Nectarine fruit (Prunus persica L. Batsch var nectarina [Ait] maxim) cultivar Fantasia were either ripened immediately after harvest at 20°C or stored for 5 weeks at 2°C prior to ripening. Fruit ripened after 5 weeks of storage did not soften to the same extent as normally ripened fruit, they lacked juice, and had a dry, mealy texture. Pectic and hemicellulosic polysaccharides were solubilized from the mesocarp of the fruit using phenol:acetic acid:water (PAW) treatment to yield PAW-soluble material and cell wall material (CWM). The carbohydrate composition and relative molecular weight (Mr) of polysaccharide fractions released from the CWM by sequential treatment with cyclohexane-trans-1,2-diamine tetra-acetate, 0.05 M Na2CO3, 6 M guanidinium thiocyanate, and 4 M KOH were determined. Normal ripening of nectarines resulted in solubilization of pectic polymers of high Mr from CWM during the first 2 d at ripening temperatures. Concurrently, galactan side chains were removed from pectic polymers. Solubilized pectic polymers were depolymerized to lower Mr species during the latter stages of ripening. Upon removal from cool storage, fruit had undergone some pectic polymer solubilization, and after ripening, pectins were not depolymerized and were of high Mr. Side chains did not appear to be removed from insoluble pectic polymers and branched pectins accumulated in the CWM. The molecular weight profiles obtained by gel filtration of the hemicellulosic fractions from normally ripening and mealy fruit were similar. The results suggest that mealiness results as a consequence of altered pectic polymer breakdown, including that associated with neutral side chains.

A kiwifruit (Actinidia deliciosa (A Chev) Liang et Ferguson cv Hayward) pulp was made using fruit harvested immature to minimize the presence of aroma volatiles. This pulp was modified by incorporating sugars and acids to simulate kiwifruit with a range of Brix and acid levels. Using sensory evaluation, flavor acceptability was found to increase with increasing Brix. As expected, perceived “ sweetness intensity” increased with increasing Brix. Acidity did not influence flavor acceptability. At high Brix, sugars were able to suppress the effects of variations in acidity. Changes in Brix did not influence “ flavor intensity”, suggesting that aroma volatiles may be important contributors to kiwifruit flavor intensity.

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