Environmental factors influence the contents of taste components, such as capsaicinoid compounds, in the fruit of chili pepper (Capsicum annuum). The present research was conducted to evaluate the effect of water supply and harvesting date after flowering on sugar and capsaicinoid contents in fruit of the Japanese chili pepper cultivars ‘Botankosho’, ‘Fushimiamanaga’, ‘Manganji’, and ‘Sapporo Oonaga Nanban’. The experiment was conducted in a greenhouse from April to October in 2016 and 2017. Three water supply treatments were applied: 260 mL (excess), 130 mL (standard), and 50 mL (drought) per application. Fruit were harvested at 20, 30, 40, and 50 days after flowering (DAF). Glucose, glutamic acid, and total sugar were measured using a portable spectrophotometer, and capsaicinoid content was measured by HPLC. Total sugar content and Brix tended to increase with later harvesting, whereas glucose content did not change significantly by DAF. Sugars in the fruit were dominated by fructose, and the ratio of fructose content to total sugar content increased as the fruit matured. Glutamic acid content in the fruit increased up to 40 DAF, and thereafter remained unchanged or decreased. The capsaicinoid content of the fruit increased with fruit maturation. Elevation in water supply induced an increase in the fruit glucose content and decrease in total sugar and glutamic acid contents. Previous studies of tomato (Solanum lycopersicum L.) found that total sugar and glucose contents decrease in response to increase in water supply. Therefore, it is suggested that sugar metabolism and accumulation differ in the fruits of tomato and chili pepper. The highest capsaicinoid content in chili pepper fruit was observed in response to the drought treatment.

环境因素会影响味道组分，如类辣椒素化合物，辣椒果实的内容（辣椒）。本研究旨在评估开花后供水和收获日期对日本辣椒品种“ Botankosho”，“ Fushimiamanaga”，“ Manganji”和“ Sapporo Oonaga Nanb​​an”果实中糖和辣椒素含量的影响。该实验于2016年和2017年4月至10月在温室中进行。应用了三种供水处理：每次施用260 mL（过量），130 mL（标准）和50 mL（干旱）。在开花后20、30、40和50天（DAF）收获果实。使用便携式分光光度计测量葡萄糖，谷氨酸和总糖，并通过HPLC测量辣椒素含量。总糖含量和白利糖度趋于随后期收获而增加，而DAF并未显着改变葡萄糖含量。水果中的糖以果糖为主，果糖含量与总糖含量的比值随着果实的成熟而增加。水果中的谷氨酸含量增加至40 DAF，此后保持不变或下降。果实中的辣椒素含量随果实成熟而增加。供水量的增加导致果实葡萄糖含量增加，总糖和谷氨酸含量降低。以前对番茄的研究（Solanum lycopersicum L.）发现总糖和葡萄糖含量随着供水量的增加而降低。因此，建议番茄和辣椒的果实中糖的代谢和积累有所不同。响应干旱处理，辣椒果实中的辣椒素含量最高。