Retention based bio accessibility of carotenoids in green leafy vegetables: effect of different Indian culinary practices

Abstract

Back ground: Green Leafy Vegetables (GLV) is pigment-rich and nutritionally relevant functional food sources with unique phytochemical constituents that include carotenoids which are precursors for vitamin A and protect cells from oxidation and cellular damage. Cooking processes and other factors such as temperature, light and alteration in moisture content generally promote either isomerization (trans to cis form) or oxidative degradation of carotenoids to epoxides. Rationale: Studies pertaining to the effect of cooking methods on dietary carotenoids bio accessibility and their retention percent are scarce, particularly in an Indian Diasporas. Objective: Present study was to determine the carotenoids retention based bio accessibility in GLV such as amaranth (Amaranthus gangeticus), spinach (Spinacia oleracea) and curry leaves (Murraya koenigii), when subjected to domestic cooking methods of microwave cooking, sautéing, pressure cooking, steaming and deep frying in oil, for a time duration of 8 and 12 minutes, either with lid closed or open. Method: The retention based bio accessibility of carotenoids were quantified by rapid separation liquid chromatography (RSLC) using RP-C-18 column (150mm×4.6µ) with 70% acetonitrile, 20% dichlomethane and 10% methanol for 20 minutes at flow rate of 0.5 ml/min. Results: The maximum retention based bio accessibility of total carotenoids and ?-carotene were observed with micro wave cooking, steaming and sautéing methods. (Spinach: 57.88% and 55.92%, Amaranth: 56.15% and 57.49%, Curry leaves: 50.55% and 52.66% respectively). Conclusion: The reduction in the contents of carotenes in GLVs in correlation to various cooking methods are discussed which would be valuable for food researchers, nutritionists as well as health practitioners and dietitians, in developing and promoting nutritionally balanced diets and minimize vitamin A deficiency in Indian context.