Which food preparation method is likely to preserve the nutritional quality of beans?

Boiling is a common method for preparing beans; however, it can lead to nutrient loss, particularly water-soluble vitamins, if the beans are boiled for too long or in too much water.

Steaming, on the other hand, is more effective at preserving the nutritional quality of beans because it involves cooking them with minimal direct contact with water. This method allows beans to retain more vitamins and minerals by reducing the leaching that occurs when they are immersed in water. Additionally, steaming can help maintain the texture and flavor of the beans while ensuring they are cooked thoroughly.

Frying and grilling involve higher temperatures and potentially longer cooking times, which can degrade the nutritional content of beans and also increase the fat content when oils are used. Therefore, steaming is the best preparation method for maintaining the beans' nutritional quality.