannin of Padina with the highest content (0.114±0.0005g kg-1) and antioxidant activity (92.65±3.43%) was purified by column chromatography. The Padina water fraction I with the highest antioxidant potential was characterized by Fourier Transform Infra-Red spectroscopy and a 5 % solution was applied as a coating on tomatoes segregated into control chilled (CC), treated chilled (TC), control non-chilled (CNC) and treated non chilled (TNC). Spoilage parameters were studied over twenty days, using a swab and spread plate methods to assess the microbial load on tomatoes. Compared to the control sets, the treated sets exhibited a low number of microbial colonies and retained a fresh look and yellow color. The antibacterial and antioxidant properties of phlorotannin coating as a natural alternative for preservatives, effectively reduced bacterial load, inhibiting the early decay of tomatoes