β-sitosterol content evolution in three maca (Lepidium meyenii Walp.) ecotypes during pre-harvest, harvest and natural post-harvest drying

The objective of this work was evaluate the β-sitosterol content during the pre-harvest, harvest and post-harvest drying stages in the hypocotyls of yellow, red and black maca. An increase in β-sitosterol content by HPLC-DAD at different times from pre-harvest to harvest stages was observed. Yellow maca hypocotyls reached their highest value at 60 days before harvest (108.34 ± 2.44 mg 100 g -1 MS), red maca hypocotyls at 30 days before harvest (101.81 ± 2.29 mg 100 g MS) and black maca hypocotyls at harvest (91.63 ± 1.17 mg 100 g MS). At harvest, the β-sitosterol content was similar in the three ecotypes. It should be noted that post-harvest drying, under traditional conditions, caused a significant loss (46.22% yellow maca 52.47 % red maca and 63.72% black maca) in β-sitosterol content. The results suggest that new drying techniques should be used to avoid loss of β-sitosterol.