As a major group of agricultural commodities, legume grains are widely grown and consumed globally, but are often utilised in the whole form. With increasing evidence of nutritional benefits, these grains are potentially sources of novel ingredients including starches. Accordingly the objective of this study has been to investigate legume starches, particularly their isolation, characterisation and incorporation into selected food products. Using chickpea, faba bean, lentil and mung bean, extraction procedures for the practical isolation of legume starches have been evaluated. A relatively simple method has been established, involving grain cracking, steeping in a mildly alkaline solution, followed by washing, double blending, double sieving and sedimentation. The starches collected for the four legumes were oven dried and the recoveries ranged between 29 and 38%. Compositional analyses confirming that the isolation procedure gave relatively pure starches and scanning electron microscopy showed that the granules were typically ellipsoidal. Laser particle size analysis showed mono-modal distributions with mean diameters between 19.6 and 23.9µm. X-ray diffractograms of legume starches were of the typical C-type, with variations in the intensities and peak distribution indicating some differences in the crystallinity of the starches. Suitable conditions for the measurement of starch gelatinisation characteristics by differential scanning calorimetry were investigated. When optimised conditions were applied, the temperature of gelatinisation ranged from 58.9 for lentil to 65.7 °C for mung bean with corresponding enthalpy values of 9.2 and 5.7 Jg-1. Hot-stage optical microscopy confirmed gelatinisation patterns. The starch pastes demonstrated opalescence with some variation in the degree of clarity. The pasting and viscosity properties measured by the Rapid Visco-Analyser showed some variation in pasting temperatures and considerable differences in peak readings with faba bean starch having lowest and mung bean the highest with values of 307 and 676 RVA units, respectively. In order to study the incorporation of the legume starches, two Asian food products having starch as an ingredient, were selected and adapted as model foods. In this context, vermicelli represented a savoury product and coconut cake a sweet product. Vermicelli and coconut cake samples that incorporated chickpea starch were both preferred by most of the panellists over those containing the other legume starches. The overall conclusions are that the starch extraction method adapted in this investigation was a practical approach, producing relatively pure, white starches. The characteristics of the four legume starches showed many similarities, but there were some variations in the properties, indicating that there may be different applications for their incorporation into food formulations. Sensory evaluations confirmed the usefulness of the starches as food ingredients that provide attractive mouthfeel and textural characteristics. Therefore legume starches offer potential as novel food ingredients warranting further evaluation and larger scale feasibility studies.

Thesis (MSc Food Sc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: In this study an industry-selected and diverse range of South African red wines were analysed for sensory and chemical attributes, as well as degree of liking using a target group of black South African consumers. Segments of consumers that differed in degree of liking were then tested for their response to intrinsic (sensory) and extrinsic (non-sensory) cues. The selection of wines included eighteen dry and natural sweet red wines, representing low-end inexpensive wines together with high-end, top quality wines. Sensory profiles for all samples were established using Quantitative descriptive analysis (QDA). The results revealed that cultivar specific dry red wines associated with a wide range of sensory descriptors such as woody, vegetative and fruity, while the sweet red wines associated with the fruity and sweet-associated attributes. Chemically there was a significant variation between wines regarding the alcohol and sugar content. Gas chromatography with flame ionisation detection (GC-FID) indicated the major volatile constituents present in the wine, i.e. esters, alcohols and fatty acids. When investigating the association between the chemical and sensory data, it was revealed that the red blends were driven by the presence of alcohols and esters, and sensory descriptors such as high roast oak, coffee and mixed spice, whereas the red cultivar wines were mostly driven by fatty acids and esters and the sensory descriptors, green bean and asparagus. The sweet red blends were closely associated with acids and the sensory descriptors sweet-associated and floral. Degree of liking of a subset of 18 wines was investigated based on the preferences of black consumers from the Western Cape area, South Africa. These consumers predominantly preferred the sweet red wines with high