This study was undertaken to determine the effect of oxygen absorber packets (OAP) (AGELESS Z.300 E) in improving the shelf-life of selected dried food products, including dried potato pearls, dried sliced apple, dried carrot, white rice, nonfat dry milk, all purpose flour, rolled oats, and wheat. Items were stored at four different temperatures (-20, 10, 21, and 29.5°C) over a period of 24 months with observations at 6-month intervals. Hunter colorimeter, thiobarbituric acid reactive substance (TBARS) germination rate, gluten weight, and volume were parameters used as quality indicators of various dried foods. Statistical analysis indicated a significant time and temperature effect for almost all the stored products. Storage at a high temperature (29.5°C) renders OAP ineffective in reducing browning during storage. Potato pearls, dried sliced apple, and dried carrot exhibit darkening by the first 6 months of storage at 29.5°C regardless of oxygen status of the container. White rice showed yellowing under the same conditions. Most of the dried food products that were stored at 10 and 21°C with or without oxygen absorber packets maintained their color as indicted by a relatively constant lightness reading (L*) over time. TBARS values rose in all stored food with increasing storage time, especially when the dried products were stored at higher temperature (29.5°C). Statistical analysis indicated a significant OAP effect in reducing TBARS concentration over time. Germination of wheat kernel was reduced to less than 80% after 24 months of storage at 29.5°C. However, when stored with oxygen absorber packets, germination was still 86%. Storage length and temperature are the primary factors that determine the quality of home-stored dried food items.

This research project was divided into three parts. In the first part, heme, nonheme, and total iron methodologies for meats were evaluated. The accuracy, precision, and specificity of each method were determined by spike recoveries of heme and nonheme iron, and by analysis of National Institute of Science and Technology standard reference materials. The most reliable and practical methods were then used to determine the total, nonheme, and heme iron contents of various meats before and after cooking. The meats analyzed were beef, pork, lamb, chicken, and turkey. The wet-ashing technique was a novel procedure in which nitric acid was used to digest most of the solids followed by peroxy-monosulfuric acid to complete the digestion. Total iron values of the meats were consistent with those previously reported, but the percentage of heme iron in red meats was much greater than commonly assumed, both before and after cooking. In the second part, the distribution of heme and total iron in heat-processed poultry products was investigated using light and dark chicken meat in the form of deep-flied chicken breasts and legs purchased from fast food restaurants and grocery stores in a ready-to-eat condition. Heme and total iron values were 1.7 ± 0.5 and 6.5 ± 2.0 μg Fe/g meat for light chicken meat and 7.6 ± 1.6 and 19.3 ± 2.2 μg Fe/g for dark chicken meat. Percent heme iron values averaged 29 and 40% for light and dark chicken meat, respectively. In the third and final part, an application for the heme and nonheme iron data assembled above was developed to give dieticians an important tool in dietary formulations designed to maintain iron homeostasis. From the data it is evident that cooked light chicken meat, taken from the breast, would provide the lowest quantity of absorbable iron among the meats investigated and that ground beef, highest in heme iron, would provide the greatest quantity of bioavailable iron. Additional research was performed on processed beef products. Cooked ground beef, frankfurters, beef steak, and roast beef were analyzed for heme and total iron. The different beef products contained similar amounts of total iron, 31.4 to 34.2 μg/g, but the heme iron content ranged from 6.2 μg/g in frankfurters to 36.3 μg/g in beef steak. Percent heme iron ranged from 33.0 to 63.8% in all meats. Total iron, heme iron, and percent heme iron varied significantly (P < 0.01) among meats, sources, and preparations. This research was published and has been reproduced in Appendix F.

Over the past decades, numerous studies have shown that curcumin has potent biological activities. As a potential chemopreventing agent, curcumin was demonstrated to exert anti-cancer effects in both in vitro and in vivo studies. However, low bioavailability of curcumin limited human clinical trials and its application to be formulated as therapeutics. In this thesis, we will summarize the anti-cancer effects of curcumin in animal studies and clinical trials. In addition, an SAR study will be introduced to elucidate the mechanism of curcumin degradation at physiological pH. We synthesized various curcumin analogues and compared their stability in phosphate buffer using HPLC and colorimetry assay. The results not only demonstrated that the -OH group and the methoxy group play a critical role in stability of curcumin in physiological environment, but also support the proposed mechanism of phenolic radical formation by which curcumin degrades to its major product bicyclopentadione.

No description available.

