Caracterização de hambúrguer elaborado com farinha de folhas de Moringa (Moringa oleífera Lam. ) / Characterization of beef burger made with Moringa (Moringa oleífera Lam. ) leaves flour

The aim of this study was to determine the antioxidant activity of Moringa (Moringa oleifera Lam.) leaves flour in beef burger during storage for 120 days. Six hamburger formulations were processed: one control (without the use of additives), four with addition of Moringa leaves flour (0.10, 0.15, 0.20, and 0.25 g/100 g aggregate), and one with addition of synthetic antioxidant Propyl Gallate (0.01 g/100 g aggregate). The products were analyzed for their chemical composition with determinations of moisture, protein, dietary fiber, lipids, ash, carbohydrate, and caloric value after preparation. Microbiological and acceptance testing were performed at the beginning and after 120 days of storage. Determination of pH, instrumental color and lipid oxidation (TBARS) were performed at 1, 30, 60, 90 and 120 days of storage. All samples showed physical-chemical and microbiological tests in accordance with the Brazilian legislation. pH measurements were between 5.48 and 5.90; however, the intensity of red has changed according to the treatments and storage periods. The addition of Moringa leaves flour had no antioxidant effect on burgers, but its inclusion not only contributed to the improvement of nutritional quality, but also did not harm product acceptance.

El objetivo de este trabajo fue verificar la acción antioxidante de una harina de hojas de Moringa (Moringa oleífera Lam.) en carne de hamburguesa bovina durante su almacenamiento por 120 días. Se procesaron seis formulaciones de hamburguesa: una de control, sin uso de aditivos, cuatro adicionadas con harina de hojas de Moringa (0,10; 0,15; 0,20 y 0,25 g/100 g de masa) y una adicionada con antioxidante sintético Propil Galato (0,01 g/100 g de masa). Los productos se analizaron, en cuanto a su composición química, con determinaciones de humedad, proteína, fibra alimentaria, lípidos, cenizas, carbohidratos y valor calórico, y, tras la preparación, análisis microbiológicos y pruebas de aceptación, realizados tanto al inicio como al cabo de 120 días de almacenamiento. También se analizaron, con determinación de pH, Color instrumental y oxidación lipídica (TBARS), a los 1, 30, 60, 90 y 120 días de almacenamiento, respectivamente. Todas las muestras presentaron características físico-químicas y microbiológicas de acuerdo con la legislación nacional vigente. Los valores de pH oscilaron entre 5,48 y 5,90 y solamente la intensidad del rojo sufrió modificaciones debido a los tratamientos y periodos de almacenamiento. La adición de harina de hojas de Moringa no ejerció efecto antioxidante en las hamburguesas, sin embargo su inclusión contribuyó para mejorar la calidad nutricional y no perjudicó la aceptación del producto.

O objetivo deste trabalho foi verificar a ação antioxidante de uma farinha de folhas de Moringa (Moringa oleífera Lam.) em produto hambúrguer bovino durante estocagem por 120 dias. Foram processadas seis formulações de hambúrguer, sendo uma controle, sem o uso de aditivos, quatro adicionadas de farinha de folhas de Moringa (0,10; 0,15; 0,20 e 0,25 g/100 g de massa) e uma com adição de antioxidante sintético Propil Galato (0,01 g/100 g de massa). Os produtos foram analisados quanto à composição química, com determinações de umidade, pro¬teína, fibra alimentar, lipídeos, cinzas, carboidratos e valor calórico após o preparo, além de análises microbiológicas e teste de aceitação realizados no início e aos 120 dias de armazenamento, e determinação de pH, cor instrumental e oxidação lipídica (TBARS), realizadas com: 1, 30, 60, 90 e 120 dias de armazenamento. Todas as amostras apresentaram características físico-químicas e microbiológicas de acordo com a legislação nacional vigente. As medidas de pH ficaram compreendidas entre 5,48 e 5,90, e somente a intensidade de vermelho sofreu alterações de acordo com os tratamentos e períodos de estocagem. A adição de farinha das folhas de Moringa não exerceu efeito antioxidante nos hambúrgueres, porém sua inclusão contribuiu para a melhoria da qualidade nutricional e não prejudicou a aceitação do produto.

