Effect of various factor on the stability of the anthocyanin pigment in passion fruit skin

Abstract

Since loss of anthocyanins is one of the major factors contributing to the colour deterioration in many highly coloured fruits, the effects of various factors such as temperature, oxygen, pH, ascorbic acid, tannic acid, thiourea and hydrogen peroxide on the stability of the anthocyanin pigment (Pelargonidin 3-diglucoside) naturally occurring in passion fruit skin (Passiflora edulis, sims). have been studied with a view to elucidate the mechanism of degradation of the pigment during refrigerated and common storage of the fresh fruit. Storage studies demonstrated that (i) ascorbic acid in the presence of oxygen accelerated the deterioration of the pigment; (ii) thiourea decreased the rate of destruction of ascorbic acid, thus indirectly preventing the rate of anthocyanin losses; (iii) tannins had a stabilizing effect on the pigment; (iv) pH had a very significant effect on the stability of the pigment; and (v) high storage temperature and H2O2 both had destructive effect on the pigment.