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Characterization of Phytochemicals Involved in the Darkening of Cranberry Beans (Phaseolus vulgaris L.) and Their Potential Health Benefits

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dc.contributor.advisor Massimo, Marcone F
dc.contributor.author Chen, Peter Xin
dc.date.accessioned 2016-09-07T16:09:38Z
dc.date.available 2016-09-07T16:09:38Z
dc.date.copyright 2016-09
dc.date.created 2016-09-02
dc.date.issued 2016-09-07
dc.identifier.uri http://hdl.handle.net/10214/9944
dc.description.abstract Post-harvest darkening (PHD) occurring during storage of dry beans (Phaseolus vulgaris L.) has a negative impact on consumer preference. Prevention of PHD has aesthetic appeal however, it may come at the expense of health-benefiting phytochemicals. In this study, regular- (RD) and non-darkening (ND) cranberry beans were compared for their phytochemical contents and measures of antioxidant and anti-inflammation activities. Seed coats and whole beans of RD and ND cultivars were examined using HPLC DAD/LC-ESI-MSn and NMR along with in vitro chemical methods (total phenolic; TPC, total flavonoid; TFC, total proanthocyanidin; PAC). Free, conjugated and bound phenolics were sequentially extracted and examined separately. PHD under greenhouse conditions for 21 d decreased TPC, TFC and PAC contents in RD beans (p < 0.05). An unknown compound saw significant increase in concentration following PHD. Purified extracts of RD and ND beans displayed strong cellular antioxidant activity in RD and dose-dependent attenuation of TNF-α-induced pro-inflammatory cytokine IL-8 secretion in a Caco-2 cell model (p < 0.05). The extracts displayed prevention of inhibition of endogenous antioxidant enzymes such as SOD, CAT, GPx and GR as well as GSH under stress conditions. Monomeric and oligomeric flavonoids were only found in RD beans. TPC and overall antioxidant activities (FRAP, DPPH, and ORAC) were significantly higher (p < 0.05) in RD seeds compared to ND. Lipophilic extracts of whole RD and ND beans were rich in polyunsaturated fatty acids (69.20–76.89%). Simulated gastrointestinal digestion was performed on cooked beans to assess phenolic bioaccessibility. Phenolics in the non-digestible fractions of RD and ND were released upon hydrolysis with carbohydrase enzymes. Results from this study suggest that flavonoids may play a key role in the PHD trait. However, despite the higher concentration of flavonoids present in RD beans, under physiological conditions, health benefits derived from RD and ND beans became less apparent. en_US
dc.description.sponsorship Agriculture & Agri-Food Canada and the Ontario Research Fund (ORF-RE 04-043) through the Applied Bean Genomics and Bioproducts project. en_US
dc.language.iso en en_US
dc.rights Attribution-NonCommercial-NoDerivs 2.5 Canada *
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/2.5/ca/ *
dc.subject dry beans en_US
dc.subject phytochemicals en_US
dc.subject polyphenols en_US
dc.subject phenolics en_US
dc.subject antioxidant en_US
dc.subject antiinflammation en_US
dc.subject caco-2 cells en_US
dc.subject inflammation en_US
dc.subject post harvest darkening en_US
dc.subject cranberry beans en_US
dc.subject health en_US
dc.subject flavonoids en_US
dc.subject catechin en_US
dc.title Characterization of Phytochemicals Involved in the Darkening of Cranberry Beans (Phaseolus vulgaris L.) and Their Potential Health Benefits en_US
dc.type Thesis en_US
dc.degree.programme Food Science en_US
dc.degree.name Doctor of Philosophy en_US
dc.degree.department Department of Food Science en_US
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