Eficiência da pasteurização lenta do leite de cabra em diferentes binômios tempo/temperatura / Efficiency of slow pasteurization of goat milk in the different time/temperature binomials

O presente estudo analisou um binômio de tempo-temperatura alternativo para ser utilizado na pasteurização lenta sobre a inativação da fosfatase alcalina no leite caprino. Sua eficiência foi demonstrada pela contagem padrão em placas, e foi feita a comparação no processamento de leite refrigerado e congelado. Foram utilizados 18 tratamentos em leite caprino cru (nove em leite refrigerado e nove em leite congelado). Estes foram acondicionados em frascos de 300 mL, pasteurizados a 60, 63 e 65°C durante 10-20-30 minutos, e testadas às enzimas fosfatase alcalina e peroxidase. A contagem padrão em placas (CPP) e coliformes a 35 e 45°C foi feita nas amostras cruas e em cada tratamento, em duplicata. Após a pasteurização, todos os tratamentos apresentaram: não crescimento de microrganismos mesófilos, coliformes com <0,3 NMP/mL, prova de fosfatase negativa e peroxidase positiva. A pasteurização foi eficiente para melhorar a qualidade microbiológica do leite tanto refrigerado quanto congelado. Todos os binômios avaliados apresentaram resultados satisfatórios para alcançar os parâmetros preconizados em legislação, sugerindo-se o menor binômio (60°C por 10 min). Não houve diferença entre as formas de armazenamento das amostras: refrigerada ou congelada. (AU)

The objective of this study was to investigate an alternative time-temperature binomial to be used in the slow pasteurization on the alkaline phosphatase inactivation in the goat milk. Its efficiency was demonstrated with the standard counting in plates, and also refrigerated and the frozen milks processing were compared. Eighteen treatments were used in the raw goat milk (nine refrigerated milk and nine frozen milk). They were packed in 300 mL-flasks, pasteurized at 60-63-65°C for 10, 20, 30 minutes, and then tested for alkaline phosphatase and peroxidase enzymes. The standard counts in plates (CPP) and coliforms at 35°C and 45°C were performed in the raw samples and in the every treatment, in duplicate. After the pasteurization process, all of the treatments showed: no growth of mesophilic microorganisms, coliforms with <0.3 MPN / mL, negative phosphatase and positive peroxidase tests. The pasteurization was efficient to improve the microbiological quality of the milk either refrigerated or frozen. All of the evaluated binomials presented satisfactory results to reach the recommended parameters preconized in the legislation, suggesting the smaller binomial (60°C for 10 min). There was no difference between the samples storage form, either refrigerated or frozen. (AU)

Eficiência da pasteurização lenta do leite de cabra em diferentes binômios tempo/temperatura / Efficiency of slow pasteurization of goat milk in the different time/temperature binomials

O presente estudo analisou um binômio de tempo-temperatura alternativo para ser utilizado na pasteurização lenta sobre a inativação da fosfatase alcalina no leite caprino. Sua eficiência foi demonstrada pela contagem padrão em placas, e foi feita a comparação no processamento de leite refrigerado e congelado. Foram utilizados 18 tratamentos em leite caprino cru (nove em leite refrigerado e nove em leite congelado). Estes foram acondicionados em frascos de 300 mL, pasteurizados a 60, 63 e 65°C durante 10-20-30 minutos, e testadas às enzimas fosfatase alcalina e peroxidase. A contagem padrão em placas (CPP) e coliformes a 35 e 45°C foi feita nas amostras cruas e em cada tratamento, em duplicata. Após a pasteurização, todos os tratamentos apresentaram: não crescimento de microrganismos mesófilos, coliformes com <0,3 NMP/mL, prova de fosfatase negativa e peroxidase positiva. A pasteurização foi eficiente para melhorar a qualidade microbiológica do leite tanto refrigerado quanto congelado. Todos os binômios avaliados apresentaram resultados satisfatórios para alcançar os parâmetros preconizados em legislação, sugerindo-se o menor binômio (60°C por 10 min). Não houve diferença entre as formas de armazenamento das amostras: refrigerada ou congelada.

The objective of this study was to investigate an alternative time-temperature binomial to be used in the slow pasteurization on the alkaline phosphatase inactivation in the goat milk. Its efficiency was demonstrated with the standard counting in plates, and also refrigerated and the frozen milks processing were compared. Eighteen treatments were used in the raw goat milk (nine refrigerated milk and nine frozen milk). They were packed in 300 mL-flasks, pasteurized at 60-63-65°C for 10, 20, 30 minutes, and then tested for alkaline phosphatase and peroxidase enzymes. The standard counts in plates (CPP) and coliforms at 35°C and 45°C were performed in the raw samples and in the every treatment, in duplicate. After the pasteurization process, all of the treatments showed: no growth of mesophilic microorganisms, coliforms with <0.3 MPN / mL, negative phosphatase and positive peroxidase tests. The pasteurization was efficient to improve the microbiological quality of the milk either refrigerated or frozen. All of the evaluated binomials presented satisfactory results to reach the recommended parameters preconized in the legislation, suggesting the smaller binomial (60°C for 10 min). There was no difference between the samples storage form, either refrigerated or frozen.

Effect of hyperbaric oxygenation on the expression of glutathione peroxidase 4 and lactoperoxidase genes in the lung of isogenic mice after ischemia/reperfusion injury in the small bowel

Abstract Purpose: To evaluate the effect of hyperbaric oxygenation (HBO) on the expression of the genes antioxidant glutathione peroxidase 4 (Gpx4) and lactoperoxidase (Lpo) in the lung of mice subjected to intestinal ischemia and reperfusion (IIR). Methods: Control group (CG) in which were subjected to anesthesia, laparotomy and observation for 120 minutes; an ischemia and reperfusion group (IRG) subjected to anesthesia, laparotomy, small bowel ischemia for 60 minutes and reperfusion for 60 minutes; and three groups treated with HBO during ischemia (HBOG + I), during reperfusion (HBOG + R) and during ischemia and reperfusion (HBOG + IR). Studied 84 genes of oxidative stress by the method (RT-qPCR). Genes with expression levels three times below or above the threshold cycle were considered significantly hypoexpressed or hyperexpressed, respectively (Student's t-test p<0.05). Results: Gpx4 and Lpo were hiperexpressed on IRG, showing a correlation with these genes with lung oxidative stress. Treated with HBO, there was a significant reduction on genic expression on HBOG+I. Conclusion: Hyperbaric oxygenation showed to be associated with decreased expression of these antioxidant genes, suggesting a beneficial effect on the mechanism of pulmonary oxidative stress whenever applied during the ischemia.

In vitro study of the effect of a lactoperoxidase-peroxidase-thiocyanate system with iodine on the cariogenicinity of streptococcus mutans / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study aimed to investigate the effect of a lactoperoxidase-peroxidase-thiocyanate (LPO-H2O-SCN-) system with different concentrations of iodine (I-) on Streptococcus mutans (S. mutans), particularly on various parameters, including growth, adhesion, glucosyltransferase (GTF) enzyme activity, and insoluble exopolysaccharide synthesis.</p><p><b>METHODS</b>S. mutans ATCC 25175 was used as experimental species. Clonal formation unit (CFU) were counted to investigate the inhibitory effect on bacterial growth. The inhibition rate of bacterial adherence was calculated to analyze the effect on adhesion. Anthrone method was used to determine the content of insoluble exopolysaccharides and the amount of reducing saccharides. GTF activity and enzyme activity were then determined.</p><p><b>RESULTS</b>The inhibitory ability of the LPO-H2O2-SCN- system with I- on the cariogenicinity of S. mutans was strengthened as I- concentration was increased. At I- concentration > or = 100 micromol x L(-1) the antibacterial effects were significantly increased compared with those of the control group (P < 0.05). At I- concentration > or = 1,000 micromol x L(-1), the antibacterial effects were significantly improved compared with those of the group with SCN-only (P < 0.05). At I- concentration > or = 100 micromol x L(-1), the inhibition rate of bacterial adherence was > 50%; insoluble exopolysaccharide synthesis and GTF enzyme activity were reduced (P < 0.05).</p><p><b>CONCLUSION</b>The antibacterial effects of the LPO-H2O2-I- system were enhanced by adding I- to overcome the antagonistic effect of physiological SCN- concentration. LPO-H2O2-SCN- system with different concentrations of I- showed statistically significant inhibitory effects on growth, adhesion, insoluble exopolysaccharide synthesis, and GTF enzyme activity.</p>

