Effects of blanching and drying process on total flavonoid content and DPPH radical scavenging activity of green asparagus spray-dried powder (Asparagus officinalis L.) ☆

In this study, the effects of blanching and spray drying processes on total flavonoid contents and DPPH radical antioxidant properties of green asparagus (Asparagus officinalis L.) spray-dried powder were investigated. Experiments were designed using one-factor-at-a-time in the blanching process and a three-level factorial with two factors, including drying temperature and the dry matter concentration in spray drying. The results showed that suitable blanching conditions were at a temperature of 85C in 4 minutes and chosen drying conditions were at a temperature of 160C and 10% dry matter concentration using maltodextrin as a carrier. Total flavonoid contents and DPPH free radical scavenging activity of asparagus spray-dried powder were 26.97 mg RE/g and 53.64 µmol TE/g, respectively.