The effects of fermenting, boiling, and steaming processes on the levels of free amino acids, organic acids, antioxidant properties （FRAP and DPPH）, phenolic compounds, and angiotensine converting enzyme （ACE） inh...The effects of fermenting, boiling, and steaming processes on the levels of free amino acids, organic acids, antioxidant properties （FRAP and DPPH）, phenolic compounds, and angiotensine converting enzyme （ACE） inhibition of sweet potato tips were investigated. Seventeen free amino acids were found in the tips. Fermenting, boiling, and steaming processes significantly reduced total free amino acid contents and steaming processes caused smaller losses than fermenting and boiling processes. Five organic acids were investigated in the tips. In comparison with the total organic acid content of unprocessed sweet potato tips, steaming and boiling processes significantly reduced it, while fermenting process increased it. Chlorogenic acid, rutin, and quercetin were investigated in the tips. The total phenolic compounds contents of sweet potato tips significantly increased by steaming and boiling processes, but a substantial loss was caused by fermenting process. A similar result was shown in FRAP value. The result of ACE inhibitory activity indicated that boiling, steaming, and fermenting processes significantly increased ACE inhibitory activity.展开更多
The potato minitubers have been widely used for the elite seed propagation to improve the seed potato system in China. However, little information is available for an efficient production of the minitubers with high p...The potato minitubers have been widely used for the elite seed propagation to improve the seed potato system in China. However, little information is available for an efficient production of the minitubers with high plant density in the protected growing conditions like plastic houses. In present research, the minitubers of a wide-grown potato variety, Favorita, were produced with the microtubers from tissue culture and the tip-cuttings of the microtuber plants. Three plant densities, 200, 400 and 600 microtubers or plants m-2 were set up with the randomized block design of 3 replications and the experiment was repeated in 4 seasons in 2009-2010. The canopy development, light interception, dry weight production and partitioning, tuberization and tuber weight were investigated to elucidate the mechanism by which the plant density affects the formation and growth of the minitubers. The results showed that the number of the tubers formed per unite area was in line with the increase in plant density. The difference in leaf area index （LAI） between the plant densities, especially in early stage of the plant growth, resulted in more radiation interception and dry weight producing in higher plant density than in lower one. However, our analysis demonstrated that the conversion coefficient of the cumulative intercepted radiation to plant weight and the dry weight partition rate to the tubers were constant between plant densities, suggesting that less amount of the photoassimilates partitioned to individual tubers is causal for more small tubers in high plant density. A negative exponential curve model, determined by total number of tubers produced per unit area and the mean tuber weight, fitted well to the tuber size distribution pattern. The optimum plant density could be estimated from this model for a maximum production of the minitubers with desired size.展开更多
基金supported by the Independent Innovation of Agricultural Sciences in Jiangsu Province, China (CX [09] 628)
文摘The effects of fermenting, boiling, and steaming processes on the levels of free amino acids, organic acids, antioxidant properties （FRAP and DPPH）, phenolic compounds, and angiotensine converting enzyme （ACE） inhibition of sweet potato tips were investigated. Seventeen free amino acids were found in the tips. Fermenting, boiling, and steaming processes significantly reduced total free amino acid contents and steaming processes caused smaller losses than fermenting and boiling processes. Five organic acids were investigated in the tips. In comparison with the total organic acid content of unprocessed sweet potato tips, steaming and boiling processes significantly reduced it, while fermenting process increased it. Chlorogenic acid, rutin, and quercetin were investigated in the tips. The total phenolic compounds contents of sweet potato tips significantly increased by steaming and boiling processes, but a substantial loss was caused by fermenting process. A similar result was shown in FRAP value. The result of ACE inhibitory activity indicated that boiling, steaming, and fermenting processes significantly increased ACE inhibitory activity.
基金supported by Earmarked Fund for Morden Agro-industry Technology Research System(CARS-10-P08)
文摘The potato minitubers have been widely used for the elite seed propagation to improve the seed potato system in China. However, little information is available for an efficient production of the minitubers with high plant density in the protected growing conditions like plastic houses. In present research, the minitubers of a wide-grown potato variety, Favorita, were produced with the microtubers from tissue culture and the tip-cuttings of the microtuber plants. Three plant densities, 200, 400 and 600 microtubers or plants m-2 were set up with the randomized block design of 3 replications and the experiment was repeated in 4 seasons in 2009-2010. The canopy development, light interception, dry weight production and partitioning, tuberization and tuber weight were investigated to elucidate the mechanism by which the plant density affects the formation and growth of the minitubers. The results showed that the number of the tubers formed per unite area was in line with the increase in plant density. The difference in leaf area index （LAI） between the plant densities, especially in early stage of the plant growth, resulted in more radiation interception and dry weight producing in higher plant density than in lower one. However, our analysis demonstrated that the conversion coefficient of the cumulative intercepted radiation to plant weight and the dry weight partition rate to the tubers were constant between plant densities, suggesting that less amount of the photoassimilates partitioned to individual tubers is causal for more small tubers in high plant density. A negative exponential curve model, determined by total number of tubers produced per unit area and the mean tuber weight, fitted well to the tuber size distribution pattern. The optimum plant density could be estimated from this model for a maximum production of the minitubers with desired size.
