Drying of acerola residues in a roto-aerated dryer assisted by infrared heating

Abstract

Acerola (Malpighia emarginata D.C.) is a tropical fruit which has attracted recent industrial interest, due to its high levels of bioactive compounds and vitamin C. However, acerola processing generates a substantial amount of wastes, which can represent up to 40% of total processed volume. The drying of acerola residues in a new dryer, developed by our research group, named as roto-aerated dryer, has been investigated. This dryer provides a better fluid-particle contact than the conventional rotatory dryer. A pre-drying system with infrared lamps has been installed in the feed of this new dryer. The effect of the pre-treatment of this fruit residues with ethanol was also investigated. The results shown that the roto-aerated dryer assisted by infrared radiation hybrid combined with a pre-treatment with ethanol is a good alternative for processing fruit residues, aiming their reuse. It was possible to identify conditions under which the phenolic, flavonoid, and antioxidant capacity presented high levels after drying. The main phenolic compounds were idenfied by HPLC.Keywords: Drying; roto-aerated dryer; infrared; acerola