Type II diabetes mellitus (T2DM) is a chronic disease that has a worldwide prevalence which is expected to rise dramatically over the course of the next thirty years. The disease has reached pandemic stages of development in many cultures, most notably in developing countries, followed somewhat closely by developed countries with access to an overabundance of refined carbohydrates and fat (refined oils). T2DM is a condition that can be prevented or managed, but not cured; therefore a method of stymieing the development of this disease is paramount to halting its progressively increasing morbidity. In this study, bartlett pear and kiowa blackberry were investigated in relation to their ability to modify and improve both glucose metabolism and hypertension management with in vitro assay models. Effectiveness and bioactive functionality was evaluated by various in vitro assays to study the properties of: 100% bartlett pear juice, 100% kiowa blackberry juice and a ratio of 70:30 pear: blackberry juice found to have increased phenolic properties due to synergy in previous studies. These assays aimed at determining: alpha-amylase and alpha-glucosidase inhibition, angiotensin converting enzyme inhibition, total soluble phenolic content and antioxidant capabilities. These juices were also fermented with Lactobacillus helveticus and Bifidobacterium longum, common yogurt culture strains, to investigate if fermentation would improve the bioactive functionality of pear: blackberry synergies. A secondary goal of the experiment was to investigate if these fruit juices could prevent the growth of Helicobacter pylori, which is a common bacterium found in the stomach which can lead to cancer.

<p>  </p> <p>Sensory perception and acceptance of disliked healthy foods can be improved through strategies such as repeated exposure. Yet, minimal work has investigated whether these approaches are effective in adult populations. Further, for interventions that do demonstrate modifications of perception or acceptance, we lack understanding of the full spectrum of contributing factors influencing the improvement of the sensory experience. For example, animal data suggest that factors such as saliva and salivary proteins are modifiable by diet and play a direct role in the perception of aversive bitter and astringent compounds, but minimal work has verified this in humans. Additionally, we know that there are myriad barriers and facilitators to healthy food consumption, but there are few investigations of these factors related to empirical assessments of liking. The work presented in this dissertation begins to address these gaps using untrained participants within a general student-aged adult population. We tested effects of repeated consumption of a bitter flavanol “tea” on bitterness intensity and salivary protein composition, demonstrating reduced bitterness intensity after repeated oral sensory exposure of the flavanol, with limited alterations in salivary protein composition attributable to flavanol exposure alone. Next, in a separate intervention, we tested the effect of repeated vegetable flavor exposure within a novel exposure matrix on liking of green vegetables. Using a game that challenged players to identify flavors in vegetable flavored gummy candies, we showed that repeated exposure using this method increased liking of initially disliked chopped vegetables. In a subsequent secondary analysis of data collected during this intervention, we identified variables related to sensory perception, food attitudes and behaviors, and other individual factors that explained variation in vegetable liking in ways that were unique between vegetables, underscoring the complexity of liking. Other chapters included in this dissertation accentuate these complexities through a methodological lens, providing evidence that stimuli choice, study population, and questionnaire design can all significantly impact results from sensory evaluations. Overall, repeated exposure is a promising strategy to help alleviate taste-related barriers to healthy eating in adults but is not a one-size-fits-all approach. Future work should investigate the generalizability of these methods in different adult populations and investigate impacts on dietary intake.</p>

Plant-derived protein has gained popularity in recent years due to its health and environmental impact. Studies comparing the health benefits of animal and plant protein have mostly focused on soy as a plant protein representative due to its popularity. Demand for other protein sources such as peas and fava beans has been increasing; thus, the health impact of plant protein sources other than soy must be assessed. Evidence has shown that diet influences the gut microbiota and the metabolites in the body. Metabolites associated with amino acids are strong contributors to the metabolite distinction between dietary animal and plant foods. Certain gut bacteria are also known to be able to metabolize amino acids, thus influencing their survival in the gut. To discern the impact of plant and animal-based proteins, namely soy, pea, faba bean, beef, chicken, and pork, on the host gut microbiota as well as the metabolic profile, male C57BL/6J mice were fed with the proteins for 8 weeks. Results showed that each protein source influenced the gut microbiota and metabolic profile differently. However, these impacts were not caused by the amino acid profile alone. Other factors, such as myoglobin in meats and phenolic compounds in plant proteins, also play a role.

Alliin is a predominant flavor precursor in garlic cloves. It interacts with the enzyme alliinase when garlic cloves are crushed, cut, or chewed to produce allicin, an unstable thiosulfinate that is the main biologically active component of fresh crushed garlic. Biological functions and health benefits of garlic include reduction of cancer risk in humans, improving immune system, and anti-microbial, anti-oxidant, and anti-hypertensive activities. The quality of fresh garlic and garlic products is usually related to its alliin content and allicin release potential. This research presents a simple, rapid, and precise HPLC method for alliin determination. It involves the use of 30:70% methanol: water and 0.05% sodium dodecylsulfate mobile phase composition, C18 5 μm disc column of size 3.9 x 150 μm, and detector set at 210 nm. The method showed good reproducibility with 0.56%-4.11% relative standard deviations, a linear response of peak area to alliin concentration of 0.4 ng/mL-80 ng/mL, and average recovery of 93.5%-101%. Determination of alliin in eight garlic samples indicated the highest amount in garlic tablet that was expected. The method presented is economical and efficient and can be used in alliin determination. The method gave a satisfactory chromatograms with methanol-hydrochloric acid extract but not with hot water extract.

