Effect of germination and elicitation on phenolic composition and bioactivity of kidney beans

Ready-to-eat sprouts are becoming popular healthy fresh foods. Germination and elicitation may be used to improve phytochemical and functional quality of sprouts. The aim of this study was to unveil the efficacy of germination and the use of elicitors (500 μM ascorbic, 50 μM folic and 5 mM glutamic acid) to enhance the phenolic composition and antioxidant and angiotensin I converting enzyme (ACE) inhibitory activities of 8 day-old Phaseolus vulgaris L. var. Pinto sprouts. Sprouting produced a general decrease in flavan-3-ols and anthocyanins of sprouts that was compensated with a higher content of flavanones and flavonols. Although elicitor treatments reduced total phenolic content of sprouts, they promoted the synthesis of specific flavanones and flavonol O-glycosides, effect that was dependent on the type of elicitor. Antioxidant activity was not affected by ascorbic and folic acid treatments whereas it was slightly reduced in glutamic acid-treated sprouts. Folic acid was the only treatment that caused an outstanding increase in the ACE inhibitory activity of sprouts. In conclusion, elicitation may produce positive changes in the phenolic profile and improve health-promoting potential of sprouts, although selection of elicitor is crucial to deliver marketplace ready to eat sprouts enriched in specific bioactive phytochemicals.