Folate content in fresh corn: Effects of harvest time, storage and cooking methods

Abstract Fresh corn is a good source of micronutrients. Here, we investigated the effects of harvest time (18–24 days after pollination), storage temperature (25 °C, 4 °C, or −20 °C), and cooking method (boiling, steaming, or microwave heating) on folate content and retention in fresh corn. Folate levels in the selected six fresh corn cultivars were 66.6–152 μg/100 g fresh weight, with 5-methyltetrahydrofolate as the predominant vitamer; and the time of harvest did not significantly impact folate levels. An average folate retention of 83 % was observed in waxy corn varieties after 5 days of storage at 25 °C, and 77 % (average) of the folates was retained in sweet corn cultivars after 3 days of storage in a 4 °C refrigerator. The average folate retention was 71 % after 14 days of storage at −20 °C, which decreased to 40 % after 120 days. A folate reduction of 45 % (average) was observed in boiled corn, whereas steaming and microwave heating involved minor folate loss of 12 % and 15 %. These results provide insight into folate contents and retention in raw and processed corn post-harvest. Our study revealed that fresh corn is rich in active folate vitamers and is thus a promising dietary source of folates.