Caprification modifies polyphenols but not cell wall concentrations in ripe figs

Figs, when ripe, move to their final colour and lose radically their firmness, and caprification (artificial pollination) leads to increased fruit softening during maturity. To identify the effects of caprification on cell wall amounts and phenolics composition, cell wall material and polyphenols were investigated in five Tunisian figs. Cell walls were isolated as alcohol insoluble solids (AIS) content. AIS yield was not affected by caprification in all cultivars. Pectin polymers decreased as the fruits fulfil their development after being caprified. The pectin in figs exhibited high degree of methylation (>50%) which increased more with caprification. Major neutral sugars components of the AIS were glucose, from cellulose, followed by arabinose. Caprification had no effect on neutral sugars composition of the cell wall. Methanol extraction followed by HPLC-DAD analysis revealed two anthocyanins, three flavonols and one hydroxycinnamic acid. For all varieties the total polyphenols were less in the flesh (up to 1.27 mg/kg FW) than in the peel (up to 12.64 mg/kg FW). Anthocyanins were the major compounds described in figs representing more than 98% of total polyphenols in both dark and white coloured fruit. Textural components and properties of figs are moderately affected by caprification, while anthocyanins biosynthesis appears to be stimulated by pollination with higher concentrations of total polyphenols in caprified fig fruits.