The covalent binding of genistein to the non-prosthetic-heme-moiety of bovine lactoperoxidase leads to enzymatic inactivation / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>Genistein, a major soy isoflavone metabolite (SIF), inactivates oxidation activity of bovine lactoperoxidase (LPO). Modification of the heme moiety of LPO by nitrogen-containing compounds has been shown to inactivate LPO. In contrast, SIF mediated inactivation of LPO does not involve a heme modification and the mechanism of SIF inhibition is poorly understood.</p><p><b>METHODS</b>After inactivation of LPO by genistein in the presence of H(2)O(2), trypsin-digested LPO peptide fragments were collected and analyzed by MALDI-TOF-MS to characterize the chemical binding of genistein(s) to LPO.</p><p><b>RESULTS</b>The heme moiety of LPO was not modified by genistein. A covalent binding study showed that (3)H-genistein bound to LPO with a ratio of ∼12 to 1. After HPLC analysis and peak collection, trypsin-digested peptide fragments were analyzed by MALDI-TOF-MS. The 3H-genistein co-eluted peptide fragments (RT=24 min) were putatively identified as 199IVGYLDEEGVLDQNR214 with two bound genistein molecules or a genistein dimer (2 259 Da), 486TPDNIDIWIGGNAEPMVER504 with two bound genistein molecules or a genistein dimer (2 663 Da), and 161ARWLPAEYEDGLALPFGWTQR182 with three bound genistein molecules or a genistein trimer (3 060 Da). The fragment with a mass of 1 792 Da (RT=36 min) was identified as 132CDENSPYR139 with three genistein molecules or a genistein trimer.</p><p><b>CONCLUSIONS</b>The results suggest that LPO was inactivated by irreversible covalent binding of genistein or genistein polymers to particular peptide fragments constituting regions of the outward domain. No genistein interaction with the prosthetic heme moiety of LPO was observed.</p>

Características físico-químicas do leite de cabra comercializado no estado da Paraíba, Brasil / Physic-chemical characteristics of goat milk marketed in Paraiba state, Brazil

O presente trabalho teve como objetivo avaliar as características físico-químicas do leite de cabra integral e pasteurizado comercializado no estado da Paraíba. O total de 24 amostras de leite de seis marcas produtoras foi coletado de estabelecimentos comerciais da cidade de João Pessoa (PB), em diferentes períodos. Entre as amostras de leite das seis marcas comerciais, as amostras de cinco marcas apresentaram-se fora dos padrões estabelecidos pela legislação vigente. Não houve diferenças significativas apenas para as variáveis lactose e cinzas entre as marcas comerciais analisadas (P>0,05). Os parâmetros com maior variação foram lipídios (1,67 a 3,57%) e sólidos não gordurosos (7,61 a 10,01%). Adicionalmente, foi detectada a atividade da lactoperoxidase em apenas 66,66% das amostras analisadas, e somente três marcas apresentaram 100% das amostras de leite positivas para essa enzima. Por outro lado, as três demais marcas apresentaram 75, 25 e 0% de amostras positivas para lactoperoxidase. Há, portanto, necessidade de adequação do processamento do leite de cabra produzido no estado da Paraíba, principalmente no que se refere à pasteurização, para que o alimento atinja os padrões requeridos pela legislação. A maior homogeneidade do leite de cabra quanto às suas propriedades fisico-químicas é fundamental para garantir aceitabilidade do produto por uma classe consumidora cada vez mais exigente e promover a expansão da caprinocultura leiteira do estado da Paraíba.

The present study aimed to evaluate the physic-chemical characteristics of integral and pasteurized goat milk marketed in Paraiba state, Brazil. Goat milk samples (n=24) from six diverse trade brands were obtained from commercial establishments located in João Pessoa, Paraiba, Brazil at different periods. Five milk brands presented milk samples which were not in accordance to the Brazilian legislation quality standards. All variables, except lactose and ashes (P>0.05), were significantly different among the analyzed trade marks. The parameters with highest variation were fat (1.67 to 3.57%) and non-fat solids (7.61 to 10.01%). Lactoperoxidase activity was adequate in 66.66% of analyzed samples only; and three commercial milk brands only showed 100% of positive samples for this enzyme. On the other hand, the other three brands showed positive enzyme activity in 25%, 0%, and 75% of analyzed samples, respectively. Therefore, the goat milk processing in Paraiba must be adjusted, focusing mainly to pasteurisation procedure, so that the standards recommended by legislation were attained. The most homogeneity of goat milk produced in Paraiba concerning its physic-chemical properties is crucial to increase the acceptability of this product by consumers, who are more and more demanding, and for promoting the goat milk production expanding in the Paraiba state.

