• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 197
  • 63
  • 40
  • 20
  • 11
  • 3
  • 3
  • 2
  • 2
  • 1
  • Tagged with
  • 360
  • 360
  • 195
  • 149
  • 77
  • 61
  • 59
  • 52
  • 47
  • 33
  • 32
  • 31
  • 30
  • 30
  • 27
  • 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.
181

Investigation of New Zealand Sauvignon Blanc Wine Using Trained Sensory Panels

Lund, Cynthia M. January 2009 (has links)
ABSTRACT A core tool of sensory science is the use of trained descriptive panels. This research describes an investigation into the role of motivation in the performance of trained panels and the use of a trained panel to develop a better understanding of the perception of Sauvignon blanc wines. Substantial investment in time and money is directed towards ensuring trained panels perform optimally. Having selected a panel, the panel leader needs to ensure that panellists provide accurate, reliable data. Panellist motivation is also an important factor to consider. While performance psychology, education and sport science fields have researched motivation extensively, knowledge about panellist motivation within sensory science is limited. However, findings from existing research in these other areas - which suggest an important role for autonomy, competence and relatedness - can be applied to sensory panels in order to increase intrinsic motivation. The initial part of the research investigated the fundamental factors that affect and influence panellists’ motivation and participation. A survey (n=74) revealed that extra income and a general interest in food were the key drivers in inspiring people to become panellists, whilst enjoyment in being a panellist, interest in food, and extra income were key drivers for people to remain panellists. In a second survey, the intrinsic motivation of seven trained panels from four countries (n=108) was assessed. External panels were found to be more intrinsically motivated than internal panels. Experienced panellists had an increased perception of competence, which is a key factor for people to be intrinsically motivated. Understanding motivational frameworks currently used in other research fields and integrating them into existing panel training protocols may enhance and sustain panellists’ intrinsic motivation. A trained panel (n=14) was then used in the second part of the thesis to identify key flavours in Sauvignon blanc wines from Australia, France, New Zealand, Spain, South Africa and USA. Sixteen characteristics were identified and measured, including sweet sweaty passionfruit, capsicum, passionfruit skin/stalk, boxwood/cat’s urine, grassy, mineral/flinty, citrus, bourbon, apple lolly/candy, tropical, mint, fresh asparagus, canned asparagus, stonefruit, apple and snowpea. Principal component analysis was used to describe differences between regions and countries. Sauvignon blanc wines from Marlborough, New Zealand (NZ), were described by tropical and sweet sweaty passionfruit characteristics, while French and South African Sauvignon blanc wines were described as having flinty/mineral and bourbon-like flavors. Chemical analyses of these wines also showed that Marlborough, NZ wines had more methoxypyrazine and thiol compounds. A consumer study (n=109) showed that New Zealanders significantly prefer New Zealand style Sauvignon blanc. The final part of this research focused on using trained panellists to explore the interactions between volatile and non-volatile wine compounds and their effects on the aroma profile of New Zealand Sauvignon blanc wine. Four volatile aroma compounds that are important in New Zealand Sauvignon blanc wine were studied (isobutyl methoxypyrazine [MIBP], 3-mercaptohexanol [3MH], 3-mercaptohexanol acetate [3MHA], and ethyl decanoate). Each of these four aroma compounds were assessed in combination with three non-volatile polyphenolic compounds commonly found in Sauvignon blanc wine: catechin, caffeic acid and quercetin. Results showed each polyphenol had a unique effect when blended with a specific aroma compound, either suppressing, accentuating, or showing little effect on the perception of the aroma compounds. The perception of MIBP, 3MH, and ethyl decanoate were largely suppressed by the added polyphenols, with a few exceptions. The perception of 3MH was accentuated with the addition of caffeic acid, and the perception of 3MHA was accentuated with the addition of catechin. The interactive effects of aroma compounds with polyphenols likely reflect non-covalent associations in the wine solution that reduce the volatility of the aroma compounds. With an understanding of the interactive effects of volatile and non-volatile compounds in wine, winemakers might optimize the impact of selected volatile compounds by managing polyphenol levels, supporting their efforts to attain desirable wine aroma profiles.
182

Development of a sensory lexicon and sensory wheel for rooibos (Aspalathus linearis) and the role of its phenolic composition on taste and mouthfeel.

