Peel colour and flesh phenolic compounds at ripening stages in pollinated commercial varieties of fig (Ficus carica L.) fruit grown in Southern Europe

Abstract

Fig fruit phenolics are beneficial to human health and contribute to attractiveness by consumers. Phenolic compounds, total carotenoids (TCAR) and total antioxidant capacity (TAC) in the flesh and chlorophylls, anthocyanins and colour in the peel were determined during ripening stages of pollinated ‘Mission’, ‘Vasilika’ and ‘Mavra Markopoulou’ (‘MM’) figs. The two latter stages studied, S3 and S4, corresponded to commercial and tree-ripe state, respectively, in each variety. Peel and flesh phenolic compounds were determined by high-performance liquid chromatography-diode array detector (HPLC–DAD). Here, the acids 2,4-dihydroxybenzoic (2,4-DHB), 2,3-dihydroxybenzoic (2,3-DHB) and sinapic, the anthocyanins delphinidin-3-O-glucoside (delph-3-glc), petunidin-O-glucoside (pt-3-glc) in flesh and malvidin-O-glucoside (malv-3-glc) in flesh and peel were revealed in figs for first time. Gallic was the prominent acid in flesh and cyanidin-O-3-rutinoside (c-3-rut) the major anthocyanin in flesh and peel in all varieties. During ripening most phenolic compounds, TCAR and TAC in flesh did not increase. Peel anthocyanins increased greatly in all varieties. The sum of anthocyanins reached 952 mg 100 g−1 fw in the dark-peel ‘MM’ at S4, corresponding to a surface colour with a hue angle value of 6.48, rendering the peel an edible part of high nutritional value. However, part of chlorophyll was still present in ‘MM’ peel. Conclusively, most of the variables determined were significantly influenced by variety and ripening stage. The hierarchical cluster analysis, a rapid and easy way of results interpretation, distinguished varieties and stages according to the variables determined, giving the opportunity for variety selection and/or ripening stage determination at harvest.