reported yellow color formation by catechin upon dissolving in aqueous solution due to catechin oxidation. This study confirmed yellow color formation by dissolving catechin (5 and 15 mg/100 mL) in water at ambient temperature for 2 h, and found that the higher the catechin concentration, the more intense the yellow color in solution. It was also observed that fortification with vitamin C increased BI due to by-products from oxidation of ACYs; thus, fading reddish color resulted in higher BI.