Impact of temperature and relative humidity on physicochemical properties of the spray dried red flesh dragon fruit powder during storage

Abstract

This study was carried out to evaluate the effects of storage temperature (5 - 7oC, 29 - 31oC, and 50oC) and relative humidity (RH 10 - 84%) on the stability of antioxidant compounds such as betacyanin, polyphenols. The changes in color, moisture content, the water activity of spray-dried red flesh dragon fruit powder during storage were also observed. The results showed that after 40 days of storage at 5 - 7oC, the samples got betacyanin content of 3.76 mg/100 g dw and a total phenolic of 28.31 mg/100 g dw. These values were higher than those of samples stored at ambient temperature (29 - 31oC) and 50oC. Besides, this study also recorded that the low relative humidity of the environment at 10 - 23% maintained the product's betacyanin (4.16 - 3.61 mg/100 g dw) and polyphenol content (27.29 - 25.66 mg/100 g dw) as well as a desirable water activity, which was better than the zone from 57% to 84% (0.28 - 0.3).