Effects of combined microwave-hot-air-drying on the physicochemical properties and antioxidant activity of Rhodomyrtus tomentosa berry powder

Rhodomyrtus tomentosa berries are rich in nutrition, but easily mildew, so it is necessary to dry them with a proper drying technique in time. The effects of the combined microwave-hot-air-drying (CD) on the physicochemical and antioxidant properties of Rhodomyrtus tomentosa berry powder were evaluated in this study, compared with those of hot air drying (HD) and microwave drying (MD). The results showed that the hydration properties and oil holding capacity of CD-berry powder were better than those of HD- and MD-ones. However, CD-berry powder showed lower fillibility and liquidity than HD-one and but similar to MD-one. There was no significant difference among the thermal stability of berry powder produced by the three drying methods. Furthermore, CD was beneficial to maintain the color, nutrition, and active ingredients of Rhodomyrtus tomentosa berry powder. CD-berry powder and MD-one had similar antioxidant properties. In general, CD is more suitable for the processing of Rhodomyrtus tomentosa berry powder.