Efeito do ácido p-hidroxibenzóico no crescimento de leveduras isoladas de mel

De entre as características do mel, destaca-se a sua composição química em que os açucares possuem um papel dominante. Possui um teor em agua de 16 a 18%, contendo também enzimas, hidroximetilfurfural, sais minerais, substancias azotadas, vitaminas, compostos aromáticos e ácidos. Os ácidos apesar de estarem presentes no me! em pequena proporção (teor máximo 0,5%) tem um efeito pronunciado no sabor e contribuem, para a resistência do mel ao ataque microbiano

Simultaneously assess goat fat depots using ultrasound technology (RTU) in association with muliple PLS and ANN models. A network proposal

A recent development to improve the prediction of goat body or carcass composition in small has been made. With the perspective to use a unique model to estimate body composition, based on a reduced number of predictors a model using artificial neural networks was proposed. On this sense the main objective of the present work will be to demonstrate the necessity to organize a world network to build a great database, covering the most relevant carcass and body compositions data, for the most important goat breeds at different maturity degrees and with carcasses that proportionate the development of general, robust, and more reliable models to swiftly assess goat and carcass body compositions, as well as to implement a modern and objective on-line technique for carcass evaluation and marketing classification

Estudo comparativo do efeito de fungicidas na actividade metabólica de leveduras

AnexoNa maior parte dos casos, são encontrados resíduos de fungicidas nos mostos. Nestas concentrações, estes produtos têm um efeito reduzido na fermentação. No entanto, quando aplicados 8 a 15 dias antes das vindimas, podem afectar negativamente a actividade metabólica das leveduras, nomeadamente as taxas específicas de crescimento e de fermentação

Simultaneously prediction of sheep and goat carcass composition and body fat depots using in vivo ultrasound measurements and live weight

The present study established multiple linear regression models using two ultrasound in vivo measurements (at lumbar and sternal regions, with different real-time ultrasonography machines and probes) and live weight, to predict simultaneously carcass composition and body fat depots of different breeds of sheep and goat. This study is important for the small ruminant industry, considering the feasibility of using the ultrasound methodology in field conditions, as well as an online system of the carcass evaluation. The multiple linear regression models were obtained by selecting the best subset of variables between using the in vivo measurements (raw variables), their second degree and interactions, evaluated in terms of prediction performance using cross-validation “K-folds” and validated by a test group. Overall, high accuracy (adj R2) was obtained from the linear relationship between predicted and experimental values of the group test for each of the nine dependent variables, with values varying between adj R2 0.88 and 0.98.The authors are grateful to Laboratory of Carcass and Meat Quality of Agriculture School of Polytechnic Institute of Bragança ‘Cantinho do Alfredo’. The authors are members of the CYTED network HEALTHY MEAT (119RT0568).info:eu-repo/semantics/publishedVersio

Comparative study of different Portuguese samples of propolis: pollinic, sensorial, physicochemical, microbiological characterization and antibacterial activity

The aim of this work was to study four propolis samples from Trás-os-Montes region of Portugal. The propolis samples’ color was different, which pollen analysis showed to be due to different botanical sources: Populus sp., Pinus sp., Quercus sp. and Castanea sativa. The data from physicochemical analysis (moisture, soluble and insoluble solids content, pH, conductivity, ash content, wax, total phenolics and flavonoids content) was treated using multivariate statistical tools as cluster heat map, principal components analysis and linear discriminant analysis with the purpose of classifying the sample accordingly to the botanical/geographical origin. The discriminant analysis was applied with stepwise to select the variables that most contribute to sample identification accordingly to pollinic profile. The cross-validation technique was applied, using the leave-one-out procedure, which showed good prediction capabilities of the samples. Microbiologically, the commercial quality was satisfactory, since the samples didn’t contain deterioration or pathogenic microorganisms. All the samples studied presented antimicrobial activity against Methicillin-resistant Staphylococcus aureus, in a dose dependent way. The antimicrobial activity was strictly related to the physicochemical composition. This work will allow connecting a particular chemical propolis type to a specific type of biological activity, what is essential for the use in therapeutic applications

Propolis phenolic compounds extraction using response surface methodology

Propolis is a complex resinous substance prepared by bees (as, Apis mellifera) using compounds collected from plants, buds and exudates, which are then mixed with wax, pollen and enzymes ofbees' saliva [1, 2]. It is used to seal openings and cracks in the hive walls, to isolate animal calcasses inside the beehive, and in the protection against parasites. This product hás attained much interest due to its chemical composition and fünctional properties. Recent publications emphasize its biological and health enhancing properties as, for instance, immunomodulatory, antitumoral, antimicrobial, anti-inflammatory. antioxidant, antiviral and antifungal [3, 4].Fmancial support received fi-om PRODER, "PA 54811 Appreciation ofapiculture by-products - Mead and vinegar production of honey", is gratefully acknowledged.info:eu-repo/semantics/publishedVersio

Evaluation of antibiotics residues levels in Portuguese honey: a concerted study with the Portuguese Beekeepers Associations

The antibiotics residual presence in honey is a current problem with negative implications, mainly commercial since according to European legislation antibiotic occurrence in honey samples is forbidden

Mead production using immobilized cells of saccharomyces cerevisiae: Reuse of sodium alginate beads