Some Biochemical properties of polyphenoloxidase from spearmint (Mentha arvensis)

Polyphenoloxidase (PPO; EC 1.14.18.1) extracted from Mentha arvensis leaves was isolated by (NH4)2SO4 precipitation and extensive dialysis. Its optimum pH and temperature varied with the substrate. The PPO showed activity with various diphenols. Km values were found 0.825, 0.928 and 7.41mM for caffeic acid, 4-methylcatechol and catechol, respectively. On heat-inactivation, half of the activity was lost after 60 and 15 sec at 70 and 75ºC, respectively. Measuring of residual activity showed a stabilizing effect of sucrose at various temperatures with activation energy (Ea) for inactivation increasing with sucrose concentration from 0 to 40 percent (w/w). Ea values of 78.13; 80.37; 82.79 and 81.00 kJ/Mol were found for 0, 15; 30 and 40 percent sucrose, respectively. PPO was inhibited by ascorbic, benzoic, cinnamic, ferulic, p-coumaric, protocatechuich acids, sodium metabisulfite, pyrogallol and resorcinol. The Ki values showed that ascorbic acid was the most effective inhibitor. The type inhibition was determined for each inhibitor.

Polifenoloxidase (PPO, EC 1.14.18.1) extraída de folhas de Mentha arvensis foi isolada por precipitação com (NH4)2SO4 e diálise extensiva. Seu pH e temperatura ótimos variaram com o substrato. A PPO apresentou atividade com vários difenóis. Valores de Km foram 0,825; 0,928 e 7,41 mM para ácido caféico, 4-metilcatecol e catecol, respectivamente. Na inativação térmica, 50 por cento da enzima foi inativada após 60 e 15 segundos a 70 e 75ºC, respectivamente. A medida de atividade residual mostrou um efeito estabilizante de sacarose a várias temperaturas e uma energia de ativação (Ea) para inativação aumentando com a concentração de sacarose de 0 a 40 por cento (p/p). Valores de energias de ativação de 78,13; 80,37; 82,79 and 81,00 kJ/Mol foram encontradas para 0, 15, 30 e 40 por cento de sacarose, respectivamente. A PPO foi inibida pelos ácidos ascórbico, benzóico, cinamico, ferulico, p-cumárico, protocatéquico, além de metabisulfito de sódio, resorcinol e pirogalol. Os valores de Ki mostram que o ácido ascórbico foi o mais efetivo inibidor. O tipo de inibição foi determinado para cada inibidor.

Changes in protein fractions, trypsin inhibitor and proteolytic activity in the cotyledons of germinating chickpea

The chickpea seed germination was carried out in 6 days. During the period it was observed a little variation on total nitrogen contents, however the non protein nitrogen was double. A decrease of 19.1 and 20.6 in relation to total nitrogen was observed to the total globulin and albumin fractions, respectively. The gel filtration chromatography on Sepharose CL-6B and SDS-PAGE demonstrated alterations on the distribution patterns of the albumin and total globulin fractions between the initial and the sixth day of germination suggesting the occurrence of protein degradation in the germination process. The assay for acid protease only appeared in the albumin fraction with casein and chickpea total globulin as substrates, whereas the former was more degraded than the latter, however the transformations detected in the protein fractions appear indicated that others enzymes could be acting during the process. The trypsin inhibitor activity had a little drop after six day of germination indicating a possible increase on the digestibility of the proteins.

Peroxidase from peach fruit: thermal stability

Peroxidase from peach fruit was purified 28.9 fold by DEAE-cellulose, Sephadex G-100 and hydroxylapatite chromatography. The purified enzyme showed only one peak of activity with an optimum pH of 5.0 and temperature of 40§C. The calculated activation energy (Ea) for the reaction was 7.97 kcal/mol. The enzyme was heat-labile in the temperature range of 60 to 80§C with a fast inactivation at 80§C. PAGE of the inactivation course at 70§C showed only one band of activity. Different sugars increased the heat stability of the activity in the following order: sucrose>glucose>fructose. Measurement of residual activity showed a stabilizing effect of sucrose at various temperature/sugar concentrations (10 to 40 per cent, w/w) with the Ea for inactivation with sucrose concentration from 0 to 20 per cent (w/w). After inactivation at 70§C the enzyme was able to be reactivated by up to 40 per cent of the initial activity when stored at 30§C