Enhancing the phytochemical composition and nutritional profiles of dry bean (Phaseolus vulgaris L.) varieties through roasting

Authors: FASHAKIN, OLUMIDE - Michigan State University; Cichy, Karen; MEDINA-MEZA, ILCE - Michigan State University

Submitted to: Journal of the Science of Food and Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/21/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Pulses, including dry beans and chickpeas are rich in nutrients and phytochemicals. Despite their health benefits, consumption of pulses is low in the U.S. Milling pulses into flours for use in convenient food products is one strategy to increase consumption. Using pulses as flours presents product functionality challenges due to lack of gluten and presence of off-flavors. Roasting has been used as a pre-treatment prior to milling to help improve the flour functionality and reduce off-flavors. From a human nutrition perspective, it is important to understand how roasting treatments impact bioactive phytochemicals present in beans and chickpeas. The goal of this research was to evaluate bean and chickpea flour, both raw and roasted for their phytochemical, lipid, and health promoting compound profiles across 12 bean types across diverse colors, from white, to yellow, to dark red. It was found that beans with darker seed coats are richer in phenolics than beans with white or lighter colors, but they are equivalent in antioxidant activity. Flavonols and saponins decreased after roasting. Saponins contribute bitterness, so this may be a positive from a flavor perspective. Roasted beans generally exhibited a slight increase in monounsaturated fatty acid content, while the levels of polyunsaturated fatty acids remained relatively stable post-roasting. Polyunsaturated fatty acid contribute to off-flavors, so choosing cultivars with lower levels may be beneficial from a flavor perspective.

Technical Abstract: Dry beans (Phaseolus vulgaris L.) and chickpeas (Cicer arietinum) are nutrient and bioactive compound dense pulses consumed worldwide. Greater utilization of pulses is hampered by their long cooking times. Use of pulses as flours is one avenue to expand use. Heat-treating prior to milling has potential to impact the functional, nutritional and health properties of pulse flours. This study examines the effects of oven roasting at 110°C for 70 minutes on the bioactive and lipid profiles of 12 dry beans and chickpea flours with varying degrees of seed coat pigmentation. Compound measurements included phenolics, flavonoids, antioxidant activity (FRAP and DPPH), carotenoids, anthocyanins, total proanthocyanidins and non-extractable polymeric proanthocyanidins (NEPA), fatty acid methyl esters (FAME), phytosterols, and saponins. Total phenolics, carotenoids, anthocyanins and NEPA tended to be higher the darker the pigmentation of the seed. Flavonols and saponins were the only compounds that changed significantly with the roasting treatment. They both decreased after roasting. Stigmasterol and ß-sitosterol were the predominant phytosterols in both raw and roasted beans. Raw and roasted bean cultivars were analyzed for their saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA). Cultivar differences were detected in fatty acid composition, but there was no impact from the roasting treatment. These findings underscore the importance of understanding seed pigmentation and roasting's impact on pulse composition, informing strategies for maximizing their processing functionality, health promoting and nutritional value in ingredient applications.