Innovative Sun-Activated Vitamin D and UV-B Enhancement in Mushrooms for Smart Food Fortification and Functional Nutrition

Abstract

This study evaluated a sustainable biofortification approach to enhance vitamin D2 content in edible mushrooms and to translate this enhancement into acceptable functional food products. Fresh and dried mushrooms (Agaricus bisporus) were exposed to controlled natural sunlight at different times of day and to calibrated UV-B irradiation to optimize the photoconversion of ergosterol to vitamin D2. Environmental parameters, including UV-B intensity, temperature, and humidity, were monitored to identify optimal exposure conditions. Both sunlight and UV-B treatments significantly increased vitamin D2 levels compared with dark-dried controls (0.4 μg/g). Maximum enrichment was achieved under midday sunlight (up to 6.0 μg/g in fresh slices and 9.0 μg/g in ground dried samples) and following 45 min of UV-B exposure (up to 12.0 μg/g in ground samples), highlighting the importance of UV dose, exposure duration, and surface area. Excessive exposure led to reduced vitamin D2 levels, indicating photodegradation beyond an optimal threshold. Protein content remained unchanged across treatments (~25.5–26.2%), confirming preservation of nutritional quality. The vitamin D–enriched mushroom powder was incorporated into instant noodle seasoning at different inclusion levels and evaluated using a 9-point hedonic sensory scale. All formulations exceeded the acceptance threshold (≥7), with high scores for taste, overall acceptability, and versatility, and a preference for higher inclusion levels. Overall, the findings demonstrate that optimized sunlight and UV-B exposure can produce nutritionally stable, vitamin D-rich mushroom powders with excellent consumer acceptability, supporting their potential as a scalable, plant-based strategy to address dietary vitamin D insufficiency.