Researchers at the Food Color and Quality Laboratory of the University of Seville studied the effects of different cooking methods used for tomatoes and carrots (oven, microwave or air fryer, among others) on the amount of carotenoids potentially available for absorption by the body after digestion of these foods. According to the study, the bioavailability index varies significantly depending on how these foods are cooked. Carotenoids are compounds of great importance due to their positive effects on health.
In the case of carrots, the bioavailability of total carotenoids increased ninefold when cooked in the oven. For tomatoes, the highest bioavailability values were obtained by cooking them either in an air fryer (190 °C for 10 min) or in a conventional oven (180 °C for 20 min). There were no significant differences between the two methods. Although the increase in bioavailability was more modest (1.5-fold increase), it was also significant compared to raw tomatoes.
The researchers also highlight that increases in the bioavailability of vitamin A carotenoid precursors in tomatoes (α-carotene and β-carotene) ranged from 26 to 38-fold and 46 to 71-fold, respectively, compared to those in raw carrots. Cooking is therefore a sometimes overlooked strategy to combat vitamin A deficiency, one of the world’s most serious nutritional problems.
Energy efficiency
The main innovation of these studies lies in identifying the cooking methods that led to the greatest increase in bioavailability per unit of electricity consumption. In the case of carrots, cooking in a microwave oven was found to be the most efficient technique, with a 96% reduction in electricity consumption compared to cooking in a conventional oven. In the case of tomato, cooking in an air fryer resulted in the highest bioavailability values, while also allowing an 80% reduction in energy consumption.
The results were recently published in the journals Food & Function (2024) and Food Chemistry (2026) and provide experimental evidence to define the concept of “sustainable cooking” from a nutritional and energy point of view. According to the researchers, if the idea is adopted and implemented in millions of households and facilities on a daily basis, it could make a significant contribution to a more sustainable food system.
Implications for public health and nutritional cosmetics
Carotenoids are compounds of great importance for health promotion. Some, such as α- and β-carotene, are precursors to vitamin A, an essential nutrient involved in many processes. In addition, both carrots and tomatoes are good sources of the colorless carotenoids phytoene and phytofluene. These have attracted considerable interest due to their biological activities. They accumulate in the skin, where they can provide protection by absorbing UV radiation.
