Current research developments on polyphenolics of rapeseed/canola: a review

The utilization of rapeseed/canola as a source of food-grade proteins is still limited due the presence of glucosinolates, phytates, hulls and phenolics. Phenolic acids and condensed tannins are the predominant phenolic compounds found in rapeseed. The content of phenolic compounds in rapeseed/canola products is much higher than that found in corresponding products from other oleaginous seeds. Phenolics such as free phenolic acids, sinapines and condensed tannins may contribute to the bitter taste and astringency of rapeseed products. In addition, both phenolic acids and condensed tannins may form complexes with proteins, thus lowering the nutritional value of rapeseed products. The specific mode of interaction of rapeseed phenolics with proteins is still not well understood. Therefore, a better knowledge of factors which influence the interactions between phenolics and proteins would be beneficial in developing more efficient technologies for production of phenolic-free rapeseed protein isolates.