Effects of roasting on bioavailability and bioactivities of Vigna angularis and potential of coffee‐like beverage

Containing similar aroma and flavor profile of coffee after roasting, Vigna angularis have potential to be a caffeine‐free coffee‐like beverage. Microwave roasting process was conducted in a microwave oven at 600 W for 7, 14, and 21 min at 2‐min intervals, and fluidized bed roasting process was conducted in a fluidized bed roaster at 200°C for 9, 18, and 27 min. In order to compare the roasted beans, color, fat, ash, crude protein, crude fiber, antioxidant activity, and total phenolic content measurements were performed. In addition, effects of roasting methods on protein bioavailability and antinutritional factors were investigated. Sensory test was conducted to compare the coffee and coffee‐like beverages. Fluidized‐bed roasted beans had higher scores than microwave roasted beans in terms of sensory acceptability (p ≤ 0.05). Roasting process increased the total phenolic contents up to 25.32 (mg GAE/g) and the protein bioavailability up to 89.82 ± 0.11%. The results of this study revealed that roasting can be used as a tool to increase nutritive value, bioavailability, antioxidant activity, and potential of coffee‐like beverage of V. angularis. Practical Application Since Vigna angularis beans contain similar aroma and flavor profile of the coffee after roasting, they have a potential to be a caffeine‐free coffee alternative. Although coffee is very popular in demand, most of the coffee drinkers think that caffeine is very harmful. Having similar sensory scores as coffee beverages in certain roasting degrees, V. angularis beverages could be a delicious caffeine‐free alternative.