ISHS Acta Horticulturae 768: XXVII International Horticultural Congress - IHC2006: International Symposium on The Role of Postharvest Technology in the Globalisation of Horticulture
INFLUENCE OF PREHARVEST CALCIUM TREATMENTS ON APPLE SOLUBLE SOLIDS, TITRATABLE ACIDS AND VITAMIN C CONTENT AT HARVEST AND AFTER STORAGE |
| Authors: | U. Moor, K. Karp, P. Põldma, M. Starast |
| Keywords: | Malus domestica, storage, vitamin C, soluble solids, quality |
| Abstract:
The effects of preharvest Ca treatments (Ca(NO3)2 + CaCl2) on the soluble solids, titratable acids and vitamin C content of the apple cultivars ‘Krameri Tuviõun’ and ‘Talvenauding’ at harvest and after storage was investigated. Preharvest Ca treatments were applied three times in summer 2002 and four times in summer 2003. In 2002 a 1% Ca(NO3)2 solution was sprayed on 9 and 30 July, at 660 L ha-1, and a 0.5% CaCl2 solution was applied on 22 August, at the same volume per ha. In 2003 Ca(NO3)2 was applied on 14 and 28 July, and CaCl2 on 8 August and 1 September. Samples of 300 fruit per plot were stored in a commercial cool store in temperature ranging from +2 to 5°C and at RH 80-85% in air for four months. Fruit dry matter content, soluble solids content (SSC) and titratable acidity (TA) were determined at harvest and after storage in both years. Fruit vitamin C content was determined in 2003 only. At harvest in 2002 fruit SSC, TA and dry matter content were significantly reduced by calcium treatment. At harvest in 2003 Ca treatment increased SSC, but did not affect TA. Based on TA content, the Ca treatment made apples taste less acid in a warm and dry summer. Mean vitamin C contents of ‘Krameri Tuviõun’ and ‘Talvenauding’ were 21.8 and 23.9 mg 100 g-1 respectively, and not affected by Ca treatment. In the second year, fruit Mg content was positively correlated with fruit DM, TA and vitamin C content, and negatively correlated with fruit SSC content, which indicated that fruit with higher Mg content had better quality after storage. Correlations with fruit Ca content were contrary and thus in this year preharvest Ca treatment appeared to have an adverse effect on quality of ‘Talvenauding’ after storage. | |
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