Cleiton Antônio Nunes

Chemoface: a novel free user-friendly interface for chemometrics

Um software para analise multivariada foi desenvolvido com o objetivo de oferecer uma ferramenta computacional livre com interface grafica amigavel para pesquisadores, professores e estudantes com interesse em quimiometria. O Chemoface possui modulos capazes de resolver problemas relacionados com planejamento experimental, reconhecimento de padroes, classificacao e calibracao multivariada. E possivel obter uma variedade de graficos e tabelas para explorar os resultados. Neste trabalho, as principais funcionalidades do Chemoface sao exploradas usando estudos de caso reportados na literatura, tais como otimizacao de adsorcao de corante indigo em quitosana usando planejamento fatorial completo, analise exploratoria de amostras de propolis caracterizadas por ESI-MS (espectrometria de massas com ionizacao electrospray) usando PCA (analise de componentes principais) e HCA (analise hierarquica de agrupamentos), modelagem MIA-QSAR (analise multivariada de imagem aplicada a relacoes quantitativas estrutura-atividade) para predicao de parâmetro cinetico relacionado a atividade de peptideos contra dengue usando PLS (metodo de quadrados minimos parciais), e classificacao de amostras de vinho de diferentes variedades usando PLS-DA (PLS para analise discriminante). Todos os exemplos sao ilustrados com graficos e tabelas obtidos no Chemoface. A software for multivariate analysis was developed in order to provide a free computational tool with user-friendly graphical interface for researchers, professors and students with interest in chemometrics. Chemoface comprises modules that can solve problems related to experimental design, pattern recognition, classification and multivariate calibration. It allows obtaining a variety of high quality graphics and tables to explore results. In this work, the main features of Chemoface are explored using case studies reported in the literature, such as optimization of adsorption of indigo dye on chitosan using full factorial design, exploratory analysis of propolis samples characterized by ESI-MS (electrospray ionization-mass spectrometry) using PCA (principal component analysis) and HCA (hierarchical cluster analysis), MIA-QSAR (multivariate image analysis applied to quantitative structure activity relationship) modeling for the prediction of kinetic parameter related to activities of peptides against dengue using PLS (partial least squares), and classification of wine samples from different varieties using PLS-DA (PLS discriminant analysis). All examples are illustrated with graphs and tables obtained by means of Chemoface.

SensoMaker: a tool for sensorial characterization of food products

SensoMaker is a free software for data analysis from sensory studies, which has modules with user-friendly interface. Data acquisition can be performed using different methods, such as category scale, linear scale, temporal dominance of sensations (TDS), and time-intensity (TI). Results can be analyzed by a variety of methods, such as conventional internal and external preference mapping, three-way internal and external preference mapping, principal component analysis, hierarchical cluster analysis, TDS and TI curves, in addition to Tukey and Dunnett tests. High quality graphics are easily obtained and exported to several formats. The software is useful during the development or improvement of products, when it is important to carefully note consumer preferences and to relate it to descriptive characteristics in order to ensure good product acceptance.

Estimation of surface area and pore volume of activated carbons by methylene blue and iodine numbers

micropore volume and total pore volume using multiple regression. The models obtained from the calibrations were used in predicting these physical properties of a test group of activated carbon samples produced from several raw materials. In all cases, the predicted values were in good agreement with the expected values. The method allows extracting more information from the methylene blue and iodine adsorption studies than normally obtained with this type of material.

Use of allyl isothiocyanate and carbon nanotubes in an antimicrobial film to package shredded, cooked chicken meat

We developed antimicrobial packaging incorporated with allyl isothiocyanate (AIT) and carbon nanotube (CNT), and this packaging was used for shredded cooked chicken meat inoculated with Salmonella Choleraesuis. The following parameters were analysed during the 40 days of storage: microbial counts, colour characteristics and changes in the oxidation of the meat as well as changes in the mechanical properties of the film, the structure of the antimicrobial film and the diffusion of the antimicrobial agent into the food. The incorporation of AIT into the films increased the elongation at the break (E) value of the films and decreased the tensile strength (TS) value of the films. The CNT was important to retain the AIT which is a volatile substance in the film. The diffusion of the AIT from the film into the chicken reduced the microbial contamination, controlled oxidation and reduced the colour changes. Thus, these packages were effective for the 40 days of storage.

Introducing new dimensions in MIA-QSAR: a case for chemokine receptor inhibitors.

Multivariate image analysis applied to quantitative structure-activity relationships (MIA-QSAR) is a very simple correlative method that uses pixels (binaries) of chemical structures built from 2D viewer programs as descriptors; structural changes correspond to different pixel coordinates, which explain the variance in the bioactivities block. The MIA-QSAR method has shown to be predictive and capable of encoding some chemical information, but introduction of more descriptive information, such as atom size and colors to differentiate atom types, would improve predictability and interpretability. The bioactivities of a series of chemokine receptor (CCR2) inhibitors have been modeled using both conventional and atom color/size-dependent MIA-QSAR (namely aug-MIA-QSAR); the latter showed to be better. Moreover, the results were comparable to those obtained by 3D methodologies, indicating that 2D shape and substituent size are more significant descriptors than the conformational profiles required by field fit techniques.

