Oxalate content of New Zealand grown and imported fruits

• Published in: Journal of food composition and analysis 2013-09, Vol.31 (2), p.180-184
• Main Authors: Nguyễn, Hà Vũ Hồng, Savage, G.P.
• Format: Article
• Language: English
• Subjects: Acca sellowiana (O. Berg) Burret; Averrhoa carambola; Averrhoa carambola L; Biological and medical sciences; Carambola; Feijoa; Food analysis; Food composition; Food industries; Food safety; Fruit; fruits; Fundamental and applied biological sciences. Psychology; General aspects; Goji berries; high performance liquid chromatography; Imported fruit; Indian gooseberry; Insoluble oxalate; ion exchange; Lycium barbarum L; Methods of analysis, processing and quality control, regulation, standards; oxalates; Phyllanthus emblica; Phyllanthus emblica L; Rheum rhabarbarum; Rheum rhabarbarum L; Rhubarb; Soluble oxalate; temperature; Total oxalate
• ISSN: 0889-1575; 1096-0481
• DOI: 10.1016/j.jfca.2013.06.001

•Oxalate contents determined in 21 local and 9 imported fruits consumed in New Zealand.•Local fruits contain low but variable amounts of total and soluble oxalates.•All fruits studied are low in oxalate, except for the following five.•Feijoa, Indian gooseberry, carambola, rhubarb and goji berry contain high oxalate.•Rhubarb contained the highest levels of oxalates of locally grown fruits. Total and soluble oxalate contents of 21 locally grown and 9 imported fruits commonly consumed in New Zealand were determined by extracting total oxalates with 2M HCL for 20min and soluble oxalates with nanopure water for 20min at room temperature (21°C). The extracted oxalates were analysed by ion exchange HPLC. Total oxalate content of locally grown fruit ranged from 2.0 to 640.2mg/100g fresh weight (FW) while the soluble oxalate ranged from not detected to 431.3mg/100g FW. The total oxalate content of a selection of imported fruits ranged from 2.9 to 7566.5mg/100g FW and the soluble oxalate content ranged from 1.2 to 3855.4mg/100g FW. Very high levels of total oxalates were measured in 2 imported fruits, Indian gooseberry (Phyllanthus emblica L.) and carambola (Averrhoa carambola L., star fruit), and in New Zealand-grown rhubarb (Rheum rhabarbarum L.), at 7566.5, 436.1 and 640.2mg/100g FW, respectively, and their soluble oxalates were also the highest measured of all the fruits.