Comparison of Taiwan paddy- and upland-cultivated taro (Colocasia esculenta L.) cultivars for nutritive values

Taro (Colocasia esculenta L.), an important food staple for millions of people, is grown exclusively in the tropical and semitropical regions of the world. It is cultivated mainly in developing countries, rarely on large plantations but on small farms with little technology. The purpose of this study was to investigate the effect of cultivars and field preparations of taro corms on the nutrient content and protein nutritional quality. Three local cultivars of taro corms were grown by paddy and upland cultivation in Taiwan. The results showed that taro contained 63.6%–72.4% moisture, and upland-cultivated taro corms retained a higher moisture content compared to paddy taro. Results revealed that taro corms also contained 21.1%–26.2% starch and 1.75%–2.57% crude protein and provided total energy in the range of 97.1–118.3 kcal/100 g fresh taro. Taro corms had reasonably high contents of potassium and magnesium, whose ranges were 2251–4143 and 118–219 mg/100 g dry matter, respectively. Upland-cultivated taro tended to have higher mineral content than paddy taro. Taro corms are moderately good sources of water-soluble vitamins, such as thiamin, riboflavin and ascorbic acid, compared to other tropical roots. A higher soluble sugar content in upland-cultivated taro corms was found than in paddy taro. The cultivar Mein contained higher soluble fibre levels than two other cultivars. Total oxalate and phytic acid levels of taro corms were in the range of 234–411 and 139–169 mg/100 g dry matter, respectively, which included 60%–75% of water-soluble oxalate. Essential amino acid contents of taro proteins from both paddy and upland cultivation were fairly similar to the FAO reference pattern, except for the contents of sulfur-containing amino acids, tryptophan, and histidine.