Survival of Saccharomyces cerevisiae in refrigerated fresh orange juice treated with cinnamon leaf essential oil and thermo-sonication.

Abstract

The survival of Saccharomyces cerevisiae in refrigerated fresh orange juice processed by combined use of thermo-sonication and cinnamon leaf essential oil (CLEO) was evaluated. The concentration of CLEO accepted by consumers in orange juice was determined by sensory analysis as 20 ppm. The resistance of S. cerevisiae cells to the action of ultrasound (24 KHz; 33.31 W mL-1; 30 minutes) at 50°C in orange juice with CLEO was analyzed. The survival of S. cerevisiae in the fresh orange juice untreated (control) and treated with thermo-sonication, or thermo-sonication plus 20 ppm CLEO and kept under refrigeration (5°C) for 28 days was studied. The best result was obtained with thermo-sonication and 20 ppm CLEO treatment. This treatment produced a reduction from an initial population of 5.18 log of S. cerevisiae in fresh orange juice to 2.60 ± 0.26 log after 30 min of sonication at 50°C. The best result of inhibition obtained during refrigeration was achieved with orange juice treated with 30 min of sonication at 50°C and 20 ppm CLEO because the treated juice kept under refrigeration at 5°C for 28 days diminished the S. cerevisiae population 1.33 ± 0.17 log.