Date of Graduation

12-2017

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Cell & Molecular Biology (PhD)

Degree Level

Graduate

Department

Biological Sciences

Advisor

Franck Carbonero

Committee Member

Steve Ricke

Second Committee Member

Sami Dridi

Third Committee Member

Charles Rosenkrans

Abstract

The Maillard Reaction (MR) is a non-enzymatic chemical reaction which results in linkage between the amino group of amino acids and the carbonyl group of reduced sugars. This reaction generates Maillard reaction products (MRPs) which are not present naturally in foods, and are responsible for a range of colors, odors, flavors, and other sensory properties. Conflicting reports of MRPs impacts on human health are probably due to the fact that bioconversion of these digestible molecules by the gut microbiota has been marginally taken into account. This study aimed to determine the effects of different MRPs on rodent’s gut microbiota through16S rRNA amplicon sequencing over three different studies. Study 1 focused on the impact of NƐCarboxymethyllysine (CML) on the composition of mice gut microbiota and potential association with severity of experimental colitis. Study 2 focused on the impact of bread melanoidins on the composition of healthy and experimental colitis mice gut microbiota. Study 3 focused on the impact of consumption of increasing amounts of malt melanoidins on mice gut microbiota. It was found that CML induced limited changes in gut microbiota profiles of healthy mice, but was found to significantly relieve the bacterial dysbiosis imparted by one (but not the other) inflammation-inducing chemical, especially the Proteobacteria bloom. Bread crust model (high in melanoidins) showed significant decreases of Bacteroides spp. and Enterobacteriaceae, while it increased Faecalibacterium spp. Also, bread crust model limited to increase Enterobacteriaceae in colitis model. High amounts of malts rich melanoidins rapidly and persistently led to significantly different gut microbiota profiles. There was a trend for decrease of Lactobacillus and Ruminococcus and increase of Akkermansia and Bifidobacterium with higher amounts of dietary melanoidins. We concluded that CML and melanoidins are not detrimental in terms of their impact on the gut microbiota, and that they may even have prebiotic properties.

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