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Full-Text Articles in Life Sciences

Biotransformation Of Polymethoxyflavones By Gut Microbiome And Molecular Characterization Of Polymethoxyflavones By Surface Enhanced Raman Spectroscopy, Changchu Ma Nov 2015

Biotransformation Of Polymethoxyflavones By Gut Microbiome And Molecular Characterization Of Polymethoxyflavones By Surface Enhanced Raman Spectroscopy, Changchu Ma

Doctoral Dissertations

Polymethoxyflavones (PMFs), a unique class of flavonoids found in citrus fruits has shown beneficial bioactivities. Biological fate of PMFs in the gastrointestinal tract is critical for their bioactivities. PMFs can be biotransformed to produce various metabolites with different bioactivities, and PMFs can also interact with the food matrix, which in turn affects their bioactivities. Therefore, we investigated the biotransformation of two PMFs, namely nobiletin (NBT) and 5-hydroxylnobiletin (5HN) by the gut microbiome. Mice were fed with NBT or 5HN, and small intestinal contents were collected and subjected to anaerobic fermentation by gut microbiome isolated from mice and human volunteers. HPLC …


Fabrication, Characterization And Biological Fate Of Phytochemical Delivery System, Jingjing Chen Nov 2015

Fabrication, Characterization And Biological Fate Of Phytochemical Delivery System, Jingjing Chen

Doctoral Dissertations

Polymethoxyflvones (PMFs) are a group compounds with promising cancer preventing activities and many other health benefits. There's a growing interest in fabricating delivery systems for PMFs as well as other phytochemicals due to their low water solubility. Firstly, we use nanoemulsion delivery system to encapsulate β-carotene. Sonication assisted method was developed to dissolve β-carotene to ensure minimum degradation. Powdered nanoemulsion was obtained after spray dry and freeze dry. Sample obtained after freeze dry showed better physiochemical characteristics. Then we use protein nanoparticle delivery system to encapsulate PMFS. The nanoparticle delivery system was fabricated by mixing the aqueous phase …


Pro- And Antioxidant Effects Of Phospholipids On Lipid Oxidation In Bulk Oil, Leqi Cui Nov 2015

Pro- And Antioxidant Effects Of Phospholipids On Lipid Oxidation In Bulk Oil, Leqi Cui

Doctoral Dissertations

The aim of this thesis is to explore how phospholipids at concentrations similar as in refined vegetable oils impact bulk oil lipid oxidation. The possible formation of association colloids and synergism with primary antioxidants are considered. The results provided a better understanding of the pro- and antioxidant activities of phospholipids. Lipid oxidation leads to quality deterioration by generating off-flavor, nutrient loss, color alteration, texture changes, and even generation of potential toxic products. Phospholipids are important minor components in edible oil that play a role in lipid oxidation. Surface active phospholipids have an intermediate hydrophilic–lipophilic balance value, which allows them to …


Structural Design Approaches For Creation Of Reduced Fat Products, Bicheng Wu Nov 2015

Structural Design Approaches For Creation Of Reduced Fat Products, Bicheng Wu

Doctoral Dissertations

In awake of the health issues related with high-calorie diet, there was a strong focus in the development of reduced-fat products in the food industry. However, fat plays an important role in determining the quality attributes of food products such as texture, appearance, flavor and stability, therefore there has been limited success for reduced-fat products. This thesis project thus targeted liquid and semi-solid products such as dressings, sauces, and aimed to address problems associated with low-fat by utilizing structural designed approach. The first part of this project focused on using controlled aggregation of protein-stabilized lipid droplets to regulate the microstructure …


Physicochemical And Toxicological Assessment Of Antimicrobial Ε-Polylysine-Pectin Complexes, Cynthia L. Lopez Pena Aug 2015

Physicochemical And Toxicological Assessment Of Antimicrobial Ε-Polylysine-Pectin Complexes, Cynthia L. Lopez Pena

Doctoral Dissertations

ε-Polylysine is an appealing FDA-approved, all natural antimicrobial biopolymer effective against a wide range of microorganisms. Its implementation is greatly limited by its strong cationic charge, which has been linked to instability in food systems, perceived astringency and bitterness, and the ability to inhibit lipid digestion. Previous studies have shown that controlled complexation of ε-polylysine with anionic pectin is able to prevent instability and astringency in simplified model food systems, while maintaining the antimicrobial character of polylysine. Isothermal titration calorimetry, micro-electrophoresis, microscopy, and turbidity analyses of the stability of electrostatic pectin-polylysine complexes in the presence of strongly anionic κ-carrageenan, and …


Spray Fabrication Of Layer-By-Layer Antimicrobial N-Halamine Coatings, Anna Denis-Rohr Jul 2015

Spray Fabrication Of Layer-By-Layer Antimicrobial N-Halamine Coatings, Anna Denis-Rohr

Masters Theses

Antimicrobial coatings in which the active agent (e.g. N-halamine) can regenerate activity represent a promising way to prevent microbial cross-contamination. A reported method for applying coatings containing antimicrobial N-halamines is layer-by-layer (LbL) application of polyelectrolytes, which form N-halamines upon cross-linking. Prior reports on dip layer-by-layer (LbL) fabrication have demonstrated the potential of this coating technology; however, spray LbL fabrication would enable more rapid coating and represents a more commercially translatable application technique. In this work, dip and spray LbL methods were used to coat polypropylene (PP) with N-halamine containing bilayers consisting of cross-linked polyethylenimine (PEI) and poly(acrylic acid) (PAA). Further …


Rationalizing Nanoemulsion Formation For Encapsulation, Protection And Delivery Of Bioactive Food Components, Ying Yang Mar 2015

Rationalizing Nanoemulsion Formation For Encapsulation, Protection And Delivery Of Bioactive Food Components, Ying Yang

Doctoral Dissertations

The objective of this thesis was to design and develop novel food-grade nanoemulsion-based delivery systems for the encapsulation, protection and delivery of lipophilic bioactive food components. These delivery systems could be widely applied in aqueous-based fortified food products, such as beverages, salad dressing and yogurt etc. Both the low- and high-energy methods could be used for fabricating nanoemulsions (r < 100 nm). The microfluidization method could form nanoemulsions at low surfactant-to-oil ratios (SOR < 0.1), but it required the use of high-energy inputs and expensive equipment. On the other hand, the spontaneous emulsification method could also form ultrafine emulsions and moreover it was simple and inexpensive, but it required much higher surfactant-to-oil ratios (SOR > 0.5) for forming nanoemulsions. Q-Naturale® is a natural food-grade surfactant, which is got from the bark of the Quillaja saponaria Molina tree. By using high pressure homogenization (microfluidization), Q-Naturale® could form relatively small droplets (d < 200 nm) at low surfactant-to-oil ratios (SOR < 0.1), but the droplets were not as small as those produced using Tween 80 under similar conditions (d < 150 nm). The emulsions formed by using Q-Naturale® …