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  • Author or Editor: Ming-Wei S. Kao x
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The physical and chemical characteristics of two melting flesh (MF) cultivars, TropicBeauty and Flordaprince, and two non-melting flesh (NMF) cultivars, UFSun and Gulfking, with advancing maturities, were determined at harvest, after ripening at 20 °C for 7 days (i.e., direct ripening) and after storage at 0 °C for 14 days then ripening at 20 °C for 7 days (i.e., ripening following low temperature storage). The NMF cultivars were able to retain flesh firmness better than the MF cultivars as fruit matured and ripened on the tree and after the two storage treatments. The NMF fruit of the least mature to the most advanced maturity groups (MGs) were ≈2 to 7 times firmer than the MF fruit in the same MGs after ripening in both storage conditions. For both MF and NMF fruit, a significant reduction of titratable acidity (TA) occurred with no significant changes in soluble solids content (SSC) and total soluble sugar (TSS) as maturity and ripening progressed on the tree and after ripening in both storage conditions. Minimum quality standards of “ready for consumption” peaches were used as general guidelines to determine the optimum harvest maturity of all four cultivars. The NMF fruit ripened directly had wider optimum harvest maturity ranges and could be harvested at more advanced stages than the MF fruit. The MF fruit that ripened following low temperature storage needed to be picked at earlier maturity stages than those that were directly ripened. The optimum harvest maturity of NMF UFSun for the low temperature storage treatment was more advanced than that of the other three cultivars due to abnormal softening found in the lower MGs after ripening. Linear correlation analyses showed that the skin ground color (GC) a* values of both MF cultivars and NMF ‘UFSun’ were highly correlated with the flesh color (FC) a* values, suggesting that GC a* values can be an informative harvest indicator for this NMF cultivar instead of the traditionally used FC. The GC a* values also had high linear correlation with TA for all four cultivars, suggesting that TA can be a potential maturity index for both MF and NMF peaches. Significant correlations of GC a* values and flesh firmness (GC-FF) were found in all four cultivars in one year but only in MF peaches in both years, showing that flesh firmness was the most consistent maturity indicator for the MF cultivars in this study.

Open Access

Some physiological and biochemical properties of melting flesh (MF) and non-melting flesh (NMF) peaches [Prunus persica (L.) Batsch] were determined during ripening for 5 days at 20 °C. Respiration rates and ethylene production of MF ‘Flordaprince’, MF ‘TropicBeauty’, NMF ‘UFSun’, and NMF ‘Gulfking’ were measured at different harvest skin ground color-based maturity stages. The MF cultivars at harvest were mostly preclimacteric or at the onset of ripening. The NMF cultivars generally had higher ethylene production at harvest and throughout ripening than the MF cultivars; thus, the NMF fruit had started ripening on the tree before harvest. Some of the NMF fruit harvested at more advanced stages quickly became postclimacteric during the storage period. Quality determination after fruit ripening showed that MF ‘TropicBeauty’ had the highest soluble solids content (SSC), but also the highest titratable acidity (TA). The NMF cultivars had lower TA than the MF cultivars. NMF ‘Gulfking’ consistently had high SSC/TA, which was the result of it having the lowest TA. The NMF cultivars retained firmer texture than the MF cultivars during ripening. The flesh firmness of the NMF cultivars was four to five times greater than that of the MF cultivars. To investigate the reason for this significant textural difference, the activities of the cell wall modification enzymes pectin methylesterase (PME) and polygalacturonase (PG) were quantified in all four cultivars at advanced ripeness stages. PME activity appeared to be more directly related with peach fruit softening than PG activity.

Free access

The health status of Alabama's population ranks above the national average with respect to the prevalence of poor overall health indicators. Consumer knowledge of the health benefits of consumption of fresh fruit is lacking. The compositional and nutritional qualities of fruit are highly variable among states with different climate, soil, and other environmental conditions. Compositional and nutritional data of fresh fruit that reflect Alabama growing conditions is limited. Commercially fully ripened kiwi fruit (Actinidia deliciosa cvs. Fitzgerald and Hayward) were compared for fruit quality (pH, TA, °Brix, °Brix/TA, and soluble sugars), and antioxidant properties; Vitamin C (reduced, oxidized, and total), Vitamin C Equivalent Antioxidant Capacity (VCEAC), ferric reducing antioxidant power (FRAP), DPPH radical scavenging activity, total phenolics, and flavonoids. In general, `Fitzgerald' ranked higher in overall fruit quality and antioxidant properties when compared to `Hayward'.

Free access