caffeine; caffeoylquinic acids; HPLC;
Effects of different drying methods on the chemical, nutritional and colour of yerba mate (Ilex paraguariensis) leaves International Journal of Food Engineering , 17(7): 551–560This work investigates the effect of differentdrying processes on chemical, nutritional and leavescolour characteristics forIlex paraguariensisleaves. Theseprocesses were composed of typical drying techniques(roasting+rotary dryer and roasting+conveyor dryer), andcutting-edge techniques (microwave oven [MW], freeze-drying (FD) and oven dryer [OD]). The MW can be analternative technique, this is because the content ofphenolic compounds (77 mg/g), antioxidant capacity(DPPH and ABTS) (∼370 and∼1040μM TE/g), methylxan-thines and caffeoylquinic acids (2–4 mg/g) were similar,and sometimes higher, to the conventional drying pro-cesses. Leaves dried with MW also exhibited satisfactorynutritional analysis for protein (16.4%), dietaryfibre(52.3%), ash (6.4%), lipid (6.1%) and moisture (5.7%),implying that yerba mate is a potential source offibre andprotein. Furthermore, the MW preserved leaves greencolour (high and low scores of b* and a*, respectively).