산수유 열매 추출물 첨가 방법에 따른 로스팅 커피의 저장 중 항산화 활성의 변화

Abstract

Medi-coffee with the addition of Cornus officinalis fruit extracts was prepared by heat immersion(HTI) or ultrasonic immersion(USI), and the changes in the antioxidant activity were analyzed during its storage at 40℃ for 4 weeks. It was observed that the total polyphenol and flavonoid contents decreased over time. The total polyphenol content was the highest in the HTI at 441.95(week 0) and 386.51(week 4) mg GAE/g, and the lowest in the control(CON) at 357.38(week 0) and 330.29(week 4) mg GAE/g. The total flavonoid content showed a similar tendency. The total polyphenol and flavonoid contents were in the following order: HTI>USI>CON implying that HTI was more effective in ensuring high levels of polyphenols or flavonoids than USI. The DPPH and ABTS radical scavenging activities and SOD-like activity decreased with the increase in the storage period. The CON showed the lowest DPPH radical scavenging activity at 85.24%(week 0) and 81.17%(week 4), while HTI showed the highest at 91.99%(week 0) and 87.84%(week 4). The antioxidant activities were in the order of HTI>USI>CON. The changes in the ABTS radical scavenging activity and SOD-like activity showed similar patterns during the entire storage period. The acid value(AV) and peroxide value(POV) increased as the storage period increased. However, medi-coffee prepared with the addition of Cornus officinalis showed lower AV and POV than those of CON, which suggests that the Cornus officinalis fruit extract endowed a protective effect against lipid oxidation to the green coffee beans. The changes in AV were the highest in CON from 14.26(week 0) to 29.93(week 4) mg/g, and the lowest in HTI from 11.54(week 0) to 19.08(week 4) mg/g. The POV also showed the same tendency. Overall, it is expected that coffee with the addition of Cornus officinalis could be useful for its high antioxidant activity.