Resumo Estudaram-se as melhores condições de hidrólise da sacarose in vitro a partir da invertase de Candida guilliermondii (ICg), também se determinou os parâmetros cinéticos KM, Vmax e a estabilidade térmica da ICg. A levedura Candida guilliermondii (Cg) extraída, isolada e liofilizada de resíduo de pêssego foi identificada usando o método API 20C AUX. Posteriormente, a levedura Cg foi submetida a um processo de autólise, usando NaHCO3 a 200 mM sob agitação a 200 rpm e 40°C, por período de 24 horas. Os extratos enzimáticos obtidos foram recuperados por precipitação com acetona seguido de diálise e cromatografia de troca iônica. O extrato purificado por precipitação com acetona teve a atividade de 27,7 U.mg-1 e 56% de recuperação, sendo que, por cromatografia, obtiveram-se 46,5 U.mg-1 e 44,8%. As condições ótimas na hidrólise da sacarose foram pH de 5,0 e 50°C, apresentando KM de 30,5/mM e 28,7 mM de sacarose, respectivamente, a 25°C e a 50°C, ambas com comportamento Michaeliano. A inativação térmica da ICg mostrou uma cinética aparente de primeira ordem, e sua atividade residual foi tipicamente linear entre 40°C - 70°C. Por meio de eletroforese, foram detectadas três isoenzimas.

Abstract The best conditions for in vitro sucrose hydrolysis based on invertase from Candida guilliermondii (ICg) were studied and the kinetic parameters KM,Vmax, and thermal stability of ICg were determined. Candida guilliermondii (Cg) yeast isolated and lyophilized from peach solid wastes was identified using the API 20C AUX method. Subsequently, the Cg was submitted to an autolysis process using NaHCO3 at 200 mM under 200 rpm stirring and 40 °C for 24 h. The enzyme extracts obtained were recovered through precipitation with acetone followed by dialysis and ion-exchange chromatography. The extract purified through precipitation with acetone had activity of 27.7 U.mg-1 and 56% recovery whereas the chromatography process yielded 46.5 U.mg-1 and 44.8%. The optimal sucrose hydrolysis conditions were pH 5.0 and 50 °C, resulting in KM of 30.5 mM and 28.7 mM sucrose, respectively, at 25 °C and 50 °C, both with Michaelian behavior. Thermal inactivation of ICg exhibited first-order apparent kinetics and its residual activity was typically linear between 40 °C and 70 °C. Three isoenzymes were detected through electrophoresis.

Abstract The extraction was performed using an autolysis process where enzymes degrade cell structures and release the cytoplasmic contents to the extracellular medium. The autolysis process was carried out in shake flasks with different agitation speeds (50 - 350 rpm) and the concentration of sodium bicarbonate (50 -350 mM NaHCO3) at 40 ° C for 24 hours, using a central composite design adapted for two variables and five levels and response surface methodology (RSM) and canonical analysis to define the optimal conditions of extraction of invertase S. cerevisiae from peach puree (ISc). In great condition extraction, we studied the effect of the liofilization and purified in the invertase activity using colorimetric method of 3,5-dinitrosalicílico (DNS) at 490 nm to monitor their activity. One unit (U) defined as 1 mg glicose.min-1. Protein concentrations were determined by Lowry and invertase comercial yeast (ICY). The influence of concentration NaHCO3 and stirring speed to extract the enzyme invertase showed linear effect, quadratic and interactive. The polynomial model of second order could explain the extraction phenomenon of invertase with R2 of 0.80, with significantly dependent on both variables activity. The maximum extraction was observed in the experimental center point (200 mM NaHCO3 and 200 rpm) with an activity of 14.7 U.mg-1. The stationary point is a point of maximum extraction, differing by at least 10% of the experimental center point. Based on these characteristics, the optimal conditions for extraction of S. cerevisiae invertase from peach puree (ISc) are 200 mM NaHCO3 as autolysis agent, 200 rpm orbital shaking at 40ºC for 24 hours and freeze-dried using biomass. Ethanol is more effective than acetone for recovery of specific activity.

