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Food choice and preference have been linked to post-ingestive consequences of food consumption. Many ultra-processed foods deliver calories rapidly and are highly rewarding. In literature surrounding substances of abuse, the speed at which a drug reaches the brain affects its abuse potential; this is known as the "rate hypothesis." Here, we test whether the rate hypothesis of addiction may apply to food, specifically whether caloric availability, or the speed at which carbohydrate becomes available for use, contributes to food reward and preference. To do this, we use beverages with novel flavors (conditioned stimulus (CS)) mixed with either a slow metabolizing carbohydrate (maltodextrin and inulin; CS+Slow), a fast-metabolizing carbohydrate (sucrose; CS+Fast), or no carbohydrate (sucralose; CS-). Participants are given each of these drinks 6 times to consume (conditioning period). 2 of these consumption periods occur during in-lab sessions. In one session, blood glucose is measured over one hour post-consumption. In another, we perform indirect calorimetry to assess post-consumption changes in substrate oxidation rates. At the post-testing session, changes in self-reported liking, wanting, and ad libitum intake of each beverage are recorded. Brain response to each flavor cue (without calories) is measured using fMRI at the post-test. We hypothesize the flavor paired with the CS+Fast will be the most liked, wanted, and consumed. We expect greater BOLD (blood oxygenated level dependent) activation to the CS+Fast relative to the CS+Slow and CS- in the nucleus accumbens and hypothalamus. This is an ongoing study and, here, we present our preliminary analysis of the data. / Doctor of Philosophy / People make food choices every day throughout their lives, but why? Research in the past has shown that there are aspects of an individual's life that may be affecting their preferences for foods. One of the aspects investigated in this analysis is metabolism. The way and speed that the body uses carbohydrates plays a large role in how an individual views food options. Here, we test if the speed at which the body is able to use carbohydrates affects their choices of food and if there are any neural components to these food options. To do this, we tested multiple carbohydrates to determine which were the best for comparisons of slow- and fast-metabolizing. These carbohydrate groups were tested against a drink containing no carbohydrates in two metabolic measurements: blood glucose and energy expenditure. We then used a magnetic resonance imaging scan to test brain activity when participants are given small amounts of each drink without carbohydrates. Each carbohydrate condition was paired with a novel flavor so participants wouldn't have a preconceived idea about the caloric load. We found drinks with sucrose, a common household sugar, had the fastest change in metabolic measures. Additionally, areas in the brain related to rewards and learning were activated by flavors associated with sucrose. This leads us to believe that carbohydrates that are quickly used by your body are more rewarding in the brain and may have implications for preferences down the line.

It was desired to isolate and identify the flavor material obtained by hydrolysis and oxidation from Acer saccharum wood. This has been done and the material is shown to be 3-methoxy-hydroxycinnamic aldehyde or coniferyl aldehyde. It has been shown definitely that the flavor is not due to vanillin. An extraction procedure has been worked out for the best isolation of the material without the losses attendant upon the methods previously given. It has been shown that previous methods of isolation may destroy some of the material by virtue of the alkaline reagents used. A number of products have been shown to be present in the wood extract and to be extractable from this aqueous wood extract by means of chloroform. Among these are lignin-like materials, gums, a phenol thought to be guaiacol, and malic and probably vanillic acid. Ground-work has been done for further investigation into the materials obtained by hydrolysis of the wood. / M.S.

