Physiological and Quality Characteristics in Four Genotypes of Mulberry Fruit (Morus alba L.) during Ripening

Physiological and quality features in fruit of a known hybrid 'Fengchisang' and three other genotypes (A1, A2 and K) of mulberry tree (Morus alba L.) at two maturity stages after harvest were studied. The berries from 'Fengchisang' were harvested only at the fully mature stage, whereas the rest fruit at two maturity stages, partly and fully mature. At the fully mature stage fruit of genotypes A1 and A2 remain white, while K become red and 'Fengchisang' purple. Fruit weight, respiration and ethylene production rates, firmness, total soluble solids (TSS), pH, titratable acidity (TA), color, concentrations of total phenolics (TP), flavonoids (TF) and anthocyanins (TAN), and total antioxidant capacity (TAC), as FRAP and DPPH, were determined. Fruit weight, pH and TSS in all genotypes, as well as TAC and TAN in colored berries, increased with advanced maturity, whereas firmness and color parameters of h(o) and C* decreased in all genotypes. Values of L* color parameter, TP and TF in white fruit, and ethylene and respiration rates in all genotypes did not show significant changes in relation to maturation. At the fully maturity stage the levels of TP, TF, TAN and TAC were highest in 'Fengchisang' and followed by those in genotype K. Linear relations with high correlation coefficients were also observed among antioxidant variables. The present results indicated that the high TAC of the colored berries could be attributed primarily to anthocyanins.