Effects of cooking methods and processing stages on vitamin C in traditional Lebanese meals. (Special Issue: Micronutrients.)

摘要

Purpose - Lebanese meals rich in vitamin C are taken for granted to contain this vitamin without consideration of its losses during the cooking and storing processes. This paper aims to examine the impact of different cooking pots, refrigeration and conventional reheating or via microwaving (MWR) on vitamin C depletion. Design/methodology/approach - Two samples of three meals rich in vitamin C (AB: Aadas Bhamoud made of lentils and Swiss chard; CS: cauliflower stew; ML: Meloukhieh made of Jew's mallow) were analyzed in triplicates when they were raw, cooked in double based stainless steel (DBSS) or pressure cookers (PCs), refrigerated at 4 degrees C for 48 h, and when reheated in an open pot or in a microwave reaching 70 degrees C. The titration with 2,6-dichlorophenolindophenol method was used for vitamin C analysis. Findings - Relative vitamin C losses throughout the processing stages were 37.64, 65.43 and 79.00 percent for ML, CS and AB, respectively. DBSS tended to deplete vitamin C less than PC. AB lost 34.4 and 49.2 percent vitamin C with DBSS and PC, respectively; CS lost 52.3 and 57.5 percent with DBSS and PC, respectively; and ML lost 16.3 and 27.4 percent with DBSS and PC, respectively. Vitamin C loss at refrigeration was significant for both cooking pots used for the meals AB and ML but not for CS. Reheating resulted in further significant losses across meals and reheating methods. Practical implications - The study highlights the importance of avoiding unnecessary cooking practices to minimize vitamin C depletion and more accurately estimating its daily intake. Originality/value - The study presents for the first time the quantification of vitamin C losses in Lebanese meals subjected to different processing types and stages.