<p> The research in this thesis investigated the effects of different vitamin C forms [ascorbic acid (Asc), sodium ascorbate, and calcium ascorbate] on gelatinization, pasting, and short-term retrogradation of wheat starch. Vitamin C is the third most supplemented nutrient in the U.S. and necessary for prevention or treatment of many illnesses. Asc is also used in food products as an acidulant that decreases microbial growth and extends shelf-life, flavoring agent that promotes sour taste, and bread improver that increases gluten development and dough strength in wheat doughs. Ascorbate salts are used as vitamin C sources when a sour taste or pH decrease is undesirable. The gelatinization temperature (Tgel) of wheat starch in solutions of the vitamin C forms and related acids and salts at 0.5, 1.0, and 1.5 M concentrations (or equivalent) was measured using a differential scanning calorimeter and, compared to starch in water, was increased by all the salt solutions and decreased only by Asc. Calcium ascorbate increased Tgel more than the other salts due to hydrogen bonds between ascorbate and starch and strong hydration by water of Ca2+ that stabilized the starch-water structure and inhibited gelatinization. Asc decreased starch Tgel while similarly acidic solutions did not because Asc caused more extensive starch hydrolysis, which promoted granule swelling and amylose leaching. The paste viscosity values of wheat starch in solution were measured with a rapid visco analyzer and, compared to starch in water, were increased by all salt solutions except NaCl and increased by all acidic solutions until breakdown, then decreased. Ascorbate salts increased paste viscosities significantly more than chloride salts due to the stabilization effect of ascorbate hydrogen bonds that increased the amount of larger starch structures, which increased the viscosity during pasting and short-term amylose retrogradation. Ascorbate-containing acidic solutions increased starch peak viscosity and decreased trough and final viscosities more than HCl because increased granular swelling and amylose leaching results in a more rapid and greater initial increase in viscosity and subsequent decrease in viscosity when granular breakdown overtakes swelling. The results of this work could be used by food researchers and product developers to supplement or fortify vitamin C in a starch-based food and/or modify the functions of starch within that food.  </p>

The taste of a preferred food, pizza, was adulterated with quinine sulfate and the effects of taste experience on subsequent measures of palatability were measured. The measures of palatability were salivary responses to the thought and presentation of pizza. Additional measures were latency to start eating, amount eaten, meal duration, rate of eating and preference ratings of the pizza's taste, aroma and appearance. Thirty-six subjects received access to regular and/or adulterated pizza over two experimental sessions. The resulting groups of nine subjects each received either adulterated and adulterated, adulterated and regular, regular and regular, or regular and adulterated pizza over the two sessions. In a third session all subjects received regular pizza. In session two, groups which had received regular pizza in session one showed a reliably greater salivary response on the presentation trial than on the thought trial. Groups which had received adulterated pizza showed minimal differences in salivation between these trials. In session three, groups which had received regular pizza in session one yielded reliably greater salivation on the presentation trial than did groups which had received adulterated pizza in session one. Furthermore, nonshift groups, which had received the same pizza condition over sessions one and two, showed a greater difference between thought and presentation trial responses than did shift groups, which had received different pizza conditions over sessions one and two. An approach-avoidance conflict model of behavior was applied to the salivation data. Preference ratings of the pizza's taste, the amount eaten and the rate of eating data yielded reliably greater responses for groups which received regular pizza than for groups which received adulterated pizza in sessions one and two. Positive and negative contrast effects were also evidenced by these data. The meal duration and latency to start eating data yielded highly similar responses among groups over days. / M.S.

Both the theory of sequential analysis developed by Wald and that developed by Rao may be applied to binomial distributions and may be used to select judges for taste testing experiments. The duo-trio or triangle test may both be used as the fundamental test in either sequential process. Wald has applied his sequential analysis to binomial distributions and it was only necessary to associate duo trio and triangle trials with his examples on industrial sampling inspection. This was done by associating incorrect tasting decisions with defectives in industrial sampling. It has been noted Ghat choice of α and β, the risks of type I and type II errors, may depend on the availability of potential judges and on the time and material available to the experimenter. / Master of Science

