Ripening dependent changes in skin color, physicochemical attributes, in-vitro glycemic response and volatile profiling of banana varieties

Abstract

The colour of banana skin significantly influences purchasing and consumption choices. Though a ripening stage-dependent colour chart is available for the var. Grand Naine, such information are meagerly documented for other traditional varieties Rasthali, Poovan, Karpuravalli, Ney Poovan. Furthermore, investigations into glycemic response and volatile compound markers of these varieties have remained elusive. In this study, we identified more than eight distinct ripening stages these varieties. Notably, unlike the Grand Naine, the var. Ney Poovan and Karpuravalli varieties exhibited the retention of firmness even after progressive ripening to the 7–8 stages, rendering them suitable for more days of consumption. A comprehensive analysis, including a heat-map, unveiled the intricate correlations between skin colour and texture attributes, underscoring the interplay between visual appearance and fruit quality. Irrespective of varieties, sugar to acid ratio enhanced considerably over the ripening stages coupled with increase in physiological loss in weight and pulp-peel ratio. The estimated glycemic index (e-GI) values for Karpuravalli (65%) and Rasthali (67%) was higher at Stage 4, whereas the varieties like Ney Poovan and Grand Naine recorded lower GI values. GC-MS analyses at various ripening stages revealed a prevalence of esters and a concurrent reduction in unsaturated aldehydes, during the ripening, implying their pivotal role in aroma development. Besides, principal component analysis of volatile compounds at ripe stages underscored the distinctive aromatic profiles exhibited by Ney Poovan and Rasthali, setting them apart from other banana varieties.