Chemical, Physical–Chemical, and Sensory Characteristics of Lychee (Litchi chinensis Sonn) Wines

UNLABELLED Four lychee (Litchi chinensis Sonn) wines (prepared with 3 yeast strains [UFLA CA11, UFLA CA1183, and UFLA CA1174]) and a spontaneous fermentation (SPON) were done in order to add value to the fruit while preventing waste arising from the short shelf life of lychee. The fermentation was monitored daily by analyzing the soluble solids, pH, acidity, ethanol, and sugar. At the end of fermentation, the wines were subjected to chemical, physical-chemical, and sensory analysis. The wines prepared showed greater variations in the qualitative than in the quantitative analysis of their constituents. The sensory analysis indicated that the wines fermented by yeast UFLA CA1183 and UFLA CA11 had rates of acceptance above 75%. The principal components analysis separated the wines into 2 groups according to the analyzed compounds. Based on these analyses, the wine produced by inoculation with UFLA CA1183 proved to be the most suitable for the production of lychee wines. PRACTICAL APPLICATION Development of new products and adding value to fruits. Importance of selection of specific yeasts for production of fruit wine.

Salt equivalence and temporal dominance of sensations of different sodium chloride substitutes in butter.

Studies indicate a positive association between dietary salt intake and some diseases, which has promoted the tendency to reduce the sodium in foods. The objective of this study was to determine the equivalent amount of different sodium chloride replacements required to promote the same degree of ideal saltiness in butter and to study the sensory profile of sodium chloride and the substitutes using the analysis of Temporal Dominance of Sensations (TDS). Using the magnitude estimation method, it was determined that the potencies of potassium chloride, monosodium glutamate and potassium phosphate relative to the 1% sodium chloride in butter are 83·33, 31·59 and 33·32, respectively. Regarding the sensory profile of the tested salt substitutes, a bitter taste was perceived in the butter with potassium chloride, a sour taste was perceived in the butter with potassium phosphate and sweet and umami tastes were dominant in the butter with monosodium glutamate. Of all the salt substitutes tested calcium lactate, potassium lactate, calcium chloride and magnesium chloride were impractical to use in butter.

Characterization of Brazilian green propolis throughout the seasons by headspace GC/MS and ESI-MS

BACKGROUND A screening of the chemical composition of eight commercial classes of raw Brazilian green propolis throughout the seasons was carried out. A multivariate exploratory analysis of chemical composition obtained by gas chromatography associated with mass spectrometry with headspace extraction (HS-GC/MS), and by mass spectrometry with electrospray ionization (ESI-MS) was carried out using principal component analysis (PCA). RESULTS Differences in the volatile and polyphenolic profiles of propolis samples were verified during the seasons. Within each season, the high quality commercial classes of propolis presented similar characteristics, while the low quality classes presented distinct compositions. In spring and summer, propolis of the trimming class, commonly considered of low quality by beekeepers, presented a composition similar to the superior quality propolis. CONCLUSION Seasonality influences the chemical composition of the commercial classes of raw Brazilian green propolis. Headspace-GC/MS and ESI-MS assisted by PCA are effective to characterize volatile and non-volatile compounds of the propolis samples, and to correlate it to the seasons.

Equivalence salting and temporal dominance of sensations analysis for different sodium chloride substitutes in cream cheese

The purpose of the study was to determine the potency and equivalence of salt substitutes (potassium chloride, magnesium chloride, monosodium glutamate, potassium lactate, calcium lactate and potassium phosphate monobasic) in cream cheese and to evaluate sensory flavour profiles. The methods used were magnitude estimation and temporal dominance of sensations (TDS). Equivalent salting of cream cheese containing 1% sodium chloride was obtained using: 1.2% potassium chloride, 2.56% monosodium glutamate, 2.5% magnesium chloride and 2.98% potassium phosphate. The TDS revealed that, other than salty taste, the most significant flavours produced were sour and bitter. The potencies of salt substitutes are much lower than that of sodium chloride.

Evaluation of the Jelly Processing Potential of Raspberries Adapted in Brazil

UNLABELLED Generally raspberry products as jams, jellies, and preserves are made with red raspberry, however, yellow raspberry and especially black raspberry are also fruits adapted in Brazil, presenting even better productivity and quality. Thus, the aim of this study was to evaluate the processing potential of other varieties of raspberry, but the red, in the preparation of jellies through mixture design and response surface methodology (RSM). These techniques were used to optimize the following 3 variables: yellow (Golden Bliss cultivar, Rubus idaeus), black (Rubus niveus), and red raspberries (Batum cultivar, Rubus idaeus) to formulate a mixed raspberry fruit jelly through sensory evaluations. It was found that jelly formulated with a mix of colored raspberries grown in subtropical regions is a viable and alternative way to use yellow and black raspberries. The mixed raspberry jelly must have 0% to 30% yellow raspberries, 25% to 50% black raspberries, and 30% to 75% red raspberries. Within this region, the optimum formulation has ideal characteristics that are often not observed in formulations with 100% black or yellow raspberries. PRACTICAL APPLICATION The black and yellow raspberries are little explored in fresh consumption and in the development of products such as jams and jellies. From these work, using mixture design and response surface methodology, has been verified that the production of a mixed raspberry jelly seems feasible and is an interesting alternative to use the yellow and black raspberries. The results serve as a guide to the production of jams and jellies from these types of raspberries.