Pulses (legumes) are the edible seeds of leguminous plants, and so are borne in fleshy pods. While the term denotes both fresh and dried seeds, it is usually applied to dried peas, beans and lentils.
Of major importance to the human diet, pulses have been a staple since ancient times. They are excellent sources of protein, and contain the essential amino acid lysine, which is deficient in cereals. Thus pulses consumed in conjuction with cereals achieve a full complement of amino acids. They are rich in complex carbohydrates, B vitamins and some essential minerals. Unlike seeds, with some notable exceptions, pulses contain little fat.
Some pulses contain anti-nutritional properties and toxic substances, many of which can be denatured by proper cooking. The most notorious effect, however, is the propensity of pulses to cause flatulence: the oligosaccarides that are responsible are linked in a manner that human digestive enzymes cannot process, causing these sugars to reach the lower intestine unchanged, where they are metabolized by bacteria, giving off gases in the process
Seeds are the fertilized ovules of plants which, when sown, can produce a new generation of such plants. Those which contain a food store inside their protective coating are often a rich source of nutrition for humans.
Those termed "seeds" in culinary parlance are more narrowly characterized; they are generally small, crunchy and mildly nut-like. Typically they are high in dietary fibre, minerals and oil, predominantly unsaturated, and contain moderate amounts of protein and small amounts of starch. Some are consumed as a food in their own right while others are used primarily as flavouring.