본 연구는 로스팅 뽕잎차(X1)와 로스팅 페퍼민트차(X2)의 최적 혼합비율을 도출하고자 반응표면분석법(RSM)을 이용하여 로스팅 뽕잎차(X1)와 로스팅 페퍼민트차(X2)를 독립변수로, 항산화 활성(Y1), 미백활성(Y2), 항주름 활성(Y3) 및 항당뇨 활성(Y4)을 종속변수로 실험을 설계하였다. 항산화와 미백 활성이 최대로 발현된 로스팅 뽕잎차와 로스팅 페퍼민트 차의 혼합 비율은 로스팅 뽕잎차(A)가 1.49, 로스팅 페퍼민트차(B)가 0.75일 때였다. 이때 total polyphenol 함량은 42.09 mg TAE/g, total flavonoid 함량은 45.65 mg QE/g, DPPH radical 소거능은 71.65%, ABTS radical 소거능은 38.39%, tyrosinase 저해 활성은 53.30%로 예측되었다. 이 혼합 비율에서는 로스팅 페퍼민트차가 흥미구간 내 최고점을 나타냈다. 이에 로스팅 뽕잎차와 로스팅 페퍼민트차 함량을 실험범위내로 확장하여 항산화와 미백 활성이 최대로 발현되는 최적 혼합 비율을 추가로 예측해보았다. 실험구간 내에서 항산화와 미백 활성이 최대로 발현된 로스팅 뽕잎차와 로스팅 페퍼민트차의 혼합 비율은 로스팅 뽕잎차(A)가 1.79, 로스팅 페퍼민트차(B)가 0.80일 때였다. 이때 total polyphenol 함량은 42.17 mg TAE/g, total flavonoid 함량은 49.48 mg QE/g, DPPH radical 소거능은 74.32%, ABTS radical 소거능은 40.23%, tyrosinase 저해 활성은 53.74%로 예측되었다. 항산화와 항주름 활성이 최대로 발현된 로스팅 뽕잎차와 로스팅 페퍼민트차의 혼합 비율은 로스팅 뽕잎차(A)가 1.11, 로스팅 페퍼민트차(B)가 0.75일 때였다. 이때 total polyphenol 함량은 43.78 mg TAE/g, total flavonoid 함량은 42.32 mg QE/g, DPPH radical 소거능은 71.57%, ABTS radical 소거능은 38.10%, elastase 저해 활성은 25.08%로 예측되었다. 항산화와 항당뇨 활성이 최대로 발현된 로스팅 뽕잎차와 로스팅 페퍼민트차의 혼합 비율은 로스팅 뽕잎차(A)가 0.53, 로스팅 페퍼민트차(B)가 0.75일 때였다. 이때 total polyphenol 함량은 46.37 mg TAE/g, total flavonoid 함량은 37.24 mg QE/g, DPPH radical 소거능은 71.44%, ABTS radical 소거능은 37.66%, α-glucosidase 저해 활성은 53.59%로 예측되었다. 결과적으로 본 연구를 통해 로스팅 뽕잎과 로스팅 페퍼민트 혼합차의 항산화와 미백 활성, 항산화와 항주름 활성, 항산화와 항당뇨 활성이 최대로 발현될 수 있는 최적 혼합 비율이 도출되었다. 향후 본 연구결과를 바탕으로 다양한 천연물 소재들 간의 혼합을 통한 시너지 효과가 밝혀지길 기대한다.
This study aimed to find out the optimal mixing ratio of roasted mulberry leaf tea(X1) and roasted peppermint leaf tea(X2). To this end, we designed the study using the roasted mulberry leaf tea(X1) and the roasted peppermint leaf tea(X2) as independent variables, while antioxidant activity(Y1), whitening activity(Y2), anti-wrinkle activity(Y3) and antidiabetic activity(Y4) as dependent variables, through response surface methodology(RSM). Antioxidant and whitening activities were expressed maximally when the mixing ratio of the roasted mulberry leaf tea(A) to the roasted peppermint leaf tea(B) was 1.49 to 0.75. At this ratio, the total polyphenol content was predicted to be 42.09 mg TAE/g, the total flavonoid content to be 45.65 mg QE/g, DPPH radical scavenging to be 71.65%, ABTS radical scavenging to be 38.39% and tyrosinase inhibitory activity to be 53.30%. The roasted peppermint leaf tea exhibited the peak point in the section of interest at this mixing ratio. We, accordingly, increased the contents of the roasted mulberry leaf tea and roasted peppermint leaf tea into the experimental range, and tried to predict the optimal mixing ratio at which antioxidant and whitening activities would be expressed maximally. In the experimental section, antioxidant and whitening activities were expressed maximally when the mixing ratio of the roasted mulberry leaf tea(A) to the roasted peppermint leaf tea(B) was 1.79 to 0.80. At this ratio, the total polyphenol content was predicted to be 42.17 mg TAE/g, the total flavonoid content to be 49.48 mg QE/g, DPPH radical scavenging to be 74.32%, ABTS radical scavenging to be 40.23% and tyrosinase inhibitory activity to be 53.74%. Antioxidant and anti-wrinkle activities were expressed maximally when the mixing ratio of the roasted mulberry leaf tea(A) to the roasted peppermint leaf tea(B) was 1.11 to 0.75. At this ratio, the total polyphenol content was predicted to be 43.78 mg TAE/g, the total flavonoid content to be 42.32 mg QE/g, DPPH radical scavenging to be 71.57%, ABTS radical scavenging to be 38.10% and elastase inhibitory activity to be 25.08%. Antioxidant and antidiabetic activities were expressed maximally when the mixing ratio of the roasted mulberry leaf tea(A) to the roasted peppermint leaf tea(B) was 0.53 to 0.75. At this ratio, the total polyphenol content was expected to be 46.37 mg TAE/g, the total flavonoid content to be 37.24 mg QE/g, DPPH radical scavenging to be 71.44%, ABTS radical scavenging to be 37.66% and α-glucosidase inhibitory activity to be 53.59%. In conclusion, this study successfully derived the optimal mixing ratios of the mixed teas of roasted mulberry leaves and roasted peppermint leaves, at which antioxidant and whitening activities, antioxidant and anti-wrinkle activities, and antioxidant and antidiabetic activities could be expressed maximally. Based on these findings, we expect that the synergy effects through the mixing of various natural materials will be revealed.