Effect of Lactobacillus plantarum and prebiotics in reduction of aflatoxin B1 in milk

The aim of this study was to evaluate the influence of Lactobacillus plantarum isolated and associated with prebiotics (inulin, oligofrutose, β-glucan and polydextrose) on the aflatoxin B1 (AFB1) reduction in artificially contaminated milk.info:eu-repo/semantics/publishedVersio

Sensory classification of table olives using an electronic tongue: Analysis of aqueous pastes and brines

Table olives are highly appreciated and consumed worldwide. Different aspects are used for trade category classification being the sensory assessment of negative defects present in the olives and brines one of the most important. The trade category quality classification must follow the International Olive Council directives, requiring the organoleptic assessment of defects by a trained sensory panel. However, the training process is a hard, complex and sometimes subjective task, being the low number of samples that can be evaluated per day a major drawback considering the real needs of the olive industry. In this context, the development of electronic tongues as taste sensors for defects sensory evaluation is of utmost relevance. So, an electronic tongue was used for table olives classification according to the presence and intensity of negative defects. Linear discrimination models were established based on sub-sets of sensor signals selected by a simulated annealing algorithm. The predictive potential of the novel approach was first demonstrated for standard solutions of chemical compounds that mimic butyric, putrid and zapateria defects (93% for cross-validation procedures). Then its applicability was verified; using reference table olives/brine solutions samples identified with a single intense negative attribute, namely butyric, musty, putrid, zapateria or wineyvinegary defects (93% cross-validation procedures). Finally, the E-tongue coupled with the same chemometric approach was applied to classify table olive samples according to the trade commercial categories (extra, 1st choice, 2nd choice and unsuitable for consumption) and an additional quality category (extra free of defects), established based on sensory analysis data. Despite the heterogeneity of the samples studied and number of different sensory defects perceived, the predictive linear discriminant model established showed sensitivities greater than 86%. So, the overall performance achieved showed that the electrochemical device could be used as a taste sensor for table olives organoleptic trade successful classification, allowing a preliminary quality assessment, which could facilitate, in the future, the complex task of sensory panelists.This work was financially supported by Project POCI-01–0145FEDER-006984 – Associate Laboratory LSRE-LCM and by Project UID/QUI/00616/2013 – CQ-VR both funded by FEDER - Fundo Europeu de Desenvolvimento Regional through COMPETE2020 Programa Operacional Competitividade e Internacionalização (POCI) – and by national funds through FCT - Fundação para a Ciência e a Tecnologia, Portugal. Strategic funding of UID/BIO/04469/2013 unit is also acknowledged. Nuno Rodrigues thanks FCT, POPH-QREN and FSE for the Ph.D. Grant (SFRH/BD/104038/2014)

Quantification of table olives' acid, bitter and salty tastes using potentiometric electronic tongue fingerprints

The intensities of the gustatory attributes of table olives is one of the sensory set of parameters evaluated by trained sensory panels accordingly to the recommendations of the International Olive Council. However this is an expensive and time-consuming process that only allows the evaluation of a limited number of samples per day. So, an electronic tongue coupled with multivariate statistical tools, is proposed for assessing the median intensities of acid, bitter and salty tastes perceived in table olives. The results showed that the device, coupled with linear discriminant analysis, could be used as a taste sensor, allowing classifying aqueous standard solutions according to the three basic tastes (repeated K-fold cross-validation: 98% ± 3% of correct classifications) based on the electrochemical signals of 5 sensors. It was demonstrated that the taste sensor with multiple linear regression models, enabled quantifying the median intensities of the three basic tastes (repeated K-fold cross-validation: R2 ? 0.96 ± 0.04) perceived in table olives by a trained sensory panel, based on the potentiometric fingerprints (2125 signal profiles) of aqueous olive pastes and brines. The overall satisfactory results showed the electronic tongue potential to assess the intensities of gustatory attributes of table olives, formerly only achievable by sensory panels.This work was financially supported by Project POCI-01–0145-FEDER-006984 – Associate Laboratory LSRE-LCM and by Project UID/QUI/00616/2013 – CQ-VR both funded by FEDER - Fundo Europeu de Desenvolvimento Regional through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) – and by national funds through FCT - Fundação para a Ciência e a Tecnologia, Portugal. Strategic funding of UID/BIO/04469/2013 unit is also acknowledged. Nuno Rodrigues thanks FCT, POPH-QREN and FSE for the Ph.D. Grant (SFRH/BD/104038/2014)

