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Full-Text Articles in Food Chemistry

Kinetic And Mass Spectrometric Characterization Of Anti-Greening Mechanisms Of Cysteine And Glutathione In Chlorogenic Acid-Lysine Solutions, Charles Taylor Drucker May 2023

Kinetic And Mass Spectrometric Characterization Of Anti-Greening Mechanisms Of Cysteine And Glutathione In Chlorogenic Acid-Lysine Solutions, Charles Taylor Drucker

Food Science (MS) Theses

Effective decolorization methods mitigating green compound formation from alkaline chlorogenic acid-amino acid reactions can facilitate greater consumption of chlorogenic acid-rich products. While thiols show promise as decolorization agents to replace sulfites, their application has not been optimized. In this work, cysteine and glutathione were probed for their varying kinetic effects on the onset of chlorogenic acid-lysine induced greening. A six-parameter model developed from a reparametrized Weibull cumulative distribution function accurately captured the time- and thiol concentration-dependence of greening in chlorogenic acid-lysine-thiol solutions at pH 8.0 and 9.0, illustrating the pH-dependence of each thiol’s effectiveness at lowering terminal greening magnitude as …


Characterization Of Gangliosides And Fatty Acids In Extracellular Vesicles From Human Milk, Aliya Amin May 2022

Characterization Of Gangliosides And Fatty Acids In Extracellular Vesicles From Human Milk, Aliya Amin

Food Science (MS) Theses

Extracellular vesicles (EVs) are bioactive components of human milk that may impact functionality to regulate growth, cognitive development, metabolism, and immunity in newborns. The biogenesis of EVs and the mechanism by which EVs elicit biologic effects in vivo have not been characterized entirely. Gangliosides and fatty acids are integral in the formation, release, stability, and functionalities of EVs. Presumably, EV function is related to EV composition and lipids in EVs influence the bioavailability of EV cargo and downstream functions of EVs. The objective of this research was to characterize the fatty acid and ganglioside composition of EVs in human milk. …


Color And Structural Modifications Of Alkaline Extracted Sunflower Protein Concentrates And Isolates Using L-Cysteine And Glutathione, Akira Ishii May 2021

Color And Structural Modifications Of Alkaline Extracted Sunflower Protein Concentrates And Isolates Using L-Cysteine And Glutathione, Akira Ishii

Food Science (MS) Theses

Sunflower protein can be extracted at alkaline pH with sulfites or organic solvent de-phenolization of sunflower seed meals if greening is unwanted. This greening is promoted at alkaline pH when chlorogenic acid (CGA) oxidizes and reacts with free amine groups from amino acids, such as lysine. Thiol-containing dough conditioners: L-cysteine hydrochloride and reduced glutathione (GSH) were investigated as an alternative de-greening strategy to de-phenolization. Varying pH from 7 to 11 and concentration of 0.82 to 5.6 mM were randomly assigned by Response Surface Methodology (RSM) to evaluate the combined and additive greening inhibition effect of thiol and extraction pH. The …


Effect Of Dried Mushroom Powder On Thiol Content In Lyophilized And Native Bovine Myofibrillar Protein, Allany Chayasing May 2020

Effect Of Dried Mushroom Powder On Thiol Content In Lyophilized And Native Bovine Myofibrillar Protein, Allany Chayasing

Food Science (MS) Theses

Thiol oxidation can form disulfide bonds that modify protein conformations, resulting in lower free thiol content. The effect of dried (lyophilized and oven-dried) mushroom powder (Agaricus bisporus or Pleurotus ostreatus) added to bovine lyophilized and native myofibrillar proteins (MP) on thiol oxidation was investigated. Mixtures of 10mg/mL MP with 0.1% and 0.2% mushroom powder in 0.3M NaCl were stored at 2ºC and 80 ºC for 10 days. Oven-dried A. bisporus had higher Folin-Ciocalteu reducing capacity at 8.05±0.71 gallic acid equivalent (GAE) mg/g compared to 4.97±0.20 GAE mg/g oven-dried P. ostreatus. Lyophilized P. ostreatus contained 164% more ergothioneine than …


Effect Of Low Dose Irradiation On Expression Of Genes Involved In Ethylene Biosynthesis Of 'Granny Smith' Apples, Brian Nyakundi May 2020

