Cycloamyloses (CA) from high-amylose rice starch (Dodamssal, 50.94% amylose) was produced to form a complex with anthocyanin extracted from black rice (sihtoheukmi). The effects of CA concentration (1, 5, 10 and 30%, w/v), pH (2, 4, 6, and 8), UVB irradiation time (~24h) and thermal treatment time (~24h) on the oxidant capacity of the complex were investigated. Anthocyanin consisting of 95% cyanidin-3-glucoside (C3G) was extracted from the black rice by suspending in 60%(v/v) ethanol containing 0.2%(v/v) hydrochloric acid for 90 min at 50°C. Cycloamyloses (CA) produced by 4-α-glucanotransferase (4αGTase) formed complexes with C3G by shaking the mixture for 48 hours at 30°C. Antioxidant activities (radical scavenging capacity) were determined by using ABTS [2,2'-azinobis-(3-ethylbenzothiazoline- 6-sulfonic acid)]. The antioxidant activities of the complexes increased with pH increasing. Upon UVB irradiation and heat treatment, the antioxidant activities were more retained for the complexes incorporating 10% CA concentration or above compared to the C3G control. Degradation rate constant (Kd) and half-life (T1/2) were obtained from degradation data of CA complex with cyanidin-3-glucoside. The effect of CA complex formation with C3G is significantly observed at pH4. The results suggest that the CA complex formed with C3G indeed has an enhanced antioxidant potential toward UVB and thermal degradation.

• Yun-Kyoung Jung(Department of Biosystems and Biomaterials Science and Engineering, and Center for Food and Bioconvergence, Seoul National University)
• Jung-Sun Hong(Department of Biosystems and Biomaterials Science and Engineering, and Center for Food and Bioconvergence, Seoul National University)
• Yong-Ro Kim(Department of Biosystems and Biomaterials Science and Engineering, and Center for Food and Bioconvergence, Seoul National University)