The total, soluble and insoluble oxalate contents of the leaves and stems of curly leaf (Petroselinum crispum) and flat leaf (P. crispum var. neapolitanum) parsley cultivars were extracted from fresh tissue and measured using HPLC chromatography. There were no significant differences between the total and insoluble oxalate contents of the leaves between the flat leaf and curly leaf cultivars. There was a small difference (P < 0.05) between the soluble oxalate contents of the leaves of the two cultivars. The mean total, soluble and insoluble oxalates of the leaves of the two cultivars were 1137.0, 177.9 and 959.3 mg/100 g dry matter (DM), respectively. The mean total, soluble and insoluble oxalate contents of the stems were 1680.7, 386.2 and 1294.5 mg/100 g DM, respectively, and these were significantly higher than the mean values for the leaves of the two cultivars. Insoluble oxalate made up a mean of 77.0% of the curly leaf stems and leaves compared to a mean of 84.4% found in the flat-leaved cultivar. Unavailable calcium, that is, calcium bound to oxalate as insoluble oxalate, made up a mean of 26.9% of the total calcium in the leaves of both cultivars while the unavailable calcium made up 45.0% of the total calcium in the stems of the two cultivars. Overall, the oxalate contents of both parsley cultivars are relatively high, on a dry matter basis, but their overall contribution to dietary intake is likely to be quite small as parsley is an herb that is only used in small amounts to garnish foods.
References
[1]
Zarembski, P. M. and Hodgkinson, A. (1962) The Oxalate Content of English Diets. British Journal of Human Nutrition, 16, 627-634. http://dx.doi.org/10.1079/BJN19620061
[2]
USDA (1984) Agriculture Handbook No. 8-11, Vegetables and Vegetable Products. USDA, Washington DC.
[3]
Noonan, S.C. and Savage, G.P. (1999) Oxalate Content of Foods and Its Effect on Humans. Asia Pacific Journal of Clinical. Nutrition, 8, 64-74. http://dx.doi.org/10.1046/j.1440-6047.1999.00038.x
[4]
Abdel-Moemin, A.L. (2014) Oxalate Content of Egyptian Grown Fruits and Vegetables and Daily Common Herbs. Journal of Food Research, 3, 66-77. http://dx.doi.org/10.5539/jfr.v3n3p66
[5]
AOAC (1999) Official Methods of Analysis International. 17th Edition, Association of Analytical Communities, Gaithersburg.
[6]
Santamaria, P., Elia, A., Serio, F. and Todaro, E. (1999) A Survey of Nitrate and Oxalate Content in Fresh Vegetables. Journal of the Science of Food and Agriculture, 79, 1882-1888.
http://dx.doi.org/10.1002/(SICI)1097-0010(199910)79:13<1882::AID-JSFA450>3.0.CO;2-D
[7]
Food Standards Australia New Zealand (2015) http://www.foodstandards.gov.au
[8]
Savage, G.P., Vanhanen, L., Mason, S.M. and Ross, A.B. (2000) Effect of cooking on the soluble and insoluble oxalate content of some New Zealand foods. Journal of Food Composition and. Analysis, 13, 201-201.
[9]
Kohlmeier, M. (2003) Nutrient Metabolism. Academic Press, Amsterdam.
[10]
Linster, C.L. and Van Schaftingen, E. (2007) Vitamin C, Biosynthesis, Recycling and Degradation in Mammals. FEBS Journal, 274, 1-22. http://dx.doi.org/10.1111/j.1742-4658.2006.05607.x
[11]
Ruiz, R.P. (2001) Gravimetric Determination of Water by Drying and Weighing. In: Chandra, V., Ed., Current Protocols in Food Analytical Chemistry, John Wiley & Sons, Inc., Hoboken, New Jersey, A1.1.1-A1.1.6.
http://dx.doi.org/10.1002/0471142913.faa0101s00
[12]
Holloway, W.D., Argall, M.E., Jealous, W.T., Lee, J.A. and Bradbury, J.H. (1989) Organic Acids and Calcium Oxalate in Tropical Root Crops. Journal of Agricultural and Food Chemistry, 37, 337-341.
http://dx.doi.org/10.1021/jf00086a014
[13]
Simpson, T.S., Savage, G.P., Sherlock, R. and Vanhanen, L.P. (2009) Oxalate Content of Silver Beet Leaves at Different Stages of Maturation and the Effect of Cooking with Different Milk Sources. Journal of Agricultural and Food Science, 57, 10804-10808.
