Storage characteristics of microencapsulated extra virgin olive oil powder: physical and chemical properties

Abstract

In this study, physical and chemical properties of microencapsulated extra virgin olive oil powder (MEVOP) produced through spray drying were investigated during storage under different temperatures (4, 25 and 60 °C). The effect of homogenization methods in terms of rotor–stator (RSH) and ultrasonic (UH) were also examined on MEVOP along storage period. The physical and chemical properties of MEVOP obtained either RSH or UH showed that water activity, tapped density, Carr index (flowability), caking degree, surface oil content, peroxide value (PV) and free fatty acid (FFA) significantly increased, while bulk density, microencapsulation efficiency (ME), total phenolic content and antioxidant capacity significantly decreased during storage at 4, 25 and 60 °C. However, as the particle size of MEVOPs stored at 4 °C decreased along storage time, particle size of samples stored at 25 and 60 °C increased due to increase in surface oil content and particle–particle cohesion. The MEVOPs stored 4 and 25 °C had higher particle density compared to the sample stored at 60 °C during storage. Rapid changes in antioxidant capacity and total phenolic content of MEVOP were also determined during storage with increased storage temperature. There was a significant effect of homogenization method on particle size, for this reason physical and chemical properties of powder changed. When all quality characteristics and oxidative stability were evaluated, MEVOP should be stored at ambient or lower temperature in order to increase its shelf life.