Determination of Total Available Carbohydrates in Plants

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Abstract
A new method of estimating the total available carbohydrate of plant material in a single detn. is described. Small samples of finely ground, air-dry material are digested by taka-diastase under conditions resulting in the breakdown of starch, dextrins, and maltose to glucose, while other sugars and fructosans are extracted at the same time. After clarifica-tion of the digest the latter compounds are converted to hexose sugars by acid hydrolysis, following which the reducing power of the neutralized hydrolysate is detd. Results obtained with this method were higher than the combined amts. of sugars, fructosans, dextrins, and starch when detd. separately and calculated as glucose; this apparently resulted from the hydrolysis of carbohydrate groups not included in the commonly employed methods of fractionation. The results of the total available carbohydrate determination showed a positive correlation of high significance with those of the fractionation method. The method is suitable for large scale routine analyses.