Techniques for the Evaluation of Microbiological Quality in Honey

The aim of this chapter is to describe the most commonly used techniques to evaluate the microbiological characteristics of honey for the purpose of identifying its contaminant flora, its significance and its control in this type of food. Honey is a product that is rich in simple sugars, minerals, vitamins and bioactive compounds and possesses an antimicrobial activity of great significance for human health. However, as it has physical and chemical properties that are unfavourable for the proliferation of micro-flora, honey can contain a large population of microorganisms from two sources of contamination—the first primarily represented by pollen, the digestive system of the bee, dust, air and the flower itself; and the second as the result of negligence and the absence of good health practices during handling and use; for example, placing honey in wooden beehives directly on the floor or the use of improperly washed honey extraction equipment, rather than equipment based on the oxidizable material, or using very dark honeycombs and storing the honey for long periods in wooden beehives. As honey is a natural product, the risks inherent to the lack of industrial processing, such as pasteurization and strict microbiological quality control, are often overlooked

Avaliação rápida não invasiva de parâmetros de qualidade em soja triturada com uso de espectroscopia de infravermelho próximo

The objective of this work was to evaluate multivariate calibration models to predict total lipids, crude protein, and moisture content in grinded soybean grains using near-infrared spectroscopy and partial least squares (PLS). Three hundred samples of grinded soybean, evaluated in duplicate, were used for reference and spectral measurements. The PLS models for total lipids, crude protein, and moisture were validated by figures of merit for accuracy and precision, respectively, of 0.75 and 0.67 for total lipids, 0.51 and 0.46 for crude protein, and 0.97 and 0.99 for moisture. The PLS models developed for total lipids, crude protein, and moisture can be used as an alternative methodology for the determination of physicochemical parameters, and, therefore, they can be applied inquality control in soybean processing industries.O objetivo deste trabalho foi avaliar modelos de calibração multivariada para previsão de teores de lipídios totais, proteína bruta e umidade em grãos de soja triturados, com uso da espectroscopia de infravermelho próximo e do método de mínimos quadrados parciais (PLS). Foram utilizadas 300 amostras de grãos de soja trituradas, avaliadas em duplicata, quanto a medidas de referência e espectrais. Os modelos PLS para lipídios totais, proteína bruta e umidade foram validados por meio das figuras de mérito para exatidão e precisão, respectivamente, de 0,75 e 0,67 para lipídios totais, 0,51 e 0,46 para proteína bruta, e 0,97 e 0,99 para umidade. Os modelos PLS desenvolvidos para lipídios totais, proteína bruta e umidade podem ser utilizados como metodologia alternativa para determinação de parâmetros físico-químicos e, portanto, podem ser aplicados no controle de qualidade em indústrias processadoras de soja

Utilização de argila residual recuperada como meio adsorvente de óleo de fritura para produção de biodiesel

