Production of yanggaeng containing phenolic extract from Spiraea salicifolia with antioxidant and α-glucosidase inhibitory activities

The purpose of this study was to evaluate the biological activities of the water extract of Spiraea salicifolia (SSWE). The total phenolic content (TPC) of the SSWE was 12.73 mg/g. Among the extracted components, the phenolic compounds exhibited superior biological activities compared with the solid extract. The DPPH scavenging activity of phenolic extract was 83.90-83.96% at a TPC concentration of 100-200 μg/mL. Similarly, the ABTS radical scavenging activity of the phenolic extract was 81.59-99.80% at the same concentration. The antioxidant protection factor (PF) ranged from 0.97 to 1.09 PF. The TBARS inhibition rate was 12.28-47.76% at 100-200 μg/mL TPC concentration. The α-glucosidase inhibitory activity of the phenolic extract was 15.18-28.58% within the same concentration. Based on these results, yanggaeng supplemented with SSWE powder was prepared, and its physicochemical and sensory properties were evaluated. Regarding physicochemical properties, the addition of the SSWE powder resulted in decreased values of lightness, yellowness, and redness. Textural properties, such as hardness, springiness, cohesiveness, and chewiness, decreased with increasing SSWE concentration, whereas water activity increased. Sensory evaluation indicated that the optimal addition level was 3% SSWE powder. Based on these results, SSWE shows potential for application as a functional food ingredient.