Oxalate Content of Taro Leaves Grown in Central Vietnam.

Hang Du Thanh,Geoffrey Savage,Tuan Le Minh,Hai Phan Vu,Ngoan Le Duc,Hai Vu Van

doi:10.3390/foods6010002

Hang Du Thanh, Geoffrey Savage + Show 4 more

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https://doi.org/10.3390/foods6010002

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Abstract

Leaves were harvested from four different cultivars of Colocasia esculenta and three cultivars of Alocasia odora that were growing on nine different farms in central Vietnam. The total, soluble and insoluble oxalate contents of the leaves were extracted and measured using HPLC chromatography. Total calcium determinations were also carried out on the same samples. The total oxalate content of the leaves ranged from 433.8 to 856.1 mg/100 g wet matter (WM) while the soluble oxalate ranged from 147.8 to 339.7 mg/100 g WM. The proportion of soluble oxalate ranged from 28% to 41% (overall mean 35%) of the total oxalate content of the leaves. The equivalent insoluble oxalate proportion ranged from 59% to 72% of the total (overall mean 65%). There was little difference between the Colocasia esculenta and Alocasia odora taro cultivars, although the total oxalate content was significantly higher in Alocasia odora cultivars. The overall mean total calcium content was 279.5 mg/100 WM and the percentage of insoluble calcium bound as calcium oxalate ranged from 31.7% to 57.3% of the total calcium content (overall mean 47.1%). The oxalate content in taro leaves is a major factor to consider when different cultivars of taro are recommended for human or animal consumption.

Highlights

Taro (Colocasia esculenta) has been reported to yield up to 370 t/ha/year of foliage [1]
Taro leaves are rich in protein (3.2% to 3.9% of wet matter (WM)) while the petioles are rich in soluble carbohydrates [1,2,3,4]
Seven cultivars derived from two taro species, Colocasia esculenta and Alocasia odora, were evaluated for their potential use for humans and animals

Summary

Introduction

Taro (Colocasia esculenta) has been reported to yield up to 370 t/ha/year of foliage (leaves and petioles) [1]. In central Vietnam, there are seven main varieties of taro, which are widely grown and have local names. Taro leaves are rich in protein (3.2% to 3.9% of wet matter (WM)) while the petioles are rich in soluble carbohydrates [1,2,3,4]. Taro is grown extensively as tubers for human consumption while the foliage (leaves and petioles) is used as a feed ingredient, mainly for pigs [1,3,4]. Taro foliage is rich in nutrients, such as crude protein and calcium, and would provide a useful vegetable for human use [4]

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