본 연구는 홍시라떼 분말화의 최적조건 설정을 위하여 반응표면분석법(RSM)을 이용하였으며, 독립변수는 inlet temperature(X1), air flow rate(X2), 시료의 공급속도인 feed flow rate(X3)로 설정하고 종속변수로는 회수량(Y1), 수분흡 수지수(Y2), total phenolic compounds(Y3)로 설정하였다. 각 종속변수에 따른 회귀식은 모두 p<0.001 수준에서 유의성이 인정되었다. 홍시라떼의 경우 과당이 풍부하여 분말의 부착성이 높기 때문에 유리전이 온도와 입자의 표면 온도 차이가 낮을수록 회수량은 높아졌으며, 분말의 결정성과 응집성은 증가하여 수분흡수지수는 낮아졌다. 또한 낮은 inlet temperature(X1)와 높은 feed flow rate(X3)는 입자의 표면 온도와 열의 접촉 시간을 모두 낮추어 total phenolic compounds의 손실을 최소화 하였다. 각 독립변수와 종속변수의 영향을 나타내는 반응표면그래프를 이용하여 최적 분말화 조건을 예측한 결과 inlet temperature(X1) 90℃, air flow rate(X2) 53 mL/min, feed flow rate(X3) 17.00 mL/min로 결정되었다.

The purpose of this study was to determine the optimum spray drying conditions of soft persimmon latte using response surface methodology that is a statistical procedure used for optimization studies. A central composite design was applied to investigate the effects of independent variables, inlet temperature (X1), air flow rate (X2), and feed flow rate (X3), on responses such as yield, water absorption index, and total phenolic compounds. Statistical analysis revealed that independent variables significantly affected all the responses. A maximum yield of 8.11 g was obtained at 90℃ of X1, 51.82 mL/min of X2 and 7.00 mL/min of X3. A minimum water absorption index of 0.58 was obtained at 101℃ of X1, 60.00 mL/min of X2 and 17.00 mL/min of X3. A maximum total phenolic compounds of 298.02 μg/mL was obtained at 90℃ of X1, 43.33 mL/min of X2 and 17.00 mL/min of X3. In conclusion, the best spray drying conditions were as follows: X1, 90℃; X2, 53 mL/min; X3, 17 mL/min. Under those optimal conditions, the powder’s yield (7.46 g), water absorption index (0.54), and the content of total phenolic compounds (294.75 μg/mL) were estimated.

Abstract
 서 론
 재료 및 방법
  재 료
  홍시라떼 제조
  분무건조 최적화를 위한 실험계획
  회수량 측정
  수분흡수지수(WAI) 측정
  Total phenolic compounds의 함량 측정
  통계처리
 결과 및 고찰
  분무건조를 이용한 홍시라떼의 분말화
  회수량
  수분흡수지수(WAI)
  Total phenolic compounds
  홍시라떼의 분말화 조건의 최적화
 요 약
 감사의 글
 References

• Mi-Jeong Park(Department of Agro-Food Resources, National Institute of Agricultural Sciences, Rural Development Adminstration, 농촌진흥청 국립농업과학원 농식품자원부) | 박미정
• Sang-Bum Kim(Department of Agro-Food Resources, National Institute of Agricultural Sciences, Rural Development Adminstration, 농촌진흥청 국립농업과학원 농식품자원부) | 김상범
• Sook-Jin Kim(Department of Agro-Food Resources, National Institute of Agricultural Sciences, Rural Development Adminstration, 농촌진흥청 국립농업과학원 농식품자원부) | 김진숙
• Kyung-Mi Kim(Department of Agro-Food Resources, National Institute of Agricultural Sciences, Rural Development Adminstration, 농촌진흥청 국립농업과학원 농식품자원부) | 김경미
• Song-Yi Choi(Department of Agro-Food Resources, National Institute of Agricultural Sciences, Rural Development Adminstration, 농촌진흥청 국립농업과학원 농식품자원부) | 최송이
• Mi Chang(Department of Agro-Food Resources, National Institute of Agricultural Sciences, Rural Development Adminstration, 농촌진흥청 국립농업과학원 농식품자원부) | 장미
• Gi-Chang Kim(Department of Agro-Food Resources, National Institute of Agricultural Sciences, Rural Development Adminstration, 농촌진흥청 국립농업과학원 농식품자원부) | 김기창 Corresponding author