The polyphenol pathway and Maillard reaction (polycondensation of sugars and amino acids) are regarded as important pathways in natural humification. The significance of linking the Maillard reaction and polyphenol pathways into an integrated humification pathway has been addressed. However, the ability of mineral colloids commonly occurring in tropical and temperate environments to promote the Maillard reaction and integrated polyphenol-Maillard humification pathways remained to be uncovered. Furthermore, the effect of the nature and relative abundance of biomolecules on humification and associated reaction products remained to be studied.<p>The results of this study show that the structure of polyphenols and the relative molar ratio of polyphenol, glucose and glycine, significantly affected humification processes and the associated carbonate formation in the integrated polyphenol-Maillard reaction catalyzed by birnessite. Increasing the molar ratio of ortho-polyphenols (catechol and pyrogallol) to Maillard reagents in the polyphenol-Maillard pathway catalyzed by birnessite enhanced humification while suppressing the formation of rhodochrosite (MnCO3). The opposite trend of MnCO3 formation was observed in the meta-polyphenol (resorcinol)-Maillard reaction system. Increasing the amount of glucose in the integrated catechol-Maillard system under the catalysis of birnessite promoted the formation of Maillard reaction-type humic acid in the supernatant and MnCO3 in the solid phase.<p>The catalytic abilities of commonly occurring mineral colloids from temperate and tropical regions greatly differed in influencing humification processes and products in the Maillard reaction and integrated polyphenol-Maillard pathways. Compared with layer silicate colloids, the poorly ordered Fe and Mn oxides were by far the strongest catalysts of humification reactions in the Maillard and catechol-Maillard pathways. This accounted for the significant difference in reactivity between the sesquioxide-rich Oxisol clay from the high rainfall region of South Africa and the Mollisol clay from the Canadian Prairies. Furthermore, the nature of the mineral colloids also affected the extent of organic C accumulation in the solid phase upon humification, and related mineral surface alteration. The metal oxide- and Oxisol clay-catalyzed Maillard and catechol-Maillard reaction systems had the highest accumulation of organic C in the solid phase, indicating their significance in contributing to C sequestration in the environment.<p>The findings obtained in this study are of fundamental significance in understanding the influence of the atomic bonding, structural configuration and related surface properties of mineral colloids, and the nature and abundance of biomolecules on the abiotic humification pathways and related reaction products in natural environments.

The polyphenol pathway and Maillard reaction (polycondensation of sugars and amino acids) are regarded as important pathways in natural humification. The significance of linking the Maillard reaction and polyphenol pathways into an integrated humification pathway has been addressed. However, the ability of mineral colloids commonly occurring in tropical and temperate environments to promote the Maillard reaction and integrated polyphenol-Maillard humification pathways remained to be uncovered. Furthermore, the effect of the nature and relative abundance of biomolecules on humification and associated reaction products remained to be studied.<p>The results of this study show that the structure of polyphenols and the relative molar ratio of polyphenol, glucose and glycine, significantly affected humification processes and the associated carbonate formation in the integrated polyphenol-Maillard reaction catalyzed by birnessite. Increasing the molar ratio of ortho-polyphenols (catechol and pyrogallol) to Maillard reagents in the polyphenol-Maillard pathway catalyzed by birnessite enhanced humification while suppressing the formation of rhodochrosite (MnCO3). The opposite trend of MnCO3 formation was observed in the meta-polyphenol (resorcinol)-Maillard reaction system. Increasing the amount of glucose in the integrated catechol-Maillard system under the catalysis of birnessite promoted the formation of Maillard reaction-type humic acid in the supernatant and MnCO3 in the solid phase.<p>The catalytic abilities of commonly occurring mineral colloids from temperate and tropical regions greatly differed in influencing humification processes and products in the Maillard reaction and integrated polyphenol-Maillard pathways. Compared with layer silicate colloids, the poorly ordered Fe and Mn oxides were by far the strongest catalysts of humification reactions in the Maillard and catechol-Maillard pathways. This accounted for the significant difference in reactivity between the sesquioxide-rich Oxisol clay from the high rainfall region of South Africa and the Mollisol clay from the Canadian Prairies. Furthermore, the nature of the mineral colloids also affected the extent of organic C accumulation in the solid phase upon humification, and related mineral surface alteration. The metal oxide- and Oxisol clay-catalyzed Maillard and catechol-Maillard reaction systems had the highest accumulation of organic C in the solid phase, indicating their significance in contributing to C sequestration in the environment.<p>The findings obtained in this study are of fundamental significance in understanding the influence of the atomic bonding, structural configuration and related surface properties of mineral colloids, and the nature and abundance of biomolecules on the abiotic humification pathways and related reaction products in natural environments.