In order for the oils to achieve the desired sensory quality, they undergo refining steps. Clarification is one of these steps, where clarifying clays are used in which natural undesired pigments adhere to the oil, making it visually more attractive to consumers. The problem is the incorrect disposal given to these clays wich are disposed of in landfills causing damage to the environment. Similarly, waste frying oils cause problems when disposed of in sinks and drains, compromising groundwater. Thus, a solution to this drawback would be the production of biodiesel, since it is produced through oils and fats, even in a state of deterioration provided that the physicochemical quality standards are met. The objectives of this work were to thermally activate the residual clay, to purify the residual oil in this recovered clay and to produce via biodegradable residual oil and purified oil biodiesel. All physicochemical analyzes were performed according to official methodologies and the near infrared (NIR) spectra were treated by Principal Component Analysis (PCA). Physicochemical analyzes were performed after thermal activation of the clay. Results were obtained of humidity of 1.07%, acidity of 0.16 g oleic acid.100g-1 and peroxides 19.01 meq.kg-1. For the insoluble in ether, no significant values were obtained, besides the difference between the recovered residual clay and virgin clay by the NIR technique. With the results, the acidity values in the purified oil and residual oil remained within the standards, stipulated by the National Health Surveillance Agency (Anvisa), but the peroxide index above the recommend values, showing that the oil was deteriorating. It is concluded that thermally activating the clay from the industrial process together with the residual oil is a good alternative for its reuse, as it contributes to the fact that this material is not lost and possibly incorrectly discarded and halso has advantages over the production of biofuel by acid transesterification.Para que os óleos atinjam qualidade sensorial desejada, eles passam por etapas de refino. A clarificação é uma dessas etapas, em que são usadas argilas clarificantes as quais aderem pigmentos indesejados naturais do óleo, tornando-o visualmente mais atraente para os consumidores. O problema está no descarte incorreto destinado a essas argilas, que são dispostas em aterros sanitários causando danos ao meio ambiente. Da mesma forma, óleos residuais de fritura trazem problemas quando descartados em pias e ralos, comprometendo os lençóis freáticos. Assim, uma solução para esse inconveniente seria a produção de biodiesel, já que este é produzido mediante óleos e gorduras, mesmo em estado de deterioração desde que atingidos os padrões físico-químicos de qualidade. Os objetivos do trabalho foram ativar termicamente a argila residual, purificar o óleo residual nessa argila recuperada e produzir via transesterificação ácida o biodiesel do óleo residual e do óleo purificado. Todas as análises físico-químicas foram realizadas de acordo com metodologias oficiais, e os espectros obtidos por meio do infravermelho próximo (NIR) foram tratados mediante Análise dos Componentes Principais (PCA). Foram realizadas análises físico-químicas após a ativação térmica da argila, obtendo-se resultados de umidade de 1,07%, acidez de 0,16 g ácido oleico.100g-1 e peróxidos 19,01 meq.kg-1. Para os insolúveis em éter não foram obtidos valores significativos, além de, por meio da técnica de NIR, ficar nítida a diferença existente entre a argila residual recuperada e a argila virgem. De posse dos resultados, os valores de acidez no óleo purificado e no óleo residual se mantiveram dentro dos padrões estipulados pela Agência Nacional de Vigilância Sanitária (Anvisa), porém o índice de peróxidos ficou acima dos valores recomendados, evidenciando que o óleo se encontrava em processo de deterioração. Conclui-se que ativar termicamente a argila proveniente do processo industrial com o óleo residual é uma boa alternativa para a sua reutilização, pois contribui para que esse material não seja perdido e possivelmente descartado de forma incorreta, e, ainda, traz vantagens com relação à produção de biocombustível por meio de transesterificação ácida

UV-Vis spectroscopy and chemometrics applied to residues monitoring in sewage

Edible oil residues (EOR) and detergents/soaps (NBDS) are a considerable problem in the water systems. The layer due to presence of these residuals covers the water surface damaging the aquatic life by hampering the sun light to touch its bottom, diminishing algae quantity and, consequently, microorganisms and fishes, which depend on it to survive, changing the local biosphere. Knowing this potential effect, the objective was monitor edible oil residues and detergents/soaps presence in two sewage treatment station located in Brazil. To this, samples were collected from 3 different sewage treatment stages and evaluated by ultraviolet-visible spectroscopy. Chemometrics was applied to recover spectra profiles and relative concentration of residuals. The results indicate that the proposed methodology is feasible to monitoring these residues in sewage

Study on the influence of radiation and pH at the knetic behavior of anthocynins from plants of hibiscus gender by chemometrics methods

