Dehydrated olive-waste cake as a source of high value-added bioproduct: Drying kinetics, physicochemical properties, and bioactive compounds

Elsa Uribe1, Roberto Lemus-Mondaca1*, Alexis Pasten1, Sebastian Astudillo1, Antonio Vega-Gálvez1, Luis Puente-Diaz2, and Karina Di Scala3
Olive (Olea europaea L.) oil processing produces significant amount of waste that can be utilized for the production of high value-added ingredients for various industrial applications. In this work, the effects of temperature on drying kinetics and quality indexes of the olive-waste cake during convective dehydration (40-90 °C) were investigated. Results on effective moisture diffusivity, physicochemical parameters, fatty acid profile, total phenolic, flavonoid, and flavanol contents as well as antioxidant capacity are also reported. Most of the fatty acids increased their content with respect to control sample with a temperature increase, i.e. oleic and linoleic acids increased with 48% and 43% at 70 and 40 °C, respectively. Total flavanol content increased with temperature (48-62 mg catechin equivalents [CTE] 100 g-1 DM) excepting at 80 °C. Total phenolic and total flavonoid contents were highly correlated to antioxidant capacity (0.923 < r < 0.992), except at 70 and 80 °C, the rest of the samples maintained their initial antioxidant capacity by ORAC analysis. Thus, these parameters show that dried olive-waste has a high bioactive compound content with a potential use as additives for the food or other industries.
Keywords: Antioxidant capacity, drying process, fatty acids, Olea europea, olive waste, phenolic compounds.
1Universidad de La Serena, Departamento de Ingeniería en Alimentos, Av. Raúl Bitrán s/n, La Serena, Chile. *Corresponding author (rlemus@userena.cl).
2Universidad de Chile, Departamento de Ciencia de los Alimentos y Tecnología Química, Av. Vicuña. Mackenna 20, Santiago, Chile.
3Universidad Nacional de Mar del Plata, Ingeniería en Alimentos, Av. Juan Justo 4302, Mar del Plata, Argentina.