EFFECT OF HIGH-TEMPERATURE ON THE POSTHAR VEST BIOSYNTHESIS OF CAROTENES AND ALPHA-TOCOPHEROL IN TOMATO FRUIT

Mature green tomato fruits were initially stored at 20 degrees, 30 deg rees and 35 degrees C and then transferred to other temperatures at va rious times within a 25-day storage period. 1. Fruits transferred from 20 degrees C to 30 degrees C (20 degrees-->30 degrees C) or from 20 d egrees C to 35 degrees C (25 degrees-->35 degrees C) developed less co lor depth and contents of phytoene and lycopene than did those retaine d at 20 degrees C, but carotene contents increased temporarily in the 20 degrees-->30 degrees C treatment. Conversely, fruit transferred fro m 30 degrees C to 20 degrees C (30 degrees-->20 degrees C) or from 35 degrees C to 20 degrees C (35 degrees-->20 degrees C) progressively be came redder. 2. Ratio of lycopene precursors, phytoene, phytofluene an d zeta-carotene to total carotenes was highest in tomatoes kept at 20 degrees C. In the 30 degrees-->20 degrees C or 35 degrees-->20 degrees C treatments, total carotene contents became almost the same as those kept at 20 degrees C, but the ratio of the precursors to total carote nes became smaller while that of lycopene to total carotenes increased . 3. Tomatoes at 30 degrees C, beta-carotene content and level of cis- isomer increased, but those in the 20 degrees-->30 degrees C treatment , the beta-carotene remained constant. 4. Alpha-Tocopherol content inc reased in tomatoes kept at 30 degrees C and 35 degrees C, whereas it d id not increase significantly at 20 degrees C; it increased after the tomatoes were transferred from 30 degrees to 20 degrees C or from 35 d egrees to 20 degrees C. The data indicated that the rates of synthesis of lycopene, beta-carotene and alpha-locopherol differ according to t emperature. The effect of high temperature or treatment with changing temperature on each pathway may be explained by changes in metabolism of precursors of both carotenoid and tocopherol.