EFFECT OF TOMATO DECAY PROPORTION ON ERGOSTEROL LEVEL AND SOME TOMATO PULP PROPERTIES

There is a need to develop a chemical method to determine the amount of decayed tomatoes used to produce tomato products. Tomato pulp samples produced from surface decayed tomatoes as sound, 30, 60 and 100% were tested for pH, brix, titrable acidity, Hunter L, a and b, Howard Mold Count (HMC) and ergosterol values. Tomato pomace for each decay portion was tested for HMC and ergosterol. Ergosterol analysis was carried out by high‐pressure liquid chromatography (HPLC). Decay proportion was linearly correlated with HMC (r = 0.97) and ergosterol (r = 0.96) in pulp samples but not to pH and acidity. Only ergosterol measurement was applicable in tomato pomace and correlated well (r = 0.95) with the decay proportions. In general, the color values of the samples produced from 100% decayed tomatoes were high compared with the others. The measurement of ergosterol has the potential to be used for the quality assessment of tomato products made from Red Top tomatoes.