The effect of cultivar and harvesting stage on the chemical composition of processing tomato fruit

Abstract

Field-grown processing tomatoes are harvested in the red stage, however a significant part of fruits remaining on the crop are at the turning stage and in the mature-green stage. This is a part of the crop that can still be used after post-harvest ripening. The aim of the study was to compare the quality of the three determinate tomato cultivars harvested in the field during the red stage with that of red tomatoes obtained after ripening on shelf (harvested in the turning and mature-green stages). Red fruits were analysed immediately after harvest. The remaining fruits were stored and analysed after they had reached the red stage. Experiment showed that unripe tomatoes harvested in mature green phase during shelf ripening can achieve a good fruit quality, comparable to those harvested red. There was found no impact of the degree of ripeness at harvest on the content of dry matter. The relationship between content of extract, soluble sugars and organic acids and the degree of ripeness at harvest depended on the vegetation period. In 2009 fruits harvested green or pink reached higher content of extract, soluble sugars and organic acids than fruits harvested red. In 2010 it was quite contrary; all parameters were worst in fruits collected green or pink. In 2011 there were no differences in extract, whereas level of sugars and organic acids were higher in fruits collected unripe, stored and analysed after they had reached the red stage. Regardless of the year of research, vitamin C level was always the highest in the fruits collected red.