Koch, Ilona Sabine 03 1900 (has links)
Thesis (MSc Food Sc)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The sensory characteristics and chemical composition of rooibos infusions were analysed to establish the extent of variation in sensory attributes and compositional parameters, and investigate whether correlations exist between the sensory characteristics and the phenolic composition. To capture as much potential variation as possible, 69 rooibos samples were collected throughout the 2009 harvesting season from different production areas. The samples were also representative of the different quality grades (A, B, C or D) which are based on the appearance of the leaves, and the colour and flavour of the infusion. Quantitative descriptive analysis was used to develop sensory profiles for each of the rooibos infusions. Considerable variation in the sensory characteristics was observed, highlighting the need for standardised terminology that can be used to describe what is often referred to as “characteristic” rooibos flavour. Aroma, flavour, taste, and mouthfeel descriptors were generated and assembled into a rooibos sensory wheel. The most recurring attributes were selected to compile a rooibos sensory lexicon which provides a definition and a reference standard for clarification of each term. A combination of “honey”, “woody” and “fynbos-floral” notes with a slightly sweet taste and subtle astringency may be regarded as “characteristic” rooibos attributes indicative of good quality tea. Pleasant “caramel” and “fruity-sweet” notes were also observed in a number of infusions, whereas negative descriptors, associated with poor quality rooibos, included “green” and “hay” flavours. Large variation in the composition of rooibos infusions was revealed through the quantification of soluble solids (SS), total polyphenols (TP), tannins and 14 monomeric phenolic compounds, as well as spectrophotometric colour measurements. High quality rooibos was associated with higher levels of SS, TP, tannins and phenolic compounds than low quality rooibos. Correlations between the compositional parameters and sensory attributes of the infusions indicated that several non-volatile compounds, including enolphenylpyruvic acid-2-glucoside, quercetin-3-glucoside, and iso-orientin, were associated with the characteristic sweet taste of rooibos, while bitterness was related to certain flavonoids such as luteolin, quercetin and aspalathin. The only compound significantly correlated to astringency was rutin, although it is likely that aspalathin and several other monomeric flavonoids also contribute to astringency. The tannin content was not associated with astringency possibly because of the limitations associated with the tannin quantification method. To determine whether compositional changes resulting from steam pasteurisation of rooibos leaves influence the sensory quality of rooibos infusions, differences in the phenolic composition and sensory attributes of infusions, prepared from unpasteurised and pasteurised rooibos, were analysed. Steam pasteurisation significantly reduced the SS, TP and aspalathin content of rooibos infusions, as well as the absorbance, especially at a wavelength of 450 nm. It also resulted in significant reductions in the intensities of most of the aroma and flavour attributes, especially the “green” notes associated with low quality rooibos. After steam pasteurisation the prominent “green” flavour of certain samples was frequently replaced by a “hay” flavour. The taste attributes, sweetness and bitterness, remained unchanged, whereas the astringency of rooibos infusions decreased significantly. / AFRIKAANSE OPSOMMING: Die sensoriese eienskappe en chemiese samestelling van rooibostee is geanaliseer ten einde die mate van variasie van die sensoriese sowel as die chemiese profiel te bepaal, asook om vas te stel of korrelasies bestaan tussen die sensoriese eienskappe en die fenoliese samestelling van rooibostee. Om soveel as moontlik potensiële variasie in te sluit, is 69 rooibos monsters tydens die 2009 oesseisoen van verskillende produksiegebiede versamel. Die monsters is ook verteenwoordigend van die verskillende kwaliteitgrade (A, B, C en D), wat op grond van die voorkoms van die teeblare, en die kleur en geur van die tee toegeken is. Kwantitatiewe beskrywende analise is gebruik om ‘n sensoriese profiel vir elke rooibostee op te stel. Aansienlike variasie in die sensoriese eienskappe is waargeneem. Dit het die behoefte aan gestandaardiseerde terminologie onderskryf, wat gebruik kan word om die term “karakteristieke” rooibos geur in meer detail te omskryf. Spesifieke terme vir aroma, geur, smaak en mondgevoel is geformuleer, en gebruik om ‘n sensoriese wiel vir rooibostee saam te stel. Terme wat die meeste voorgekom het, is gekies om in ‘n sensoriese leksikon vervat te word wat ‘n definisie en ‘n verwysingstandaard vir elke term voorstel. Die “karakteristieke” sensoriese eienskappe van goeie kwaliteit rooibostee kan soos volg gedefinieer word: ’n kombinasie van “heuning”, “houtagtige” en “fynbos-blom” geure met ‘n effense soet smaak en ‘n sagte vrankheid. Aangename “karamel” en “vrugtige-soet” geure is ook waargeneem, terwyl terme soos “groen” en “hooi” met swak kwaliteit rooibostee geassosieer is. Groot variasie in die samestelling van rooibostee is verkry deur kwantifisering van die inhoud van oplosbare vastestowwe (SS), totale polifenole (TP), tanniene, en 14 monomeriese fenoliese verbindings, asook spektrofotometriese kleurmetings. Hoë kwaliteit rooibostee is geassosieer met hoër vlakke van SS, TP, tanniene en fenoliese verbindings in vergelyking met lae kwaliteit rooibos. Korrelasies tussen laasgenoemde parameters en die sensoriese eienskappe het aangedui dat sekere nie-vlugtige verbindings, bv. fenielpirodruiwesuurglukosied, kwersetien-3-glukosied en iso-orientien, geassosieer is met die kenmerkende soet smaak van rooibos, terwyl ‘n bitter smaak geassosieer is met spesifieke flavonoïede soos luteolien, kwersetien and aspalatien. Die enigste verbinding wat betekenisvol gekorreleer het met vrankheid was rutien, maar dit is waarskynlik dat aspalatien en ander monomeriese flavonoïede ook bygedra het tot vrankheid. Die tannieninhoud het nie verband gehou met vrankheid nie, vermoedelik as gevolg van die beperkinge van die chemiese metode vir tannienbepaling. Om te bepaal of stoompasteurisasie van rooibos die sensoriese kwaliteit en chemiese samestelling van rooibostee beïnvloed, is die verskille in fenoliese samestelling en sensoriese eienskappe van die tee, berei van ongepasteuriseerde en gepasteuriseerde rooibos, ondersoek. Stoompasteurisasie het ‘n betekenisvolle verlaging teweegebring van die SS, TP en aspalatien inhoud, sowel as van die absorbansie van die tee, veral by ‘n golflengte van 450 nm. Dit het ook gelei tot ‘n statisties betekenisvolle vermindering van die intensiteit van die meeste aroma en geur eienskappe, veral die sogenaamde “groen” eienskap wat met swak kwaliteit rooibos verbind word. As gevolg van stoompasteurisasie is die opmerklike “groen” geur van sekere ongepasteuriseerde monsters herhaaldelik vervang deur ‘n “hooi” geur. Die smaakeienskappe, soet en bitter, was onveranderd, terwyl vrankheid statisties betekenisvol afgeneem het as gevolg van pasteurisasie.
183