sugar content, in a blind tasting session. Purchase intent was also evaluated by viewing actual photographs of packaging formats of the respective wines and the results indicated that the consumers preferred the well-known cultivar wines with a perception of value and style. Cluster analysis was furthermore performed to ascertain whether these consumers differed in their degree of liking of the intrinsic character of the respective wines. Four different clusters of consumers were identified: 1) Consumers preferring both dry and sweet red wines equally, 2) Consumers who strongly favoured sweet red wines and moderately liked dry red wines, 3) Consumers who strongly favoured sweet red wines with little preference for dry red wines; and 4) Consumers preferring dry red wines. Consumers were also probed on their general opinions or perceptions on the extrinsic character of the wines, and thus factors that influence the purchasing process. It was found that black consumers who don‟t consume wine often, preferred wines that they are familiar with, while consumers that drink wine more frequently enjoy to broaden their horizons by experimenting with more expensive wine brands. Extrinsic or non-sensory cues such as alcohol content, label, vintage, price and cultivar were found to be the most important considered factors when purchasing red wines, while awards and type of closure were regarded as the least important. It was also found that the discerning consumers, who purchase high-end wines, took more of the latter aspects into consideration, whereas consumers who purchase low-end wines considered a limited number of the non-sensory cues. / AFRIKAANSE OPSOMMING: In hierdie studie is 'n diverse reeks industrie-geselekteerde, Suid-Afrikaanse rooiwyne geanaliseer vir hul sensoriese en chemiese eienskappe. Verbruikersvoorkeur van die wyne is getoets, asook tot watter mate verbruikersvoorkeure beïnvloed word deur intrinsieke (sensoriese) en ekstrinsieke (nie-sensoriese) faktore. Die reeks van agtien wyne het bestaan uit droë en soet rooi wyne, wat op hul beurt verder verdeel kan word in goedkoper, kwaliteit wyne en duurder, ultra-premium wyne. Die sensoriese profiel van al die wyne is bepaal deur beskrywende sensoriese analise. Resultate het getoon dat die kultivar-spesifieke droë rooiwyne geassosieer word met 'n wye reeks sensoriese eienskappe soos houtagtig, kruidagtig en vrugtig, terwyl die soet rooiwyne beskryf is as vrugtige en soet-geassosieerd. In terme van die chemiese analises was daar betekenisvolle verskille betreffende die alkohol- en suikerinhoud van die wyne. Gas chromatografie gekoppel met vlam-ioniserende deteksie (GC-FID) het die mees vlugtige verbindings teenwoordig in die wyn aangedui, naamlik esters, alkohole en vetsure. Met die korrelasie van die chemiese en sensoriese data is gevind dat die droë versnitwyne gedryf word deur die teenwoordigheid van alkohole en esters, asook sensoriese eienskappe soos gehout, koffie, en gemengde spesery, terwyl die kultivar-spesieke wyne weer meestal gedryf word deur vetsure en esters en sensoriese eienskappe soos groenboontjie en aspersie. Die soet rooiwyne het chemies geassosieer met sure en sensoriese terme soos soet-geassosieerd en blomagtig. Die aanvaarbaarheid van 'n kleiner groepering wyne is bepaal deur gebruik te maak van swart verbruikers in die Wes-Kaap area, Suid-Afrika. Die verbruikers het in 'n blinde proesessie onderskeie wyne se wynverpakking besigtig en aangedui of hulle die wyne sou koop. Hierdie resultate het getoon dat die verbruikers bekende kultivarwyne verkies wat 'n persepsie van waarde en styl geïllustreer het. Segmentasie tegnieke is op die data uitgevoer ten einde te bepaal of verbruikers in groepe verdeel kan word, wat betref hul voorkeur van die sensoriese of intrinsieke eienskappe van die wyne. Vier verskillende groepe is geïdentifiseer, nl. verbruikers wat 1) droë en soet rooiwyne ewe veel verkies; 2) soet rooiwyne en tot 'n mate ook droë rooiwyne verkies; 3) soet rooiwyne en tot 'n mindere mate droë rooiwyne verkies; en laastens 4) slegs droë rooiwyne verkies. Verbruikers se algemene opinies en persepsies betreffende die ekstrinsieke eienskappe van die wyne is ook ondersoek, met ander woorde faktore wat die aankoop van wyne beïnvloed. Daar is gevind dat swart verbruikers wat nie gereeld wyn drink, bekende handelsmerke verkies, terwyl verbruikers wat gereeld wyn drink, daarvan hou om hul horisonne te verbreed en te eksperimenteer met 'n verskeidenheid handelsmerke. Ekstrinsieke of nie-sensoriese aspekte soos, alkohol-inhoud, etiket, oesjaar, prys en kultivar is die belangrikste faktore wat in ag geneem word wanneer rooiwyne gekoop word, terwyl wyntoekennings en die feit dat die wyn met kurke gebotteleer word, nie as belangrik beskou word nie. Daar is ook gevind dat die meer ingeligte verbruiker, wat hoë kwaliteit wyne koop, meer van die bogenoemde aspekte in ag neem tydens die aankoopproses, terwyl die verbruiker wat meer geneig is om goedkoper wyne te koop, slegs 'n paar ekstrinsieke faktore in ag neem.

