Effect of different cooking oils and methods on physicochemical, nutritional, and microbial safety for mixed vegetables focusing on Bangladesh

Abstract

Cooking is an essential aspect of everyday life. Cooking oils and methods exert enormous effects on the nutritional, physicochemical, microbial qualities, and bioactive compounds of vegetables. Most of them are either directly or indirectly related to human health. Hence, the present investigation was undertaken to find out the effect of two cooking methods (traditional and steam cooking) and four selected culinary oils (soybean oil, mustard oil, extra virgin olive oil, and extra virgin coconut oil) on the cooked vegetables. The results indicated that steam-cooked mixed vegetables retained more nutrients than traditional ones. The traditional cooking method of preparing mixed vegetables with soybean oil revealed higher amounts of crude fat, 26.90 ± 0.10%, whereas steam cooking and traditionally cooked vegetables without oils showed lower amounts of crude fat, 1.21 ± 0.04%, and 1.94 ± 0.04%, respectively. The highest crude fibre from 5.68 ± 0.20 to 6.48 ± 0.02% was recorded by the steam-cooked vegetables in comparison with traditionally prepared mixed vegetables. Traditionally cooked vegetables with mustard oil showed a higher crude protein (13.30 ± 0.10%). The mixed vegetables that were steam-cooked using extra virgin olive oil revealed a decreased percent of carbohydrates, 49.42 ± 0.03%. Most of the essential minerals especially for the human body like Ca, Mg, Fe, Cu, and Zn were found notable in both traditional and steam-cooking processes using extra virgin olive oil, and mustard oil. The leading bioactive compound ß-carotene 67.04 ± 0.04 mg/100 g was noted by the steam-cooked vegetables with mustard oil. The highest anthocyanin 32.69 ± 0.02 mg/100 g and ascorbic acid 42.31 ± 0.01 mg/100 g were recorded in the steam-cooked vegetables without culinary oils. Steam-cooking with extra virgin coconut and olive oil resulted in high total carotenoid and phenolic content (31.60 ± 0.05 and 3.11 ± 0.04 mg/100 g, respectively). However, the findings suggest that culinary oils used in the present study retained more essential minerals and bioactive compounds than soybean oil. Only sufficient amount of edible oil may be used for vegetables cooking and proper functioning of fat-soluble vitamins.