Thiophene ended poly(ethylene oxide) (ThPEO) and random copolymer (RPEO) of 3-methylthienyl methacrylate and p-vinylbenzyloxy poly (ethyleneoxide) units were synthesized chemically. Further graft copolymerization of RPEO and ThPEO with pyrrole (Py) and thiophene (Th) were achieved in H2O - sodium dodecylsulfate (SDS), H2O - p-toluenesulphonic acid (PTSA) and acetonitrile (AN) - tetrabutylammonium tetrafluoroborate (TBAFB) solvent electrolyte couples via constant potential electrolyses. Characterizations were performed by cyclic voltammetry (CV), nuclear magnetic resonance spectroscopy (NMR), and fourier transform infrared spectroscopy (FTIR). The morphologies of the films were examined by scanning electron microscopy (SEM). Conductivities of the samples were measured by using four-probe technique. Moreover, spectroelectrochemical and electrochromic properties of the copolymers obtained from thiophene were investigated by UV-Vis spectrometry and colorimetry. . Immobilizations of alcohol oxidase and polyphenol oxidase enzymes were performed in the matrices obtained via copolymerization of ThPEO and RPEO with pyrrole. Immobilization was carried out via entrapment of enzyme in matrices during the polymerization of pyrrole. Temperature optimization, operational stability and shelf-life of the enzyme electrodes were investigated. Maximum reaction rate (Vmax) and Michaelis-Menten constant (Km) were determined. It is known that wine includes phenolic groups that give astringency in high concentrations. Polyphenol oxidase (PPO) converts mono and diphenols to quinone. By analyzing the product, one can find out the amount of phenolic groups. By using the enzyme electrodes via immobilization of PPO, amount of phenolics in different wines were analyzed.

Turkey is important major licid opium poppy (Papaver Somniferum) producer for medicinal and scientific purposes in the world and one of the two traditional producer country. The poppy seeds which are unique part of the opium poppy are used for food purpose. About 25.000 ton/year poppy seeds were produced for food purpose. Recent years morphine content of commercially available poppy seeds were speculated. Some studies have been reported that poppy seeds from different origins contain a wide variation of morphine (2 &ndash / 294) &mu / g/g content. They have been used also different sample preparation method (extraction and derivatization) and different instruments (GC-MS) during analyses. In this study morphine content was determined in Turkish origin which were white, yellow and blue poppy seeds colors by using high pressure liquid chromatography (HPLC). Different sample preparation method (without derivatization) was used. Morphine was eluted from poppy seeds by acidic water through stationary phase activated aluminum oxide. Poppy seed samples were collected from 13 provinces and 35 different sowing fields of Turkey. The determined morphine contents in poppy seeds were ranged between (9.73 to 37.46) &mu / g/g. Any study was not found in the literatures on determination of total phenolic in poppy seed. In this study, the optimum condition for extraction of polyphenols in poppy seeds was determined and then, total phenolic values were obtained in three different colours seeds by spectrophotometric method. At the end of experiments the total phenolic contents in white, yellow and blue colours poppy seed were found to be 4.44, 3.05 and 3.67 mg/g respectively.

Polyphenol oxidases are enzymes that catalyze the oxidation of certain phenolic substrates to quinones in the presence of molecular oxygen. Polyphenol oxidases are widely used in several applications. In food industry, they are used for enhancement of flavor in coffee, tea and cocoa production, and determination of food quality. In medicine, they have several uses in treatments of Parkinson&rsquo / s disease, phenlyketonurea and leukemia. In wastewater treatment, they are used for the removal of phenolic pollutants from wastewaters. In pharmaceutical industry, differentiation of morphine from codeine is possible by means of polyphenol oxidase immobilized electrodes. In this study, a thermophilic fungus, Thermomyces lanuginosus was evaluated in terms of poyphenol oxidase production. The effect of different nutrient sources, inducers and fermentation parameters on enzyme production were investigated and maximum PPO activity of 97 U/ml was observed in bioreactor experiments at 50&deg / C, 400 rpm and pH 8.0 in a fermentation medium containing 1.4% yeast extract, 0.3% MgSO4, 1% KH2PO4, 0.003% CuSO4, 0.032% gallic acid. Type of polyphenol oxidase produced by Thermomyces lanuginosus was determined as laccase. For biochemical characterization studies, the enzyme was enriched by electrophoresis. Temperature and pH optima for the enzyme were determined as 60&deg / C and 8.0, respectively. Enzyme retained 67% activity after 1 h incubation at 80&deg / C and retained 87% of its activity after 1 hour of incubation at pH 9.0 at room temperature. The enzyme obeys Michealis-Menten kinetics with Km and Vmax values being 5 mg /ml catechol and 38 U/ml, respectively. Molecular weight of the enzyme was determined as 29 kDa and isoelectric point of enzyme was found to be approximately 6.0.