This work studied the production of mead using second category honey and the immobilized cells of Saccharomyces cerevisiae in sodium alginate, with concentrations of 2% and 4%, and their reuse in five successive fermentations. The immobilized cells with 4% alginate beads were mechanically more stable and able to allow a greater number of reuses, making the process more economical. The fermentation’s consumption of sugars with free cells (control) and immobilized cells showed a similar profile, being completed close to 72 h, while the first use of immobilized cells finished at 96 h. The immobilized cells did not significantly influence some oenological parameters, such as the yield of the consumed sugars/ethanol, the alcohol content, the pH and the total acidity. There was a slight increase in the volatile acidity and a decrease in the production of SO2. The alginate concentrations did not significantly influence either the parameters used to monitor the fermentation process or the characteristics of the mead. Mead fermentations with immobilized cells showed the release of cells into the wort due to the disintegration of the beads, indicating that the matrix used for the yeast’s immobilization should be optimized, considering the mead production medium.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2019).info:eu-repo/semantics/publishedVersio

Cuantificacio´n de tres clases feno´ licas y contenido feno´ lico total de extractos de propo´ leos utilizando un u´ nico espectro UV-Vis

This work presents a methodology for simultaneously measuring the total content of three classes of phenolic compounds (hydroxybenzoic acids, hydroxycinamic acids and flavonoids), as well the total phenolic content using a single UVvis spectrum. To test the methodology, samples of propolis were used. Firstly, an experimental design based in the Response Surface Methodology established that the best hydroethanolic solution for propolis phenolic compounds extraction had 80% of ethanol. Secondly, calibration models were developed with multiple linear regression, coupled with the leaps algorithm for variable selection, using UV-vis spectra of mixed standard solutions (gallic acid, ferulic acid and quercetin mixtures), all with orthogonal concentrations established by a multilevel fractional factorial design. The model’s estimation and prediction performance had linearity between predicted and expected concentration values, with slope ranging from 0.996–1.04 and determination coefficients higher than 0.995. A quality control solution presented acceptable repeatability and accuracy (relative standard deviation percentage and percentage relative error were lower than 4.8%). Analysis of propolis phenolic compounds extracts showed acceptable precision (relative standard deviation percentages lower than 1.6%) and acceptable accuracy (recoveries assays ranged between 98 and 112%). Overall, the present multi-parametric analytical technique can be a first approach for chemical characterization of phenolic compounds extracts, such as that obtained from the propolis samples, considering its advantages of simplicity, rapidity, precision and accuracy. Moreover, this methodology can be adapted to other sample matrices, provided that the typical UV-vis absorption spectra of their classes of phenolic compounds shows partial overlapping, allowing multivariate calibration.Este trabajo presenta una metodologı´a para medir simulta´neamente el contenido total de tres clases de compuestos feno´ licos (a´cidos hidroxibenzoicos, a´cidos hidroxicina´micos y flavonoides), ası´ como el contenido feno´ lico total usando un solo espectro UV-Vis. Para probar la metodologı´a, se utilizaron muestras de propo´ leos. En primer lugar, un disen˜o experimental basado en la metodologı´a de la respuesta en superficie establecio´ que la mejor solucio´n hidroetano´ lica para la extraccio´n de compuestos feno´ licos de propo´ leos tenı´a un 80% de etanol. En segundo lugar, se desarrollaron modelos de calibracio´n con regresio´n lineal mu´ ltiple, junto con el algoritmo de saltos para la seleccio´n variable, utilizando espectros UV-Vis de soluciones esta´ndar mixtas (a´cido ga´lico, a´cido feru´lico y mezclas de quercetina), todas con concentraciones ortogonales establecidas por un disen˜o factorial fraccional multinivel. La estimacio´n del modelo y el rendimiento de la prediccio´n tenı´an linealidad entre los valores de concentracio´n previstos y esperados, con una pendiente que variaba de 0,996 a 1,04 y coeficientes de determinacio´n superiores a 0,995. Una solucio´n de control de calidad presento´ aceptable repetibilidad y precisio´n (porcentaje de desviacio´n esta´ndar relativa y porcentaje de error relativo inferiores al 4,8%). El ana´lisis de extractos de compuestos feno´ licos de propo´ leos mostro´ una precisio´n aceptable (porcentajes de desviacio´n esta´ndar relativa inferior al 1,6%) y una precisio´n aceptable (los ensayos de recuperacio ´n variaron entre 98 y 112%). En general, la presente te´cnica analı´tica multiparame´trica puede ser un primer enfoque para la caracterizacio´n quı´mica de extractos de compuestos feno´ licos, como el obtenido a partir de las muestras de propo´ leos, considerando sus ventajas de simplicidad, rapidez, precisio´n y precisio´ n. Adema´s, esta metodologı´a puede adaptarse a otras matrices de muestra, siempre que los espectros de absorcio´n UV-Vis tı´picos de sus clases de compuestos feno´ licos muestren solapamiento parcial, permitiendo la calibracio´n multivariante.This work was financially supported by CQ-VR, Centro de Química – Vila Real, University of Trás-os-Montes e Alto Douro [Project UID/QUI/00616/2013]; Centre of Molecular and Environmental Biology, University of Minho [Project UID/ BIA/04050/2013]; funded by FEDER (Fundo Europeu de Desenvolvimento Regional) through COMPETE2020 (Programa Operacional Competitividade e Internacionalização, POCI); by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal); by Project 56343–“New products derived from sausage”, Measure 4.1 – Cooperation for Innovation, PRODER program, Portugal.info:eu-repo/semantics/publishedVersio