Valor nutricional, capacidade antioxidante e utilização de folhas de espinafre (Tetragonia tetragonoides) em pó como ingrediente de pão de forma. / Nutritional value and antioxidant capacity using spinach (Tetragonia tetragonoides) leaves powder as an ingredient of bread.

Azevedo, Fátima de Lourdes Assunção Araújo de 04 September 2012 (has links)
Made available in DSpace on 2015-04-17T14:49:22Z (GMT). No. of bitstreams: 1 Arquivototal.pdf: 2587496 bytes, checksum: 770af7c77e4e43893609f4e8cfe5c7eb (MD5) Previous issue date: 2012-09-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Spinach is a dark green leafy vegetables in the diet that helps with the intake of vitamins, proteins, minerals, especially calcium and iron, and bioactive compounds not common in other plants. The objective of this research was to characterize the spinach Tetragonia tetragonoides, fresh and powdered (bleached and un bleached) on the content of nutrients, antinutritional and bioactive compounds, evaluating the effects of bleaching on these compounds, the antioxidant capacity of bioactive compounds and functional potential of spinach bleached powder as an ingredient in the formulation of bread. The powder of spinach leaves, subjected to bleaching, decreased concentrations of nutrients, antinutritional and bioactive compounds, compared to the same product is not bleached. The greatest losses were observed for iron (19,4 %), calcium (18,3 %), oxalic acid (36,4 %), phytic acid (33,5 %) and ascorbic acid (18,74 %). The reduction in bioactive compounds resulted in lower antioxidant capacity of spinach powder bleached, as assessed by FRAP methods and linoleic β-caroteno/ácido, however, this effect was not observed by the DPPH method, and spinach powder, subjected or not to bleaching, presented the same antioxidant power. When the spinach bleached powder was added to the formulation of the loaf of bread, the concentrations of 1 %, 2 % and 3 % was observed better sensory acceptability in the formulation of 3 % was noted that the other as the softness. This formulation showed a higher content of protein, calcium, iron and phosphorus than the control bread. Therefore, the use of spinach as an ingredient of bread can be a good alternative to inclusion of the hardwood vegetables in the diet, contributing to improved nutrition and presenting, in the form bleached, reduced antinutritional content. / O espinafre é uma hortaliça folhosa verde-escuro que presente na dieta contribui com o aporte de vitaminas, proteínas, minerais, especialmente cálcio e ferro, e compostos bioativos não comuns em outros vegetais. O objetivo na presente pesquisa foi caracterizar o espinafre Tetragonia tetragonoides, in natura e em pó (branqueado e não branqueado) quanto ao teor de nutrientes, antinutricionais e de compostos bioativos, avaliando os efeitos do branqueamento sobre esses compostos, a capacidade antioxidante dos compostos bioativos e a utilização do espinafre em pó branqueado como ingrediente na formulação de pão de forma. O pó das folhas de espinafre, submetidas ao branqueamento, apresentou redução nas concentrações dos nutrientes, antinutricionais e compostos bioativos, quando comparado ao mesmo produto não branqueado. As maiores perdas foram observadas para ferro (19,4 %), cálcio (18,3 %), ácido oxálico (36,4 %), ácido fítico (33,5 %) e vitamina C (18,74 %). A redução nos compostos bioativos resultou em menor capacidade antioxidante do espinafre em pó branqueado, quando avaliado pelos métodos FRAP e β-caroteno/ácido linoléico, entretanto, esse efeito não foi verificado pelo método DPPH, tendo o espinafre em pó, submetido ou não ao branqueamento, apresentado o mesmo poder antioxidante. Quando o espinafre em pó branqueado foi adicionado à formulação do pão de forma, nas concentrações de 1 %, 2 % e 3 %, observou-se uma melhor aceitação sensorial para a formulação com 3 %, que se destacou das demais quanto à maciez. Essa formulação apresentou maior teor de proteínas, cálcio, ferro e fósforo que o pão controle. Portanto, a utilização do espinafre como ingrediente de pão de forma pode ser considerada uma boa alternativa de inclusão dessa hortaliça folhosa na dieta, contribuindo para a melhoria nutricional e apresentando, na forma branqueada, reduzido teor de antinutricionais.
184

