18B-13

Y. MA¹, J. Tang², and C. Han². (1) Dept. of Food Engineering, Harbin Univ. of Commerce, Box 36, 138 Tongda St, Daoli Dist, Harbin, 150076, China, (2) Dept. of Food Engineering, Harbin Univ. of Commerce, 138 Tongda St Daoli Dist., Harbin, 150076, China

Wood ear Auricularia auricular have been cultivated in China for thousands of years, although they have been known as Chinese traditional healthy foods, the functional factors are not clear. Our objectives were to isolate and purify polysaccharides from wood ear and evaluate their hypoglycemic, hypolipidemic and antioxidant activities. Three methods, hot water, alkali, and proteinase and cellulase, were used to extract polysaccharides and the results were compared. The chemical compositions and molecular weight of the extracts by proteinase and cellulase were studied by DEAE-Cellulose 52 column and Sepharose CL-4B column chromatography, and Sephadex G-100 column chromatography, respectively. Rats were used to evaluate the hypoglycemic, hypolipodemic and antioxidant activities of the extracted polysaccharides at the levels of 50, 100, 200, and 400 mg/kg. The results showed that the extraction rate of the polysaccharides by proteinase and cellulase was 7.82%, higher than hot water and alkali methods. The results from DEAE-Cellulose 52 column and Sepharose CL-4B column chromatography revealed that there were two main polysaccharides in the extracts, containing no protein, free monosaccharides, starch and polyphenols; and the results from Sephadex G-100 column chromatography showed that the molecular weight of the two main polysaccharides weight were 31.7°Á104,and 18.3°Á104, respectively. The functional experiments showed that the extracted polysaccharids can lower the fasting blood glucose and improve the glucose tolerance of diabetic rats; increase the total-antioxidant ability and the activity of SOD, GSH-Px and reduce the content of MADA in the blood of normal rats; lower the blood TC, TG and LDL levels and enhance the level of blood HDL HDL /TC and HDL/LDL in hyperlipidemia rats. This study provides the new method to isolate and purify the polysaccharides from wood ear and the principle basis for the development of functional foods from wood ear.

Session 18B, Food Chemistry: Antioxidant and bioactive agents
2:00 PM - 5:30 PM, Sunday PM Room Hall I-2

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