Seasonal variation in fruit growth, quality attributes and antioxidant capacity of pomegranate during maturation

This study presents key findings on pomegranate ('Ruby') fruit growth pattern as well as the evolution of biochemical component and antioxidant capacity during fruit maturation over two seasons. The time course and pattern of fruit growth between 54 and 139 days after full bloom (DAFB) was studied. At five distinct developmental stages, total soluble solids (TSS), pH, titratable acidity (TA), phenolic contents and antioxidant capacity were investigated. Regression analysis was used for prediction of fruit growth while Pearson correlation was used to visualize the changes in major chemical indices and assess the inter-relationships amongst them. Fruit lineal dimensions (length and diameter) and weight showed a linear growth pattern in both seasons. Furthermore, there were significant increases in total soluble solids (TSS), with concomitant significant decline in titratable acidity (TA) with advancing maturity. Fruit at advanced maturity stages showed intense pigmentation of peel and aril, due to bioaccumulation of anthocyanins. TSS and TA showed strong relationships with most of the chemical indices, both showing significantly (p<0.05) strong correlations with phenolics and antioxidant capacity (ferric reducing antioxidant power, FRAP, and 2,2-diphenyl-1-picrylhydrazyl, DPPH). Amongst the investigated parameters, juice absorbance, TSS, TSS/TA and BrimA did not show significant (p>0.05) seasonality suggesting their potential to predict fruit harvest maturity. The combination of these quality attributes account for sugar content, acidity, colour, and could that could serve as reliable maturity indicators for the investigated cultivar. This information could serve as a tool to monitor and manage fruit maturation and readiness for harvest.