Composition of Tubers

Data are presented on three edible species of tuber (<igna frutescens, Eminia entennulifa, and Ipomoea transvaalensis) consumed by Hadza foragers in northern Tanzania. These species are collected almost year-round by Hadza women but previous analyses of their macronutrient composition are variable and provide results based on the analysis of whole tuber. We examined only edible portions of tuber by simulating chewing in the presence of salivary amylase and by removing from analysis the typically expectorated inedible component. Edible portions of the three peeled tubers ranged from 42.5 to 91.8 g/100 g dry wt., were low in protein (2.3}6.9 g/100 g dry wt.), and contained 19.6}26.0 g/100 g of starch. The sum of monosaccharides and disaccharides ranged from 6.2 g/100 g in the <igna frutescens to 48.3 g/100 g of edible portion of Ipomoea transvaalensis. In addition, our analysis of 5 samples of <igna frutescens had a 5-fold range in energy available to consumers, an important consideration for energetic studies. This range was due, in part, to the variation in edible portion (4}22 g/100 g of dry tuber). Our data, in comparison with those reported previously, show generally lower energy levels and higher levels of indigestible material for some of these tubers. These discrepancies are likely due to di!erences in analysis of whole tuber versus edible portion, method of measuring indigestible carbohydrate, and age of tuber. ( 2001 Academic Press