18C-25

E. Y. JANG¹, J.-B. Eun¹, J.-S. Im², and Y.-M. Kang¹. (1) Dept. of Food Science & Technology, Chonnam National Univ., Gwangju, 500-757, South Korea, (2) Dept. of Food Sci. & Biotechnol., Konyang Univ., San 26 Naedong, Nonsan, 320-711, South Korea

Mulberry leaves has been very popular in Korea. They are dried, made into powder and added to tea, bread and Korean rice cake etc. However, drying of mulberry leaves has not been studied yet. In this study, physicochemical characteristics of mulberry leaf powders (MLP) manufactured by different drying methods were investigated. Mulberry leaves were freeze-dried, room temperature air dried at 20C, and hot-air dried at 45, 50, 55, and 60C. After drying, the leaves were ground to make powder passing 40 mesh. Proximate composition was analyzed by AOAC methods and color was measured by a colorimeter. Total phenolic content was determined by Folin-Denis method and vitamin C content was measured by indophenol method. The flavonoid content was determined by spectrometry. No significant difference was found in proximate composition between various drying methods. With decreasing hot-air drying temperature, Hunter L, a and b color values of MLP were decreased. Freeze-dried MLP showed the highest values in color a and b values, while the room temperature air-dried did the lowest values. The drying temperature did not affect total phenolic contents of MLP. In vitamin C content, the freeze-dried MLP was the highest, 166.7 mg/100 g, while the room temperature air-dried MLP was lowest, 100 mg/100 g. Flavonoid content increased with increasing temperature up to 55C and then decreased. The reason that MLP dried at lower temperature has lower flavonoid content needs further study. These results showed that freeze-drying would be the best to make MLP because it had the highest vitamin C content and most intact green color. In addition, room temperature drying is not suitable for MLP production.

Session 18C, Food Chemistry: Food composition, analysis and volatiles
2:00 PM - 5:30 PM, Sunday PM Room Hall I-2

2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana