Aplicação das fórmulas CIELAB e CIEDE2000 na avaliação da cor de folhas vegetais irradiadas por uma fonte de Cobalto-60

A cor dos alimentos está directamente associada à sua aceitação pelo consumidor. A procura de métodos de processamento seguros e eficazes destaca a radiação ionizante, já que permite a desinfecção do alimento e a extensão do seu tempo de prateleira [1]. O espaço de cor CIELAB é comummente utilizado para avaliar diferenças de cor (ΔE*) entre dois objectos. No entanto, a fórmula CIEDE2000 permite atenuar variações entre valores calculados e percepcionados [2]. O impacto da radiação ionizante na cor de um vegetal folhoso foi avaliado durante o tempo de armazenamento e os resultados discutidos utilizando ambas as fórmulas de ΔE*.

Anthraquinones from the Fungus Dermocybe sanguinea as Textile Dyes

This study is based on the multidiciplinary approach of using natural colorants as textile dyes. The author was interested in both the historical and traditional aspects of natural dyeing as well as the modern industrial applications of the pure natural compounds. In the study, the anthraquinone compounds were isolated as aglycones from the ectomycorrhizal fungus Dermocybe sanguinea. The endogenous beta-glucosidase of the fungus was used to catalyse the hydrolysis of the O-glycosyl linkage in emodin- and dermocybin-1-beta-D-glucopyranosides. The method, in which 10.45 kg of fresh fungi was starting material, yielded two fractions: 56.0 g of Fraction 1 (94% of the total amount of pigment,) consisting almost exclusively of the main pigments emodin and dermocybin, and 3.3 g of Fraction 2 (6%) consisting mainly of the anthraquinone carboxylic acids. The anthraquinone compounds in Fractions 1 and 2 were separated by one- and two-dimensional thin-layer-chromatography (TLC) using silica plates. 1D TLC showed that neither an acidic nor a basic solvent system alone separated completely all the anthraquinones isolated from D. sanguinea, in spite of the variation of the rations of the solvent components in the systems. Thus, a new 2D TLC technique was developed, applying n-pentanol-pyridine-methanol (6:4:3, v/v/v) and toluene-ethyl acetate-ethanol-formic acid (10:8:1:2, v/v/v/v) as eluents. Fifteen different anthraquinone derivatives were completely separated from one another. Emodin, physcion, endocrocin, dermolutein, dermorubin, 5-chlorodermorubin, emodin-1-beta-D-glucopyranoside, dermocybin-1-beta-D-glucopyranoside and dermocybin, and five new compounds, not earlier identified in D. sanguinea, 7-chloroemodin, 5,7-dichloroemodin, 5,7-dichloroendocrocin, 4-hydroxyaustrocorticone and austrocorticone, were separated and identified on the basis of their Rf-values, UV/Vis spectra and mass spectra. One substance remained unidentified, because of its very low concentration. The anthraquinones in Fractions 1 and 2 were preparatively separeted by liquid-liquid partition, with isopropylmethyl ketone and aqueous phosphate buffer as the solvent system. Advantage was taken of the principle of stepwise pH-gradient elution. The multiple liquid-liquid partition (MLLP) offered an excellent method for the preparative separation of compounds, which contain acidic groups such as the phenolic OH and COOH groups. Due to their strong aggregation properties, these compounds are, without derivatization, very difficult to separate on a preparative scale by chromatographic methods. By the MLLP method remarkable separations were achieved for the components in each mixture. Emodin and dermocybin were both obtained from Fraction 1 in a purity of at least 99%. Pure emodin and dermocybin were applied as mordant dyes to wool and polyamide and as disperse dyes to polyester and polyamide, using the high temperature (HT) technique. A mixture of dermorubin and 5-chlorodermorubin was applied as an acid dye to wool. In these experiments, synthetic dyes were used as references. Experiments were also performed using water extract of the air-dried fungi as dye liquor for wool and silk. The main colouring compounds in the crude water extract were emodin and dermocybin, which indicated that the O-glycosyl linkages in emodin- and dermocybin-1-beta-D-glucopyranosides were broken by the beta-glucosidase enzyme. Apparently, the hydrolysis occurred during the drying of the fungi and during the soaking of the dried fruit bodies overnight when preparing the dyebath. The colour of each dyed material was investigated in terms of the CIELAB L*, a* and b* values, and the colour fastness to light, washing and rubbing was tested according to the ISO standards. In the mordant dyeing experiments, emodin dyed wool and polyamide yellow and red, depending on the pH of the dyebath. Dermocybin gave purple and violet colours. The colour fastness of the mordant-dyed fabrics varied from good to moderate. The fastness properties of the natural anthraquinone carboxylic acids on wool were good, indicating the strength of the ionic bonds between the COO- groups of the dyes and the NH3+ groups of the fibres. In the disperse dyeing experiments, emodin dyed polyester bright yellow and dermocybin bright reddish-orange, and the fabrics showed excellent colour fastness. In contrast, emodin and dermocybin successfully dyed polyamide brownish-orange and wine-red, respectively, but with only moderate fastness. In industrial dyeing processes, natural anthraquinone aglycone mixtures dyed wool and silk well even at low concentrations of mordants, i.e. with 10% of the weight of the fibre (owf) of KAl(SO4)2 and 1 or 0.5% owf of other mordants. This study showed that purified natural anthraquinone compounds can produce bright hues with good colour-fastness properties in different textile materials. Natural anthraquinones have a significant potential for new dyeing techniques and will provide useful alternatives to synthetic dyes.

Algorithms for colour image processing based on neurological models

373 p. : il., gráf., fot., tablas

Anwendungsmöglichkeiten instrumenteller Texturanalyse zur Charakterisierung industriell hergestellter Farcen

Commercially processed and for industrial purpose destined minces of several fish species were characterised with regard to their texture using texture profile analysis (TPA) of boiled specimen and by measuring the penetration force on raw minces as well as with regard to their colour by instrumental measurements of CIELab values. Concerning the parameters investigated the minces were in most cases significantly different. It was evident that the fish species is responsible for the functional properties of these intermediate products. For the TPA the influence of the measurement conditions was demonstrated and an appropriate method derived. IEF of proteins was used to verify the declared fish species. Unfortunately, this was not possible in all cases due to the lack of comparable pattern. Both the DMA and FA content were found to be in the normal range except those for saithe.

Bewertung der Farbe von frischen und tiefgefrorenen Räucherlachsseiten mittels objektiver Farbmessung

Colour measurements were performed on smoked Norwegian salmon sides using an objective method based on the CIELab-system. The influence of a freeze/thaw cycle was evaluated. Already after a short frozen storage of 8 hours a signiticant colour difference could be noticed. This was manifested by an increase in lightness as well as in redness and yellowness as result of the freeze/thaw cycle. These colour changes were observable by eyes too.

Farbmessungen an panierten Fischerzeugnissen

The colour based on a CIELab system of both, breaded deep frozen and fried fish products, was measured using a Chroma-Meter Type 300 (Minolta). Remarkable differences especially with the deep frozen fish fillets were recognized. Due to prefrying the colour differences of the fish fingers were moderate. After frying to make the products ready to eat the colour differences between the fillets and the fingers were largely equalized. In general, the frying process was connected with a decrease of lightness L* and with strong to very strong total colour differences ΔE.

Avaliação de imagens através de Similaridade Estrutural e do conceito de Mínima Diferença de Cor Perceptível.

A avaliação objetiva da qualidade de imagens é de especial importância em diversas aplicações, por exemplo na compressão de imagens, onde pode ser utilizada para regular a taxa que deve ser empregada para que haja a máxima compressão (permitindo perda de dados) sem comprometer a qualidade final; outro exemplo é na inserção de marcas dágua, isto é, introdução de informações descritivas utilizadas para atestar a autenticidade de uma imagem, que devem ser invisíveis para o observador. O SSIM (Structural SIMilarity) é uma métrica de avaliação objetiva da qualidade de imagens de referência completa projetada para imagens em tons de cinza. Esta dissertação investiga sua aplicação na avaliação de imagens coloridas. Para tanto, inicialmente é feito um estudo do SSIM utilizando quatro diferentes espaços de cores RGB, YCbCr, Lαβ e CIELAB. O SSIM é primeiramente calculado nos canais individuais desses espaços de cores. Em seguida, com inspiração no trabalho desenvolvido em (1) são testadas formas de se combinar os valores SSIM obtidos para cada canal em um valor único os chamados SSIM Compostos. Finalmente, a fim de buscar melhores correlações entre SSIM e avaliação subjetiva, propomos a utilização da mínima diferença de cor perceptível, calculada utilizando o espaço de cores CIELAB, conjuntamente com o SSIM. Para os testes são utilizados três bancos de dados de imagens coloridas, LIVE, IVC e TID, a fim de se conferir consistência aos resultados. A avaliação dos resultados é feita utilizando as métricas empregadas pelo VQEG (Video Quality Experts Group) para a avaliação da qualidade de vídeos, com uma adaptação. As conclusões do trabalho sugerem que os melhores resultados para avaliação da qualidade de imagens coloridas usando o SSIM são obtidas usando os canais de luminância dos espaços de cores YCbCr, Lαβ e especialmente o CIELAB. Também se concluiu que a utilização da mínima diferença de cor perceptível contribui para o melhoramento dos resultados da avaliação objetiva.

Relationships between antioxidant activity, color, and flavor compounds of crystal malt extracts

Aqueous extracts were prepared from five barley crystal malts (color range 15-440 degrees EBC, European Brewing Convention units). Antioxidant activity was determined by using the 2,2'-azinobis(3-ethylbenothiazoline-6-sulfonic acid) (ABTS(.+)) radical cation scavenging method. Antioxidant activity increased with increasing color value although the rate of increase decreased with increasing color value. Color was measured in CIELAB space. Extracts of the 15, 23, and 72 degrees EBC malts followed the same dilution pathway as did the 148 degrees EBC sample at higher dilution levels, indicating that they could each be used to give the same color by appropriate dilution. The 440 degrees EBC sample followed a different dilution pathway, indicating that different compounds were responsible for color in this extract. Fifteen selected volatile compounds were monitored using gas chromatography/mass spectrometry (GC/MS). Levels of methylpropanal, 2-methylbutanal, and 3-methylbutanal were highest for the 72 degrees EBC sample. When odor threshold values of the selected compounds were taken into account, 3-methylbutanal was the most important contributor to flavor., Relationships between levels of the lipid oxidation products, hexanal and (E)-2-nonenal, and antioxidant activity were complex, and increasing antioxidant activity for samples in the range of 15-148 degrees EBC did-not result in reduced levels of these lipid-derived compounds. When different colored malt extracts were diluted to give the same a* and b* values, calculated antioxidant activity and amounts of 3-methylbutanal, hexanal, and (E)-2-nonenal decreased with increasing degrees EBC value.

Valorização de resíduos industriais na formulação de produtos e pigmentos cerâmicos: processamento e desenvolvimento de cor