Resumen La extracción fue realizada a través de un proceso de autolisis, donde las enzimas degradan las estructuras celulares y liberan el contenido citoplasmático al medio extracelular. El proceso de autolisis fue realizado en shaker con diferentes velocidades de agitación (50 - 350 rpm) y concentraciones de bicarbonato de sodio (50 -350 mM NaHCO3) a 40 °C por 24 horas, usando un diseño experimental compuesto central adaptado para dos variables y cinco niveles, así como una metodología de superficie de respuest a (MSR) y análisis canónico para definir las condiciones óptimas de extracción de invertasa de S. cerevisiae aislada de puré de durazno (ISc). En la condición optima de extracción, se estudió el efecto de la liofilización y purificación en la actividad de la invertasa, usando el método colorimétrico del ácido 3,5-dinitrosalicílico (DNS) a 490 nm para acompañar su actividad expresada en unidades. Una unidad (U) es definida como 1 mg glucosa.min-1. El valor de proteínas fue cuantificado por el método Lowry y la invertasa de levadura comercial (ILC) como testigo. La influencia de la concentración de NaHCO3 y de la velocidad de agitación en la extracción de la enzima invertasa indicó efecto lineal, cuadrático e interactivo. El modelo de forma polinómica de segundo orden explicó el fenómeno de extracción de la invertasa con un R2 de 0,80, y con actividad significativamente dependiente de ambas variables. La máxima extracción fue observada en el punto central experimental (200 mM NaHCO3 y 200 rpm) con una actividad de 14,7 U.mg-1. El punto estacionario es un punto de máxima extracción, el cual difiere en menos de 10% del punto central experimental. De acuerdo a estas características, las óptimas condiciones para extracción de la invertasa de S. cerevisiae aislada de puré de durazno son 200 mM NaHCO3 como agente de autolisis, 200 rpm de agitación orbital a 40oC durante 24 horas y usando una biomasa de levaduras liofilizadas. El etanol es más efectivo que la acetona para la recuperación de la actividad específica.

O objetivo deste trabalho foi estudar a influência das diferentes condições de extrusão nas propriedades térmicas e reológicas de biopolímeros de glúten de trigo plastificado com glicerol. A temperatura das zonas de aquecimento da extrusora co-rotativa de parafuso duplo influi nas propriedades térmicas e reológicas dos biopolímeros. Temperaturas entre 55 ºC e 60 ºC produziram extrusados de bom aspecto e pouca rugosidade. Os extrusados apresentaram elevados valores de G’ e G’’ e a modelagem do processo de extrusão mostrou que a mudança na configuração das zonas de aquecimento influencia principalmente na localização da deformação ao longo da extrusora.

The main objective of this work was to study the influence of different extrusion conditions on thermal and rheological properties of biopolymers of wheat gluten plasticized with glycerol. The temperature of the heating zones of the extruder co-rotating twin screw influences the rheological and thermal properties of biopolymers. Temperatures between 55 ºC and 60 ºC produced extrudates with good looks and low roughness. The extrudates showed high values of G’ and G’’ and shaping the extrusion process showed that the change in configuration of the heating zones mainly influences the location of the deformation along the extruder.

The objective this work was to obtain bioplastics from mixtures of wheat gluten and glycerol by two different processes and evaluate their respective rheological properties. The mixtures and their respective bioplastics were obtained through direct batch mixing under approximately adiabatic and isothermal conditions. The bioplastics showed high values for the storage (G') and loss (G") moduli, suggesting a stronger protein network formed in both processes. The temperature onset and the percentage of weight loss to be estimated were found to be near in both bioplastics. The bioplastics have demonstrated to be materials of interesting potential of use as biodegradable barrier materials.

The aim of this work was to study the enzymatic modification on rice flour using lipase pancreatic and amyloglucosidase to obtain resistant starch. For this, Response Surface Methodology (RSM) was used to determine the best operating conditions for each enzyme. For lypase pancreatic, the highest value for resistant starch (45%) was achieved within 2 h reaction at pH 7 using an enzyme/substrate ratio of 4% (w/w) and Dp= 100/200 tyler. For amyloglucosidase, optima conditions corresponded to an enzyme/substrate ratio of 0,006 mL/g and Dp= 100/200 tyler at 45 ºC, yielding 57% of resistant starch in 2 h reaction. These results show the potential of using both enzymes to modified rice flour, increasing the resistant starch in about 5.7 folds in relation to the flour without treatment (resistant starch=10.6%).