Abstract
In Anthrone method, the need of drying and diethyl-ether extraction of sample to measure water soluble carbohydrate (WSC), elution of polysaccharides by heated water extraction, and warming time of color development at measurement, the comparison to HPLC method with modified method were examined. No significant difference was observed in WSC content by with or without drying and diethyl-ether extraction of the sample, and the former was believed to be unnecessary for grass and mixed sward samples. In heating extraction by boiling water, the elution of starch has been kept low in ten minutes. The elution rate of other polysaccharides was constant over the ten minutes. Warming time for color development had a high influence in the result of WSC. Fructose absorbance was higher than glucose after adding anthrone, and it was a factor of overestimate of WSC. Both sugar absorbance equaled in 25-30 minutes and warming time was different from existing reports. WSC was higher than the HPLC method. The elution of polysaccharides and starch could be related to this difference. The modified method was as follows: Using the sample without treatment of drying and diethyl-ether extraction. 0.2g of sample was taken into the test tube and 30ml of distilled water was added. The time of extraction of WSC was during 10minutes in boiling water. Warming time for color development was changed to 25minutes. Other than these conditions, the conventional method was used.
