Thermal processing of tomatoes by air frying and baking: effects on coloured and colourless carotenoid bioaccessibility

This study evaluated the effects of air frying (AF) and conventional baking (B) on the concentration and bioaccessible content of carotenoids (CBC) in cherry tomatoes, with a focus on both coloured (lycopene, β-carotene, lutein, ζ-carotene) and colourless (phytoene, phytofluene) compounds. Tomatoes were cooked at 180-200 °C for 2-20 min, and carotenoids were quantified by rapid-resolution liquid chromatography (RRLC). CBC was assessed using the standardized INFOGEST 2.0 in vitro digestion protocol. Both AF and B improved total CBC compared to raw tomatoes. Maximum CBC was achieved at 190 °C/10 min (AF) and 180 °C/20 min (B), with no significant differences. Colourless carotenoids were more thermally stable and bioaccessible than coloured ones. Phytoene and phytofluene retained high CBC even after prolonged cooking, while lycopene was heat-sensitive. AF reduced energy consumption by 78.6% versus baking. These results suggest that AF is a sustainable and efficient method for enhancing carotenoid bioaccessibility in tomatoes.