Thesis (M.A.)--Dept. of Psychology, Concordia University, 1995. / Includes bibliographical references (leaves 76-84). Available also on the Internet.

Pain sensitivity is typically reduced in individuals with higher blood pressure although the nature of this relationship is poorly understood. Relatedly, the ingestion of sweet tasting solutions has been shown to reduce pain, possibly by an opioid mediated mechanism. The objective of the present research was to investigate the effects of blood pressure and sweet taste on pain sensitivity in healthy adults. The first aim was to test whether blood pressure interacts with sweet taste to affect pain sensitivity. The second aim was to test whether endogenous opioids mediate the effects of sweet taste and blood pressure on pain. In Study One, participants held sweet, bitter and plain water solutions in their mouths during exposure to a painful cold pressor test. Replicating previous research, individuals with higher blood pressure were found to have generally higher pain tolerance than those with lower blood pressure. Sweet taste was associated with an increase in pain tolerance but only in individuals with lower range blood pressure, increasing their tolerance to the level of those with higher blood pressure. In Study Two, participants held sweet solution, plain water or nothing in their mouths during cold pressors on two days. To test the involvement of endogenous opioids, participants were administered an opioid antagonist on one of the test days. Participants with higher resting blood pressure again showed increased tolerance and reduced unpleasantness ratings of the pain tasks, as well as dampened mood reactivity to the testing. In these individuals, the opioid antagonist reduced their pain tolerance and partially reversed their lower mood reactivity. As in Study One, sweet taste increased pain tolerance in participants with lower but not higher blood pressure, but this was unaffected by opioid blockade. Taken together these results suggest some overlap between non-opioid mechanisms of sweet taste and blood pressure related analgesia. These results are also consistent with work suggesting that endogenous opioid activity may play a role in the reduced pain sensitivity, and perhaps mood reactivity, of individuals with higher blood pressure and that multiple processes are involved in blood pressure-related hypoalgesia.

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Orientador: Helena Maria André Bolini / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-25T13:25:19Z (GMT). No. of bitstreams: 1 Voorpostel_CristianeRamos_D.pdf: 3281202 bytes, checksum: c4b849cb9e7c47aaefd6cd63b376f3ef (MD5) Previous issue date: 2014 / Resumo: O objetivo da presente pesquisa foi realizar a determinação da diluição e doçura ideal do néctar de uva, doçura equivalente de diferentes edulcorantes, análise descritiva quantitativa (ADQ), análise tempo-intensidade e análise de aceitação de néctares de uva adoçados com sacarose e diferentes edulcorantes: aspartame, ciclamato/sacarina blend 2:1, neotame, estévia e sucralose. Com exceção da ADQ todos os testes foram realizados com duas equipes de avaliadores, uma com indivíduos tabagistas e outra com indivíduos não tabagistas com o objetivo de verificar se o hábito de fumar pode influenciar na percepção de doçura dos edulcorantes. Os resultados mostraram que a quantidade de polpa de uva (suco integral de uva 14° brix) ideal pelo teste de determinação da diluição ideal foi de 50% para o preparo de néctar de uva, enquanto que a quantidade de sacarose considerada ideal pelo teste de doçura ideal foi de 5,6% entre os consumidores não tabagistas e 6,7% entre os tabagistas. A concentração equivalente de cada edulcorante para substituir a sacarose no néctar de uva foi: 0,0307% de aspartame, 0,0199% de ciclamato/sacarina (2:1), 0,0009% de neotame, 0,0088% de sucralose e 0,0550% de estévia no teste realizado com assessores não tabagistas e 0,0368% de aspartame, 0,0241% de ciclamato/sacarina (2:1), 0,0010% de neotame, 0,0106% de sucralose e 0,0670% de estévia. Na ADQ as amostras diferiram em seis dos dezenove atributos gerados. Os atributos de sabor foram os que mais sofreram alterações. A amostra preparada com estévia caracterizou-se por apresentar níveis mais elevados de amargor e amargor residual. A amostra adoçada com neotame apresentou perfil sensorial caracterizado pelo gosto doce e gosto residual doce. As amostras adoçadas com sacarose e sucralose não diferiram significativamente (p>0,05) em nenhum termo descritivo avaliado. Pelas curvas tempo-intensidade (TI) para o gosto doce, as amostras que apresentaram maior intensidade e duração deste gosto foram aquelas adoçadas com neotame e estévia. Este resultado ocorreu nas análises tempo-intensidade com ambos os grupos de assessores não havendo diferença significativa (p?0,05) entre eles para intensidade máxima e tempo da intensidade máxima .Quanto ao TI para o gosto amargo, a amostra preparada com estévia se destacou quanto à intensidade e duração desse estímulo. Na análise tempo-intensidade realizada com assessores não tabagistas as amostras preparadas com aspartame, ciclamato/sacarina 2:1 e sucralose apresentaram o comportamento sensorial que mais se aproximou à amostra preparada com sacarose para ambos os gostos doce e amargo. Para os consumidores não tabagistas, as amostras preparadas com sucralose e ciclamato/sacarina e sacarose tiveram as maiores médias de impressão global. (p>0,05). Entre os