Ascorbic Acid Treatments Reduce Physiological Browning Disorder in Flavedo Tissue Discs of Citrus Hassaku and Tangor 'Kiyomi' Fruits

Studies on Vitamin C of Fruits and Vegetables-Part IX

Abstract

The roles of phenols and L-ascorbic acid (AsA) in the development of peel browning disorder in Hassaku (Citrus hassaku Hort. ex Tanaka) and tangor 'Kiyomi' (Citrus sinensis×C. tangerina) fruits were investigated. Flavedo tissue (colored portion of peel) discs that were prepared from Hassaku and 'Kiyomi' fruits were incubated in phosphate buffer (pH 6.4) containing different types of phenolic compounds (10^-2 M) at 20°C for 25 and 20 h, respectively. Brown discoloration was noted most severely with flavedo tissue discs incubated with pyrogallol in both Hassaku and 'Kiyomi' fruits. AsA and dehydroascorbic acid (DHA) contents in the flavedo tissue decreased markedly during incubation. Flavedo tissue discs treated with 1% and 1.5% AsA solution showed no browning when incubated with pyrogallol.