Effects of the thermosonication clarification on the rheological properties of apple juice

Abstract

In this study, the clarification of apple juice (AJ) was performed by using a bathb type sonicator at different temperatures. The effects of thermosonication applied on the rheological properties, and some physico-chemical characteristics (total soluble solids: Brix, pH, titratable acidity, color, cloud value and total phenolics content) of these apple juices were studied. Using four different rheological models, namely Herschel Bulkley, Power-law, Bingham, and Newtonian, the flow behaviors of apple juices were assessed. The results showed higher lightness values for thermosonicated apple juices. The amounts of total soluble sugar and titratable acidity of control and thermosonicated apple juices weren’t affected. The total phenolic contents of thermosonicated apple juices were significantly higher than control. The apple juices were found to be pseudoplastic fluids with a shear thinning nature. The thermosonication treatment was statistically significant in the change of rheological properties. The Herschel Bulkley model was found to be the best fit to the experimental data of all samples. Results revealed that the sonication technique could successfully be implemented on an industrial scale for the processing of apple juices. The obtained data could be taken into account in the industrial production of AJ with ultrasound treatment, particularly in the estimation of pumping requirement and the change of velocity profiles.