Effects of processing, storage temperature and storage duration on physico-chemical, sensory quality, and antioxidant properties of Michigan Montmorency cherry juice concentrate

Unpasteurized and pasteurized tart cherry juice concentrate was stored for 48 weeks at 4, 21 and 38°C. Microbial activity, total soluble solids, pH, titratable acidity, Hunter color, and turbidity were measured over time. Concentrate was analyzed for total antioxidant capacity (Oxygen Radical Absorbance Capacity) total anthocyanins (pH-differential) and total phenolic content (Folin-Ciocalteu). Sensory quality was measured by trained and consumer panels. Results for yeast and mold were found negative. Pasteurization had minimal to no significant effect on all attributes tested. Storage temperature and duration had minimal to no effect on Hunter "L" and "b" values, pH and total phenolics. Total soluble solids and titratable acidity showed significant decrease for ambient and elevated storage conditions. Hunter "a" value, turbidity and anthocyanin content showed significant change over time, showing a significantly higher decrease at ambient and elevated temperature conditions. Storage duration decreased ORAC values significantly; however, no differences were seen among storage conditions. Analytical analysis and sensory panels showed most overall stable concentrate quality for refrigerated temperatures while ambient storage condition showed poor quality after week 12 and elevated storage conditions after week 2.