In this study, the aim was to find an economical plant source for polyphenol oxidase (PPO) production as an alternative to mushroom and possible application areas by characterization and immobilization of the PPOs. For this purpose, tissues of various plants of no commercial value were screened for their PPO activities. Mulberry leaf tissues showed the highest PPO activity against 4-methyl catechol which was comparable to that of mushroom. Average Km and Vmax values of free mulberry leaf PPOs were found as 7 mM and 218 U/ml, respectively. Mulberry leaf PPOs were immobilized in a polypyrole matrix and the Km and Vmax values of immobilized PPOs were calculated as 35 mM and 3 U/ml, respectively. Mulberry leaf PPO was the most active at 45&deg / C and pH 7. By using electrophoretic analysis, laccase and catechol oxidase type activities of PPOs and in addition, peroxidase activity were detected. Molecular weights of laccase, peroxidase and catechol oxidase were found to be about 62, 64 and 62-64 kDa, with pI values of 8.0-8.5, 4.5 and 10, sequentially.

A new thiophene derivative containing menthyl group (MM) was synthesized and polymerized via chemical and electrochemical methods. Polymers obtained and MM itself were used to synthesize copolymers with pyrrole under conditions of constant potential electrolysis. Cyclic Voltammetry, thermal analysis and scanning electron microscopy analyses were performed for the characterization of samples. Immobilization of invertase and polyphenol oxidase enzymes was performed in the matrices obtained via copolymerization of MM with pyrrole. Immobilization was carried out via entrapment of enzyme in matrices during the polymerization of pyrrole. Temperature optimization, operational stability and shelf-life of the enzyme electrodes were investigated. Maximum reaction rate (Vmax) and Michaelis-Menten constant (Km) were determined. It is known that wine includes phenolic groups that give astringency in high concentrations. Polyphenol oxidase (PPO) converts mono and diphenols to quinone. By analyzing the product, one can find out the amount of phenolic groups. By using obtained enzyme electrodes via immobilization of PPO, amount of phenolics in different wines were analyzed.

The aim of this thesis work was to extract lipids and antioxidants from wheat germ using an ultrasonic bath. Alternative solvents: Ethanol, isopropanol and acetone were used for the extraction purposes and for the fat content determination hexane was used. Alternative solvents dissolve wax, phospholipids and some other proteins because of their polar nature which increased the yield. Since waxes and some proteins can be added to the soaps and creams which were made from carrier oils, obtaining these substances together with the oil in the extract was very useful. For isopropanol a linear relation was found between the extract ratio and ultrasonication time. The highest extract ratios were achieved with ethanol. For 30 minutes of ultrasonication 0.10 g extract / g germ was obtained. After the extraction in order to enhance the phase separation between the solid phase (germ and other solids) and the extract phase, combinations of centrifugation, storage in the refrigerator and decantation were tested. The technique involving storage the extracts in the refrigerator for 24 hours and centrifugation at 2800 rpm for 20 minutes gave the second highest yield but the best phase separation. Ethanol extracts from both roasted and nonroasted wheat germs were characterized in terms of their total polyphenol contents. For non roasted wheat germs total polyphenol contents of 200 mg gallic acid / L solution and for roasted wheat germs an average of 170 mg gallic acid / L solution were obtained for 30 minutes of ultrasonic extraction. For nonroasted wheat germs weak but significant linear relations were found between total polyphenol contents of the extracts and ultrasonication time.

