18E-1

S.-H. YOO¹, K. H. Lee², H. H. Baek³, and H. G. Lee². (1) Department of Food Sicence and Technology, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul, 143-747, South Korea, (2) Department of Food and Nutrition, Hanyang University, 17 Haengdang-dong Songdong-gu, Seoul, 133-791, South Korea, (3) Department of Food Engineering, Dankook University, San 29, Anseo-dong, Cheonan, 330-714, South Korea

Physicochemical characteristics and biological activities of Sphingomonas gellan (S-gellan) and its derivative were investigated. The S-gellan weight fractions of glucose (Glc) and glucuronic acid (GlcUA) were 0.45 and 0.25, respectively, and the molar ratio of Glc : Rha (Rhamnose) : GlcUA was approximately 4:2:3. The S-gellan was chemically derivatized with diethylaminoethyl chloride-HCl (DEAE-HCl), and the resulting modified S-gellan contained both positive and negative charges. The elemental and IR analyses were conducted to confirm the successful incorporation of DEAE groups into S-gellan. Large increase in nitrogen fraction was observed from the derivatized S-gellan by elemental analysis. The IR absorption bands induced by C-H, C-N, C-O-C stretching were noticeable at 2950, 1310-1380, 1000-1150 cm^-1, respectively, resulting from the DEAE substitution. The characteristic CH₃ and CH₂ peaks originated from DEAE group were detected in ¹H-NMR spectrum of the derivatized S-gellan as well. Solubility of native S-gellan was improved almost twice from 40 to 75% after DEAE-derivatization, while water holding capacity (WHC) drastically decreased from 10026% to 245%. Oil binding capacity (OBC) of S-gellan also significantly dropped from 1528 to 331% after the derivatization. The bile acid binding capacity of S-gellan was indirectly determined by measuring the holding capability of cholic acid inside the dialysis membrane. Once S-gellan was DEAE-derivatized, there was substantial increase in the cholic acid retardation index (CRI). Up to 9 h of dialysis, the derivatized S-gellan released 29.3% less of cholic acid than did control group. From these results of the improved water solubility and stronger bile acid binding capacity, it would be suggested that the DEAE-derivatized S-gellan take advantages over gellan itself for functional food applications.

Session 18E, Nutraceutical & Functional Foods: General I
2:00 PM - 5:30 PM, Sunday PM Room Hall I-2

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