Changes in the odors of squeezed apple juice during thermal processing

Abstract Effects of processing temperature and time on the odors of squeezed apple juice were investigated by the combined of sensory and analytical method. Freshly squeezed apple juice was treated by a flow system under the conditions of residence time 2–320 s and treatment temperature 80–120 °C. The odors of the juices were evaluated by a paired-comparison test and quantitative descriptive analysis. There was a complex change in the nature of the odors with treatment temperature and residence time. The quality optimum points were observed around 45 s for 90 °C, 20 s for 100 °C and 20 s for 110 °C. Changes in the volatility of aroma compounds were extremely complicated with respect to thermal processing conditions. Principal component analysis indicated that the treatment temperature more affected the volatility than the treatment time. Present data demonstrated the existence of optimum conditions in the thermal processing of squeezed apple juice.