Carolina Pereira Kechinski

Degradation kinetics of anthocyanin in blueberry juice during thermal treatment.

The kinetics of anthocyanin degradation in blueberry juice during thermal treatment at 40, 50, 60, 70, and 80 degrees C were investigated in the present study. Anthocyanin degradation was analyzed up to the level of 50% retention using a pH differential method. The degradation of anthocyanin at each temperature level followed a first-order kinetic model, and the values of half-life time (t(1/2)) at temperatures of 40, 50, 60, 70, and 80 degrees C were found to be 180.5, 42.3, 25.3, 8.6, and 5.1 h, respectively. The activation energy value of the degradation of the 8.9 degrees Brix blueberry juice during heating was 80.4 kJ.mol(-1). The thermodynamic functions of activation (DeltaG, DeltaH, and DeltaS) have been determined as central to understanding blueberry degradation.

Formulation and characterization of poloxamer 407®: thermoreversible gel containing polymeric microparticles and hyaluronic acid

The influence of the composition and preparation method on the sol-gel transition temperature (Tsol-gel) and rheological response of poloxamer-based formulations was determined. Manual and more complex mechanical stirring were found to provide similar results. In addition, a linear dependence of Tsol-gel on the poloxamer content was observed in the range of concentrations analyzed, and a Poloxamer 407® concentration of 18% was selected. The addition of hyaluronic acid did not lead to significant changes in the Tsol-gel values. In contrast, the addition of microparticles caused a reduction in Tsol-gel without a significant reduction in gel strength, and pseudoplastic characteristics were observed, indicating that a thermoreversible gel was obtained with a rheology suitable for application in the treatment of burn wounds.

The Use of Ozone in a CIP System in the Wine Industry

This study tested the efficacy of ozone in a CIP system of a wine industry, for that, a hose that transported wine was submitted to the following treatments: ozonated water at 28 ± 1 °C (in concentrations of 0.38 and 1.03 ppm for one, five and nine minutes); hot water (85 ± 1 °C for 15 minutes); peracetic acid (0.3% for 15 minutes); and a caustic soda solution (2%) with peracetic acid (0.3% for 15 minutes). The results indicate that the use of ozonated water is more effective than the isolated use of peracetic acid and the combined use of soda and peracetic acid.

Study of mass transfer during the osmotic dehydration of blueberry.

.Summary Osmotic dehydration is used to partially remove water from plant tissues by immersion in a hypertonic solution. The objective of this work was to investigate the effect of the temperature (30-50 °C) and concentration (45-60 °Brix) of the osmotic solution on the mass transfer mechanism during the osmotic dehydration of blueberry. The effective diffusivity of the water was determined using the analytical solution of Fick’s Second Law based on the data for binary solutions of sucrose/ water. Peleg’s model was used to predict the moisture content of the product at equilibrium. The temperature of the osmotic solution showed a great influence on the parameters of the model and on the values for effective mass diffusivity. Both, an increase in sucrose concentration of the osmotic solution and an increase in process temperature, resulted in higher values for the effective mass diffusivity of the water, with values in the range from 0.65 to 2.28 x 10 -10 m 2 s –1

Effects of Ozone in Combination with Hydrothermal Treatment and Wax on Physical and Chemical Properties of Papayas

This study evaluated the effects of ozone in combination with hydrothermal treatment and wax on physical and chemical properties of papayas. The ozone concentrations used in this study were 2 and 4 mg/L. Heat treatments were applied with a hot water brushing system at temperatures of 45, 55 and 65 °C. No mold was observed under the wax film of fruits treated with hot water, ozonated water and wax, indicating that the combined treatment effectively disinfected the papaya fruits.

Viabilidade de células de levedura em massas congeladas de pão francês

The preparation and storage of frozen bread has proved to be advantageous for the market and to the final consumer. First because of loss reduction and need for smaller physical storage space and workforce, second because it provides always fresh bread. This study aimed to investigate the influence of storage on the viability of yeast cells in frozen French bread. In order to that, frozen French breads were prepared by the direct-dough method: the ingredients (premix for French bread, fresh yeast and water) were mixed until the dough was fully developed and then divided into portions of 60g and moulded. Freezing was held in ultra freezer at -32°C and the storage was made in chambers at temperatures of -18oC and -40°C. To estimate the shelf life, the study of reduction of leavening cells viability in frozen French bread dough was analyzed. This test was performed in Petri dishes containing Sabouraud agar with chloramphenicol 0.2% at 28°C during 5 days. The kinetics of reduction of leavening cells viability followed a first-order reaction, which rate constants were 0.027 days-1 (R²=0.931) and 0.026 day-¹ (R²=0.938) for -18°C and -40°C temperatures, respectively. For both temperatures, the 50% reduction in the number of leaven occurred in approximately 25 days.