Effect Of Low Dose Irradiation On Expression Of Genes Involved In Ethylene Biosynthesis Of 'Granny Smith' Apples, Brian Nyakundi

Food Science (MS) Theses

Superficial scald is a physiological disorder characterized by skin browning that appears during or after storage of ‘Granny Smith’ apples. The mechanism for scald development is not fully understood, but it is hypothesized that scald formation is related to increased ethylene production. In apples, low dose irradiation induced ethylene reduction appears to be directly related to prevention of superficial scald. However, the molecular basis of such an irradiation induced effect is not known. In this study, effort was made to better understand the molecular basis of the decrease in ethylene production in apple fruit after treatment with x-ray irradiation. ‘Granny …


Formation Of Maillard Reaction Products And Chlorogenic Acid-Quinone Induced Green Pigments In Gluten-Free Pretzels Made Using Sunflower Flour, Rashi Bhatnagar Jan 2020

Formation Of Maillard Reaction Products And Chlorogenic Acid-Quinone Induced Green Pigments In Gluten-Free Pretzels Made Using Sunflower Flour, Rashi Bhatnagar

Food Science (MS) Theses

The two color-developing reactions that occur when soft pretzels are baked using sunflower flour (SFF) in aqueous alkali environment are chlorogenic acid (CGA)-quinone induced greening and Maillard browning. This study aimed to determine how CGA content in two different SFFs containing 45% and 55% protein (Heliaflor® 45 and 55, respectively) affected the formation of green trihydroxybenzacridine (TBA) and Maillard reaction products (MRPs) in soft baked pretzels. Pretzels were baked with five doughs prepared using a pre-blended gluten-free flour, consisting of sweet white rice flour, whole grain brown rice flour, potato starch, whole grain sweet white sorghum flour, tapioca flour, …


Oyster Mushroom (Pleurotus Ostreatus) Stipe Peptides As In-Vitro Radical Scavenging, Ferrous Iron Chelating, & Ferric Reducing Antioxidant Compounds, Suraj Meharwade Jan 2020

Oyster Mushroom (Pleurotus Ostreatus) Stipe Peptides As In-Vitro Radical Scavenging, Ferrous Iron Chelating, & Ferric Reducing Antioxidant Compounds, Suraj Meharwade

Food Science (MS) Theses

Ferrous iron chelating, ABTS radical scavenging, and ferric reducing antioxidant activity of mushroom stipe peptides obtained using Protamex® and V8 protease has not been investigated. Additionally, the effects of peptides on protein carbonyl formation during myofibrillar oxidation is unknown. Oxidation of lysine, arginine, and proline in myofibrillar protein from red meat results in reduced meat quality owing to changes in water composition. Therefore, the objective of this study was to compare the antioxidant performance of <1 kDa and 1-3 kDa mushroom peptides obtained by Protamex®-V8 hydrolysis against mushroom hydrolysate, mushroom protein, and mushroom stipe for radical scavenging, ferrous chelating, and ferric reducing activity, as well as their effects on protein carbonyl formation within a protein oxidation system. <1 kDa peptides exhibited significantly higher (p < 0.05) in-vitro ferrous iron chelating activity and ABTS radical scavenging activity as compared to mushroom stipe and 1-3 kDa peptides. Whereas, 1-3 kDa peptides demonstrated significantly …


L-Cysteine Effects On Chlorogenic Acid Quinone-Amino Acid Induced Greening And Browning: Mechanism And Effects On Antioxidant Capacity, Yundi Liang Jul 2019

L-Cysteine Effects On Chlorogenic Acid Quinone-Amino Acid Induced Greening And Browning: Mechanism And Effects On Antioxidant Capacity, Yundi Liang

Food Science (MS) Theses

The formation of green trihydroxy benzacridine (TBA) derivatives when chlorogenic acid (CGA) quinones and amino acids react can be visually unappealing in some applications where CGA containing ingredients are used. Cysteine was studied as an amino acid anti-greening strategy, because cysteine-CGA conjugates are colorless. Buffered CGA: lysine: cysteine solutions at pH 8.0 and 9.0 were prepared and incubated for a maximum of 48 h at ambient temperature. Color intensity was periodically monitored using a UV-Vis spectrophotometer. Quantification and identification of conjugate formation were conducted by HPLC and LC-MS, while Antioxidant capacity was assessed by Trolox Equivalent Antioxidant Capacity and Folin-Ciocalteu …