consumidores tabagistas, além das amostras adoçadas com sacarose, sucralose, ciclamato/sacarina 2:1, a amostra adoçada com aspartame também apresentou maior média para impressão global (p>0,05). Para ambos os grupos de as amostra preparada com estévia obteve as menores médias de impressão global. As médias de aceitação global foram estatisticamente (p?0,05) menores entre os consumidores tabagistas. Para ambos os grupos as amostras contendo sacarose e sucralose tiveram as melhores notas de intenções de compra / Abstract: The aim of this study was to determine the optimal dilution and sweetness of grape nectar by equivalent sweetness of different sweeteners, quantitative descriptive analysis (QDA), time-intensity analysis, and acceptance test of grape nectar sweetened with sucrose and different sweeteners including aspartame, cyclamate / saccharin blend (2:1), neotame, stevia and sucralose. With the exception of QDA, all tests were performed with two groups of assessors (smokers and nonsmokers) in order to verify if smoking can influence the perception of sweetness of the sweeteners. The results showed that the optimal amount of grape pulp determined by the optimal dilution test was 50% for the preparation of grape nectar, while the optimal amount of sucrose, determined by the ideal sweetness test was 5,6% among nonsmokers, and 6,7% among smokers. The equivalent concentration of each sweetener to replace sucrose in grape nectar, determined by the test with nonsmoker assessors, was: 0,0307% aspartame, 0,0199%, cyclamate / saccharin (2:1), 0,0009% neotame, 0,0088% sucralose and 0,0550% stevia, while the test with smokers indicated 0,0368% aspartame, 0,0241% cyclamate / saccharin (2:1), 0,0010% neotame, 0,0106% sucralose and 0,0670% stevia. The QDA showed that the samples differed in six of the nineteen attributes studied. The flavor was the most attribute influenced by the addition of high intensity sweeteners. The sample sweetened with stevia was characterized by higher bitterness and bitter aftertaste. The sample sweetened with neotame presented sensory profile characterized by sweet and sweet aftertaste. The samples sweetened with sucralose and sucrose did not differ significantly (p>0,05) for all attributes. Through the time-intensity curves for the sweet taste, it was observed that the samples with greater intensity and duration of stimulus were those sweetened with neotame and stevia. This result occurred with both groups of assessors, with no significant difference (p?0,05) between them for the values of maximum intensity (Imax) and time of maximum intensity. Regarding the time-intensity for the bitter taste, the sample sweetened with stevia stood out on the intensity and duration of stimulus, with no statistical difference between the groups for the parameter maximum intensity and total time. When the time-intensity analysis was performed with nonsmoker assessors, the samples sweetened with aspartame, cyclamate / saccharin (2:1), and sucralose showed sensory behavior closer to the sample sweetened with sucrose for both sweet and bitter tastes. In the acceptance test among nonsmokers, the samples sweetened with sucralose and cyclamate / saccharin and sucrose had the highest overall acceptance, and did not differ significantly (p>0,05) between them. Among smokers, the sample sweetened with aspartame was very well accepted as well as those sweetened with sucrose, sucralose and cyclamate /saccharin 2:1 (p>0,05). For both groups of consumers, the sample sweetened with stevia obtained the lowest acceptance scores, followed by the sample containing neotame. The mean overall acceptance was significantly (p?0,05) lower among smoker consumers. Possibly this lower acceptance is due to the reduced pleasure for sweet taste among smokers as previously reported in literature. For both groups, samples sweetened with sucrose and sucralose had the best purchase intentions / Doutorado / Consumo e Qualidade de Alimentos / Doutora em Alimentos e Nutrição

Body weight in mammals is defended so that small changes in weight evoke neuroendocrine and metabolic responses that encourage a return to one’s previous weight. While these homeostatic responses have been more commonly studied in the case of weight loss, our lab has developed a mouse model of overfeeding to study the physiology of defense against weight gain. In response to overfeeding-induced weight gain, the return to previous body weight is mediated primarily by a striking reduction in food intake, which persists until pre-overfeeding body weight is restored. However, preliminary data do not suggest activation of anorectic POMC neurons which reduce food intake or inhibition of the appetite stimulating AgRP or NPY neurons in the arcuate nucleus of the hypothalamus. Furthermore, we found that adipose tissue from overfed mice does not show the same inflammatory response as mice that have become obese slowly due to ad libitum high-fat diet (HFD) consumption. Paradoxically, despite the existence of mammalian systems that defend against weight gain, average body weight in humans has been on the rise over the last half century. Concomitant with the rise in obesity rates, has been increasing availability and consumption of processed and fast foods which are generally high in sugar, salt, and fat making them extremely palatable and calorically dense. Both the caloric density and enticing taste of the foods have been implicated in causing overconsumption and contributing to a rise in