Alzheimer's disease (AD) is the most common cause of dementia. No strong disease-modifying treatments are currently available. Amyloid-beta peptide (Abeta) appears to play a pivotal role in the pathogenesis of AD. We focused our interest on revealing the pathogenesis of the disease and developing novel therapeutic modalities. The thesis consists of three projects: 1. Prevention of AD by intramuscular delivery of an anti-Abeta single chain antibody (scFv) gene: Immunotherapy is effective in removing brain Abetaƒzbut was associated with detrimental effects. In the present study, the gene of an anti-Abeta scFv was delivered in the hind leg muscles of APPSwe/PS1dE9 mice with adeno-associated virus at three months of age. Six months later, we found that brain Abeta accumulation, AD-type pathologies and cognitive impairment were significantly attenuated in scFv-treated mice relative to enhanced green fluorescence protein (EGFP)-treated mice. Intramuscular delivery of scFv gene was well tolerated by the animals. These findings suggest that peripheral application of scFv is effective and safe in preventing the development of AD, and would be a promising non-inflammatory immunological modality for prevention and treatment of AD. 2. Prevention of AD with grape seed derived polyphenols: Polyphenols extracted from grape seeds are able to inhibit Abetaƒnaggregation, reduce Abeta production and protect against Abeta neurotoxicity in vitro. We investigated the therapeutic effects of a polyphenol-rich grape seed extract (GSE) in vivo. APPSwe/PS1dE9 transgenic mice were fed with normal AIN-93G diet (control diet), AIN-93G diet with 0.07% curcumin, or diet with 2% GSE beginning at 3 months of age for 9 months. Total phenolic content of GSE was 592.5 mg/g dry weight, including gallic acid, catechin, epicatechin and proanthocyanidins. Long-term feeding of GSE diet was well tolerated. The Abetaƒnlevels in the brain and serum of the mice fed with GSE were reduced by 33% and 44% respectively compared with the mice fed with the control diet. Amyloid plaques and microgliosis in the brain of mice fed with GSE were also reduced by 49% and 70% respectively. In conclusion, polyphenol-rich GSE is promising to be a safe and effective drug to prevent the development of AD. 3. Roles of p75NTR in the development of AD: P75NTR has been suggested to mediate Abeta induced neurotoxicity. However, its role in the development of AD is undetermined. APPSwe/PS1dE9 transgenic mice were crossed with p75NTR knockout mice to generate APPSwe/PS1dE9 mice with p75NTR gene deleted. P75NTR mainly expressed in the basal forebrain neurons and degenerative neurites in neocortex and hippocampus. Genetic deletion of p75NTR gene in APPSwe/PS1dE9 mice reduced soluble Abeta levels, but increased the insoluble Abeta accumulation and Abeta plaque formation in the brain. P75NTR deletion decreased Abeta production of cortical neurons in vitro. Recombinant extracellular domain of p75NTR attenuated the oligomerization and fibrillation of synthetic Abeta42 peptide in vitro, and reduced local Abeta plaques after hippocampus injection in vivo. Our data suggest that p75NTR plays an important role in AD development and may be a valid therapeutic target for the treatment of AD.

Master of Science / Food Science Institute - Animal Sciences & Industry / Fadi M. Aramouni / Sweet potatoes are a significant crop and are popular among consumers, particularly as french fries. Because the processing steps of making white potato french fries may be detrimental to the quality of a sweet potato fry, it is important to understand the impact of processing on quality and consumer acceptability. The variety of sweet potatoes can affect the texture, appearance, and consumer preference. Peeling processes have evolved from harsh lye treatments to more quick and efficient methods such as steam peeling. Blanching is one of the most important steps because it deactivates enzymes, including polyphenol oxidase and amylases, that affect texture and appearance. While hot water blanching is used by majority of french fry manufacturers, novel techniques like microwave blanching may be similarly effective and less detrimental to the texture and nutritional composition. Time and temperature of the blanching method can affect the texture and flavor by weakening cell walls and leaching sugars. Drying of sweet potato fries prepares the product prior to frying. Drying drives moisture off and allows the starch on the surface of the fries to gelatinize. Many types of dryers, including vacuum, hot air, and fluidized bed, have been evaluated for the rate of moisture loss and final product texture. Drying should not be done too quickly because case hardening will occur and make the product have a tough and chewy bite. Frying uses oil at elevated temperatures to develop color, flavor, and a crispy external texture. The type of oil, oil temperature, and time of frying will affect the finished product attributes. Low oil temperature may lead to higher oil uptake into the sweet potato fries. Vacuum frying compared to deep fat frying can create sweet potato fries with less darkening and less oil uptake, but this method would be difficult in large scale manufacturing. Opportunities in creating high quality sweet potato french fries are directly related to consumer acceptability and manufacturing capability.