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Composition and bioavailability of oxalates in baked taro ( Colocasia esculenta var. Schott) leaves eaten with cows milk and cows milk and coconut milk
Author(s) -
Mårtensson Louise,
Savage Geoffrey P.
Publication year - 2008
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2008.01855.x
Subject(s) - colocasia esculenta , oxalate , food science , chemistry , meal , composition (language) , citric acid , bioavailability , zoology , botany , biology , bioinformatics , linguistics , philosophy , organic chemistry
Summary Taro leaves are an important food in the Pacific Islands but the overall oxalate composition and its nutritional effect has not been investigated. The oxalate contents of taro leaves were determined using chemical and in vitro extraction methods. Maori‐type taro leaves contained 524.2 ± 21.3 mg total oxalates 100 g −1 fresh weight (FW) and 241.1 ± 20.9 mg soluble oxalates 100 g −1 FW while the Japanese‐type leaves contained 525.6 ± 19.9 mg total oxalates 100 g −1 FW and 330.4 ± 28.3 mg soluble oxalates 100 g −1 FW. Maori‐type taro leaves contained 416.4 ± 1.5 mg gastric soluble oxalates 100 g −1 FW and 212.4 ± 34.8 mg intestinal soluble oxalates 100 g −1 FW while the Japanese‐type leaves contained 433.3 ± 9.7 mg gastric soluble oxalates 100 g −1 FW and 224.2 ± 38.7 mg intestinal soluble oxalates 100 g −1 FW). Human feeding experiments were conducted to determine the availability of the oxalates in the baked leaves following additions of cows milk and coconut milk. The consumption of a test meal of baked taro leaves resulted in a significant increase ( P < 0.001) in the output of urinary oxalate in the following 6 h when compared to the output of oxalate during a reference collection. When the leaves were baked with cows milk or cows milk and coconut milk combined and consumed there was a small non‐significant reduction in urinary oxalate output which suggests that less soluble oxalate was absorbed from these mixtures.