ABSTRACT
Proteins can be an excellent byproduct of the biorefining of lignocellulosic materials. In this work, extraction conditions for the white leaf proteins (cytoplasmic) of ammonia-treated dwarf elephant grass were established to obtain a protein juice suitable for the production of leaf protein concentrates. A calcium hydroxide solution was used as extracting agent, at several solid-liquid ratios, pHs, temperatures, and times. Extractions were carried out in Erlenmeyer flasks containing 5 g (dry basis) of forage with constant agitation (100 rpm). The soluble protein content was determined by the Lowry method. Optimal extraction conditions for the ammonia-treated forage were 12.60 pH, 1:10 solid-liquid ratio, 90 degrees C, and 30 min extraction time, resulting in 52.65% extraction yield. The ammonia treatment significantly increased (p<0.05) the release of proteins from the fibrous matrix, facilitating their extraction.
Subject(s)
Ammonia/chemistry , Chemical Fractionation/methods , Pennisetum/chemistry , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Plant Leaves/chemistry , Plant Proteins/chemistry , Plant Proteins/isolation & purification , Hydrogen-Ion Concentration , TemperatureABSTRACT
Desde tiempos muy remotos a la miel se ha reconocido propiedades antibacterianas y terapéuticas, siendo utilizada en el tratamiento de quemaduras y afecciones respiratorias entre otras. El presente trabajo consistió en evaluar la actividad antibacteriana de miel de abejas procedentes de cuatro zonas apícolas del estado Zulia: Agronomía, La Rinconada, Mara y Caja Seca durante la época seca (ES): noviembre-abril y lluviosa (EII): mayo-octubre. Se analizó una muestra representativa de 20 panales de miel por zona, llevando a cabo diluciones de 50 a 5 por ciento de concentración utilizando como diluyente agua destilada estéril. Las muestras fueron analizadas por triplicado utilizando cepas patógenas indicadoras de Staphylococcus aureus Pseudomonas aeruginosa, Echerichia coli, Bacillus subtilis, Listeria monocytogenes y Proteus mirabilis en concentraciones de 1x10 elevado a la 6 ufc/ml y utilizando la técnica de difución agar. La actividad antibacteriana fue elevada como halos de inhibición medidos en milímetros. Los resultados obtenidos revelaron que la miel de abejas procedente de las cuatro zonas del estado Zulia, mostraron actividad antibacterina del tipo bacteriostático contra las cepas bacterianas analizadas. La dilución de las muestras de la miel contribuyó a disminuir el efecto antibacteriano de manera independiente de la zona, época y concentración
Subject(s)
Agar , Diffusion , Honey , Food Technology , VenezuelaABSTRACT
Xylanase production of Trichoderma reesei Rut C-30 was examined at different initial pH values (4.8, 5.9, and 7.0) on rice straw in shake flasks, and in a fermentor, for the best pH condition. Enzyme performance was tested on ammonia-treated dwarf elephant grass. The maximum xylanase activities, 92 and 122 IU/mL, were obtained at pH 4.8 in the shake flasks and fermentor, respectively, in which good growth of the fungus was observed during the first 24 h and consumption of proteins dissolved from the rice straw caused the pH to rise later to values between 6.4 and 6.7 (optimal for xylanase production). The xylanases from T. reesei were as effective as Multifect XL, a commercial enzyme preparation, in hydrolyzing ammonia-treated elephant grass.