This study set out to establish artificial neural networks (ANN) as an alternate to regression methods (multiple linear, principal components and partial least squares regression) to predict consumer liking from trained sensory panel data. The study has two parts viz., I) Flavour study - evaluation of ANNs to predict consumer flavour preferences from trained sensory panel data and 2) Fragrance study ??? evaluation of different ANN architectures to predict consumer fragrance liking from trained sensory panel data. In this study, a multi-layer feedforward neural network architecture with input, hidden and output layer(s) was designed. The back-propagation algorithm was utilised in training of neural networks. The network learning parameters such as learning rate and momentum rate were optimised by the grid experiments for a fixed number of learning cycles. In flavour study, ANNs were trained using the trained sensory panel raw data as well as transformed data. The networks trained with sensory panel raw data achieved 98% correct learning, whereas the testing was within the range of 28 -35%. A suitable transformation methods were applied to reduce the variations in trained sensory panel raw data. The networks trained with transformed sensory panel data achieved between 80-90% correct learning and 80-95% correct testing. In fragrance study, ANNs were trained using the trained sensory panel raw data as well as principal component data. The networks trained with sensory panel raw data achieved 100% correct learning, and testing was in a range of 70-94%. Principal component analysis was applied to reduce redundancy in the trained sensory panel data. The networks trained with principal component data achieved about 100% correct learning and 90% correct testing. It was shown that due to its excellent noise tolerance property and ability to predict more than one type of consumer liking using a single model, the ANN approach promises to be an effective modelling tool.

Call number: LD2668 .T4 1984 J32 / Master of Science

Call number: LD2668 .T4 1985 L96 / Master of Science

Assignment (MComm)--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: This study is the result of part-time work done at a product development centre. The organisation extensively makes use of trained panels in sensory trials designed to asses the quality of its product. Although standard statistical procedures are used for analysing the results arising from these trials, circumstances necessitate deviations from the prescribed protocols. Therefore the validity of conclusions drawn as a result of these testing procedures might be questionable. This assignment deals with these questions. Sensory trials are vital in the development of new products, control of quality levels and the exploration of improvement in current products. Standard test procedures used to explore such questions exist but are in practice often implemented by investigators who have little or no statistical background. Thus test methods are implemented as black boxes and procedures are used blindly without checking all the appropriate assumptions and other statistical requirements. The specific product under consideration often warrants certain modifications to the standard methodology. These changes may have some unknown effect on the obtained results and therefore should be scrutinized to ensure that the results remain valid. The aim of this study is to investigate the distribution and other characteristics of sensory data, comparing the hypothesised, observed and bootstrap distributions. Furthermore, the standard testing methods used to analyse sensory data sets will be evaluated. After comparing these methods, alternative testing methods may be introduced and then tested using newly generated data sets. Graphical displays are also useful to get an overall impression of the data under consideration. Biplots are especially useful in the investigation of multivariate sensory data. The underlying relationships among attributes and their combined effect on the panellists’ decisions can be visually investigated by constructing a biplot. Results obtained by implementing biplot methods are compared to those of sensory tests, i.e. whether a significant difference between objects will correspond to large distances between the points representing objects in the display. In conclusion some recommendations are made as to how the organisation under consideration should implement sensory procedures in future trials. However, these proposals are preliminary and further research is necessary before final adoption. Some issues for further investigation are suggested. / AFRIKAANSE OPSOMMING: Hierdie studie spruit uit deeltydse werk by ’n produk-ontwikkeling-sentrum. Die organisasie maak in al hul sensoriese proewe rakende die kwaliteit van hul produkte op groot skaal gebruik van opgeleide panele. Alhoewel standaard prosedures ingespan word om die resultate te analiseer, noodsaak sekere omstandighede dat die voorgeskrewe protokol in ’n aangepaste vorm geïmplementeer word. Dié aanpassings mag meebring dat gevolgtrekkings gebaseer op resultate ongeldig is. Hierdie werkstuk ondersoek bogenoemde probleem. Sensoriese proewe is noodsaaklik in kwaliteitbeheer, die verbetering van bestaande produkte, asook die ontwikkeling van nuwe produkte. Daar bestaan standaard toets- prosedures om vraagstukke te verken, maar dié word dikwels toegepas deur navorsers met min of geen statistiese kennis. Dit lei daartoe dat toetsprosedures blindelings geïmplementeer en resultate geïnterpreteer word sonder om die nodige aannames en ander statistiese vereistes na te gaan. Alhoewel ’n spesifieke produk die wysiging van die standaard metode kan regverdig, kan hierdie veranderinge ’n groot invloed op die resultate hê. Dus moet die geldigheid van die resultate noukeurig ondersoek word. Die doel van hierdie studie is om die verdeling sowel as ander eienskappe van sensoriese data te bestudeer, deur die verdeling onder die nulhipotese sowel as die waargenome- en skoenlusverdelings te beskou. Verder geniet die standaard toetsprosedure, tans in gebruik om sensoriese data te analiseer, ook aandag. Na afloop hiervan word alternatiewe toetsprosedures voorgestel en dié geëvalueer op nuut gegenereerde datastelle. Grafiese voorstellings is ook nuttig om ’n geheelbeeld te kry van die data onder bespreking. Bistippings is veral handig om meerdimensionele sensoriese data te bestudeer. Die onderliggende verband tussen die kenmerke van ’n produk sowel as hul gekombineerde effek op ’n paneel se besluit, kan hierdeur visueel ondersoek word. Resultate verkry in die voorstellings word vergelyk met dié van sensoriese toetsprosedures om vas te stel of statisties betekenisvolle verskille in ’n produk korrespondeer met groot afstande tussen die relevante punte in die bistippingsvoorstelling. Ten slotte word sekere aanbevelings rakende die implementering van sensoriese proewe in die toekoms aan die betrokke organisasie gemaak. Hierdie aanbevelings word gemaak op grond van die voorafgaande ondersoeke, maar verdere navorsing is nodig voor die finale aanvaarding daarvan. Waar moontlik, word voorstelle vir verdere ondersoeke gedoen.

