Modeling mango ripening during shelf life based on pulp color nondestructively measured by time-resolved reflectance spectroscopy

Abstract

Non-destructive techniques could help mango growers to pick fruit at the proper maturity degree and to monitor fruit quality during storage and marketing to satisfy the consumer expectations. The absorption coefficient non-destructively measured at 540 nm (μa540) by time-resolved reflectance spectroscopy (TRS) was shown to be a maturity index for mango fruit and was highly correlated with pulp color parameters and carotenoids content. The aim of this work was to model μa540 using the biological shift factor theory to verify if μa540 is able to assess the maturity degree of individual mango fruit and then to use μa540 to model pulp color in order to relate μa540 to an important index of mango ripening.Mango fruit (Mangifera indica L. cv Tommy Atkins) at commercial maturity for ship and air transport maturities, were measured by TRS, ranked according to decreasing μa540 (decreasing maturity), randomized into six batches per transport maturity and analyzed for μa540 and pulp color parameters after 0, 1, 2, 5, 6 and 7 days of shelf life at 20 °C.The μa540 as a function of biological shift factor increased during ripening following a logistic/exponential model (R2adj=99%) with a faster rate in less mature fruit than in more mature ones. The changes in pulp color during mango ripening depended on fruit maturity (i.e., μa540) and on time of shelf life at 20 °C. By converting the μa540 into the biological shift factor it was possible to model the increasing trend of a*, b*, C*, and IY and the decreasing trend of L* and h° during the shelf life period explaining 91.2–99.8% of the variation and to differentiate mango fruit according to their biological age. Similarly to μa540, color changes occurred earlier in more mature fruit and later in less mature ones with the same pattern in time.There is a synchronization between changes of μa540 and changes of a*, b*, C* and yellowness during ripening in mango fruit which allows to use μa540 to sort fruit according to their maturity degree and then to optimize fruit management along the supply chain.