Bioaccessibility of ferulic acid in barley
| dc.contributor.author | Drawbridge, Pamela | |
| dc.contributor.examiningcommittee | House, James (Food and Human Nutritional Sciences) | en_US |
| dc.contributor.examiningcommittee | Yang, Chengbo (Animal Science) | en_US |
| dc.contributor.examiningcommittee | Hosseinian, Farah (Carleton University) | en_US |
| dc.contributor.supervisor | Beta, Trust | |
| dc.date.accessioned | 2023-04-28T21:28:01Z | |
| dc.date.available | 2023-04-28T21:28:01Z | |
| dc.date.copyright | 2023-03-27 | |
| dc.date.issued | 2023-03-27 | |
| dc.date.submitted | 2023-03-27T21:45:44Z | en_US |
| dc.degree.discipline | Food and Human Nutritional Sciences | en_US |
| dc.degree.level | Doctor of Philosophy (Ph.D.) | en_US |
| dc.description.abstract | Whole grain barley contains bioactive compounds including phenolic acids which exhibit antioxidant and anti-inflammatory effects. The major phenolic acid in barley, ferulic acid, is predominately found bonded to arabinoxylans in the cell wall. However, the bound form cannot be absorbed in the small intestine and thus is not bioaccessible. Therefore, the objectives of this research were to 1) characterize the phenolic acid composition of raw, cooked and digested barleys, 2) determine the ferulic acid bioaccessibility and when the ferulic acid is primarily released, and 3) examine factors which may influence the bioaccessibility of ferulic acid including bran layer thickness, and arabinoxylan content and structural characteristics. The phenolic acid compositions of four hulless barley varieties were examined using HPLC. A static digestion model was used to simulate gastrointestinal digestion and determine the bioaccessibility of phenolic acids. Pearled barley fractions were analyzed in terms of arabinoxylan content and A/X ratio by gas chromatography, and ferulic and p-coumaric acid content by HPLC. Ferulic acid bioaccessibility was greatest in the variety Peru-35 (173%). The release of ferulic acid was strongly influenced by digestive enzymes, minimally affected by pH, and primarily occurred during the final hour of small intestinal digestion. The amount of ferulic and p-coumaric acids positively correlated with arabinoxylan content and was greatest in the outermost fraction and progressively decreased towards the endosperm-containing fraction. The A/X ratio varied among fractions and correlated with bound p-coumaric content. Additionally, a polyamine, N1, N8-dicaffeoyl spermidine, was identified for the first time in wholegrain barley and may provide additional anti-inflammatory and antioxidant effects. This research is the first to investigate the bioaccessibility of ferulic acid in hulless barley. The research provides a foundation for determining factors which influence ferulic acid bioaccessibility in grains and facilitates the selection of barley fractions for functional food development. | en_US |
| dc.description.note | May 2023 | en_US |
| dc.identifier.uri | http://hdl.handle.net/1993/37303 | |
| dc.language.iso | eng | en_US |
| dc.rights | open access | en_US |
| dc.subject | Hordeum vulgare | en_US |
| dc.subject | bioaccessibility | en_US |
| dc.subject | food-grade | en_US |
| dc.subject | ferulic acid | en_US |
| dc.subject | in vitro digestion | en_US |
| dc.subject | phenolic acids | en_US |
| dc.subject | hydroxycinnamic acid amide | en_US |
| dc.subject | spermidine | en_US |
| dc.title | Bioaccessibility of ferulic acid in barley | en_US |
| dc.type | doctoral thesis | en_US |
| local.subject.manitoba | no | en_US |
| oaire.awardTitle | University of Manitoba Graduate Fellowship | en_US |
| project.funder.identifier | https://doi.org/10.13039/100010318 | en_US |
| project.funder.name | University of Manitoba | en_US |