Evaluation of the quality attributes of Ghanaian Robusta coffee subjected to different degrees of roasting

In recent years, there has been increasing interest in functional beverages that provide health benefits and an energy boost. With the underutilized Ghanaian Coffea canephora (Robusta) emerging as a promising beverage, this study investigated the impact of roasting on the proximate composition, minerals, phytochemicals, oxidative stability, antioxidant, and antimicrobial activity of Ghanaian Robusta coffee beans (green, light, medium, and dark roasts). Moisture and total carbohydrate contents significantly (p ≤ 0.05) decreased with roasting, while ash, protein, fat, and caloric value increased. Total phenolics (99.21 ± 4.29 mg GAE/g), flavonoids, and antioxidant activity (19.92 ± 0.05 mg TEAC/g) peaked in light roast, whereas phenolic acids were highest in medium roast (53.60 ± 1.32 mg CAE/g). Calcium increased ninefold across roasts relative to green coffee beans, while green coffee had the highest contents of potassium, magnesium, iron, zinc, manganese, and copper. Toxic elements were not detected, confirming the safety of the coffee samples. Increasing roasting intensity decreased the oxidation induction time of roasted coffee compared to green coffee. All coffee samples exhibited significant inhibitory activity against the tested microorganisms. The findings of this study provide valuable insights into the quality of Ghanaian Robusta coffee and enhance its potential in the global functional beverage market.