Boiling pulses does not destroy their protein value, but it can slightly reduce the bioavailability of certain amino acids. The overall protein content remains largely intact.
Pulses, like lentils, beans, and chickpeas, are excellent sources of plant-based protein. When you boil pulses, the heat can cause some denaturation of the proteins. Denaturation is simply the unfolding of the protein structure, which can actually make it easier for your body to digest and absorb the amino acids. However, prolonged or excessive boiling can lead to a slight loss of certain water-soluble vitamins and a minor reduction in the bioavailability of some amino acids, such as lysine. This means your body might not absorb quite as much of those specific amino acids as it would from raw pulses (which are generally inedible and even toxic). The key is to cook pulses properly – soaking them beforehand and boiling them until they are tender but not mushy – to maximize nutrient retention and digestibility. The benefits of cooking pulses, including making them safe to eat and improving digestibility, far outweigh the minimal potential loss of some nutrients.
Soak pulses for several hours or overnight before boiling. This reduces cooking time, improves digestibility, and can help to minimize any potential nutrient loss during boiling. Discard the soaking water before cooking.