가열 및 초음파 침지법으로 제조한 단삼메디커피의 저장 중 항산화 특성

Abstract

Purpose: Medi-coffee prepared with the addition of Salvia milthiorrhiza to green coffee beans was developed using the heat immersion (HEAT) or ultrasonic immersion (SONI) methods to improve antioxidant activity. Methods: Green coffee beans immersed in Salvia milthiorrhiza extracts using HEAT or SONI were roasted and stored at 40° C for four weeks. The changes in antioxidant activities and lipid rancidity were analyzed every week during storage. Results: The total polyphenol contents(TPC) decreased over time during storage. However, the medi-coffee showed a higher level of TPC than the control. The TPC of the coffee prepared using HEAT was higher than SONI in order of HEAT>SONI>control. The decrease in TPC was from 492.45 to 406.94 mg GAE/g for HEAT, from 430.50 to 369.85 mg GAE/g for SONI, and from 357.62 to 330.55 mg GAE/g for control. Flavonoid contents showed similar decrease. The changes in DPPH and ABTS radical scavenging activities and superoxide dismutase (SOD)-like activity showed the same patterns, in that they all decreased with increasing storage time. However, while the DPPH radical scavenging activity of the control coffee decreased remarkably from 85.09% to 80.98%, the HEAT coffee retained its highest activity at 94.49% and decreased to 90.39%. Heating immersion was more effective than ultrasonic immersion to achieve higher antioxidant activity. The acid value (AV) and peroxide value (POV) of all coffee samples increased during the storage. However, medi-coffees showed a lower increase than control, and HEAT coffees showed significantly lower values than SONI. At the end of the four week storage, the AV of the control increased to 29.96 from 14.24 mg/g, while that of HEAT changed from 10.13 to 16.91 mg/g. POV also showed an increase in the order of HEAT>SONI>control. Conclusion: Overall, when the Salvia milthiorrhiza extract is added to green coffee beans, the antioxidant components of the extract are transferred to the green coffee beans, which endows them with high antioxidant activity. The heat immersion method is more effective than ultrasonic immersion for transferring the active compounds to coffee.