Iron is one of the most common trace elements in natural water sources and an important component to living systems. The existence of iron may not only cause metallic flavor, it may also deeply impact health of human and animals by interacting with constituents in the related biological fluids such as saliva and milk. The overall goal of this study is to investigate the taste interaction between iron and sweeteners, and the interaction between iron and proteins in bovine milk and human saliva. Based on pairwise-ranking sensory test, we have found that sweetness of sweeteners was varied with different concentrations of minerals in water and with different types of sweeteners. Sweet-metallic taste interaction between sucrose and ferrous ions significantly (p<0.05) increased the acceptance of very hard water (3 mg Fe/L). The sweet-metallic interaction created a unique selection of the emotional term 'mild'. High iron concentration in bovine drinking water (2 mg Fe/L or higher), causing oxidative stress in dairy cattle, affected expression of both casein and whey proteins in the milk. Direct addition of iron above 5 mg Fe/L in processed whole commercial milk led to lipid oxidation during storage at 4°C. Oxidation level was positively associated with increasing concentration of added iron. Minerals (Mg, P, Na, K, Ca, Zn) in milk were not affected with the added iron in milk. Dietary supplementation with metal-binding protein significantly decreased (p<0.05) taste and smell abnormality score in cancer patients receiving chemotherapy, and this effect lasted at least 30 days after the treatment was ended. Although supplementation did not effectively reduce (p>0.05) the metallic taste intensity stimulated by ferrous sulfate solution (1 mg Fe/L), it significantly (p<0.05) decreased salivary Fe for both healthy subjects and cancer patients. The production of metallic taste perception both induced by chemotherapy and ferrous sulfate solution, might be associated with the decreased expression of low-abundance proteins (pH 5.5-8.5, MW 25-75kDa), which were mainly immune proteins in saliva. Supplementation may improve taste disorder by recovering low-abundance salivary proteins in cancer patients. / Ph. D.

Vine tea (Ampelopsis grossedentata) is a Chinese herbal tea, rich in the natural antioxidant dihydromyricetin, that has multiple health properties and potential food and beverage applications. However, there is little information available on vine tea aroma, color and sensory characteristics. In this study, volatile components of vine tea infusions were identified by headspace solid-phase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). Commercial vine teas samples were brewed with distilled water and Blacksburg (VA, USA) tap water and analyzed in triplicate. Vine tea infusions had acidic pH values and dark, reddish-yellow color. Type of water and vine tea sample both affected the overall volatile chemical composition of vine tea infusions. A total of fifty-six volatile components were identified in vine tea infusions. However, only seven aldehydes (hexanal, (E)-2-hexenal, (Z)-4-heptenal, nonanal, (E,Z)-2,4-heptadienal, (E,E)-2,4-heptadienal, and β-cyclocitral), two ketones (6-methyl-5-hepten-2-one and β-ionone), and one alcohol (1-penten-3-ol) were identified in more than 90% of all vine tea infusions (n=54). Results of this study may help further investigations in chemical and sensorial characteristics of vine tea, and the development of new healthy products. / Master of Science in Life Sciences

In the first experiment, effects of brewing time, chlorine, chloramine, iron, copper, pH and water hardness were investigated for their effects on extraction of epigallocatechine gallate (EGCG) and caffeine in green tea and oolong tea aqueous infusions. The extraction of EGCG and caffeine were lower when green tea was brewed in hard water compared to distilled water. Brewing green tea and Oolong tea in tap water resulted in higher extraction of caffeine but had no effect on EGCG compared to distilled water. The extraction of EGCG and caffeine were significantly increased (P<0.05) when green tea and Oolong tea were brewed in the chlorinated water at 4.0 mg free chlorine per liter. The purpose of the second experiment was to optimize SDE conditions (solvent and time) and to compare SDE with SPME for the isolation of flavor compounds in Jin Xuan oolong tea using Gas Chromatography- Mass Spectrometry (GC-MS) and Gas Chromatography- Olfactrometry (GC-O). The concentration of volatile compounds isolated with diethyl ether was higher (P<0.05) than for dichloromethane and concentration was higher at 40 min (P<0.05) than 20 or 60 minutes. For SDE, 128 volatiles were identified using GC-MS and 45 aroma active compounds using GC-O. The number of volatiles identified using GC-MS was lower in SPME than SDE. For SPME, 59 volatiles and 41 aroma active compounds were identified. The composition of the volatiles isolated by the two methods differed considerably but provided complementary information. The goal of the third experiment was to determine effects of panning on flavor volatile compositions of oolong using GC-MS and GC-O. Simultaneous Distillation and Extraction (SDE) and Solid Phase Microextraction (SPME) techniques were applied for extraction of volatiles in panned and unpanned teas. A total of 190 volatiles were identified from SDE and SPME extractions using GC-MS and GC-O. Trans-nerolidol, 2- hexenal, benzaldehyde, indole, gernaiol, and benzenacetaldehyde contents were significantly decreased (P<0.05) by panning; however, panning increased (P<0.05) contents of linalool oxide, cis jasmone, methyl salicylate in oolong tea. Overall, panning significantly changes the volatile compositions of the tea and created new aroma active compounds. / Ph. D.

In this research project, real natural strawberries bought from different local sources were profiled by gas chromatography-mass spectroscopy (GCMS). These profiles were then used as a reference to compare GCMS profiles of commercial artificial strawberry flavor products such as strawberry flavored Cool Splashers™, Gatorade®, and Aquacal® flavored water. The chromatograms obtained were patterned using simple visual observations, scatter plot designs, Mann-Whitney U Test, and correlation coefficients. The artificially flavored commercial products tend to have simpler chromatograms. The Burger King® milkshake, Gatorade®, and Hi-C® are the most similar to that of the natural strawberry flavor. Their correlation coefficients are 0.972, 0.870, and 0.984 respectively. The Mann-Whitney U Test results also support the conclusions from correlation coefficients. However, the natural products tend to have more constituents including the main flavoring compounds. Thus fresh produce have better flavor and are more nutritious for a good reason.

The common tomato of our garden belongs to the natural order Solanaceae and the genus Lycopersicum. The name from lykos, a wolf, and persica a peach, is given to it because of the supposed aphrodisiacal qualities, and the beauty of the fruit. By culture and use it is a vegetable, botanically it is a fruit and among the fruits, it is a berry being indehiscent, pulpy, with one or more seeds that are not stones. Though the tomato was not recognized as a valuable food until about a century ago, its merit is now universally accepted. Often it is referred to as "the poor man's orange" for it is rich in vitamins and in malic and citric acids, possessing besides, a fine appetizing flavor. The popularity of the tomato in man's diet is due to the fact that it is a most rewarding crop for the home garden. It grows well practically everywhere, affording high nutritional values. The demand for and acceptance of fresh tomato fruit is based largely on its nutritional value, flavor, aroma, taste, and other characteristics, such as color and texture. These quality criteria are dependent primarily on the structure and chemical composition of the fruit. The importance of quality in tomatoes beyond that which can be expressed in calories per gram, or even in vitamin content, is generally accepted in the United States. In order to meet this increasing demand throughout the year tomatoes often have to be grown in the greenhouses. Therefore, in commercial greenhouses, the tomato has replaced lettuce as the principal crop and it is likely to remain as an important underglass crop. Flavor is a composite of taste and odor. Odor is produced by many aromatic substances which are present in fruit. Flavor itself is a very complex sensation. The physiological basis of flavor perception is extremely complex and not clearly understood. Flavor chemistry is a comparatively new field of research. Tomato fruit quality is determined mainly by the sugar acid ratio, pectins, color, and flavor. Among these color and flavor are probably the most useful criteria for estimating maturity of tomato fruit. Higher quality is associated with redness of color and prominence of flavor. The flavor of a fruit becomes pronounced when the sugar content is at its maximum and the color of the skin acquires the richest shade. Isolation of volatile components from natural products is often difficult. Typical flavor and aroma of tomato fruit is primarily due to its volatile components. Neither complete analysis for nor synthesis of tomato flavor has been accomplished due to the marathon of problems associated with the extraction, separation, and identification techniques. The primary aim of this investigation was to separate and identify some of the major flavor and aroma components in the developing tomato fruit and also to assess the influence of certain physiological and biochemical changes on the biosynthesis of these components during fruit growth.