Effects of Postharvest Storage Methods on Retention of Carotenoids in Malawian Local and Hybrid Orange Maize Varieties

Vitamin A deficiency (VAD) is a critical public health issue in Malawi. Orange maize, which is rich in provitamin A carotenoids, offers a promising solution to combat VAD. However, carotenoid degradation during storage is a challenge. This study investigated the effects of two storage methods (Purdue Improved Crop Storage (PICS) bags and normal woven bags (NWBs)) in three Malawian orange maize varieties (Mthikinya, MH43A and MH44A) on retention of total carotenoid content (TCC). Measurements were conducted at monthly intervals over a period of 6 months. Results show that Mthikinya, although initially having the highest TCC (56.05 ± 0.22 mg/kg), over MH43A (44.30 ± 1.55 mg/kg) and MH44A (41.65 ± 0.93 mg/kg) experienced the most rapid degradation ( p ≤ 0.05). The greater degradation of TCC in Mthikinya was linked to biochemical variations and structural characteristics. PICS bags were slightly better than NWBs in preserving TCC over the 6 months period. The results showed that over a six‐month period, PICS bags retained 3.33%, 1.34% and 2.21% higher than NWBs for Mthikinya, MH43A and MH44A, respectively. This is attributable to the conditions inside PICS bags, which bars entry of oxygen responsible for degradative reactions for TCC. In this study, the retention of carotenoids observed in PICS bags was significantly different from the NWBs ( p < 0.05). Furthermore, the findings of the study emphasise the need for integrated approaches that consider both genetic and environmental factors to optimize carotenoid retention in orange maize and combat VAD in Malawi.