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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Sensory perception of different acidulants in flavoured sports drinks

Kinnear, Marise 29 January 2009 (has links)
This study investigated the implications of substituting citric acid with other acidulants; malic acid, fumaric acid and tartaric acid and a combination thereof (Fruitaric® acid), in a flavoured sports drink. A trained sensory panel (n=10) compared the sourness intensity of the acidulants at both equal sour and equal weight concentrations in water and in a Grape and a Lemon&Lime flavoured sports drink. The sensory panel compared the temporal character of the acidulants at equal sour concentrations in water and both sports drink flavours. This included determining the rate, onset, duration and maximum intensity parameters of the perceived sourness. To determine if repeated exposure testing of sports drinks with the different acidulants added at equal sour concentrations would lead to hedonic adjustment, consumers (n=128) were repeatedly exposed to a Lemon&Lime flavoured sports drink over a period of 22 days. Citric acid, the acidulant currently used in the sports drinks, served as a reference in all the comparisons. Previously determined equal sour concentrations of tartaric and Fruitaric® acids as determined in water was found to be equally sour to citric acid when applied to water and a Lemon&Lime flavoured sports drink but less sour than citric acid when compared in the Grape flavoured sports drink. Malic and tartaric acids were found to be equal sour to citric acid in water and both sports drink flavours. The application of equal sour concentrations seemed to be flavour specific. Sourness of water and more complex solutions, such as flavoured sports drinks, seemed to be dependant on multiple factors including pH, titratable acidity, molecular weight, acidulant concentration and oBrix. The results from this study rejected anecdotal reports that acidulants differ in their temporal sensory profiles, although the lack of significant differences may be a function of the specific concentration level (0.2%) used. Repeated exposure testing of Lemon&Lime flavoured sports drinks with different acidulants resulted in hedonic adjustment. Consumer preferences post exposure could not have been predicted with a traditional consumer taste test at the start of the study. The findings of this study surely challenge the validity of sensory evaluation test strategies that rely on single exposure testing to predict long term consumer preferences. / Dissertation (MSc)--University of Pretoria, 2009. / Food Science / unrestricted
2

The effects of sports drinks containing caffeine and carbohydrate on soccer-specific skill performance during match-induced fatigue

Jacobson, Marc A. 26 April 2011 (has links)
A ninety minute competitive soccer match consists of many intermittent sprints resulting in fatigue, and consequently, a reduction in skill performance. The combination of caffeine and carbohydrate (CHO) has been shown to have ergogenic effects which help maintain skill measures during fatiguing states, however, there has been little research investigating this combination on soccer performance. Therefore, the aim of this study was to examine the effects of three sports drinks, including a placebo (PLA), a 6% CHO drink, and CHO + caffeine (CCAF; 5 mg/Kg body mass (BM)) on soccer-specific skills, throughout a fatigue-inducing soccer match. Twelve male soccer players completed three ninety minute intersquad matches played outdoors on a grass field in a randomized crossover design. Players consumed 5 ml/kg BM 45 minutes prior to kickoff and 3 ml/kg BM every 15 minutes during match play. Soccer passing skill was measured using the Loughborough Soccer Passing Test (LSPT), shot speed, and 20m sprint performance were measured pre-match, immediately at halftime and immediately post-match. Countermovement jump (CMJ) was measured pre-match and post-match. Heart rate (HR) was measured continuously. Blood lactate, rating of perceived exertion (RPE), and perceived fatigue were assessed every fifteen minutes throughout the match. Urine was collected pre-match for analysis of urine specific gravity (USG). BM was measured pre-match and post-match. LSPT total performance time was significantly better in the CCAF trial compared to the PLA trial at halftime (55.3 ± 10.3 s vs 66.5 ±8.7 s, p = .027). There were also significant improvements in penalty time (CCAF 8.2 ± 7.6 s vs. PLA 16.6 ± 7.8 s, p = .042) and movement time (CCAF 8.2 ± 7.6 s vs. PLA 16.6 ± 7.8 s, p = .028) during the CCAF trial in comparison to the PLA at halftime. HR and blood lactate was elevated throughout the PLA trial in comparison to the CHO trial. There were no other significant findings. Most players (50% - 83%) started all three matches in a dehydrated state (USG > 1.020). The CHO trial had significantly lower sweat rates (0.83 ± 0.25 L/hr) than both the PLA trial (1.06 ± 0.26 L/hr, p = .038) and the CCAF trial (1.11 ± 0.19 L/hr, p = .009). The addition of caffeine to a CHO sports drink significantly improved passing performance (quicker completion time and fewer penalties accumulated) over a PLA. All three sports drinks appeared to be equally as effective in preventing deterioration of soccer skill performance during a game situation. This suggests that the total volume of fluid consumed is of greater importance than the type of fluid. Caffeine appeared to have limited ergogenic effects on skill performance without any negative consequences. / Graduate
3

