ISHS Acta Horticulturae 464: International Postharvest Science Conference Postharvest 96
EATING QUALITY OF ‘COMICE’ PEARS IN RELATION TO MATURITY AT HARVEST, AND STORAGE AND RIPENING CONDITIONS |
| Authors: | P. Eccher Zerbini, S. Grazianetti, M. Grassi, G. De Colellis |
| Abstract:
Italian consumers require soft, juicy, full-flavoured pears. This research was carried out in order to verify the effect of maturity at harvest on the eating quality of ‘Comice’ pears after storage, and the interaction with ripening conditions. ‘Comice’ pears were harvested from an orchard in Emilia-Romagna (Northern Italy) at three harvest dates according to skin colour, and stored in CA (2.5% O2, 4.5% CO2). After 6 months' CA storage or after a further 15 days in air at 0°C, fruits were ripened in controlled conditions at 17°C and 90% RH or in room conditions in the laboratory at about 20°C. Quality variables were measured at harvest, after storage and after ripening, and sensory evaluation was carried out after ripening. After storage, acidity and firmness decreased with increasing maturity at harvest. The skin background colour was greener and less intense in fruit kept for a further period of air storage than in those analysed directly after CA storage, indicating that regreening had occurred, the effect being most marked with second harvest fruits. Penetrometer readings indicated that fruits ripened in controlled conditions were firmer on average than those ripened in room conditions: after ripening in controlled conditions, first-harvest fruits were quite firm, while in room conditions they were the softest. Acidity increased with maturity at harvest when fruit was analysed immediately after CA storage, and decreased with maturity if storage had been prolonged in air. Skin greenness was highest in second-harvest fruits ripened after CA, and increased with maturity in fruits ripened after further air storage; first-harvest fruits were less green, especially if ripened after further air storage or in room conditions. Soluble solids content may have been affected by relative humidity in the different storage and ripening conditions, but it was also related to fruit maturity. In controlled conditions it was lowest in the first-harvest fruits if ripening was carried out directly after CA, and in the third harvest fruits after a further period of air storage, while in room conditions the first-harvest fruits showed the highest soluble solids content if ripened after further air storage. Percent juice content was higher on average in fruits ripened soon after CA and fell with further air storage, especially in the fruits of the third harvest and in those ripened in controlled conditions. The second-harvest fruits had the highest juice content on average. Sensory juiciness showed a trend similar to that of % juice content; fruits ripened in room conditions after CA were juicier with later harvesting, and the opposite was true if fruits were ripened in controlled conditions after further air storage. Storage and ripening conditions had a big influence on fruit quality, especially texture; texture in turn affects release of juice, hence the availability in the mouth of acids, sugars and volatile substances which determine the flavour of pears. Fruits which ripened soon after CA were soft, juicy and aromatic; at 17°C and 95% RH, softening was reduced compared to room conditions. Optimum maturity for harvest has to be defined in relation to storage and ripening conditions: early harvested fruits could be kept in cold storage after CA with only a minor loss of juiciness, while late harvested fruits in these conditions did not become juicy. In general the fruits of the second harvest were of good quality in all the conditions tested, as they were juicy and aromatic, with high acidity and soluble solids content, and had a green hue of the skin. | |
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