A valorização de diferentes resíduos industriais provenientes dosector de tratamento/revestimento de superfícies metálicas pode ser obtida utilizando-os como matérias-primas na formulação de pigmentos cerâmicos, sintetizados pelo método cerâmico convencional. Neste trabalho avaliou-se a viabilidade de incorporar lamas geradas pelos processos de (i) anodização, ricas em alumínio, (ii) de niquelagem e cromagem de torneiras, usadas como fonte de níquel e crómio, e (iii) da decapagem química de aços de uma trefilaria, ricas em ferro, utilizadas por si só, ou em conjunto com matérias-primas comerciais, para a obtenção depigmentos cerâmicos que coram, de forma estável, diversas matrizes cerâmicas e vítreas. Esta solução assegura ainda a inertização de potenciaisespécies perigosas presentes nos resíduos, resultando produtos inócuospara a saúde pública. Procedeu-se à caracterização de cada resíduo, em termos de composição química e mineralógica, comportamento térmico, grau de toxicidade, distribuição granulométrica, teor de humidade, etc. Verificou-se a constância das características das lamas, recorrendo à análise de lotes recolhidos em momentos distintos. Os resíduos são essencialmente constituídos por hidróxidos metálicos e foram utilizados após secagem e desagregação. No entanto, a lama de anodização de alumínio sofreu um tratamento térmico suplementar a 1400ºC. O método de síntese dos pigmentos englobou as seguintes etapas: (i) doseamento; (ii) homogeneização; (iii) calcinação; (iv) lavagem e moagem.Procedeu-se à caracterização dos pigmentos, avaliando a cor por espectroscopia de reflectância difusae pelo método CIELAB e determinando as características físico-químicas relevantes. Posteriormente, testou-se o seu desempenho em produtos cerâmicos distintos (corpos e vidrados), aferindo o desempenho cromático e a estabilidade. Numa primeira fase, desenvolveram-se e caracterizaram-se tipos distintos de pigmentos: (i) com base na estrutura do corundo (ii) verde Victória deuvarovite (iii) violeta de cassiterite com crómio (iv) pigmento carmim de malaiaíte; (v)pretos e castanhos com base na estrutura da espinela. Aprofundaram-se depois os estudos do pigmento carmim de malaiaítee do pigmento preto com base na estrutura da espinela. O pigmento carmim de malaiaíte, CaSnSiO5:Cr2O3, é formulado coma lama gerada no processo de niquelagem e cromagem. Avaliou-se a influência do teor de lama na temperatura de síntese e na qualidade cromática, em comparação com um pigmento formulado com reagentes puros. O pigmento preto com estrutura de espinela de níquel, crómio e ferro, foii formulado exclusivamente a partir das lamas geradas nos processos de cromagem/niquelagem e de decapagem química do aço. Avaliaram-se as características cromáticas e o grau de inertização dos elementos tóxicospresentes, em função da estequiometria e do tratamento térmico. Estudou-se ainda um novo sistema com base na estrutura da hibonite(CaAl12O19), que permite a obtenção de pigmentos azuis e que utiliza a lama de cromagem e niquelagem. As espécies cromóforas (Ni2+ ou Co2+) assumem coordenação tetraédrica quando substituem os iões Al3+ que ocupam as posições M5 da rede da hibonite. A formação simultânea de anortite permite reduzir a temperatura de síntese.Para além do carácter inovador deste pigmento de dissolução sólida, a qualidade cromática e a sua estabilidade são interessantes. Além disso, os teores de cobalto ou níquel são reduzidosrelativamente aos utilizados em formulações comerciais de pigmentos azuis, o que se traduz em importantes vantagens económicas e ambientais.

Inclusão da microalga (Phaedactylum tricornutum) em rações de acabamento para dourada: efeito na pigmentação e outros atributos da qualidade

Dissertação de mestrado, Aquacultura, Faculdade de Ciências e Tecnologias, Universidade do Algarve, 2015

Identification of image attributes that are most affected with changes in displayed image size