Senzorické hodnocení vybraných sýrů a analogových produktů / Sensory evaluation of selected cheeses and analogue products

LAFATOVÁ, Veronika January 2014 (has links)
This diploma thesis is focused on the evaluation of processed sliced products (cheese and analogues). For this purpose, was carried out sensory analysis of these products, a serial test and a questionnaire. Evaluation carried out a total of 65 assessors - 23 men and 42 women. The analysis of ranking showed that in the group of assessors was best evaluated processed wafer product (analogue) (average rank of 2,6) and processed sliced cheese (average rank of 2,7). For sensory analysis was found a significant role of fat on the dry basis of the product and the presence of added substances (extract from peppers, Emmental) on the perception of assessors. The survey was focused on the preference of the attractiveness of packaging of selected processed cheese slices and sliced processed products, furthermore focused on understanding the concept of the analogue product. Assessors have demonstrated their knowledge of the concept of analogue product only in 14% of cases.
185

Viskozita a kyselost vybraných druhů bílých jogurtů / Viscosity and acidity of selected type of natural yoghur

BÁRTOVÁ, Zuzana January 2015 (has links)
The aim of the thesis was to evaluate the acidity and viscosity of natural yoghurt depending on the different addition of skimmed milk powder and using of the methods of sensory analysis to evaluate the perception of these properties by young consumers. Part of this work was to analyse acidity and viscozity in selected kinds of natural yoghurts purchased in the market network of the Czech Republic (CR). The literature search mentions basic characteristic of yoghurts and their classification, acidity and rheological properities of yoghurts including the factors, which affect them and sensory analysis. In the experimental part of the study the acidity value, total solids and viscosity measurements were detected by physico-chemical analyses of samples of natural yoghurts. At samples of yoghurts with different content of skimmed milk powder the sensory evaluation was also subjected and the graphs of sensory profile were compiled. The observed results showed, that from the samples of yoghurts made in the laboratory was the most satisfactory sample containing 10 % of skimmed milk powder. At samples purchased in the market network of CR were detected very low leveles of titratable acidity.
186

Vliv použitých sladidel na senzorické vlastnosti džemů z vybraných druhů ovoce / Effect of used sweeteners on sensory properties of fruit jams

PIHLÍK, Pavel January 2017 (has links)
This thesis deals with the sorting and use of sweeteners in the production of fruit spreads. The theoretical part focuses on the sorting of sweetening agents and their classification. Furthermore, it presents procedures of production of fruit spreads and their assortment. The main goal is to compare sensory attributes of jams that I produced according to an assigned recipe, which is described in the practical part of this thesis. These jams were made from regional fruits (strawberries, apricots, sour-cherries) and sweetened with both natural (sucrose, sorbitol, Steviol glycosides) and artificial (sucralose) sweetening agents. The control group of this research were the students and employees of the University of South Bohemia in České Budějovice in the age of 24-60 years. The evaluators filled in a sequence test protocol and a questionnaire for consumers. The results of the sensory analysis were processed into tables and graphs with the aid of statistical methods.
187

Vliv surovin a technologie na senzorickou jakost čokolády

ŠINÁKLOVÁ, Petra January 2017 (has links)
The theoretical part of the diploma thesis titled "The Effect of Raw Materials and Technology on the Sensory Quality of Chocolate" describes the commodity and the related legislation, the raw materials used for the production of chocolate, the substitutes for some basic raw materials, and the production procedures. The theoretical part also describes the significance of chocolate for human nutrition and analyses the defects that may occur in chocolate. The objective of the practical part is to ascertain the opinions of a selected group of consumers on the selected sorts of chocolates. The results are divided into two parts. In the first part I carried out a collective evaluation (men and women together), and in the second part I evaluated the results separately for each gender (men separately from women) in order to find out any differences in the sensory evaluation of this commodity between the groups. The evaluators' preferences between three sorts of dark chocolates of the same brand with a different cocoa quantity were tested and evaluated by means of a ranking test. The preferences between two sorts of dark chocolates with orange flavour produced by two different producers were evaluated by means of a pair test. I also carried out and evaluated a questionnaire survey aimed at ascertaining the liking for various sorts of chocolates with different composition.
188

Elaboração de novo produto gelificado à base de extrato hidrossolúvel da amêndoa da castanha de caju: estudo dos parâmetros sensoriais / Development of new product based gelled soluble almond extract of cashew nuts: study of sensory parameters

Costa, Vanderson da Silva January 2013 (has links)
COSTA, Vanderson da Silva. Elaboração de novo produto gelificado à base de extrato hidrossolúvel da amêndoa da castanha de caju: estudo dos parâmetros sensoriais. 2013. 78 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Tecnologia de Alimentos, Fortaleza-CE, 2013 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-30T14:11:28Z No. of bitstreams: 1 2013_dis_vscosta.pdf: 1081233 bytes, checksum: b4954dea317cbf8070be5051d6323fd0 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-30T14:11:51Z (GMT) No. of bitstreams: 1 2013_dis_vscosta.pdf: 1081233 bytes, checksum: b4954dea317cbf8070be5051d6323fd0 (MD5) / Made available in DSpace on 2016-06-30T14:11:51Z (GMT). No. of bitstreams: 1 2013_dis_vscosta.pdf: 1081233 bytes, checksum: b4954dea317cbf8070be5051d6323fd0 (MD5) Previous issue date: 2013 / Considering the economic importance of cashews nuts for the state of Ceará, Brazil's main exporter of this product and the high percentage of broken kernels during processing Chestnut considerably decreases the profit-making in this sector, it is necessary to search for new alternatives for utilization of this raw material as a way of adding value to it. Thus , this research aimed to develop a product based on watersoluble extract of almond cashew (EHACC) and blend of guar gum/carrageenan (CG) using the orthogonal factorial design 2² with three central points and the technique of response surface for optimization of sensory characteristics. By applying affective sensory testing scale relative to the ideal and structured hedonic scale of nine points , the center point of the formulations with different percentages of sucrose were evaluated for selecting the optimal sucrose concentration by linear regression analysis , analysis of the ideality firmness and acceptance of attributes color, aroma, texture, flavor and overall impression . The formulations of the experimental design with the addition of the ideal percentage of sucrose were analyzed in relation to global hedonic acceptance and ideality of visual texture, manual and oral texture texture. The optimal concentration was 22 % sweetness of sucrose. There was a trend of increasing acceptance at the midpoint of a 0,3g/100mL guar/carrageenan in 50:50 experimental design. The visual texture evaluation showed that the higher the concentration of hydrocolloids, most ideality. In the evaluation of manual and oral texture none of the samples reached 70 % of ideality. Thus, the combination of quantity and proportion of the blend midpoint contributed to greater acceptance of gelled product features and good acceptance tested showed a potential for commercial success for future marketing of the product. / Considerando a importância econômica das amêndoas da castanha de caju para o estado do Ceará, o principal exportador brasileiro deste produto e o elevado percentual de amêndoas quebradas durante o beneficiamento da castanha que diminui consideravelmente a obtenção de lucro desse setor, faz-se necessária a busca por novas alternativas de aproveitamento desta matéria-prima como forma de agregação de valor a mesma. Dessa forma, esta pesquisa objetivou desenvolver um produto à base de extrato hidrossolúvel da amêndoa da castanha de caju (EHACC) e blenda de goma guar/carragena (GC) usando o delineamento ortogonal fatorial 22 com três pontos centrais e a técnica de superfície de resposta para otimização de características sensoriais. Através da aplicação de testes sensoriais afetivos de escala relativa ao ideal e escala hedônica estruturada de nove pontos, as formulações do ponto central com diferentes porcentagens de sacarose foram avaliadas para a seleção da concentração ideal de sacarose através análise de regressão linear, análise da idealidade da firmeza e aceitação dos atributos cor, aroma, textura, sabor e impressão global. As formulações do planejamento experimental com adição da porcentagem ideal de sacarose foram analisadas em relação à aceitação hedônica global e idealidade de textura visual, textura manual e textura oral. A concentração ideal de doçura ficou em 22% de sacarose. Observou-se uma tendência de aceitação crescente no ponto central do delineamento experimental correspondente a 0,3g/100mL de guar/carragena na proporção 50:50. A avaliação de textura visual mostrou que quanto maior a concentração de hidrocolóides, maior a idealidade. Na avaliação de textura manual e oral nenhuma das amostras alcançou 70% de idealidade. Assim, a combinação quantidade e proporção de blenda no ponto central contribuiu para uma maior aceitação do produto gelificado e a boa aceitabilidade das características testadas revelaram um potencial de sucesso comercial para uma futura comercialização do produto.
189

Efeito da radiação gama sobre a redução de microrganismos patogênicos, a estabilidade dos lipídios e as características sensoriais em caudas de camarões congelados / Effect of gamma radiation in the reduction of pathogenic microorganisms, the stability of the lipids and the sensory characteristics in frozen shrimp tails

Abreu, Virgínia Kelly Gonçalves January 2006 (has links)
ABREU, Virgínia Kelly Gonçalves. Efeito da radiação gama sobre a redução de microrganismos patogênicos, a estabilidade dos lipídios e as características sensoriais em caudas de camarões congelados. 2006. 75 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Tecnologia de Alimentos, Fortaleza-CE, 2006 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-30T14:52:55Z No. of bitstreams: 1 2006_dis_vkgabreu.pdf: 431632 bytes, checksum: fb4a5fd03cc95a3e25fdd9154f2c1d2c (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-30T14:54:19Z (GMT) No. of bitstreams: 1 2006_dis_vkgabreu.pdf: 431632 bytes, checksum: fb4a5fd03cc95a3e25fdd9154f2c1d2c (MD5) / Made available in DSpace on 2016-06-30T14:54:19Z (GMT). No. of bitstreams: 1 2006_dis_vkgabreu.pdf: 431632 bytes, checksum: fb4a5fd03cc95a3e25fdd9154f2c1d2c (MD5) Previous issue date: 2006 / Irradiation represents an efficient technique to extend shelf life of several foods and the interest in using this technology has been growing in the last years because besides improving food safety it produces minimal alterations in the food constituents. Thus, this study investigated the effect of ionizing irradiation (60Co) of frozen and packaged shrimp on microorganisms as well as on some chemical and sensory characteristics of the product. Cultivated shrimp (Penaeus vannamei) from local farms processed into shrimp tails were packaged, frozen, irradiated and analyzed. The study was divided in two stages. The first stage was intended to verify the effect of the gamma radiation on the population of inoculated Vibrio cholerae O1 and Salmonella enteritidis bacteria. It used a complete randomized factorial (4 x 3) design with four irradiation doses (0, 2, 4 and 6kGy) and three inoculation modalities (one with V. cholerae O1, one with S. enteritidis and one without microorganisms). The second stage aiming to verify the effect of the gamma irradiation on the chemical stability of lipids, color and instrumental texture of shrimp followed a complete randomized factorial (4 x 5) design with four irradiation doses (0, 2, 4, and 6kGy) and five replicates. Sensorial analysis followed a complete randomized factorial of balanced complete blocks, where the panelist was considered as block. The experimental units (UE) from the first stage were analyzed for V. cholerae O1 and S. enteritidis survival after the irradiation procedure, while those from the second stage were analyzed for thiobarbituric acid reactive substances (TBARS), instrumental color and texture and sensory evaluation of the meat. As irradiating dose increased a significant (p<0.05) reduction in V. cholerae O1 and S. enteritidis counts was observed. TBARS values decreased (p<0.05) in shrimp irradiated with 6kGy related to those in non irradiated shrimp. Also, color component L* increased (p<0.05) in shrimp irradiated with 6kGy dose as compared to that irradiated with the 2kGy dose. No effect of irradiation was found on color components a* and b* or on instrumental texture values. Sensory global acceptance presented a significant reduction (p <0.05) with the dose of 6kGy as related to the doses of 2kGy or 0kGy. However, color acceptance and texture and the intensity of the attributes aroma, flavor and juiciness were not affected (p>0.05). Therefore, irradiation treatment in doses up to 6kGy on frozen and packaged shrimp tails significantly reduces V. cholerae O1 and S. enteritidis counts with minor effects on sensory characteristics in cooked shrimp. / A irradiação representa uma técnica eficiente na conservação dos alimentos, e o interesse pela sua utilização tem crescido nos últimos anos, pois além de melhorar a qualidade microbiológica, produz mínimas alterações nos constituintes dos alimentos. Sendo assim, este trabalho teve como objetivo estudar o efeito da radiação gama (60Co), aplicada ao camarão congelado e embalado, sobre a microbiota, a estabilidade química de alguns componentes, bem como sobre algumas propriedades sensoriais da carne. Foram avaliadas caudas de camarões da espécie Penaeus vannamei, provenientes da carcinicultura local. O estudo foi dividido em duas etapas, sendo a primeira destinada a verificar o efeito da radiação gama, aplicada nas doses de 0, 2, 4 e 6kGy, sobre a população de duas bactérias patogênicas inoculadas no camarão: Vibrio cholerae O1 e Salmonella enteritidis. Este estudo utilizou um delineamento experimental inteiramente casualizado, em esquema fatorial 4 x 3, em que os fatores avaliados foram as quatro doses de irradiação e três modalidades de inoculação (com V. cholerae O1, com S. enteritidis e sem inoculação de microrganismos). Já na segunda etapa foi usado um delineamento experimental inteiramente casualizado, em esquema fatorial 4 x 5, sendo quatro doses (0, 2, 4 e 6kGy) de irradiação e cinco repetições, para as análises de substâncias reativas ao ácido tiobarbitúrico (TBARS), cor e textura instrumental. Para a análise sensorial foi utilizado um delineamento de blocos completos balanceados, onde o provador foi considerado como bloco. Houve uma redução significativa (p<0,05) do número de V. cholerae O1 e de S. enteritidis de acordo com o aumento da dose de irradiação. Em relação aos valores de TBARS, houve um decréscimo (p<0,05) das amostras irradiadas com 6kGy em relação as não irradiadas. Quanto ao valor do componente de cor L* houve uma elevação significativa (p<0,05) com a dose de 6kGy em relação à dose de 2kGy. Os componentes de cor a* e b* e a textura instrumental não variaram (p>0,05) com as doses de irradiação estudadas. Com relação as características sensoriais, a aceitação global apresentou uma redução significativa (p<0,05) com a dose 6kGy quando comparada com as doses 0 e 2kGy. No entanto, os atributos de aceitação de cor e textura e a intensidade dos atributos aroma, sabor característico e suculência não foram afetados (p>0,05). Desta forma, o tratamento de irradiação com até 6kGy mostra-se efetivo na redução de microrganismos patogênicos, com leves efeitos sobre as características sensoriais da carne, quando aplicado sobre o camarão congelado e embalado.
190

Acerola (Malpighia emarginata DC) e Abacaxi (Ananas comosus L. Merril) como adjunto no processamento de cerveja: caracterização e aceitabilidade / Acerola (Malpighia emarginata DC) and pineapple (Ananas comosus L. Merrill) as adjuncts in processing beer: characterization and acceptability

Pinto, Luan Ícaro Freitas January 2015 (has links)
PINTO, Luan Ícaro Freitas. Acerola (Malpighia emarginata DC) e Abacaxi (Ananas comosus L. Merril) como adjunto no processamento de cerveja: caracterização e aceitabilidade. 2015. 87 f. Dissertação (Mestrado em Ciência e Tecnologia de Alimentos)-Universidade Federal do Ceará, Fortaleza, 2015. / Submitted by Vitor Campos (vitband@gmail.com) on 2016-10-03T22:44:54Z No. of bitstreams: 1 2015_dis_lifpinto.pdf: 2313013 bytes, checksum: c751e262e3f4623a9a5e56930d086cc4 (MD5) / Rejected by Jairo Viana (jairo@ufc.br), reason: Documento duplicado on 2016-10-04T23:34:40Z (GMT) / Submitted by Vitor Campos (vitband@gmail.com) on 2016-10-25T20:45:46Z No. of bitstreams: 1 2015_dis_lifpinto.pdf: 2313013 bytes, checksum: c751e262e3f4623a9a5e56930d086cc4 (MD5) / Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2016-10-27T17:59:30Z (GMT) No. of bitstreams: 1 2015_dis_lifpinto.pdf: 2313013 bytes, checksum: c751e262e3f4623a9a5e56930d086cc4 (MD5) / Made available in DSpace on 2016-10-27T17:59:30Z (GMT). No. of bitstreams: 1 2015_dis_lifpinto.pdf: 2313013 bytes, checksum: c751e262e3f4623a9a5e56930d086cc4 (MD5) Previous issue date: 2015 / Beer is the most consumed alcoholic beverage in the world. Its consumption is associated with festivities and celebrations, being recognized by its customers as a beverage with high caloric value. However, this beverage contains a variety of bioactive compounds, vitamins and minerals that promote benefits when its intake is made moderate manner. The market is every day looking for different and even unique products, thus arises the field of craft beers. The objective of this study was to develop a craft beer with acerola and pineapple and study their physicochemical and sensory characteristics, as it brings a new alternative in this niche market, besides the association with increased its functional characteristics. We used the rotational central composite design (CCRD) for the development of treatments where the variation of the percentage of addition of the acerola fruit juice and pineapple varied at levels of 5 to 25% of the total volume of beer. The CCRD included eleven trials: four factorial points, four axial and three repetitions at the central point. The results of the CCRD were analyzed using the Response Surface Methodology (RSM), with the response variable physico-químcos and sensory parameters. For statistical analysis was applied to analysis of variance, Tukey test and regression analysis. Processing took place in laboratory scale. The pulps were characterized by physical-chemical analysis, and then made by the addition of juice during the process of maturation that occurred simultaneously with primming process amber glass bottles of 355 ml. The results of the sugar content, total acids and pH of fruit pulps showed satisfactory being considered suitable for the maturation process. The results of physicochemical tests showed similar results in all treatments, and the factor adding fruit juice was directly proportional to parameters such as acidity and pH, and inversely proportional to parameters such as alcohol, real extract, apparent extract and extract primitive. Microbiological testing resulted in a minimum count of coliforms, thermotolerant and molds and yeasts, adapting to the standards set by law for beer, showing the process control efficiency, ensuring product quality. The means of the sensory attributes of all samples showed up outside the stopband, especially