Thesis (MScFoodSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: In this study quality control tools were developed for the rooibos industry, primarily to determine the quality of rooibos infusions. A considerable variation between samples of the same quality grade has been noted. As there are no guidelines or procedures in place to help minimise this inconsistency it was important to develop quality control tools, which could confront this problem. Both the sensory characteristics and phenolic composition of rooibos infusions were analysed in order to create and validate these quality control tools. Descriptive sensory analysis was used for the development of a targeted sensory wheel and sensory lexicon, to be used as quality control tools by the rooibos industry, and to validate the major rooibos sensory profiles. In order to ensure all possible variation was taken into account, 230 fermented rooibos samples were sourced from the Northern Cape and Western Cape areas within South Africa over a 3-year period (2011-2013). The aroma, flavour, taste and mouthfeel attributes found to associate with rooibos sensory quality were validated and assembled into a rooibos sensory wheel, which included the average intensity, as well as the percentage occurrence of each attribute. Two major characteristic sensory profiles prevalent within rooibos, namely the primary and secondary profiles, were identified. Both profiles had a sweet taste and an astringent mouthfeel, however, the primary sensory profile is predominantly made up of “rooibos-woody”, “fynbos-floral” and “honey” aroma notes, while “fruity-sweet”, “caramel” and “apricot” aroma notes are the predominant sensory attributes of the secondary profile. The predictive value of the phenolic compounds of the infusions towards the taste and mouthfeel attributes (“sweet”, “sour”, “bitter” and “astringent”) was examined using different regression analyses, namely, Pearson’s correlation, partial least squares regression (PLS) and step-wise regression. Correlations between individual phenolic compounds and the taste and mouthfeel attributes were found to be significant, but low. Although a large sample set (N = 260) spanning 5 years (2009-2013) and two production areas (Western Cape and Northern Cape, South Africa) was used, no individual phenolic compounds could be singled out as being responsible for a specific taste or mouthfeel attribute. Furthermore, no difference was found between the phenolic compositions of the infusions based on production area, a trend that was also seen for the sensory characterisation of rooibos infusions. Sorting, a rapid sensory profiling method was evaluated for its potential use as a quality control tool for the rooibos industry. Instructed sorting was shown to successfully determine rooibos sensory quality, especially based on the aroma quality of the infusions. However, determining the quality of the infusion based on flavour quality was more difficult, possibly due to the low sensory attribute intensities. Categorisation of rooibos samples based on the two major aroma profiles i.e. the primary and secondary characteristic profiles, was achieved with uninstructed sorting. The potential of using sorting as a rapid technique to determine both quality and characteristic aroma profiles, was therefore demonstrated, indicating its relevance as another quality control tool to the rooibos industry. / AFRIKAANSE OPSOMMING: Gehaltebeheer hulpmiddels is as deel van hierdie studie vir die rooibosbedryf ontwikkel, hoofsaaklik om die sensoriese kwaliteit van rooibostee te bepaal. Aansienlike verskille is tussen monsters van dieselfde gehaltegraad opgemerk, primêr omdat daar in die wyer rooibosbedryf beperkte riglyne of prosedures in plek is om kwaliteitsverskille effektief te bepaal. Dit is as belangrik geag om gehaltebeheer hulpmiddels te ontwikkel om laasgenoemde probleem aan te spreek. Spesifieke gehaltebeheer hulpmiddels is dus vir hierdie studie ontwikkel en gevalideer deur die sensoriese eienskappe en fenoliese samestelling van rooibostee te analiseer. Beskrywende sensoriese analise (BSA) is gebruik om ‘n sensoriese wiel en leksikon vir die rooibosbedryf te ontwikkel en te valideer. Om alle moontlike produkvariasie te ondervang, is 230 gefermenteerde rooibos monsters afkomstig van die Noord-Kaap en Wes-Kaap areas in Suid-Afrika oor ‘n tydperk van drie jaar (2011-2013) verkry. Die aroma, geur, smaak en mondgevoel eienskappe wat met rooibos se sensoriese kwaliteit assosieer, is bevestig en uiteindelik gebruik om die sensoriese wiel te ontwikkel. Die gemiddelde intensiteit en persentasie voorkoms van elke eienskap is in die wiel ingesluit. Twee belangrike “karakteristieke” sensoriese profiele wat met rooibos geassosieer word, is geïdentifiseer, nl. die primêre en sekondêre sensoriese profiele. Tipies van beide sensoriese profiele is ‘n kenmerkende soet smaak en vrank mondgevoel, daarenteen bestaan die primêre sensoriese profiel hoofsaaklik uit "rooibos-houtagtige", "fynbos-blomagtige" en "heuning" aromas, terwyl "vrugtige-soet", "karamel" en "appelkoos" aromas die oorheersende sensoriese eienskappe van die sekondêre profiel is. Die korrelasie tussen die fenoliese verbindings en die smaak en mondgevoel eienskappe van rooibos ("soet", "suur", "bitter" en "vrankheid") is ondersoek met behulp van verskillende tipe regressieontledings, nl. Pearson se korrelasie, gedeeltelike kleinstekwadrate regressie (PLS) en stapsgewyse regressie. Korrelasies tussen individuele fenoliese verbindings en die smaak en mondgevoel eienskappe was laag, maar steeds betekenisvol. Alhoewel die uitgebreide stel monsters (N = 260) verteenwoordigend was van vyf oesjare (2009-2013) en twee produksiegebiede (Wes-Kaap en Noord-Kaap, Suid-Afrika), kon geen individuele fenoliese verbindings uitgesonder word as betekenisvolle voorspellers van spesifieke smaak of mondgevoel eienskappe nie. Verder is daar ook geen verskil tussen die verskillende produksie-areas wat betref fenoliese samestelling gevind nie. Soortgelyke resultate is bevind vir die sensoriese karakterisering van rooibostee. Sortering, 'n vinnige sensoriese profileringsmetode, is geëvalueer vir sy potensiële gebruik as 'n gehaltebeheer hulpmiddel vir die rooibosbedryf. Gestrukteerde sortering was suksesvol om rooibos se sensoriese kwaliteit, veral die algemene aroma kwaliteit van rooibos, te bepaal. Hierdie profileringsmetode was egter nie so suksesvol om rooibos se algemene geur, smaak en mondgevoeleienskappe te bepaal nie. Hierdie tendens kan moontlik toegeskryf word aan die betekenisvolle laer intensiteite van laasgenoemde sensoriese eienskappe. Die kategorisering van die rooibos monsters op grond van hul karakteristieke primêre en sekondêre sensoriese profiele is suksesvol deur middel van ongestrukteerde sortering bepaal. In die geheel gesien is die potensiaal van die sorteringstegniek as ‘n vinnige metode om die algemene sensoriese kwaliteit, asook die karakteristieke aroma profiele van rooibos te bepaal, dus bewys. Hierdie vinnige sensoriese profileringstegniek hou dus besliste voordele in vir die rooibosbedryf as dit kom by sensoriese gehaltebeheer.

Made available in DSpace on 2015-04-17T14:49:36Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2092428 bytes, checksum: 9f2660b1eca5b207292adc4d196cdd59 (MD5) Previous issue date: 2014-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The success of the food industry depends not only on sure foods are safety for consumers, but also the capacity to innovate and supply the market trends, like the demand for food products made from health benefits ingredients. In this way, this research aimed to develop and characterize a yogurt-like fermented beverage made from a mixture of goat s milk and water-soluble soy extract (WSSE), supplemented with inulin. To established the most suitable formulation, a Central Composite Design (CCD) in conjunction with Response Surface Methodology (RSM) was used, having as independent variables the concentrations of WSSE and inulin. The response variables were water holding capacity (WHC), syneresis index, pH, acidity, and rheological and sensory properties. By using that methodology was observed that increasing WSSE concentration was related to better results for rheological properties, WHC and syneresis index, whereas, a negative influence was observed on overall acceptability of the product. Inulin concentration, at the levels studied, showed a positive influence on apparent viscosity and overall acceptability of the beverages. By using the models obtained for response variables was elaborated a treatment containing the concentrations of WSSE and inulin that promoted the most suitable result. The fermented beverage elaborated was characterized for physicochemical and sensory properties and the refrigerated storage stability was analyzed during 28 days by evaluating microbiological, chemical and physical parameters. The results obtained from this treatment were compared with the results obtained from a control treatment made using goat s milk only and without inulin supplementation. The treatment containing WSSE and inulin showed better results for physical and chemical properties, showing better stability during refrigerated storage. However, control treatment showed a better overall acceptability, presenting aroma and taste more pleasant. Regarding to microbiological parameters, no significative differences were observed for these two treatments. / O sucesso da indústria de alimentos não depende apenas da certeza de que os alimentos são seguros para o consumo, mas também da habilidade para inovar e para atender as atuais tendências de mercado, como a demanda por alimentos elaborados a partir de ingredientes que, além de nutrir, trazem benefícios adicionais a saúde. Neste contexto, este trabalho objetivou desenvolver e caracterizar uma bebida fermentada tipo iogurte elaborada a partir de uma mistura composta por leite de cabra e extrato hidrossolúvel de soja (EHS), adicionada de inulina. Para a definição da formulação mais adequada foi utilizado um Delineamento Composto Central Rotacional (DCCR) em conjunto com a Metodologia de Superfície de Resposta (MSR), tendo como variáveis independentes as concentrações de EHS e inulina e como variáveis dependentes a capacidade de retenção de água, o índice de sinerese, pH, acidez e as propriedades reológicas e sensoriais. A partir desta metodologia, foi verificado que o aumento na concentração de EHS favoreceu a obtenção de melhores resultados para as propriedades reológicas, para a capacidade de retenção de água e para o índice de sinerese, no entanto, apresentou uma influência negativa sobre a aceitação sensorial do produto. A concentração de inulina, dentro dos níveis utilizados, influenciou de forma positiva sobre a viscosidade aparente e sobre a aceitação sensorial do produto. A partir dos modelos obtidos para as variáveis dependentes estudadas, foi elaborado um tratamento contendo as concentrações de EHS e inulina que forneceram os resultados mais satisfatórios. A bebida fermentada elaborada foi caracterizada quanto as propriedades físico-químicas e sensoriais e sua estabilidade foi avaliada durante um período de armazenamento refrigerado de 28 dias com relação a parâmetros microbiológicos, físicos e químicos. Os resultados obtidos a partir deste tratamento otimizado foram comparados com os resultados de um tratamento controle elaborado apenas com leite de cabra e sem a adição de inulina. O tratamento contendo EHS e inulina obteve melhores resultados com relação as propriedades físicas e químicas, apresentando melhor estabilidade durante o armazenamento. No entanto, o tratamento controle obteve uma melhor aceitação sensorial, apresentando sabor e aroma mais agradáveis. Com relação aos parâmetros microbiológicos, diferenças significativas não foram observadas entre estes dois tratamentos.