Assessment of table olives' organoleptic defect intensities based on the potentiometric fingerprint recorded by an electronic tongue

Table olives are prone to the appearance of sensory defects that decrease their quality and in some cases result in olives unsuitable for consumption. The evaluation of the type and intensity of the sensory negative attributes of table olives is recommended by the International Olive Council, although not being legally required for commercialization. However, the accomplishment of this task requires the training and implementation of sensory panels according to strict directives, turning out in a time-consuming and expensive procedure that involves a degree of subjectivity. In this work, an electronic tongue is proposed as a taste sensor device for evaluating the intensity of sensory defects of table olives. The potentiometric signal profiles gathered allowed establishing multiple linear regression models, based on the most informative subsets of signals (from 24 to 29 recorded during the analysis of olive aqueous pastes and brine solutions) selected using a simulated annealing meta-heuristic algorithm. The models enabled the prediction of the median intensities (R2 ≥ 0.942 and RMSE ≤ 0.356, for leave-one-out or repeated K-fold cross-validation procedures) of butyric, musty, putrid, winey-vinegary, and zapateria negative sensations being, in general, the predicted intensities within the range of intensities perceived by the sensory panel. Indeed, based on the predicted mean intensities of the sensory defects, the electrochemical-chemometric approach developed could correctly classify 86.4% of the table olive samples according to their trade category based on a sensory panel evaluation and following the International Olive Council regulations (i.e., extra, 1st choice, 2nd choice, and olives that may not be sold as table olives). So, the satisfactory overall predictions achieved demonstrate that the electronic tongue could be a complementary tool for assessing table olive defects, reducing the effort of trained panelists and minimizing the risk of subjective evaluations.This work was financially supported by Project POCI-01-0145-FEDER-006984—Associate Laboratory LSRE-LCM, by Project UID/QUI/00616/2013 —CQ-VR, and UID/AGR/00690/ 2013—CIMO, all funded by Fundo Europeu de Desenvolvimento Regional (FEDER) through COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI) and by national funds through Fundação para a Ciência e a Tecnologia (FCT), Portugal. Strategic funding of UID/BIO/04469/2013 unit is also acknowledged. Nuno Rodrigues thanks FCT, POPH-QREN, and FSE for the Ph.D. Grant (SFRH/BD/104038/2014).info:eu-repo/semantics/publishedVersio

ALERGIA AO LEITE DE VACA E POSSÍVEIS SUBTITUTOS DIETÉTICOS

A alergia ao leite de vaca acomete cerca de 2 a 3% da população infantil com idade inferior a três anos e, atualmente, é a mais comum dentre as alergias alimentares. O alimento substituto deve apresentar alta qualidade nutricional e adequada às necessidades do indivíduo, assim como, apresentar pouca ou nenhuma reatividade cruzada com as proteínas do leite de vaca. Os estudos já realizados investigaram o efeito de diferentes substitutos alimentícios. O presente trabalho tem como objetivo apresentar uma revisão sobre as questões relacionadas com a alergia às proteínas do leite de vaca quanto principais alérgenos envolvidos e sintomatologia, efeito dos tratamentos tecnológicos tradicionais da indústria láctea sobre a alergenicidade ao leite de vaca e os substitutos dietéticos mais empregados nestes casos

