Physiological Activity of Coffee Beans and Roasted Black Beans (Rhynchosia nulubilis) Mixture Extracts for Coffee Alternative Beverage Development

This study was designed to develop and to qualify a coffee alternative beverage using a mixture of coffee beans and roasted black beans (Rhynchosia nulubilis). Therefore, the total isoflavone content (TIC), total phenol content (TPC), antioxidant activity, anti-inflammatory activity, NFATc1 (Nuclear factor of activated T-cells c1) expression in RANKL (receptor activator of nuclear factor kappa-B ligand)-stimulated RAW264.7 cells and sensory evaluation were measured for 5 different Cb (coffee bean)-RoS (roasted seomoktae) mixture extracts (Cb100RoS0, Cb75RoS25, Cb50RoS50, Cb25RoS75, and Cb0RoS100). Cb0RoS100 had the highest TIC ($516.83{\pm}36.61mg/100g$) and TPC ($18.11{\pm}1.77mg$ TAE/100 g) along with the highest antioxidant activity as measured by DPPH radical scavenging activity ($73.55{\pm}8.11%$) and ABTS radical scavenging activity ($63.27{\pm}7.27%$). Also, Cb0RoS100 showed the highest anti-inflammatory activity as measured by NO production ($13.57{\pm}2.21{\mu}M$) and PGE2 production ($3.25{\pm}0.21ng/mL$). The more the RoS ratio was increased in the mixtures of Cb-RoS, the more the NFATc1 protein expression was decreased in RANKL-stimulated RAW264.7 cells. In case of sensory evaluation, Cb50RoS50 had the highest scores for flavor, delicate flavor and overall quality, which were similar to those in Cb alone (Cb100RoS0). We suggest that the use of RoS replacement instead of Cb in/as a coffee alternative beverage may help to reduce the risk of caffeine-related bone loss and/or bone disease by effectively blocking NFATc1 expression in RANKL-stimulated RAW264.7 cells compared with Cb alone.