Kinetic Study of convective drying of blueberry variety O'neil ( Vaccinium corymbosum L.)

The aim of this research was to study and to model the drying kinetics of the blueberry ( Vaccinium corymbosum L.) at three temperatures (60, 70 and 80 ºC) with an airflow of 2.0 ± 0.2 m s -1 . Modeling of the desorption isotherm was carried out with the GAB (Guggenheim, Anderson and de Boer) equation, showing a good fit to experimental moisture data, giving as a result a monolayer moisture level of 0.084 g water g -1 dm. Newton, Henderson-Pabis, Page, Modified Page and Logarithmic mathematical models were applied in the study and in the modeling of the drying kinetics of this fruit. Kinetic parameters k of each model showed dependence on temperature, and were evaluated by an Arrhenius-type equation, with an activation energy of between 36.2 and 54.5 kJ mol -1 . Logarithmic and Modified Page models gave the best fits for each drying curve, based on the statistical test determination coefficient, sum square error, root mean sum errors and Chi-square. In consequence, both models are excellent tools for estimating the drying time of this product

Comparison of Chemical Composition, Bioactive Compounds and Antioxidant Activity of Three Olive-Waste Cakes

The objectives of this study were to determine the physicochemical composition, phenolic, tocopherol, flavonoid, flavanol, dietary fiber and β-carotene contents, as well as the antioxidant activity of three olive-waste cakes from varieties Picual, Frantoio and Arbequina. Frantoio presented the highest dietary fiber content and Arbequina showed the highest β-carotene content. Results indicated that total phenolic content followed the sequence (Frantoio>Picual>Arbequina). Picual presented the highest free phenolic and flavonoid contents (3499.11mg gallic acid equivalent/100g dry weight (DW) and 1331.45mg CTE/100g DW, respectively) showing the highest antioxidant capacity. The identified free phenolic compounds of the three varieties were gallic acid, 3-hydroxytyrosol, rutin hydrate, tyrosol and p-coumaric acids. The α-tocopherol was the predominant for the three varieties. Practical Aplications: Olive oil processing produces significant amount of waste that can be utilized for the production of high value-added ingredients for various industrial applications. Therefore, the information here reported may stimulate engineers to re-evaluate these wastes, with the possibility to recover significant amounts of bioactive compounds with high antioxidant capacity and dietary fiber in order to produce food additives in the scenario of functional foods.Fil: Uribe, E.. Universidad de la Serena; ChileFil: Pasten, A.. Universidad de la Serena; ChileFil: Lemus Mondaca, R.. Universidad de la Serena; ChileFil: Vega Gálvez, A.. Universidad de la Serena; ChileFil: Quispe Fuentes, I.. Universidad de la Serena; ChileFil: Ortiz, J.. Universidad de Chile; ChileFil: Di Scala, Karina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentin