ISHS Acta Horticulturae 163: Symposium on Quality of Vegetables
RAPID ASSESSMENT OF TOMATO COMPOSITION DURING HIGH QUALITY FRUIT PRODUCTION AND DISTRIBUTION |
| Authors: | G.E. Hobson, P. Kilby |
| Abstract:
Tomato fruit are generally graded according to their evenness of colour and shape, also on their size; firmness is often only assessed subjectively. As additional criteria of quality that could be linked with the physical attributes of fruit, simple tests have been developed so that the composition, especially the major taste components comprising the organic acids and reducing sugars, may be assessed quickly and inexpensively. Representative samples of tomato fruit were pulped by means of a manual food chopper and the released cell sap was separated by successive filtrations. A portable instrument was used to assess the conductivity of the sap, which previous results have shown to be closely correlated with the potassium content and the titratable acidity. Alternative direct methods for the determination of titratable acidity have been worked out. A refractometer was used to assess the total soluble solids content of sap, which is related to the sugar levels. However, with sap produced by the present method, the relation between refractive index and sugar concentration was satisfactory within, but not between, cultivars. If the limitations of the present sap-extraction system are recognised, the methods that have been brought together can give a reliable, rapid estimate of the major taste components using only a small sample of fruit and basic apparatus. The advantages of using alternative compositional factors and more sophisticated equipment have been assessed. | |
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