The impact of fermentation processes on the production, retention and bioavailability of carotenoids: An overview

Background: Carotenoids are isoprenoids compounds widely distributed in foods. A difference of carotenoids relative to other food bioactives is that some can be converted into compounds exhibiting vitamin A activity, which is essential for humans. Besides, they are more versatile as they are also natural pigments, antioxidants and can be involved in health-promoting actions. Lately, they are also attracting interest in relation to skin beauty. Their importance for different industry sector (foods, feeds, pharmaceutical, cosmetics) is therefore indisputable. Carotenoids can be obtained by different approaches including extraction from appropriate sources or synthesis. Scope and approach: Due to their advantages (easiness for the optimization of conditions to obtain higher yields, versatility, etc.) fermentative processes have been long studied and even applied at industrial scale for their production. On the other hand, food fermentation is an ancient approach that usually results in products with new characteristics, enhanced quality and/or better preservation. However, the impact of such processes on the carotenoids present in the foods and their bioavailability are not well understood yet. Key findings and conclusions: In this work, approaches used to obtain carotenoids by fermentation are reviewed as well as the impact of food fermentation on these compounds. Some research needs are also pinpointed, including further studies on the effect of food fermentations on the potential bioavailability of carotenoids, the production of carotenoids of commercial interest other than beta-carotene, lycopene or astaxanthin or that of carotenoid cleavage derivatives.