Oxalate Content of Egyptian Grown Fruits and Vegetables and Daily Common Herbs

Egyptian dieticians typically rely on foreign databases to find out oxalate content of food due to unavailability of local databases. The soil, fertilizers, climate and cultivars are often very different. Therefore, the purpose of this study is to establish a local database of oxalate content in Egyptian grown fruits and vegetables and selected daily common herbs. The current study analysed the total and the soluble oxalate in 37 Egyptian grown fruits, vegetables and 9 commonly used herbs. Two methods were used for screening the Egyptian foods for oxalate concentration; the first method was AOAC 1999 and the second was enzymatic method. Total oxalate varied greatly among the vegetables examined, ranging from 4 to 917 mg/100 g F.W. Total oxalate of analysed fruits ranged from 9 to 50 mg/100 g F.W. There is a strong correlation found between the two methods used. Vegetables were classified into 4 categories; low oxalate concentration containing less than 10 mg of oxalic acid /100 g F.W., such as cabbage, courgette, cucumbers, garlic, spring onions and turnip. Moderate oxalate concentration vegetables containing 10-25 mg/100 g F.W., such as aubergine, field bean, corn, peppers and watercress. High oxalate concentration vegetables containing 26-99 mg/100g F.W., such as fūl, green beans, celery, mallow, okra and sweet potatoes. Very high oxalate concentration containing 100-900 mg/100g F.W. such as Swiss chard, molokhia, purslane and vine leaves (fresh). Extensive amounts of total oxalate (201-4014 mg/100 g D.W.) were found in daily common herbs such as caraway seed, green cardamom, cinnamon, coriander seeds, cumin, curry powder, ginger and turmeric powder.