average body weight and prevalence of obesity. Thus, while controlling for caloric density we have investigated whether diet palatability can increase body weight and suppress defense against weight gain in mice. We designed our studies so that all diets were of the same caloric density and therefore varied only proportion of calories derived from fats, carbohydrates, and protein. Palatability is the relative subjective preference of one food over another; in our mouse studies we equated preference, when given, a choice with palatability. We confirmed that liquid diets sweetened with sucrose or the non-nutritive sweeteners sucralose and saccharin were preferred over non-sweetened diets. In 12 day feeding studies, although we found that sweetened diets were more palatable than unsweetened diets, they did not increase caloric intake or body weight. Next, we tested whether increasing percent calories from fat leads to increases in palatability or caloric intake. In a similar 12 day feeding preference study, we found diets higher in percent calories from fat (high-fat diet = HFD) were preferred to diets with lower percent calories from fat (low-fat diet = LFD) and that the access to a HFD increased caloric intake and body weight. Employing a four-week single diet feeding study, we also found a linear relationship between percent calories from fat and caloric intake consistent with our hypothesis that percent calories from fat is sensed and modulates caloric intake. To test whether HFD can suppress defense of body weight, we used an overfeeding paradigm which I help develop, to test whether ad libitum access to a HFD prevented a return to the original body weight following overfeeding. HFD did attenuate the hypophagic response to overfeeding and prevented a return to each mouse’s initial weight with the mice having access to the HFD mice stabilizing at a higher body weight. Palatability has traditionally been ascribed to sensing of smell and taste, however, macronutrients can also be sensed within intestinal tract. To determine whether the effects of percent calories from fat require naso-oral sensing to modulate feeding behavior, we used an intragastric feeding system to bypass taste and smell and deliver HFD directly into the stomach of mice. Even in the absence of oropharyngeal sensing, HFD in the gut was sufficient to increase ad libitum caloric intake of a low-fat diet and increase body weight. Finally, based on our findings of post-oral fat sensing driving caloric intake, we tested whether post-oral sensing of percent calories from fat was sufficient to condition a flavor preference. However, we found that when caloric density was controlled, a high percent calories from fat was not sufficient to condition a flavor preference.

Asian countries have become one of the largest export markets for US food developers during the past decade. Understanding consumer expectations and needs in a cross-cultural framework has gained importance for new products to succeed in the international markets. A sports-drink, which is a functional drink for athletes, has been successfully introduced in the US. The product is also growing in popularity internationally. However, the concept and product sports-drink is relatively novel among Asians. The overall objective of this study was to investigate cross-cultural consumer acceptance and fundamental factors driving diversities in food acceptance using a sportsdrink varied in sweetener concentration. In the first part of the study, respondents (372) from Indonesia, Korea, Mainland China, Taiwan, Thailand, and United States evaluated sports-drink samples at four sweetener levels. Respondents' expected sensory characteristics, concept fitness, functionality, and experience with twenty commercial beverages were also evaluated. The results show that the optimal sweetness level for the sports-drink was lower for Americans than Asians. The degree of increase in perceived sweetness intensity over sweetener levels was greater among Americans than Asians. Also, there were considerable cultural differences in expectations for various beverages. In addition, experience with a product was another key factor affecting expectations. Based on the results from the first part of the study, a model delineating the processes of hedonic and intensity rating incorporating familiarity, concepts, and context effect was developed. To investigate the significance of this model, expectations were rated and sensory testing was carried out by modifying concepts and using different contexts of beverages. People (256) from Mainland China, Indonesia, Korea, and United States (US) participated in this experiment. The length of exposure to a sports-drink was a key factor affecting the optimum sweetener level for a sports drink. Concept influenced both expectation and taste rating of a sports-drink for the panelists who had been exposed to the sports-drink longer. Less exposed panelists were only affected in their taste rating by different concepts. When the concept was less acceptable, the acceptance rating of the optimum sweetener sample was also lowered. US panelists had a different expectation for a lemon-lime flavored beverage than did Asians. Ideal sweetness intensity ratings for general beverages was a good predictor in determining for panelists' optimum sweetener level for a sports-drink. Based on the model proposed, cross-cultural diversities in sweetness preference were better understood. / Graduation date: 2000