Study On Lycopene, Citrulline, Vc And Sugar In Watermelon

The contents of lycopene, citrulline, ascorbic acid (Vc), fructose, glucose, sucrose and total sugar of watermelon fruits with different cultivar and different ploidy including diploid (2X), triploid (3X) and tetraploid (4X) were measured during fruits development. Those contents of different parts in fresh fruit of triploid seedless and fruit storaged at room temperature were also measured. The study elucidated the contents of lycopene, citrulline, ascorbic acid (Vc), sugar in watermelon fruits changes during fruit development, the contents difference between different ploidy and different parts of fruits and the changes after storaged at room temperature. The results would be provided theoretic basis for breeding, harvesting, storing and processing in watermelon. The main results were as follows:1. Optimizing extracting factors of lycopene in watermelon: extracting efficiency of lycopene with extracting solution of acetone and 2% dichloromethane adding petroleum ether were better than that of chloroform and dichloromethane. Moreover, the variation coefficient of extracting efficiency in acetone was larger than that of 2% dichloromethane adding petroleum ether. So the extracting solution in 2% dichloromethane adding petroleum ether was the best than others,2. The changes of lycopene, citrulline, Vc and sugar content in watermelon fruits with different cultivar during the fruit development were as results:2.1 It had been few lycopene in watermelon of yellow-flesh and white-flesh. The change of lycopene content in red-fleshed watermelon fruits were showed"S"curved shape during fruits development. The lycopene contents of young fruits were a little, then it were increasing rapidity in color-changed stage and achieving the maximun value in ripen fruits. Decreasing tendency in lycopene contents was easy to seen during overripening. In this experiment, the augmentation rate of lycopene of L15(red-flesh)watermelon was greater than that of L14 (pink-flesh) watermelon. The content of L14 (pink-flesh) watermelon achieved the peak (34.5mg/kg.FW) on 33rd day after pollination and that of the L15 (red-flesh) was 45.3 mg/kg.FW on 36th day.2.2 The changes of citrulline content in watermelon fruits with different cultivar were same tendency: The citrulline contents of young fruits were a little, then it accumulated slowly along with growing course then it decreased in expansion phase it were increasing rapidity in stage and achieved the peak before maturity. The decreasing tendency in content was easy to be seen during overripening.2.3 The changes of Vc contents in watermelon fruits with different cultivar were the same tendency: There was more total ascorbic acid (TAA) contents in young fruits and then accumulated slowly along with growing course as to achieve the first peak. The TAA contents decreased rapidly in expansion phase to the lowest level and then increased rapidly to achieve the second peak in ripen stage. The decreasing tendency in content was easy to be seen during overripening. Both ascorbic acid (AA), and dehydroascorbic acid (DHAA) maked the same change rule. The change of their content in different cultivar flesh watermelons were showed"M"curved shape during fruits development. 2.4 The changes of four kinds of suger contents in watermelon fruits with different cultivar were the same tendency: those contents of young fruits were a little, then it accumulated slowly along with growing course then it decreased in expansion phase it were increasing rapidity in stage and achieved the peak before maturity. The decreasing tendency in content was easy to be seen during overripening.3. The lycopene, citrulline, Vc and sugar content in different ploidy watermelon. The results were as follows: (1) lycopene, 3x>4x>2x; (2) citruline, 3x>4x>2x; (3) TAA, AA and DHAA, 4x>2x>3x; (4) fructose, glucose, sucrose and total sugar: total sugar and fructose maked the same trend, 4x>3x>2x; glucose 4x>2x>3x; sucrose, 3x>4x>2x.The correlation among lycopene, citruline, Vc and sugar content in different ploidy watermelon. The main results were as follows: The correlation between lycopene and Vc, total sugar contents content was significant at the 0.05 level;Citrulline and Vc, total sugar contents content was negative correlation;TAA, AA and DHAA contents was significant at the 0.01 level to each other, Fructose and glucose contents correlation was significant at the 0.05 level; The correlations among fructose, glucose and total sugar contents was significant at the 0.01 level.4. Lycopene, citrulline, Vc and sugar contents were significantly diverse across different watermelons cultivars and different parts of watermelon fruits, the results as follow: the contents in heart tissue of watermelon fruits were higher than those of near skin. Lycopene, Vc and sugar contents had a loss percentages in uncut seedless watermelons after storage at room temperature while citruline had a raise. The loss percentages of lycopene, Vc and sucrose contents in heart tissue of watermelon fruit was higher than those of near skin, while the sugar in heart tissue was lower. The raise percentages citrulline in heart tissue of watermelon fruit was higher than those of near skin.5.The ratio of TAA:AA in different coloures of watermelon fruits and different ploidy of watermelon fruits were about 1～2:1, The ratio of fructose: glucose: sucrose with ripen stage in yellow-flesh watermelon,green-skin white-flesh watermelon,white-skin white-flesh watermelon and red-flesh watermelon were about 6:3:1, 6:3:2, 2:1:1 and 5:3:1.