Folates: Chemistry, analysis, occurrence, biofortification and bioavailability

Folates (Vitamin B-9) include both naturally occurring folates and synthetic folic acid used in fortified foods and dietary supplements. Folate deficiency causes severe abnormalities in one-carbon metabolism can result chronic diseases and developmental disorders, including neural tube defects. Mammalian cells cannot synthesize folates de novo; therefore, diet and dietary supplements are the only way to attain daily folate requirements. In the last decade, significant advancements have been made to enhance the folate content of rice, tomato, common bean and lettuce by using genetic engineering approaches. Strategies have been developed to improve the stability of folate pool in plants. Folate deglutamylation through food processing and thermal treatment has the potential to enhance the bioavailability of folate. This review highlights the recent developments in biosynthesis, composition, bioavailability, enhanced production by elicitation and metabolic engineering, and methods of analysis of folate in food. Additionally, future perspectives in this context are identified. Detailed knowledge of folate biosynthesis, degradation and salvage are the prime requirements to efficiently engineer the plants for the enhancement of overall folate content. Similarly, consumption of a folate-rich diet with enhanced bioavailability is the best way to maintain optimum folate levels in the body. (C) 2016 Elsevier Ltd. All rights reserved.