Effects of processing on oxalate contents in plant foods: A review

Abstract

The consumption of plant foods has been encouraged to cover a high proportion of the diet due to their health benefits. However, the occurrence of anti-nutrients in plant foods, especially soluble oxalate, is often neglected. High intake of soluble oxalate from the diet can increase the risk of kidney stone formation as well as mineral deficiency and restriction of dietary oxalate is the only way to reduce urinary oxalate. This review discussed the existing knowledge on effects of food processing on oxalate contents in plant foods. Leaching, fermentation and cooking with calcium sources could be considered as the most efficient methods to reduce soluble oxalate. Time, temperature and properties of the food (pH, fibre and fat contents, and preparation methods) are the major factors determining the treatment efficiency for oxalate reduction. Pulsed electric field, ultrasonication and enzymatic treatments have been proven as potential methods to diminish oxalates.