for samples 5 and 8, which have higher pineapple juice content. The results of the response surface showed that addition of up to 16% of both pulps pineapple or additions of high concentrations (up to 28%) in groups with low concentrations of acerola (up to 6%) show a maximization of sensory attributes. It was concluded that the use of pineapple pulp and acerola as adjuncts in the beer processing proved to be a viable alternative due to satisfactory results in sensory evaluation, and physical and chemical characteristics that proved a craft beer with acidy/fruity characteristics. / A cerveja é a bebida alcoólica mais consumida no mundo. Seu consumo está associado a festividades e comemorações, sendo reconhecida pelos seus consumidores como uma bebida com alto valor calórico. Entretanto, essa bebida contém uma variedade de compostos bioativos, vitaminas e minerais, capazes de promover benefícios quando a sua ingestão é feita de maneira moderada. O mercado está a cada dia buscando produtos diferenciados e até exclusivos, surge assim o campo das cervejas artesanais. O objetivo deste trabalho foi desenvolver uma cerveja artesanal com acerola e abacaxi e estudar suas características físicoquímicas e sensoriais, pois traz uma nova alternativa neste nicho de mercado, além da associação ao aumento de suas características funcionais. Foi utilizado o Delineamento Composto Central Rotacional (DCCR) para o desenvolvimento dos tratamentos, onde a variação do percentual de adição de suco de fruta de acerola e abacaxi variou em níveis de 5 a 25% do volume total da cerveja. O DCCR incluiu onze ensaios: quatro pontos fatoriais, quatro axiais e três repetições no ponto central. Os resultados do DCCR foram analisados através da Metodologia de Superfície de Resposta (MSR), tendo como variáveis resposta os paramêtros físico-químcos e sensorias. Para a avaliação estatística foi aplicada a análise de variância, teste de Tukey e análise de regressão. O processamento ocorreu em escala laboratorial. As polpas foram caracterizadas através de análises físico-químicas e em seguida fez-se a adição do suco durante o processo de maturação que ocorreu simultaneamente ao processo de primming em garrafas de vidro âmbar de 355 mL. Os resultados do teor de açucares, ácidos totais e pH das polpas de frutas apresentaram satisfatórios sendo considerados adequados para o processo de maturação. Os resultados dos testes físicoquímicos mostraram resultados semelhantes em todos os tratamentos, sendo que o fator adição de suco de frutas foi diretamente proporcional a parâmetros como acidez e pH, e inversamente proporcional a parâmetros como teor alcoólico, extrato real, extrato aparente e extrato primitivo. Os testes microbiológicos resultaram em uma contagem mínima para coliformes totais, termotolerantes e bolores e leveduras, adequando-se aos padrões estabelecidos pela legislação para cerveja, mostrando assim a eficiência do controle do processo, garantindo a qualidade do produto. As médias dos atributos sensoriais de todas as amostras apresentaram-se fora da faixa de rejeição, com destaque para as amostras 5 e 8, as quais possuem maiores teores de suco de abacaxi. Os resultados das superfícies de resposta mostraram que adições de até 16% de ambas as polpas ou adições de elevadas concentrações de abacaxi (até 28%) em conjuntos com baixas concentrações de acerola (até 6%) mostram uma maximização dos atributos sensoriais. Concluiu-se que a utilização das polpas de abacaxi e acerola como adjuntos no processamento de cerveja mostrou-se uma alternativa viável devido aos resultados satisfatórios na avaliação sensorial, além de características físicoquímicas que comprovaram uma cerveja artesanal com características ácida/frutada.

Page generated in 0.0666 seconds