Effects Of 6 - BA On Nutrient And Antioxidant Activity Of Post - Harvest

In 1994, lotus seeds were subjected to mutation in ourter space aboard the Chinese recoverable "940703" satellite, and the mutated seeds were given the name space lotus. In comparison to traditional lotus, the space lotus numbered 36 displayed the best characters, including a long cultivation, period, large kernels, a high seed set propagation coefficient, and high yield. The seeds of this lotus have higher water and lower starch contents than normal lotus seeds, and retain their original flavor and beneficial nutrients, resulting in a high market value. On the one hand, there is a custom of eating fresh lotus seed in their life around the Zhejiang and Jiangsu province; on the other hand, lotus seed is a traditional medicine edible plant. Therefore, Planting area of space lotus increases sharply recently. However, it is easy to browning which limits the long-term storage and long-distance transportation of lotus seed. Post-harvest preservation research both at home and abroad and the research of fresh lotus also is less.Lotus were treated with 30 mg/L of 6-BA for 10 min and dried at room temperature, and then stored in the condition of (25 ± 1) ℃,85%relative humidity. The objective of this research was to clarify the action mechanism of 6-BA treatment for delaying senescence and browning harvested lotus seed by investigating tissue energy metabolism and membrane lipid metabolism related tissue senescence, and the changes of activities of enzymes related to ROS of seed. The results were showed as follows: The treatment of 30 mg/L of 6-BA inhibited the respiration rate of lotus pod,and then maintained the decrease of starch、total sugar、ATP content and energy charge level. From the results, it could be concluded that 6-BA treatment inhibited the consumption of cell metabolism of energy substances, and maintained energy status to meet the energy requirments of the normol metabolism in lotus, thus retarding the process of fruit senescence. The treatment of 30 mg/L of 6-BA inhibited activities of lipoxygenase (LOX), and maintained higher relative contents of unsaturated fatty acids, such as palmitoleic acid, oleic acid, linoleic acid, linolenic acid, along with lower relative contents of saturated fatty acids, such as palmitic acid, stearic acid. Thus,6-BA treatment retarded the index of unsaturated fatty acids (IUFA) and unsaturated degree of fatty acids. From the results, it could be concluded that 6-BA treatment decreased activities of membrane lipid-degrading enzymes, and reduced the degradation of unsaturated fatty acids of membrane lipids and maintained higher unsaturated degree of fatty acids, resulting in increasing the liquidity of membrane and maintaining integrity of cell membrane structure.The treatment of 30 mg/L of 6-BA significantly induced an increase of the reactive oxygen species scavenging ability, inhibited accumulation of malondialdehyde (MDA) content, delayed the membrane lipid oxidation.6-BA was better suited to delaying the O2·- production rate and H2O2 content during storage. The activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) in 6-BA were significantly higher than those of the control. What’s more,6-BA inhibitd the decrease of phenols and maintained the higher antioxidant activity. The results suggested that 6-BA could surpress lipid peroxidation and strength the antioxidant enzyme activities, which might account for delayed the senescence and browning.