Probiotic and prebiotics: impact on bioavailability of aflatoxin B1 in milk

Aflatoxina B1 (AFB1) é uma micotoxina altamente tóxica para os animais e os seres humanos. Esta toxina tem sido detetada no leite, e resulta da ingestão de ração contaminada pelo animal produtor. Dada a elevada toxicidade desta micotoxina, a utilização de métodos de descontaminação, com destaque para os probióticos, tem sido testados para redução da sua presença no leite. Mas a quantidade total de um contaminante ingerido nem sempre reflete o valor disponível para absorção (biodisponibilidade ou bioacessibilidade), pelo que são utilizados modelos de digestão in vitro para avaliar a bioacessibilidade oral humana de contaminantes dos alimentos. O objetivo deste estudo foi avaliar a ação do microrganismo probiótico Lactobacillus plantarum BG112 e dos prebióticos oligofrutose, polidextrose, beta-glucana e inulina, isolados ou combinados, na bioacessibilidade da AFB1 após digestão in vitro. Amostras de leite foram fortificadas com a micotoxina e adicionadas dos agentes em estudo. A aflatoxina foi quantificada antes e depois da digestão in vitro das amostras por UHPLC-FL. A adição isolada de L. plantarum em leite contaminado por AFB1 resultou numa bioacessibilidade da AFB1 de 27%, confirmando a capacidade de ligação das bactérias ácido láticas com a AFB1. Em relação aos prebióticos, os valores de bioacessibilidade foram também bastante promissores, variando entre os 15 e os 51 %. O melhor resultado para bioacessibilidade foi demostrando quando introduzidos os prebióticos inulina e oligofrutose individualmente. Em conclusão, a adição de L. plantarum e de prebióticos reduziu a bioacessibilidade da AFB1 em todos os ensaios efetuados.Aflatoxin B1 (AFB1) is a highly toxic mycotoxin, for both animals and humans. This toxin is frequently detected in milk, and it results from the ingestion of contaminated feed by producing animals. Given its high toxicity, methods of AFB1 decontamination, including the use of probiotic microorganisms, have been tested in milk. But the total amount of ingested contaminant does not always reflect the amount available for absorption (bioavailability), so in vitro digestion models are used to determine human oral bioavailability of food contaminants. The aim of this study was to evaluate the action of the probiotic Lactobacillus plantarum BG112 and prebiotics oligofructose, polydextrose, β-glucan and inulin, isolated or in a combined way, on bioavailability of AFB1 after in vitro digestion. Samples of milk were spiked with the mycotoxin and the agents under study were added. Aflatoxin was quantified by UHPLC-FL before and after digestion of samples. The addition of L. plantarum in milk contaminated with AFB1 resulted in mycotoxin bioavailability of 27 %, confirming the binding effect of lactic acid bacteria. Concerning prebiotics, bioavailability varied between 15 and 51 %. The best result was obtained with inulin and oligofructose when added alone. In conclusion, bioavailability of AFB1 was reduced by the addition of L. plantarum and prebiotics under all tested conditions.info:eu-repo/semantics/publishedVersio

PADRÃO DE IDENTIDADE E QUALIDADE DE QUEIJOS COLONIAL E PRATO, COMERCIALIZADOS NA CIDADE DE MEDIANEIRA - PR

The present study relate the hygienic and sanitary quality of Colonial and Prato cheeses, commercialized in supermarkets and free markets of Medianeira-PR. Microbiological (Salmonella sp., total and thermo-tolerant coliforms and Staphylococci coagulase-positive), physical-chemical (determination of fat, moisture and fat content on dry extract) and microscopic analyses were conducted in eight samples of Colonial cheese and eight samples of Prato cheese in two separate batches. According to the results, 50% of Colonial cheese samples were in disagreement with the current legislation for thermotolerant coliforms and 12.5% of samples showed Staphylococci coagulase-positive above the standards. Samples of Prato cheese showed heterogeneity among them and were in disagreement with the standard of identity. Colonial cheese presented a large amount of dirtiness, probabily due to the characteristics of the raw material and inadequate processing. O presente trabalho relaciona a qualidade higiênica e sanitária dos queijos Colonial e Prato, comercializados em supermercados e feiras livres da cidade de Medianeira-PR. Foram realizadas análises microbiológicas (Pesquisa de Salmonella sp., contagem de coliformes totais e termotolerantes, contagem de Estafilococos coagulase positiva), físico-químicas (determinação de gordura, umidade e teor de gordura no extrato seco) e microscópicas em oito amostras de queijo Colonial e oito amostras de queijo Prato, em dois lotes distintos. De acordo com os resultados obtidos, 50% das amostras de queijo Colonial encontraram-se m desacordo com a legislação vigente para contagem de Coliformes termotolerantes e 12,5% das amostras estavam contaminadas com Estafilococos coagulase positiva. As amostras de queijo Prato apresentaram heterogeneidade entre si, logo, encontravam-se em desacordo com o padrão de identidade. Em relação às análises microscópicas, o queijo colonial apresentou uma elevada quantidade de sujidades, decorrentes das características da matéria-prima e do processamento inadequado.