Submitted by Mario BC (mario@bc.ufrpe.br) on 2018-07-30T13:51:47Z No. of bitstreams: 1 Augusto Cesar Magalhaes Nunes.pdf: 862061 bytes, checksum: 6af3304ef2c60d8d94369d83d95df667 (MD5) / Made available in DSpace on 2018-07-30T13:51:47Z (GMT). No. of bitstreams: 1 Augusto Cesar Magalhaes Nunes.pdf: 862061 bytes, checksum: 6af3304ef2c60d8d94369d83d95df667 (MD5) Previous issue date: 2015-09-04 / The production chain goat milk in Brazil is one of the sectors with growth potential for the economy. The Northeast region stands out in the production of goat's milk, placing the country as the largest producer in South America. However, places socioeconomic conditions are an obstacle for animal husbandry and treatment of milk, causing a decrease in the quality and validity term commercial goat milk and its derivatives, which causes economic losses and offers risk to the consumer. In this context, the use of the activation of the lactoperoxidase system (SLP) to inhibit the growth of pathogenic and spoilage bacteria is presented as an efficient alternative for improving the quality of goat milk and production of derivatives such as cheese curd. The objective of this study was to evaluate the influence of SLP activation in quality and validity commercial cheese curd of goat milk. Comparisons were made through the physical, chemical and microbiological analyzes of the curd cheese from goat's milk produced from raw and pasteurized goat milk, with and without activation of SLP and submitted after manufacturing and storage at room temperature and refrigeration. It was observed that the SLP activation presented significant effect (p> 0.05) in reducing the population of aerobic mesophilic bacteria, psychotropic bacteria, Staphylococcus positive coagulase and total coliform, compared to treatments where the SLP has not been activated. Therefore, these results confirm that the SLP activation in goat milk immediately after milking, is an important alternative to maintain the quality of the raw material in the absence of refrigeration for processing and association SLP pasteurization and cold storage enhances the quality of the cheese curd, extending the period of validity of the commercial product. / A cadeia produtiva do leite de cabra no Brasil é um dos setores com potencial de crescimento para a economia do país. A região Nordeste se destaca na produção de leite de cabra, colocando o país como maior produtor da América do Sul. Entretanto, as condições socioeconômicas locais constituem um obstáculo para o manejo animal e tratamento adequado do leite, causando a diminuição da qualidade e do prazo de validade comercial do leite de cabra e seus derivados, o que ocasiona perdas econômicas e oferece risco ao consumidor. Nesse contexto, a utilização da ativação do sistema lactoperoxidase (SLP) como inibidor do crescimento de bactérias patogênicas e deteriorantes apresenta-se como uma eficiente alternativa na melhoria da qualidade do leite de cabra e na produção de seus derivados, como o queijo de coalho. O objetivo desse estudo foi avaliar a influência da ativação do SLP na qualidade e prazo de validade comercial do queijo de coalho de leite de cabra. Foram feitas comparações através das análises físico-químicas e microbiológicas entre os queijos de coalho de leite de cabra produzidos a partir do leite de cabra cru e pasteurizado, com e sem a ativação do SLP e submetidos após a fabricação e ao armazenamento em temperatura ambiente e refrigeração. Observou-se que a ativação do SLP apresentou efeito significativo (p > 0,05) na redução da população das bactérias mesófilas aeróbias, bactérias psicrotróficas, Staphylococcus coagulase positivo e coliforme totais, comparado aos tratamentos onde o SLP não foi ativado. Portanto, os resultados obtidos confirmam que a ativação do SLP no leite de cabra, logo após a ordenha, é uma importante alternativa para manter a qualidade da matéria-prima na ausência da refrigeração até o processamento, e a associação do SLP à pasteurização e ao armazenamento refrigerado melhora a qualidade do queijo de coalho, estendendo o prazo de validade comercial do produto.

In our organism, mucous surfaces are important boundaries against the environmental milieu with defined fluxes of metabolites through these surfaces and specific rules for defense reactions. Major mucous surfaces are formed by epithelia of the respiratory system and the digestive tract. The heme peroxidases lactoperoxidase (LPO), myeloperoxidase (MPO), and eosinophil peroxidase (EPO) contribute to immune protection at epithelial surfaces and in secretions. Whereas LPO is secreted from epithelial cells and maintains microbes in surface linings on low level, MPO and EPO are released from recruited neutrophils and eosinophils, respectively, at inflamed mucous surfaces. Activated heme peroxidases are able to oxidize (pseudo)halides to hypohalous acids and hypothiocyanite. These products are involved in the defense against pathogens, but can also contribute to cell and tissue damage under pathological conditions. This review highlights the beneficial and harmful functions of LPO, MPO, and EPO at unperturbed and inflamed mucous surfaces. Among the disorders, special attention is directed to cystic fibrosis and allergic reactions.

Background: The heme enzyme lactoperoxidase is found in body secretions where it significantly contributes to the humoral immune response against pathogens. After activation the peroxidase oxidizes thiocyanate to hypothiocyanite which is known for its microbicidal properties. Yet several pathologies are accompanied by a disturbed hypothiocyanite production which results in a reduced immune defense. Methods: The results were obtained by measuring enzyme-kinetic parameters using UV–vis spectroscopy and a standardized enzyme-kinetic test system as well as by the determination of second order rate constants using stopped-flow spectroscopy. Results: In this study we systematically tested thirty aromatic substrates for their efficiency to promote the lactoperoxidase-mediated hypothiocyanite production by restoring the native ferric enzyme state. Thereby hydrophobic compounds with a 3,4-dihydroxyphenyl partial structure such ashydroxytyrosol and selected flavonoids emerged as highly efficient promotors of the (pseudo-)halogenating lactoperoxidase activity. Conclusions: This study discusses important structure-function relationships of efficient aromatic LPO substrates and may contribute to the development of new agents to promote lactoperoxidase activity in secretory fluids of patients. Significance: This study may contribute to a better understanding of the (patho-)physiological importance of the (pseudo-)halogenating lactoperoxidase activity. The presented results may in future lead to the development of new therapeutic strategies which, by reactivating lactoperoxidase-derived hypothiocyanite production, promote the immunological activity of this enzyme.

Mammalian heme peroxidases are fascinating due to their unique peculiarity of oxidizing (pseudo)halides under physiologically relevant conditions. These proteins are able either to incorporate oxidized halides into substrates adjacent to the active site or to generate different oxidized (pseudo)halogenated species, which can take part in multiple (pseudo)halogenation and oxidation reactions with cell and tissue constituents. The present article reviews basic biochemical and redox mechanisms of (pseudo)halogenation activity as well as the physiological role of heme peroxidases. Thyroid peroxidase and peroxidasin are key enzymes for thyroid hormone synthesis and the formation of functional cross-links in collagen IV during basement membrane formation. Special attention is directed to the properties, enzymatic mechanisms, and resulting (pseudo)halogenated products of the immunologically relevant proteins such as myeloperoxidase, eosinophil peroxidase, and lactoperoxidase. The potential role of the (pseudo)halogenated products (hypochlorous acid, hypobromous acid, hypothiocyanite, and cyanate) of these three heme peroxidases is further discussed