Development and Characteristics of Functional Beverages Formulated with Onion Peel Extract

Oxidative stress contributes significantly to chronic diseases such as cancer, cardiovascular diseases, and diabetes. Onion (Allium cepa L.), a widely utilized vegetable, has various health benefits, including antioxidant, anti-inflammatory, and anticancer properties. Discarded onion peel contains abundant quercetin and flavonoids, potent antioxidants suitable for functional food applications. This study developed and evaluated functional beverages containing various concentrations (10%, 20%, and 30%) of onion peel extract (OPE). The physicochemical properties, antioxidant activities, and sensory attributes of the beverage enriched with onion peel extract were analyzed. The results showed significant increases in the total polyphenol and flavonoid contents, enhancing the DPPH and ABTS radical scavenging activities as the concentration of OPE increased. On the other hand, higher OPE concentrations negatively impacted the sensory attributes such as appearance, aroma, taste, and overall acceptability. The sensory evaluation showed that beverages containing 10% OPE scored highest in taste and overall acceptability (6.11 and 6.30 points, respectively), which are comparable to the control sample (6.26 points for overall acceptance). In contrast, 20% and 30% OPE concentrations showed significant declines in the sensory scores (p<0.05). Therefore, 10% OPE is optimum for balancing antioxidant functionality with sensory quality. These findings provide a scientific basis for developing onion peel extract-enhanced functional beverages that meet consumer demand for health-oriented yet palatable options.