In vitro digestibility of phenolics in grain of maize hybrids

The aim of this research was to determine the quantity of phenolic compounds in the grain of maize hybrids and their in vitro release in pig small intestine. Six maize hybrids belonging to the FAO maturity groups 200-600 were produced under the same agro-climate conditions. Phenolics were determined using Folin-Ciocalteu colorimetric method as gallic acid equivalents. The enzymatic digestion of phenolics was carried out using in vitro procedure for pigs mimicking digestion in stomach and small intestine. The concentration (mg/100g) of free (100.02-157.29), bound (973.41-1160.86) and total phenolics (1105.821293.38) varied (P<0.001) among hybrids. In addition, the digestibility of phenolics significantly differed among tested hybrids (P<0.001) and ranged from 37.09 to 45.46%. Content of phenolics in soluble fraction after digestion was higher (486.23 vs. 128.38 mg/100g) than the content of free phenolics suggesting that some amount of bound phenolics was released in small intestine.