Relationship between nondestructive firmness measurements and commercially important ripening fruit stages for peaches, nectarines and plums

Abstract

Fmit firmness measurement is a good way to monitor fmit softening and to predict bmising damage during harvest and postharvest handling. Ripening protocols traditionally utilize a destmctive penetrometer-type fmit firmness measure to monitor ripening. Until recently, methods of assessing fmit texture properties nondestmctively were not commercially available. The nondestmctive Sinclair iQ™ firmness tester was investigated to monitor ripening and predict bmising susceptibility in stone fmit. This work was carried out on four peach, three plum, and five nectarine cultivars over two seasons. The correlations between destmctive and nondestmctive firmness measurements were significant (p-value = 0.0001), although too low for commercial applications as they varied from ^ = 0.60-0.71 according to fmit type. Using a different approach, the relationship between destmctive and nondestmctive firmness measures was characterized in terms of segregating these fmit according to their stages of ripening. This was done by using discriminant analysis (66-90% agreement in ripeness stage classification was observed in validation tests). Discriminant analysis consistently segregated nondestmctive firmness measured fmit into commercially important classes ("ready to eat", "ready to buy", "mature and immature"). These represented key ripening stages with different bmising potentials and consumer acceptance. This work points out the importance to relate nondestmctive measurements directly to important commercial physiological stages rather than to correlate them with the current standard penetrometer valúes. Thus, destmctive and nondestmctive firmness measurements can be directly used to identify the stage of ripeness and potential susceptibility to bmising during postharvest changes. Further work is recommended to evalúate the performance of this nondestmctive sensor in segregating fmit according to their stage of ripeness under packinghouse or processing plant conditions.

Nectarine Fruit Ripening and Quality Assessed Using the Index of Absorbance Difference (IAD)

“…Both "SF34" and "SF26" showed a clear and different trend in ethylene production at the respective I, CM, and PM fruit maturity stages (Table 1), which agreed with Ziosi et al [20] who defined the relationship between ethylene production and ripening stage ( AD ) as cultivar specific. The AD can be regarded as a marker for peach fruit ripening that is more sensitive and confident than the physicochemical parameters commonly used to describe physiological condition including firmness, which was the most reliable measurement until now [26]. The AD value measured on fruit of "SF34" decreased following ripening from four-six weeks after full bloom (Table 2), even if at the onset of climacteric (CM) the ethylene production still remained very low (Table 1).…”

Fisiología y bioquímica de la maduración del fruto de durazno [<i>Prunus persica</i> (L.) Batsch]. Una Revisión

“…Por otro lado, Gorny et al (1999) reportan que el estado de madurez óp-timo para duraznos y nectarinas es aquel que tiene entre 13 y 27 N de firmeza de la pulpa, en estos valores el fruto alcanza la vida útil máxi-ma, y se obtiene buena calidad para consumo. Por su parte, Valero et al (2007) clasificaron el fruto de durazno en tres clases con base en la firmeza, donde 35 N es la firmeza mínima que debe tener el fruto para que este no presente daño mecánico en el manejo poscosecha, frutos con 18-35 N son catalogados como listos para comprar, y frutos con 8-13 N de firmeza son aquellos listos para consumo.…”

Does the maturity at harvest affect quality and sensory attributes of peaches and nectarines?

“…If the fruit is consumed at the proper flesh firmness*13Á18 N according to Valero et al (2007)*there are no remarkable differences between fruit that was picked 'tree-ripe' or with 60Á70 N flesh firmness. This axiom could even be incorrect for sub-acid cultivars, as the extremely low acidity of these genotypes when harvested ripe is often negatively rated by consumers.…”