SENSORY PROFILES OF VARIOUS STORED FRUIT SPECIES ARE AFFECTED BY MATURITY CLASS ASSESSED BY TIME-RESOLVED REFLECTANCE SPECTROSCOPY AT HARVEST

The absorption coefficient measured at harvest at 670 nm (µ_a670) by time-resolved reflectance spectroscopy (TRS) is a non-destructive maturity index used to evaluate the biological age of fruit, i.e., the fruit maturity stage. The µ_a670 was successfully used to classify nectarine, apple and mango fruit into maturity classes each one having distinctive ripening behaviors. Aiming at studying the influence of TRS maturity class assessed at harvest on the sensory profiles of various fruit species after storage, ‘Jonagored’ apples, ‘Abbé Fétel’ pears, ‘Morsiani 90’ nectarines and ‘Spring Belle’ peaches were measured at harvest by TRS at 670 nm, ranked on the basis of decreasing µ_a670 (increasing maturity) and classified as less (LeM), medium and more (MoM) mature. Then fruit were randomized into batches of 30 fruits, each one corresponding to a storage atmosphere (apples: CA, NA; pears: CA, NA, DCA) or to a storage temperature (peaches, nectarines: 0, 4°C). After storage, fruit were put in shelf life at 20°C to reach the ripening degree for consumption. Sensory analyses (QDA profiles) were carried out on LeM and MoM fruit using a panel of 10 assessors. Our results indicate that, for all the species, besides the influence of storage conditions, there was also a great influence of TRS maturity classification at harvest. MoM apples and pears developed physiological disorders such as mealiness and graininess when stored in NA, whereas showed well balanced sensory characteristics when stored in CA and DCA, becoming after storage soft, juicy, sweet, but sour enough. MoM nectarines stored both at 0 and 4°C became woolly, while the LeM ones stored at 0°C developed the best sensory characteristics. MoM peaches stored at 0°C showed the best sensory profile and the LeM ones stored at 4°C the worst. So TRS maturity classification at harvest can give indications on the best storage conditions in order to obtain fruit with sensory characteristics than can satisfy the consumer.