Made available in DSpace on 2016-08-31T13:29:06Z (GMT). No. of bitstreams: 1 AndrezzaACM_DISSERT.pdf: 988309 bytes, checksum: 9619badb5c59711ce4b84599afd15913 (MD5) Previous issue date: 2014-12-11 / Innovation in products elaboration is a constant purpose in the food industry in order to get differential quality attributes. For this, the development of new flavors fruit yogurt may be well received by consumers of the product, especially if these present some antioxidant properties. Thus, this study aimed to evaluate some physical and chemical properties, antioxidants and sensory of yogurt manufactured from noni pulp (Morinda citrifolia L.) and acerola (Malpighia emarginata DC.) pulp. For this, the following formulations were developed: F1- natural yogurt (control); F2 - yogurt with acerola pulp (2.5%); F3 - yogurt with noni pulp (2.5%); F4 - mixed yogurt with acerola pulp (1.25%) and noni pulp (1.25%); F5 - yogurt with acerola pulp (5%); F6 - yogurt with noni pulp (5%); F7 - mixed yogurt with acerola pulp (2.5%) and noni pulp (2.5%). The physical and chemical analysis (pH, titratable acidity, milk fat and protein), phenolic content, antioxidant activity and sensory analysis (consistency, acceptance and purchase intent) were carried out in yogurt. The data were evaluated by the Scott-Knott test and Friedman with probability of 5%. All yogurts showed physical and chemical quality according to the quality standard established by brazilian legislation. There was treatment effect on physical and chemical parameters, except to pH. The yogurts manufactured with only acerola (2.5% and 5%) obtained higher antioxidant activity (51.56% and 79.83%, respectively). There was treatment effect for the sensory attributes evaluated. The formulations F1, F2 and F4 obtained higher consistency. The yogurt with 5% noni obtained lower acceptance and purchase intention. The yogurts with noni 2.5% and 2.5% acerola obtained lower rejections. The yogurt manufactured showed acceptance similar to the natural yogurt. Thus, the new yogurt formulations show great commercial potential / A inovação na elaboração de produtos é uma finalidade constante na indústria de alimentos, visando agregar atributos de qualidade diferencial. Por isso, o desenvolvimento de novos sabores de iogurtes de frutas tende a ser bem recebido pelos consumidores do produto, ainda mais se possuírem alguma propriedade antioxidante. Assim, o objetivo deste trabalho foi avaliar algumas propriedades físico-químicas, antioxidantes e sensoriais de iogurte elaborado com polpa de noni (Morinda citrifolia L.) e acerola (Malpighia emarginata DC.). Para isto, foram desenvolvidas as seguintes formulações: F1- iogurte natural (controle); F2 - iogurte com polpa de acerola (2,5%); F3 - iogurte com polpa de noni (2,5%); F4 - iogurte misto com polpa de acerola (1,25%) e noni (1,25%); F5 iogurte com polpa de acerola (5%); F6 - iogurte com polpa de noni (5%); F7 - iogurte com polpa de acerola (2,5%) e noni (2,5%). Foram realizadas análises físico-químicas (pH, acidez titulável, gordura láctea e proteínas lácteas), teor de compostos fenólicos, atividade antioxidante e análises sensoriais (consistência, aceitação e intenção de compra). Os dados foram avaliados pelo Teste de Scott-Knott e de Friedman com probabilidade de 5%. Todos os iogurtes apresentaram qualidade físico-química conforme o padrão de qualidade estabelecido pela legislação brasileira. Houve efeito de tratamento para os parâmetros físico-químicos, exceto pH. Os iogurtes formulados somente com acerola (2,5% e 5%) apresentaram maiores atividades antioxidantes (51,56% e 79,83%, respectivamente). Houve efeito de tratamento para os atributos sensoriais avaliados. As formulações F1, F2 e F4 obtiveram as maiores consistências. A formulação com 5% de noni apresentou a menor aceitação e a menor intenção de compra. As formulações com noni a 2,5% e acerola a 2,5% apresentaram menores rejeições. A aceitação dos iogurtes formulados foi semelhante ao do iogurte natural. Assim, as novas formulações apresentam grande potencialidade comercial

The theme of this thesis is a comparison of selected quality indicators of samples from single-flower honeys from the area of the Czech Republic and honeys from different retail chains. The theoretical part focuses on the characteristics of the individual kinds of honey and how different their composition is. There are described basic physical and chemical requirements for honey including sensory requirements which are specified in Regulation No.76/2003 Code. The practical part contains a physically-chemical analysis according to the Harmonized methods of European Honey and a sensory evaluation of selected single-flower honeys (honeydew, acacia, lime, sunflower and rape). There were analysed twenty samples of honey from Czech beekeepers and fifteen samples of honey bought in different retail chains in the Czech Republic. Subsequently, these parameters were monitored - water content and acidity. Next step was a test for evidence of disruption by starchy sugar and malt extracts. Then, sensory requirements such as colour, smell, taste and consistence were evaluated. The conclusion of the comparison of honey samples indicates that individual honey samples differed the most in the taste and smell criteria and in addition the samples were often disrupted by starchy sugar and malt extracts. The samples collected from the beekeepers from the area of the Czech Republic complied with Regulation No.76/2003 Code. On the contrary, the samples from the chosen retail chains in the Czech Republic weren't in accordance with the criteria specified in Regulation No.76/2003 Code.

This thesis deals with the baking quality of the spelt wheat grain (Triticum spelta L.) compared with common wheat (Triticum aestivum L.). Mixed flours were made of different share of spelt wheat and common wheat (in total 11 mixtures). The technological quality of these mixtures was analyzed, focusing on standard evaluation methods (protein content, characteristic of gluten or swellability of protein). The analysis was supplemented by complete rheological analysis made by MIXOLAB II. Bread was used as a model product. Subsequently, sensory evaluation of baked bread from the previously prepared mixtures was done. Part of the analysis was to estimate the economic basic bread recipe with different proportions of common wheat and spelt wheat. The results were statistically analyzed via STATISTICA 9.1 (StatSoft, Inc., USA). It was proved that the flour made of spelt can give cereal products with higher nutritional value. From a technological point of view, the results have shown that the spelt grain is much more suitable for baking. Its advantage is the higher protein content and higher resistence of kneading of the dough and starch gelatinization rate, which was statistically confirmed by Tukey HSD test. The other benefits of spelt grain is the higher nutritional value in comparsion to common wheat grain. The main disadvantage is the higher price of spelt. According to the results, the ideal utilization of spelt wheat based on sensory analysis and economic calculations seems to be the mixture of spelt wheat and bread wheat, which results in an undenieble decrease of the product cost, and hence effects the common customer choice and taste preferences.

The aim of this thesis is to suggest a gluten-free mixture that will satisfy the sensory and technological properties of gluten-free pastry. To improve the structure and at the same time to substitute the gluten chia seed and chia flour were added to the dough. These two components should increase both pastry structure and nutritional value. The other ingredients that made up the mixture were one-kind flour: buckwheat, rice and corn one. The aim of the thesis was to find suitable combination of quantities of these kinds of flour, to create a draft of the recipe and to realize sensory evaluation. The thesis also includes the issues of celiac disease, problematics of labelling of gluten-free products and sensory evaluation. Sample preferences, textures, smell and flavour have been assessed here using selected methods. At the end of the thesis the results of the questionnaire survey are presented.