This paper describes an investigation of changes in image appearance when images are viewed at different image sizes on a high-end LCD device. Two digital image capturing devices of different overall image quality were used for recording identical natural scenes with a variety of pictorial contents. From each capturing device, a total of sixty four captured scenes, including architecture, nature, portraits, still and moving objects and artworks under various illumination conditions and recorded noise level were selected. The test set included some images where camera shake was purposefully introduced. An achromatic version of the image set that contained only lightness information was obtained by processing the captured images in CIELAB space. Rank order experiments were carried out to determine which image attribute(s) were most affected when the displayed image size was altered. These evaluations were carried out for both chromatic and achromatic versions of the stimuli. For the achromatic stimuli, attributes such as contrast, brightness, sharpness and noisiness were rank-ordered by the observers in terms of the degree of change. The same attributes, as well as hue and colourfulness, were investigated for the chromatic versions of the stimuli. Results showed that sharpness and contrast were the two most affected attributes with changes in displayed image size. The ranking of the remaining attributes varied with image content and illumination conditions. Further, experiments were carried out to link original scene content to the attributes that changed mostly with changes in image size.

Integrated visual vocabulary in latent Dirichlet allocation-based scene classification for IKONOS image

Scene classification based on latent Dirichlet allocation (LDA) is a more general modeling method known as a bag of visual words, in which the construction of a visual vocabulary is a crucial quantization process to ensure success of the classification. A framework is developed using the following new aspects: Gaussian mixture clustering for the quantization process, the use of an integrated visual vocabulary (IVV), which is built as the union of all centroids obtained from the separate quantization process of each class, and the usage of some features, including edge orientation histogram, CIELab color moments, and gray-level co-occurrence matrix (GLCM). The experiments are conducted on IKONOS images with six semantic classes (tree, grassland, residential, commercial/industrial, road, and water). The results show that the use of an IVV increases the overall accuracy (OA) by 11 to 12% and 6% when it is implemented on the selected and all features, respectively. The selected features of CIELab color moments and GLCM provide a better OA than the implementation over CIELab color moment or GLCM as individuals. The latter increases the OA by only ∼2 to 3%. Moreover, the results show that the OA of LDA outperforms the OA of C4.5 and naive Bayes tree by ∼20%. © 2014 Society of Photo-Optical Instrumentation Engineers (SPIE) [DOI: 10.1117/1.JRS.8.083690]

Determinação da dose eritematosa mínima como marcador de risco e sensibilidade à radiação ultravioleta

Objetivos: Determinar a dose eritematosa mínima (DEM) medida por exposição controlada à radiação ultravioleta-B (RUV-B), como limiar para dano solar agudo nos diversos fototipos, e medir a cor da pele constitucional pelo sistema colorimétrico CIELAB. Pacientes e Métodos: Um total de 194 voluntários, sadios, com idades acima de 18 anos, distribuídos em um mínimo de 30 participantes por fototipo. Todos foram classificados por fototipos segundo os critérios de Fitzpatrick. As regiões infra-axilar torácica e nádega foram irradiadas em 4 áreas de 1 cm2, assim como foi registrada a cor da pele desses locais pelo sistema CIELAB. Delineamento: Estudo transversal. Resultados: A média de idade dos participantes foi de 38 anos, sendo 68% do sexo feminino. A avaliação da associação entre as medidas das DEMs e dos valores colorimétricos da coordenada L*, mostrou uma correlação de Pearson negativa com r = -0,91 para um valor p<0,05. Para os valores das DEMs e os escores da classificação dos voluntários por fototipos, obteve-se correlação de Spearman (rs) de +0,95 para p<0,05 e, correlacionando os valores colorimétricos com os escores dos fototipos, encontrou-se em tórax um rs de -0,93 e em nádega -0,92 para um p < 0,05. Conclusões – Concluiu-se que: 1)- a mensuração dos valores colorimétricos da coordenada L* nas regiões infra-axilar torácica e nádega mostraram uma forte correlação com os valores das DEMs, sendo de menor poder invasivo e de maior praticidade para mensuração de sensibilidade à radiação ultravioleta; 2)- apesar de os escores de Fitzpatrick terem alta correlação com os valores das DEMs, mostraram superposição de valores nos fototipos adjacentes; 3)- o grau de associação das classes dos fototipos com a cor da pele permite dizer que a categoria numérica do fototipo aumenta à medida que a pele fica mais escura.

