Study on taste substances of tomato. 1 Analytical investigations into the sugar, organic acid and mineral contents
1989
Petro-Turza, M. | Szarfoldi-Szalma, I. | Fuzesi-Kardos, K. | Hajdu, F.
A comparative analysis of the sugar, organic acid and mineral contents of 2 tomato varieties K-549,/a traditional variety and Mokka, a new one suitable for machine harvesting/ and their purees was performed. More than half of the soluble dry matter /56.5 o/o for K-549 and 64.1 o/o for Mokka/ was made up of glucose and fructose present in a ratio near to 1:1. A slight decrease in the reducing sugar content was observed during puree manufacturing. Within the organic acids which constituted ca 10 o/o of the soluble dry matter in fresh tomato samples, citric acid was prevailing in both varieties while malic acid was present in traces only. The acid content increased upon evaporation due to the formation of pyrrolidone carboxylic acid. The concentrations and qualitative composition of the soluble mineral substances were practically identical in both tomato varieties, and did not change either during evaporation. The total mineral substance amounted to ca. 7 o/o of the soluble dry matter, and consisted of ca. 70 o/o of K, ca. 2 o/o of Mg, 7.5 o/o of P2O5 and 20.5 o/o of C1. It was established as well that the mineral substance content and composition were determined by the location and growth conditions but not by the variety. Out of the parameters studied significant differences between the 2 varieties were found in total and soluble dry matter and in the sugar/acid ratio.
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