Call number: LD2668 .T4 1986 R53 / Master of Science / Hospitality Management and Dietetics

The objective of this research was to determine the acceptability and preference of peanut butter and three different flavors of soynut butter among humans. Six hundred and sixty-two volunteers (401 females, 258 males and 3 unknown) between the ages of 18 and up were randomly asked to fill out a demographic survey and taste 1 tsp. (5.33 g) of three different soynut butters (creamy, creamy with honey, and creamy with chocolate) and 1 tsp. (5.33 g) of peanut butter on saltine crackers. After taste testing the soynut butters/peanut butter, volunteers were asked to rate each product on a 9-point hedonic rating scale based on appearance, texture, and flavor; the subjects were also asked as to whether they would purchase the nut butters. Demographic information such as participants' age, gender, year in school, and ethnicity were collected, along with questions concerning their frequency of exercise, eating and smoking habits, and health status of themselves and their families.The creamy with honey and creamy soynut butters were rated highest by both genders for all variables (i.e., appearance, texture, flavor, purchase). The purchase variable determined statistical significance between females and males. The females indicated by their rating that they would be more likely to purchase the chocolate soynut butter vs. the peanut butter, while the males indicated purchasing preference of peanut butter over the chocolate soynut butter.Given that both creamy with honey and creamy soynut butters were accepted by this population based on appearance, texture, and flavor, future research in this area should focus on soy foods in humans and biochemical parameters, marketing niches, specific ethnic or age preferences, and education of the health benefits of soy. / Department of Family and Consumer Sciences