Estudo das interações polifenol-proteína e das reações de escurecimento não-enzimático para o processamento de cajuína

The cashew, a fruit from Brazilian Northeast is used to produce juice due to its flavor and vitamin C richness. However, its acceptance is limited due to its astringency. Cajuína is a derivate product appreciated by its characteristic flavor, freshness and lack of astringency, due to tannin removal. Cajuína is a light yellow beverage made from clarified cashew juice and sterilized after bottling. It differs from the integral and concentrated juice by the clarification and thermal treatment steps. Many problems such as haze and excessive browning could appear if these steps are not controlled. The objective of this work was divided into two stages with the aim to supply process information in order to obtain a good quality product with uniform characteristics (sensory and nutritional). Polyphenol-protein interaction was studied at the clarification step, which is an empirical process, to provide values on the amount of clarifying solution (gelatin) that must be added to achieve a complete juice clarification. Clarification essays were performed with juice dilutions of 1:2 and 1:10 and the effect of metabissulfite and tannic acid addition was evaluated. It was not possible to establish a clarification point. Metabissulfite did not influenced the clarification process however tannic acid addition displaced the clarification point, showing the difficulty visual monitoring of the process. Thermal treatment of clarified juice was studied at 88, 100, 111 e 121 °C. To evaluate the non-enzymatic browning, vitamin C, 5-hidroximetilfurfural (5-HMF) and sugar variation were correlated with color parameters (reflectance spectra, color difference and CIELAB). Kinetic models were obtained for reflectance spectra, ascorbic acid and 5-HMF. It was observed that 5-HMF introduction followed a first order kinetic rate at the beginning of the thermal treatment and a zero order kinetic at later process stages. An inverse correlation was observed between absorbance at 420 nm and ascorbic acid degradation, which indicates that ascorbic acid might be the principal factor on cajuína non-enzymatic browning. Constant sugar concentration showed that this parameter did not contribute directly to the nonenzymatic browning. Optimization techniques showed showed that to obtain a high vitamin C and a low 5-HMF content, the process must be done at 120 ºC. With the water-bath thermal treatment, the 90 °C temperature promoted a lower ascorbic acid degradation at the expense of a higher 5-HMF level

Sistemas microemulsionados aplicados à remoção da cor de efluente têxtil

Effluent color resulting from textile dyeing processes has been one of the biggest environmental problems faced by the textile industry. In particular, reactive dyes are highly resistant to conventional wastewater treatment methods. New technologies have been contemplated, some of which have been applied in industrial treatment plants, but color removal has not been efficiently attained. Since microemulsion systems provide good results in heavy metals and proteins extraction processes, their use in dyes extraction has been suggested and investigated. In this work, a real textile wastewater from an exhaustion dyebath has been treated, which contains the following reactive dyes: Procion Yellow H-E4R (CI Reactive Yellow 84), Procion Blue H-ERD (CI Reactive Blue 160) and Procion Red H-E3B (CI Reactive Red 120), in addition to auxiliary compounds normally found in dyeing processes with reactive dyes. The dyes Remazol Blue RR and Remazol Turquoise Blue G (Reactive Blue 21) have also been examined in view of the presence of heavy metals in these molecules. The microemulsion system comprised dodecyl ammonium chloride (as a cationic surfactant), water or wastewater as aqueous phase, kerosene as oil phase, and one of the following alcohols as cosurfactant: isoamyl alcohol, n-butyl alcohol and n-octyl alcohol. The pseudo-ternary diagrams were constructed in order to define Winsor s equilibrium regions. The influence of parameters such as pH, C/S (cosurfactant/surfactant) ratio, distribution coefficient, initial dye concentration, salinity, temperature, phases relative amounts, loading capacity of the microemulsion phase and dye reextraction rate has also been investigated. An experimental planning (Scheffé Net) was used to optimize the extraction process. The removal of color and metals reached levels as high as 99%