Orientador: Ronei Jesus PoppiTese (doutorado) - Universidade Estadual de Campinas, Instituto de QuimicaResumo: A influência da radiação UV e pH no equilíbrio de espécies de antocianinas de plantas do gênero Hibiscus foi estudada por métodos quimiométricos. Antocianinas provenientes de extratos de 3 diferentes flores da família Malvaceae (Hibiscus Sabdariffa, Hibiscus Acetosella e Malvaviscus Penduliflorus) foram utilizadas no estudo. Análises espectrofotométricas nas regiões UV-Vis foram realizadas, comparando-se os espectros e a cinética resultante de análises realizadas com e sem exposição à radiação UV em soluções tampão com valores de pH variando de 1,5 até 12,7 e Análise por Injeção em Fluxo (FIA) para o cálculo das constantes de equilíbrio dos compostos encontrados. Para isso, foram utilizados métodos quimiométricos de Análise de Componentes Principais (PCA), PCA multi-modo (MPCA), Pure, Decomposição de Valores Singulares (SVD) e Resolução Multivariada de Curvas com Mínimos Quadrados Alternados (MCR-ALS). Com o objetivo de encontrar com maior confiabilidade o número de espécies presentes assim como caracterizá-las, o método MCR-ALS foi aplicado utilizando-se matrizes individuais e também com matrizes aumentadas. A partir dos resultados obtidos pela aplicação dos métodos quimiométricos foi sugerido um sistema de equilíbrio entre as diferentes formas químicas encontradas nos diferentes valores de pH, e a partir dos resultados obtidos por FIA, foram calculadas as constantes de equilíbrio para algumas das espécies encontradasAbstract: The influence of UV radiation and pH at the anthocyanin species equilibra, extracted from plants of Hibiscus gender was studied with chemometric methods. Anthocyanins from different extracts of 3 different flowers of Malvaceae family (Hibiscus Sabdariffa, Hibiscus Acetosella and Malvaviscus Penduliflorus) were used at this investigation. Spectrophotometric analysis at UV-Visible range were performed, comparing spectra and kinetic behavior from analysis with and without UV radiation exposure by using buffer solutions with pH varying from 1.5 to 12.7 and Flow Injection Analysis (FIA) to calculate the equilibra constants to the compounds found in the samples. Chemometric methods as Principal Components Analysis (PCA), Multy-Way PCA, Pure, Singular Value Decomposition (SVD), Multivariate Curve Resolution with Alterning Least Squares (MCR-ALS) were applied. Aiming to find out the number of species, as well as, to characterize them, the MCR-ALS method was applied by using individual and augmented matrix strategy. From the results of the chemometric methods application it was proposed an equilibra system to the species found at different pH values and from FIA results, the equilibra constants were calculated to some of the speciesDoutoradoQuimica AnaliticaDoutor em Ciência

Analytical procedures for identifying anthocyanins in natural extracts

Anthocyanins are among the most important plant pigments. Due to their potential benefits for human health, there is considerable interest in these natural pigments. Nonetheless, there is great difficulty in finding a technique that could provide the identification of structurally similar compounds and estimate the number and concentration of the species present. A lot of techniques have been tried to find the best methodology to extract information from these systems. In this paper, a review of the most important procedures is given, from the extraction to the identification of anthocyanins in natural extracts.12181223Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

PROPOSAL OF A DIDACTIC EXPERIMENT TO TEACH PRINCIPAL COMPONENT ANALYSIS

Principal component analysis (PCA) is a chemometric method that allows for the extraction of chemical information that would otherwise be impossible to determine. Teaching chemometrics to undergraduates can contribute to the overall professional development and training of new teachers, whose profiles have been gaining attention due to the current demand for data interpretation. In this study, a didactic experiment involving PCA is proposed. Spectrophotometry was used in the ultraviolet-visible (UV-Vis) region to assess the behavior of anthocyanins extracted from red cabbage at different pH values. The results suggest the possible separation of anthocyanin structures into three distinct groups, according to their chemical characteristics displayed in acid, neutral, and basic media. The objective is to develop educational materials targeted to undergraduate courses, which encompass a larger number of concepts and introduce instrumental techniques currently being employed in both academic research and the industrial sector. Specifically, the proposed experiment introduces concepts related to spectrophotometry in the UV-Vis range and the PCA chemometric method. The materials used are easily accessible, and UV-Vis spectroscopy equipment is less expensive in comparison with other spectroscopy methods