Pigmented grains as a source of immunomodulating bioactives

This study addresses the overall molecular properties of the phenolics and anthocyaninspr esent in the outermost fractions of the pigmented varieties of common grains. These fractions were collected by de-branning and were used for preparing nutritionally enriched foods, with negligible or minimal detrimental effects on the microstructure and appearance of the final food. Pigmented grains and controls were de-branned and milled - when required - in a labscale milling system. Analytical profiling of the phenolics in bran components/fractions separated by physical techniques was carried out by advanced LC methods. The immunomodulating effects of selected fractions from the separation procedures were assessed by using cytokine-stimulated biosynthesis of a luciferase-labeled reporter of gene activation on properly transformed Caco-2 cells. Analytical profiling of the phenolics in the various fractions separated by physical techniques indicated that the outermost fraction obtained through debranning of pigmented grains represents a very rich (and convenient) source of phenolics (and fiber, as assessed by independent measurements). Further separation into classes and sub-classes of bioactives allowed to test individual species (or mixtures of closely related species) as for their immunomodulating potential. Immunosuppressive activity of the fractions used for pasta making was dose-dependent, and was much higher than that of antocyanins from grape skin at similar concentrations. Enriched pasta was produced from wheat flour and from various types of bran from purple wheat. By using bran fractions obtained through a de-hulling step, it was possible to obtain pasta with fiber content in excess of 10%, and a content in anthocyanins in the 100 mg/kg range. These studies provide some guidelines as for achieving selective enrichment in specific bioactive compounds through physical methods. Further "engineering" of these treatments could allow to obtain fractions enriched in components with specific biological effects when incorporated into actual foods, without affecting their sensory properties.