O objetivo do trabalho foi elaborar e caracterizar tofus, com e sem adição de orégano, produzidos com duas cultivares de soja, BRS 284 e BMX Potência RR, oriundas de Mauá da Serra – PR, safra 2011/2012. Os grãos foram avaliados quanto a sua composição proximal, fibras alimentares, isoflavonas e propriedades tecnológicas. Também foram determinados a quantidade de água absorvida na maceração dos grãos, o rendimento e a composição proximal dos extratos de soja. Os tofus foram avaliados quanto à composição proximal, isoflavonas e aceitação sensorial. As duas cultivares se destacaram pelo teor de proteínas BRS 284 (33,24%) e BMX Potência RR (34,74%), lipídios BRS 284 (22,54%) e BMX Potência RR (21,72%) e fibras alimentares totais BRS 284 (26,64%) e BMX Potência RR (27,13%), sendo a maior fração constituída de fibras insolúveis. Ambas cultivares apresentaram altos valores de isoflavonas totais BRS 284 (591,70 mg.100g-1) e BMX Potência RR (865,36 mg.100g-1), devido ao local de plantio possuir temperaturas baixas. As cultivares BRS 284 e BMX Potência RR obtiveram valores para volume de intumescimento de 4,31 mL/g e 4,12 mL/g; índice de absorção de água de 2,75 g/g e 2,75 g/g e índice de absorção de óleo de 2,87 g/g e 2,60 g/g, respectivamente. Os grãos das duas cultivares de soja apresentaram diferenças nos teores de umidade, lipídios, proteínas e isoflavonas totais. Durante a maceração os grãos das duas cultivares absorveram em média 1,2 mL mL/g de água. O rendimento dos extratos de soja foram elevados, com média de 77%. Os extratos de soja não apresentaram diferença significativa em sua composição proximal. Os tofus produzidos com as duas cultivares se destacaram pelo teor de proteínas BRS 284 Padrão e Orégano (9,21% e 8,67%) e BMX Potência RR Padrão e Orégano (11,16% e 10,90%), seguido por lipídios BRS 284 Padrão e Orégano (5,26% e 4,89%) e BMX Potência RR Padrão e Orégano (4,38% e 4,24%). Os tofus das duas cultivares apresentaram altos teores de isoflavonas totais BRS 284 Padrão e Orégano (243,57 mg.100g-1 e 219,18 mg.100g-1) e BMX Potência RR Padrão e Orégano (262,64 mg.100g-1 e 330,38 mg.100g-1). Os tofus padrão e com adição de orégano da cultivar BRS 284 não apresentaram diferença para os teores de proteínas e nos produtos elaborados com a cultivar BMX Potência RR, não houve diferença nos teores de lipídios e cinzas. Os tofus com adição de orégano apresentaram melhor aceitabilidade e também maior intenção de compra pelos julgadores, comprovando a importância do atributo sabor na aceitação do tofu por parte de não consumidores. / The aim of the study was to develop and characterize tofu, with and without the addition of oregano, produced with two soybean cultivars, BRS 284 and BMX Potência RR, from Maua da Serra – PR, harvest 2011/2012. The grains were evaluated for proximate composition, dietary fiber, isoflavones and technological properties. Were also determined the amount of water absorbed in the soaking of the grains, the yield and the proximal composition of soymilk. The tofu were evaluated for proximate composition, isoflavones and sensory acceptance. Both cultivars stood out for its protein content BRS 284 (33,24%) and BMX Potência RR (34,74%), lipids BRS 284 (22,54%) and BMX Potência RR (21,72%) and total dietary fiber BRS 284 (26,64%) and BMX Potência RR (27,13%), being the largest fraction consists of insoluble fiber. Both cultivars showed high levels of total isoflavones BRS 284 (591,70 mg.100g-1) and BMX Potência RR (865,36 mg.100g-1), due to the planting site possess low temperatures. The cultivars BRS 284 and BMX Potência RR obtained values for volume swelling of 4,31 mL/g and 4,12 mL/g; water absorption index of 2,75 g/g e 2,75 g/g and oil absorption index of 2,87 g/g and 2,60 g/g, respectively. The grains of two soybean cultivars showed differences in moisture, lipids, proteins and total isoflavones. During maceration, grains of both cultivars absorbed on average 1,2 mL mL/g of water. The yield of soymilk were high, with an average of 77%. The soy extract showed no significant difference between their composition. The tofu produced in both cultivars stood out for its high protein content Standard BRS 284 and Oregano (9,21% e 8,67%) and Standard BMX Potência RR and Oregano (11,16% e 10,90%), followed by lipids content Standard BRS 284 and Oregano (5,26% e 4,89%) and Standard BMX Potência RR and Oregano (4,38% e 4,24%). The tofus of both cultivars showed high levels of total isoflavones Standard BRS 284 and Oregano (243,57 mg.100g-1 e 219,18 mg.100g-1) and Standard BMX Potência RR and Oregano (262,64 mg.100g-1 e 330,38 mg.100g-1). The standard tofu and adding oregano from cultivar BRS 284 showed no difference in the protein content, and products made with cultivar BMX Potência RR, there was no difference in the levels of lipids and ash. The tofu with oregano showed better acceptability and also better purchase intent by the judges, what indicates the importance of flavor attribute in acceptance by non-consumers.