O presente trabalho apresenta proposições para seleção de variáveis em avaliações sensoriais descritivas e de espectro infravermelho que contribuam com a indústria de alimentos e química através da utilização de métodos de análise multivariada. Desta forma, os objetivos desta tese são: (i) Estudar as principais técnicas de análise multivariada de dados, como são comumente organizadas e como podem contribuir no processo de seleção de variáveis; (ii) Identificar e estruturar técnicas de análise multivariada de dados de forma a construir um método que reduza o número de variáveis necessárias para fins de caracterização, classificação e predição dos produtos; (iii) Reduzir a lista de variáveis/atributos, selecionando aqueles relevantes e não redundantes, reduzindo o tempo de execução e a fadiga imposta aos membros de um painel em avaliações sensoriais; (iv) Validar o método proposto utilizando dados reais; e (v) Comparar diferentes abordagens de análise sensorial voltadas ao desenvolvimento de novos produtos. Os métodos desenvolvidos foram avaliados através da aplicação de estudos de caso, em exemplos com dados reais. Os métodos sugeridos variam com as características dos dados analisados, dados altamente multicolineares ou não e, com e sem variável dependente (variável de resposta). Os métodos apresentam bom desempenho, conduzindo a uma redução significativa no número de variáveis e apresentando índices de adequação de ajuste dos modelos ou acurácia satisfatórios quando comparados aos obtidos mediante retenção da totalidade das variáveis ou comparados a outros métodos dispostos na literatura. Conclui-se que os métodos propostos são adequados para a seleção de variáveis sensoriais e de espectro infravermelho. / This dissertation presents propositions for variable selection in data from descriptive sensory evaluations and near-infrared (NIR) spectrum analyses, based on multivariate analysis methods. There are five objectives here: (i) review the main multivariate analysis techniques, their relationships and potential use in variable selection procedures; (ii) propose a variable selection method based on the techniques in (i) that allows product prediction, classification, and description; (iii) reduce the list of variables/attributes to be analyzed in sensory panels identifying those relevant and non-redundant, such that the time to collect panel data and the fatigue imposed on panelists is minimized; (iv) validate methodological propositions using real life data; and (v) compare different sensory analysis approaches used in new product development. Proposed methods were evaluated through case studies, and vary according to characteristics in the datasets analyzed (data with different degrees of multicollinearity, presenting or not dependent variables). All methods presented good performance leading to significant reduction in the number of variables in the datasets, and leading to models with better adequacy of fit. We conclude that the methods are suitable for datasets from descriptive sensory evaluations and NIR analyses.

Bread has been one of the basic foodstuffs for more than 30,000 years. It´s prepared mainly by baking, where gluten plays an important role. Gluten is important for holding the gas in the dough to achieve the desired structure, texture and volume. At a time when agriculture began to develop, a disease of gluten began to emerge. One of the best known is the intolerance of gluten, the so-called celiac disease, which affect sapproximately 1 % of the world's population. The cause is gluten-rich proteins (prolamins and glutelins), found in wheat, rye, barley and oats. The second known diseaseis gluten allergy, which is often confused with celiac disease. The difference consist in a different autoimmune reaction to the presence of glucose, when the immunization on glucose produces IgE immunoglobulin and does not damage the small intestine mucosa The only possible treatment for patiens with a dinase is a strict gluten-free diet. Gluten-free breads and pastries are one of the main foods for celiac and allergy sufferers. Preparing a dough without gluten is difficult. Proper selection of raw materials plays an important role in meeting sensory properties. The aim of the diploma thesis was to prepare suitable recipe senriched with selected sources of antioxidants. In total, six different recipes were prepared, both from cereal gluten-free flour and legumes flour. Curcuma and red onion skin were selected sources of antioxidants. In the practical part a sensory evaluation of all samples of bread is performed. There was a positive evaluation of the questionnaire itself. When to Cheb the suitability of raw materials and procedures for dough preparation and baking. Based on the DPPH and FRAP tests, antioxidant aktivity was evaluated for all gluten-free bread. Bread senriched with red onion skin have the highest antioxidant activity in both basic bread and basic bread with legume flour. Thus, it can be said that onion skin effectively increase antioxidant activity. In the final part, a financial evaluation of all six types of gluten-free bread was made on the basis of raw materials used as compared to those already purchased in the shop. Based on this finding, it can be said that home preparation is a cheaper option.