With the growing concern of the accumulation of plastic-based food packaging waste, the search for bio-based biodegradable packages is on the rise. These materials differ from their petro-based counterparts in their degradation rates, which are much higher in the former. Not only do bio-based biodegradable materials degrade faster during post-usage processes but also they age faster during usage and storage, which affects their performance and functionality. The application of noninvasive testing methods with the capability to report on the matrix’s state could assist in the development of a more ubiquitous way to assess ageing in food packaging, particularly in biodegradable ones. To this end, the performance of a luminescence spectroscopy technique based on three luminescent probes, one intrinsic to the matrix and two added, was monitored and the sensitivity of the probes to report on ageing was analyzed. Biodegradable films were made of 2% gelatin (type A) and 0.5% glycerol (plasticizer). Gelatin contains an intrinsic fluorophore, the aromatic amino acid tyrosine (Tyr), which can report on the molecular mobility of a matrix. Additionally, the films were doped with two extrinsic fluorophores, Fast Green FCF (FG) at 0.124 mM and pyranine (Pyr) at 0.05 mM, which can report on the physical state and available free water within a matrix, respectively. Films were casted onto plastic Petri dishes and stored at five relative humidities (RHs), namely 2.5, 25, 33, 53, and 75%, for five weeks with measurement collection every week. Films were tested using fluorescence spectroscopy at excitation and emission range wavelengths optimized depending on the assessed probe. Additional measurements to determine moisture content, changes in secondary protein structure using FTIR spectroscopy, and mechanical properties using a Universal Testing Machine in tensile mode aided in the evaluation of the sensitivity of the luminescent probes in sensing ageing. Luminescent probes, intrinsic or added, have the capability to assess the physical state of the films in situ and can provide molecular level sensing of their local environment. Tyr emission showed a sharp increase in fluorescence intensity in films stored at low RH as a function of time. FG showed a similar pattern to that of Tyr but higher sensitivity to changes along the observed period. The two characteristics emission bands of Pyr provide information on the state of water within the matrix. Although the results on this probe hinted microstructural rearrangements within the films as a function of time, the sensitivity of this probe was not high enough at the conditions evaluated and provided limited information on films’ solvation. The sensitivity of the luminescent probes to changes during ageing were revealed through correlation of the photophysical properties of the two effective probes, Tyr and FG, and the mechanical properties of the films at different RH through storage. Both methods, mechanical and optical, were similarly sensitive to changes during ageing particularly after 3-week storage. However,, it can be speculated that because of the different scales at which optical and mechanical measurements report (local vs. bulk), the methods, they could also complement each other. These findings suggest that, in principle, a luminescence spectroscopy technique using intrinsic and extrinsic probes can replace mechanical testing to noninvasively monitor structural changes and stability of biodegradable packaging as a function of time.

Plant-derived protein such as pea protein is a promising replacement for animal protein and is becoming popular in recent years because of its high nutritional value and potential reduction of environmental footprint. However, the increasing demand for plant-derived proteins is accompanied by the increase of wastes during protein processing such as wastewater containing dilute protein content, which may raise the cost for the downstream processing. Therefore, there is an emerging need to develop novel processing strategies to reduce waste while valorizing useful ingredients. Several researchers suggest that foam fractionation technology can be a viable approach to extract and concentrate protein from dilute wastewater effluent. This technology has already been applied to the chemical and food industry for the extraction of surfactant and animal proteins from wastewater. To design and apply foam fractionation to the plant-derived protein industry, fundamental knowledge on foaming properties of dilute plant-derived protein solution is needed and is currently lacking. Therefore, the objective of this thesis is to advance a fundamental understanding of the foaming properties of dilute pea protein solutions (protein concentration ≤ 1wt%). To achieve the objective, a multiscale approach is used, which is comprised of a detailed investigation of both bulk and interfacial properties of pea protein solutions and foaming properties such as foaming capacity and stability with the help of bubble structure and foam volume kinetics. The focus of this thesis is on the effect of protein concentration. Results demonstrate that protein adsorption kinetics can be characterized by four distinctive regimes: lag phase, diffusion-limited regime, transitional regime, and conformation change regime, which are highly dependent on the protein concentration. However, apparent viscosity is less affected by the protein concentration. Results also show that depending on the protein concentration, two regimes can be distinguished for foam capacity and foam stability. For the first time, these regimes can be rationalized by contrasting characteristics times of protein adsorption kinetics and processing time scale – residence time of bubbles during the foam formation. New findings from this fundamental research will shed light on the control and optimization of foaming properties of plant-derived protein solutions for applications ranging from food processing design to food product development.