The influence of hypotonic carbohydrate electrolyte solutions on muscle metabolism and exercise capacity with regards to intermittent high intensity shuttle running

Foskett, Andrew January 2003 (has links)
Performance and exercise capacity in prolonged continuous exercise has been shown to be enhanced by the ingestion of dilute (-6%) carbohydrate-electrolyte (CHO-E) solutions during exercise. There is a wealth of literature on the effects of CHO-E solutions on prolonged, continuous exercise however this is not the case for highintensity intermittent exercise. One reason for this is the difficulty of replicating the demands of multiple-sprint sports within the laboratory. The development of the Loughborough Intermittent Shuttle Running Test (LIST), a protocol that simulates the physiological demand of multiple-sprint sports, has allowed for further study in this area. Sports drinks contain a variety of different types of carbohydrate, including synthetic polymers of maltodextrins. The rationale for these is two-fold; firstly there is some evidence to suggest that these glucose polymers of low osmolality may empty faster than isoenergetic glucose solutions especially at dilute (-6%) concentrations. Secondly CHO-E solutions formulated from maltodextrins with low dextrose equivalents are less acidogenic and have lower cariogenic potential than simple glucose solutions, thus making them preferable for tooth health. Therefore the purpose of this thesis was to examine the effects of a 6.4% hypotonic synthetic polymer maltodextrin CHO-E solution on muscle metabolism and physiological performance during prolonged high-intensity intermittent running (LIST). This thesis contains four experimental studies. From the results of study 1 it was concluded that the ingestion of a 6.4% hypotonic CHO-E solution provided no ergogenic benefit to running capacity during the LIST despite blood and hormonal data suggesting that the solution was effective at delivering glucose. As isotonic CHO-E solutions have shown to have ergogenic properties during LIST running the purpose of study 2 was to compare isoenergetic hypotonic and isotonic CHO-E solutions during LIST running. The results from this study suggested that performance, as measured by exercise capacity and sprint speed, was not affected by either treatment. In study 3 the protocol was modified to extend the exercise duration so that a greater demand was placed on the subjects' glycogen reserves. The results from this study further confirmed that exercise capacity in LIST running was not influenced by CHO provision during exercise however the habitual CHO intake of the subjects may have masked any ergogenic properties of the CHO-E solution and led to increased performance in the control trials. In the final study the subjects' pre-trial exercise and dietary CHO intake was manipulated to increase endogenous glycogen concentrations. The results showed that in these subjects the ingestion of a 6.4% hypotonic CHO-E solution increased exercise capacity during the LIST by 21%. Muscle biopsy analyses revealed a lower net muscle glycogen utilisation in the CHO trial post-90 min (p=0.07). There is evidence in the literature to suggest that there is an ergogenic effect of CHO ingestion during the LIST. However the results presented in this thesis suggest that when endogenous glycogen stores are moderate the ingestion of a CHO-E solution may suppress lipid oxidation without a concomitant increase in CHO oxidation and thus LIST capacity is not enhanced. In contrast, when endogenous glycogen concentrations are elevated through dietary manipulation there is an ergogenic benefit from the ingestion of hypotonic CHO-E solutions during LIST exercise.
4

Gatorade’s approach to obesity in the Hispanic market

Winsett, Annie 17 February 2011 (has links)
As the largest and fastest growing U.S. minority, the Hispanic market has become an increasingly significant contributor to the nation as a whole. More so than ever, marketers would greatly benefit from reaching out to this demographic, drawing inspiration from the all of the characteristics that make it unique. In seeking to increase the appeal of their products, advertising plans should be developed such that all efforts take advantage of an opportunity such as this without negatively affecting any serious conditions prevalent among the population. In the case of Latino adolescents who are more likely to consume certain products such as sports drinks, but suffer disproportionately from obesity, it is crucial that food and beverage manufacturers like Gatorade approach this target strategically. Gatorade’s strong dedication to improving athletic performance offers the chance to become a positive contributor to the health and well being of Hispanic teens. The analysis and recommendations herein seek to guide Gatorade in addressing Hispanics in light of recent trends and demographic shifts. The tactics considered include the promotion of the many healthy options among Gatorade’s existing product lines, as well as ways to develop new ones targeted at young Latino males. Drawing from current advertising reaching out to the leading sports drink consumers, ‘REPLAY The Series’ would be another method that could be tailored to reach a greater number of this ethnicity. Finally, in recognition of the many advancements in digital technologies such as location based services, and young Hispanics’ greater likelihood to make use of cell phone applications, a mobile component is recommended, focusing on bringing these teens together and facilitating physical activity. With marketing ideas built upon the role sports drinks could play in getting Hispanic adolescents active, Gatorade can continue its dedication to superior athletic performance with further potential to become a role model for the marketing industry as a whole / text
5

