Bioaccessibility of phenolic acids in Canadian hulless barley varieties

Abstract

In order to gain understanding of bioaccessibility of phenolic acids in food-grade barley, an investigation was conducted using four cooked whole-grain, hulless, barley varieties. An in vitro digestion model was used to mimic human upper gastrointestinal digestion. Boiling enhanced the extractability of bound phenolic acids while digestion increased the level of free phenolic acids. The high bioaccessibilities observed were likely due to the release of bound phenolic acids during cooking and digestion. The major bioaccessible phenolics were ferulic and p-coumaric acids with bioaccessibility ranging from 131 to 173% and 51-135%, respectively. Peru-35 had significantly greater bioaccessibility of ferulic acid compared to other varieties. A hydroxycinnamic acid amide not reported before in boiled barley, N¹, N⁸- dicaffeoyl spermidine, was identified in free phenolic extracts with relatively high abundance compared to the phenolic acids. It may provide additional anti-inflammatory and antioxidant functions. These cooked whole-grain, hulless barley varieties are sources of bioaccessible phenolic acids.

Keywords: Bioaccessibility; Food-grade barley; Hulless barley; Hydroxycinnamic acid amide; In-vitro digestion; Phenolic acids; Phytochemicals; Whole-grain.