Enhancing phytochemical composition and nutritional profiles in dry bean varieties through roasting

Dry beans and chickpeas are nutritionally valuable legumes widely consumed worldwide. This study examines the impact of oven roasting (110 °C for 70 min) on the phytochemical, antioxidant, fatty acid and saponin profiles of 12 pulses, including 11 common beans and 1 chickpea.

Roasting significantly affected the phytochemical composition and antinutritional factors with distinct variations among samples. Cranberry bean CRAN-1 exhibited the highest total phenolic content in raw samples (19.12 g kg^-1 GAE g^-1 DW), which decreased by 6.79% post-roasting. Pigmented beans including dark red kidney and CRAN-2 showed strong antioxidant activities pre-roasting (DPPH scavenging: 73.94% and 50.16%, respectively). CRAN-2 also had the highest anthocyanin content (0.057 to 0.036 g kg^-1 DW) among pigmented cultivars, which decreased slightly after roasting. Non-extractable polymeric proanthocyanins remained stable, while saponin content significantly decreased (up to 77% in some cultivars), suggesting improved flavor. Stigmasterol and β-sitosterol were the predominant phytosterols with enhanced availability after roasting. Fatty acid analysis revealed that saturated fatty acids are predominant, ranging from 54.7% (Manteca) to 70% (Great Northern), while the fatty acid composition was similar across all cultivars.

These findings underscore that roasting under mild controlled conditions retains and improves key bioactive compounds in common bean flours. Pigmented varieties, in particular, offer superior antioxidant and phytochemical properties. This research provides a foundation for incorporating roasted pulses into functional formulations with both dietary and industrial applications. © 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.