Processing powder from Keo mango peel created a semi-product with better value by utilizing the Keo mango peel by-product from the mango processing industry. The study's objectives were as follows: To develop a drying curve model for Keo mango peel powder dried by the hot air convection and to investigate the effects of pretreatment (freezing and not – freezing treatment; blanching at 90℃ for two minutes and not – blanching) and drying techniques (heat pump drying at 28℃, freeze drying, and hot air convection at 50, 60, 70℃) on the powder's quality. The drying of Keo mango peel at 50, 60, and 70℃ using hot air convection is well illustrated by the Lewis – Newtonian model. Drying blanched fresh raw materials by hot air convection at 60^oC was the most effective method. The color values of L*, a*, b*, and water activity of the mango peel powder showed 70.97±0.32, 6.27±0.12, 39.67±0.35 and 0.47±0.01, respectively. Water absorption capacity, swelling power, and water-soluble solids were respectively 7.59±0.07 g/g, 6.78±0.27%, and 6.71±0.27%. The total polyphenol content was 28.84±0.34 mgGAE/g, and the free radical DPPH scavenging was 90.43±0,12%. Drying blanched fresh raw materials by hot air convection at 60^oC can retain the best biological activity and is appropriate for the economic conditions of the Mekong Delta.

Keywords: blanching, drying, freezing, mango peel, pre – treatment