Effect of a low oxygen storage condition on betacyanin and vitamin C retention in red amaranth leaves

We investigated the effects of different O-2 concentrations (air or 2 kPa O-2) and temperatures (5 degrees C or 20 degrees C) on the respiration rate, betacyanin content and VC content to provide basic information on the most optimal conditions for practical storage and transportation of red amaranth. The respiration rates were obviously reduced by low temperatures and low O-2 treatments. However, an increase in the CO2 production was detected in red amaranth stored at 20 degrees C-2 kPa O-2 after 30 h. The total betacyanin content changed slightly after storage for 3 days, and there was no significant difference among storage treatments. The VC contents of all the treatments were greatly reduced (more than 50%) after storage. The VC content of red amaranth stored under low temperature either with or without low O-2 was not different from the control. Nevertheless, low O-2 (2 kPa) at 20 degrees C significantly slowed the loss of VC. Our results mainly suggested that the O-2 level is one of the key factors affecting the quality of red amaranth during storage.