ISHS Acta Horticulturae 379: International Symposium on Quality of Fruit and Vegetables: Influence of Pre- and Post- Harvest Factors and Technology
SUGAR, ACID AND PECTIN CONTENT IN RELATION TO RIPENING AND QUALITY OF PEACH AND NECTARINE FRUITS1 |
| Authors: | R. Selli, S. Sansavini |
| DOI: | 10.17660/ActaHortic.1995.379.43 |
| Abstract:
The interrelations of organic sugar, acid and pectin contents and fruit quality were studied in four distinct peach genotypes, the white-fleshed ‘Pieri 81’, the yellow-fleshed ‘Suncrest’, the nectarine ‘Stark Red Gold’ and the cling ‘Babygold 6’, by monitorings carried out every two weeks and then weekly from the end of pit hardening to ripening (weeks 9–18 AFB). The four tested cultivars, which all ripen at the same late date, evinced the greatest changes in the mesocarp's organic compounds in the three weeks preceding harvest. The overall data show that by week 15 AFB sugar levels (mainly sucrose and sorbitol) increased, acids notably decreased and the chief biometric parameters (fresh and dry weight, diameter, length) increased rapidly. By week 16 AFB, sugars showed an even sharper rise and the acids, as well as the protopectins, an accentuated drop. This means that fruit quality as expressed by the sugar-to-acid ratio also changes in relation to harvest date. Indeed, over the last three weeks of fruit development the ratio of sugars to acids grows greater daily, the former increasing and the latter decreasing. Thus, the choice of harvest date also depends on the type of quality and consumer taste desired. The results show that the sugars, acids and pectins can be discriminating factors between genotyps in determining fruit quality. The pros and cons of early and late harvesting are discussed. | |
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