Evaluation of folate retention in ready-to-serve and ready-to-cook foods

This study analyzed folate and folic acid contents in 41 commercially available ready-to-serve (RTS) and ready-to-cook (RTC) foods in Korea, focusing on the effects of cooking methods and retention factors. Samples included chicken, seafood, and meat, were analyzed in both raw and cooked states (grilled, fried, and air-fried). Folate levels were determined using a microbiological assay using trienzyme extraction coupled with Lactobacillus casei method. The analytical method showed good precision (RSDr 2.63% and RSDR 9.66%) and accuracy (recovery 96.5%). Folate was detected in all samples, ranging from 2.45 to 45.37 μg/100 g (wet basis), with a 19-fold variation among items. Folic acid was identified in dumplings, likely from fortified flour. While no consistent pattern was observed across cooking methods, air frying generally showed higher retention, up to 1.23. Comparing wet and dry basis values revealed significant impacts of moisture on folate contents. These findings provide reliable folate data for RTS and RTC products and support improvements in the national food composition database.