Polyphenols in Grain Pulses and Their Contribution to Health Benefits Associated with the Pulses.

Grain pulses are major dietary components around the world. Even though traditionally regarded as a source of complementary proteins for cereals, evidence suggest that grain pulses are major contributors to various health benefits and longer lifespan, partly due to their polyphenol composition. Emerging evidence suggests that the polyphenols found in cereals and legumes contribute synergistic bioactive properties when consumed together, due to their structural differences. Thus health benefits derived from cereals and legumes may be superior to those predicted by testing the different commodities in isolation. Grain pulses contain significant amounts of diverse polyphenols that have been directly and indirectly linked to various health benefits, including immune system modulation, anti-inflammatory and antioxidant properties, and protective effects against some forms of cancer. Among the major polyphenols in pulses are flavonols (especially quercetin glycosides), monomeric and polymeric flavanols, anthocyanins, and phenolic acids. Most of these polyphenols are found in the seed coat, thus processes that remove the seed coat will significantly diminish any health benefits associated with the compounds. In many parts of the world, the pulses as consumed as whole grains, thus largely preserving the beneficial polyphenols. Recent evidence suggests that the composition of specific polyphenols is more important than content in terms of predicting bioactive properties of the grain. It has been demonstrated in common beans (Phaseolus vulgaris) and cowpea that seed color color is a good predictor of phenolic composition of the grain. Thus, with growing evidence on composition/structure-activity relationships, it will be feasible to select specific varieties to provide targeted health benefits based on seed coat color. Large scale studies that demonstrate specific health benefits of grain pulse consumption in the context of other dietary components, and innovative processes to incorporate more legumes in modern diets are needed.