Effect of cooking and processing methods on oxalate content of green leafy vegetables and pulses

Green leafy vegetables (spinach and bathua) and pulses (green pea and bengal gram) are widely consumed and hold an important place in the diet of people of India. Vegetarians who consume a greater amount of vegetables will have a higher intake of oxalate, which may reduce calcium availability. The objectives of this present research were to investigate the effect of different domestic cooking and processing methods on anti-nutrient content, oxalate in selected green leafy vegetables and pulses. The effect of cooking methods for green leafy vegetables and pulses via blanching, pressure cooking, open pan cooking, drying, boiling and sprouting on oxalate was determined on raw and cooked samples. Among the treatments given, blanching for 10 minutes (green leafy vegetables) and sprouting for 48 hour (pulses) were found to be the best methods for lowering the phytic acid and oxalate contents. The average reduction ranges on cooking for oxalate were 40.4% (spinach) and 115.9% (bathua) for green leafy vegetables and 24.9% (green pea and bengal gram) for pulses. Cooking methods showed considerable reduction in oxalate and phytate, but blanching and sprouting were fairly effective. The reduction of anti-nutrients on cooking is expected to enhance the nutritional value of these green leafy vegetables and pulses. Statistical analysis shows that there was significant influence of various cooking methods on oxalate content of selected samples at (p≤0.05).