Browsing by Author "Van Buiten, Charlene, advisor"

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Open Access
Characterization of protein-polyphenol interactions between novel plant proteins (pea and hemp) and blueberry polyphenols with respect to polyphenol binding and delivery
(Colorado State University. Libraries, 2022) Chima, Bianca, author; Van Buiten, Charlene, advisor; Johnson, Sarah, committee member; Prenni, Jessica, committee member
Despite the numerous health benefits associated with polyphenols, dietary intake of this class of compounds is low in the United States due to low intake of fruits and vegetables. It has been shown that dairy foods (i.e. milk, yogurt) increase polyphenol bioavailability due to polyphenols interacting with whey protein, enhancing polyphenol stability and uptake throughout digestion. However, increasing concerns for sustainability and health have introduced a variety of novel plant-based proteins as dairy alternatives. This study aimed to investigate the abilities of edible pea and hemp protein isolates to form complexes with blueberry polyphenol extract (BPE) and characterize the physical and biological functionalities of these complexes compared to whey proteins. Protein/polyphenol solutions were analyzed using UV-Vis spectroscopy to determine if complexation occurred. Secondary structures and binding affinities were analyzed by far-UV CD Spectroscopy and fluorimetry, respectively. In vitro digestion was performed to determine whether the protein profile changed in the presence of BPE via SDS-PAGE and determination of free amino acids using the ninhydrin method. Protein isolates from pea and hemp successfully formed complexes with BPE with binding affinities for the compound similar to whey protein. Relative helicity of the hemp protein was higher than the other protein sources and increased upon complexation with BPE. Furthermore, the SDS-PAGE profiles of all the proteins were the same whether BPE was present or not and the free amino acid content increased after digestion for the protein and protein/polyphenol solutions. Overall, complexation of BPE with plant proteins was successful. Fluorescence quenching and changes to the secondary structure of the proteins in the presence of BPE indicate that polyphenols were bound but the mechanisms and structures responsible for complexation seem to vary between proteins. More research is needed to determine the interactions that cause binding between the polyphenols and the proteins and whether the bioavailability of the compounds will increase when bound to the proteins in cell model and/or clinical study. This study provides a foundation for exploring the effects of plant-based proteins on phytochemical functionality in complex, "whole food" matrices.
Embargo
Molecular and sociocultural exploration of sourdough: impacts on gluten sensitivity and bread characteristics
(Colorado State University. Libraries, 2023) Clark, Caitlin, author; Van Buiten, Charlene, advisor; Stone, Martha, committee member; Weir, Tiffany, committee member; Gentile, Chris, committee member; Prenni, Jessica, committee member
Sourdough is a bread product fermented by communities of wild bacteria and fungi known as a starter culture. Previous work has examined the effects of specific starter organisms on bread quality, but the relationships between whole microbiomes and dough/bread physicochemical properties are currently unknown. The objective of this study was to investigate the relationship between physicochemical properties of sourdough breads and the microbiomes of their starter cultures. Twenty sourdough starters with characterized microbiomes were used to produce wheat-based dough and bread. The chemical properties (pH, titratable acidity, free amino acids, Aw) of dough and physical properties (loaf volume, crust color, texture) of the breads were compared to a control fermented with baker's yeast. The degradation and toxicity of gliadin resulting from fermentation with the sourdough samples was also studied in vitro. Results indicate that sourdough-fermented breads produced under real-world conditions are distinct from yeast-fermented bread in terms of physicochemical parameters and proteolysis, which may exert downstream effects on the inflammatory capacity of gluten. We also investigated the beliefs and behaviors of gluten-sensitive sourdough consumers and professional sourdough bakers. We found that commercial sourdough is not reported to relieve gluten-mediated symptoms for consumers diagnosed with celiac disease (CD) or non-celiac gluten sensitivity (NCGS), but undiagnosed (UD) gluten-sensitive consumers may benefit from it. We also determined that sourdough bakers act as brokers of health advice in the gluten-sensitive community.
Open Access
Physicochemical modification of gliadin by black tea polyphenols: insight towards a nutraceutical therapy for celiac disease
(Colorado State University. Libraries, 2022) Mathews, Paul, author; Van Buiten, Charlene, advisor; Gentile, Chris, committee member; Chung, Jean, committee member
Celiac disease is an autoimmune disorder that affects approximately 1% of the global population. The pathogenesis of celiac disease is complex, involving the innate and adaptive immune responses. Exposure to gluten amongst genetically susceptible individuals initiates and propagates the disease process, with autoimmunity against endogenous tissue-transglutaminase enzymes manifesting intra- and extra-intestinal symptoms. Currently, the only mitigation strategy for celiac disease is an adherence to a gluten-free diet, which can be difficult to maintain. Recent advances in synthetic and natural products chemistry may offer therapeutic alternatives to the total abstinence from gluten containing products. The overarching objective of our research is to develop a nutraceutical approach to treating celiac disease using dietary polyphenols from tea. Within this thesis, we used a multi-spectroscopic approach to show that black tea polyphenols, which are rich in theaflavins and other flavanols, interact with gluten proteins in vitro to form colloidal complexes that result in structural change to the protein. These changes have the potential to reduce the immunogenicity of gluten via interference with digestion, sequestration, and conformational changes which may reduce recognition of the protein by immune cells. The interactions investigated here offer promise as a nutraceutical, plant-based therapy to acute gluten exposure in susceptible individuals.