An Optimization Study on the Ultrasonic Treatments for Saccharomyces cerevisiae Inactivation in Red Grape Juice with Maintaining Critical Quality Attributes

摘要

This study was conducted to decrease Saccharomyces cerevisiae cell count and to maximize levels of quality characteristics in red grape juice during ultrasound process using response surface methodology (RSM). The effects of three process parameters (considered as independent variables), namely temperature (25–50C), time (20–40 min) and frequency (0–135 Hz), on the yeast inactivation, total anthocyanin content (TAC), total color difference (TCD), antioxidant activity (AA), polymeric color content (PCC), pH, total titratable acidity (TTA) and total soluble solids (TSS) (considered as dependent variables) were studied based on RSM. The optimum operating conditions for the maximum yeast inactivation and the optimal juice quality characteristics were found to be frequency of 135.0 kHz, temperature of 30.9C and time of 40.0 min. In these conditions, the yeast inactivation, TAC, PCC, AA, TCD, pH, TTA and TSS were 1 cfu/mL, 808.0 mg/g, 67.85%, 0.94 mmol/L, 1.64, 3.47, 977.4 mg citric acid/100 mL and 20.04, respectively.