Determinação de corantes sintéticos em bebidas isotônicas empregando extração em fase sólida dispersiva e HPLC-UV/Vis / Determination of synthetic dyes in sports drinks by dispersive solid-phase extraction and HPLC-UV/Vis

Floriano, Luana 05 August 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Sports drinks are specially formulated for people who are undertaking physical activity, being mainly composed by carbohydrates, electrolytes and vitamins. Synthetic dyes are food additives commonly used in sports drinks to improve their consumer characteristics and appearance. Besides the lower cost of production in relation to dyes of natural origin, synthetic colorants have several advantages such as high stability to light, oxygen and pH, color uniformity and low microbiological contamination. However some of these compounds cause adverse health effects (allergy, asthma, hyperactivity, thyroid tumors, etc.), especially when consumed in excess. Thus, their use is strictly controlled around the world. The present study aimed to develop a simple, fast and efficient method for the determination of the synthetic dyes tartrazine, sunset yellow, amaranth, ponceau 4R, indigo carmine and brilliant blue in sports drinks employing dispersive solid-phase extraction (d-SPE) and high eficiência liquid chromatography with ultraviolet/visible detection (HPLC-UV/Vis) In the extraction step, it was used 25 mg of the polymeric sorbent Oasis® HLB and the elution step was performed with metanol:ammonium hydroxide (95:5, v/v). Recovery results, evaluated at 2.0; 4.0 and 6.0 mg L-1, were between 76 and 108% with relative standard deviation (RSD) <18%. Method limits of detection and quantification were 0.6 and 2 mg L-1, respectively. The method was applied on 8 commercial samples of sports drinks and the results indicated that all studied samples presented dye levels in conformity with the Brazilian legislation. The proposed d-SPE method for the determinatios of 6 synthetic dyes in sports drinks using HPLC-UV/Vis shown to be rapid, effective and cheap, and can be applied in routine analysis. / As bebidas isotônicas são especialmente formuladas para pessoas que praticam atividade física, sendo compostas principalmente por carboidratos, eletrólitos e vitaminas. Os corantes sintéticos são aditivos alimentares comumente utilizados em bebidas isotônicas para aprimorar suas características de consumo e aparência. Além do menor custo de produção em relação aos corantes de origem natural, os corantes sintéticos apresentam diversas vantagens, tais como alta estabilidade à luz, oxigênio e pH, uniformidade de cor e baixa contaminação microbiológica. No entanto, alguns destes compostos podem causar efeitos adversos à saúde (alergia, asma, hiperatividade, tumores de tireoide, etc.), especialmente quando consumidos em excesso. Assim, seu uso é estritamente controlado em todo o mundo. O presente estudo teve como objetivo desenvolver um método simples, rápido e eficiente para a determinação dos corantes sintéticos tartrazina, amarelo crepúsculo, amaranto, ponceau 4R, azul de indigotina e azul brilhante em bebidas isotônicas empregando extração em fase sólida dispersiva (d-SPE) e cromatografia líquida de alta eficiência com detecção por ultravioleta/visível (HPLC-UV/Vis). Na etapa de extração utilizou-se 25 mg do sorvente polimérico Oasis® HLB e a etapa de eluição foi realizada com seringa, empregando uma solução de metanol:hidróxido de amônio (95:5, v/v). Os resultados dos ensaios de recuperação, avaliados nos níveis 2,0, 4,0 e 6,0 mg L-1, foram entre 76 e 108% com desvio padrão relativo (RSD) <18%. Os limites de detecção e de quantificação do método foram 0,6 e 2 mg L-1, respectivamente. O método foi aplicado em 8 amostras de bebidas isotônicas comerciais e os resultados indicaram que todas as amostras estudadas apresentaram corantes dentro dos limites máximos permitidos pela legislação brasileira. O método d-SPE proposto para a determinação de 6 corantes sintéticos em bebidas isotônicas empregando HPLC-UV/Vis demonstrou ser rápido, barato e eficaz, podendo ser aplicado em análises de rotina.

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