Physical and chemical characterization of yacon tuberous roots at different altitudes and planting times

ABSTRACT The post-harvest quality of yacon tuberous roots produced at different altitudes and planting times were characterized in this study. The experiment was conducted in the South of Espírito Santo State in two locations, one at 837 m altitude and the other one at 113 m altitude. The experimental design, in each place, was randomized blocks with four replications, and the treatments consisted of three planting seasons: April (autumn), July (winter) and September (spring). After harvest of the tuberous roots, we evaluated pH, titratable total acidity, moisture content, soluble solids, reducing sugars, crude fiber and ash, as well as color, hardness (maximum force recorded in the first penetration or compression cycle) and chewiness index (energy required to chew food, given by gumminess x elasticity). Tuberous roots grown at 837 m altitude, independent of planting times, presented higher soluble solids content and lighter juice, conferring better quality. However, at 113 m altitude, from April to July, the roots showed better quality, since it presents lower hardness and lighter juice.

摘要 本研究针对不同海拔与种植时段下产出的亚贡（yacon）块根的采后品质展开表征分析。试验于圣埃斯皮里图州（Espírito Santo）南部两处地点开展，一处海拔837米，另一处海拔113米。两地均采用随机区组试验设计，设置4次重复，处理组涵盖3个种植时段：4月（秋季）、7月（冬季）与9月（春季）。待块根采收后，本研究测定了其pH值、可滴定总酸度、含水率、可溶性固形物含量、还原糖含量、粗纤维含量与灰分含量，同时检测了色泽、硬度（首次穿透或压缩循环中记录的最大作用力）以及咀嚼性指数（由胶黏性与弹性的乘积得出的食物咀嚼所需能量）。结果显示，无论种植时段如何，海拔837米处种植的块根可溶性固形物含量更高、汁液色泽更清亮，品质更优；而在海拔113米处，4月至7月种植的块根硬度更低、汁液色泽更清亮，品质更佳。