Evaluación de un activador del sistema lactoperoxidasa en leche sin refrigerar recolectada de pequeños productores / Evaluation of an of lacto-peroxidase system activator in milk without refrigeration on small dairy farms

La investigación se realizó en el Centro de Acopio Lechero del sector Mune Alto, comuna de Pitrufquén, IX región, Chile. Los objetivos de éste estudio fueron evaluar el efecto de la aplicación de un activador del Sistema Lactoperoxidasa compuesto por 700 tiocin de sodio y 1,7 grs de percarbonato de sodio. (Sistema LP), sobre el crecimiento bacteriano en leche entregada por los pequeños productores asociados al Centro de Acopio y mantenida a temperaturas ambientales durante la época de verano por 12 y 15 horas; evaluar la reactivación del sistema lactoperoxidasa luego de 8 horas y evaluar el activador del sistema lactoperoxidasa, bajo las condiciones de calidad higiénica exigidas por la industria lechera en Chile. Para evaluar el efecto del activador del Sistema LP, se seleccionaron al azar dos tarros de leche fresca recién ordeñadas de 50 litros cada uno. Una vez homogenizado su contenido, esta mezcla se dividió nuevamente en dos tarros de 50 litros, que conformaron la leche cruda (LC), sin aplicación del activador y la leche tratada (LT), con aplicación del activador, procedimiento que se repitió en nueve oportunidades. Para evaluar el efecto de la reactivación del Sistema LP, se utilizó el mismo procedimiento anterior, homogenizando la leche de tres tarros, conformando la LC, sin aplicación del activador; la LT1, con aplicación del activador; y la LT2, con aplicación del activador y una segunda dosis de percarbonato de sodio a las 8 horas de almacenamiento. De todos los tarros de leche se obtuvieron muestras, a los distintos tiempos determinados para el estudio, Las cuales fueron sometidas a análisis de recuentos bacterianos, presencia de inhibidores y peróxidos. Los resultados obtenidos muestran diferencias estadísticamente significativas (P<0,05) en el incremento de recuentos bacterianos entre la LC y LT al cabo de 12 horas de almacenamiento de la leche fresca a temperatura ambiente. La reactivación del Sistema LP, no muestra diferencias estadísticas significativas en el desarrollo de las cargas bacterianas entre el LT1 y LT2 (P>0,05) a las 15 horas de almacenamiento de la leche fresca a temperatura ambiente, pero sí entre estos dos y el LC (P>0,05)

Oxidation of phenols by horseradish peroxidase and lactoperoxidase compound II--kinetic considerations.

Oxidation of para substituted phenols by horseradish peroxidase compound II (HRP-II) and lactoperoxidase compound II (LPO-II) were studied using stopped flow technique. Apparent second order rate constants (kapp) of the reactions were determined. The kinetics of oxidation of phenols by HRP-II and LPO-II have been compared with the oxidation potentials of the substrates. Reorganization energies of electron-transfer of phenols to the enzymes were estimated from the variation of second order rate constants with the thermodynamic driving force.

Antibacterial property of goat milk lactoperoxidase.

The goat milk lactoperoxidase was purified using CM sephadex C-50 and sephadex G 100. The purity of protein was confirmed by SDS-PAGE. The purified protein was found to have antibacterial action against most of the disease causing bacteria.

Comparative analysis of surface components of adult, micro-filariae and infective larvae of Brugia malayi.

A comparative analysis of surface proteins of adult, microfilariae and infective larvae of Brugia malayi, the human filarial parasite, has been carried out using IODOGEN (1,3,4,6-tetrachloro-3,alpha 6 alpha-diphenyl-glycoluril) and lactoperoxidase methods. SDS-polyacrylamide gel electrophoretic and autoradiographic analyses revealed the presence of 9 proteins (15-200 kDa) in adults, while microfilariae and infective larvae showed 8 and 6 proteins (15-120 kDa), respectively. The pattern of proteins radiolabelled by IODOGEN method was very similar to that of proteins labelled by the lactoperoxidase method. Since these proteins are released by the protease treatment of whole parasites, they are likely to be present on the surface of the parasite.

Potentialization of the lactoperoxidase system for preservation of raw milk in the tropics

Se aumentó la capacidad antimicrobiana del sistema lactoperoxidas, mediante la adición de tiocianato y peróxido de hidrógeno en cantidades mayores a las sugeridas por otros autores. Los resultados de laboratorio y las pruebas de campo revelaron que por otros autoes. Los resultados de laboratorio y las pruebas de campo revelaron que el sistema potencializado pudo preservar leches de baja calidad microbiológica, a temperaturas "tropicales" por períodos más largos que al usarlo como se recomienda en la literatura. Se pudo conservar leches a 20-C por más de un día, sin menoscabo de su calidad general. A 36-C, las leches no acusaron desarrollo de acidez durante el término de 10 horas. Las pruebas realizadas en condiciones reales de recolección y transporte validaron los resultados de laboratorio. Se logró así probar que el sistema lactoperoxidasa es viable de uso en la práctica, y que su poder bactericida/bacteriostático sobre la flora deterioradora de la leche puede aumentarse a fin de superar las condiciones especialmente adversas que involucra el menejo de la leche en los trópicos