Combined Infrared Freeze Drying and Infrared Drying of Rose-Flavored Yogurt Melts—Effect on Product Quality

Abstract

This study evaluated the use of infrared freeze drying for different durations in combination with infrared drying (IRFD-IRD) as a means to reduce the drying time and energy consumption without sacrificing the dried product quality during the production of rose-flavored yogurt melts. Total required drying time and energy consumption were examined and compared with those required by IRFD alone. Comparison was also made in terms of physical properties (color, odor, bulk density, hardness, and rehydration time), total phenolic and anthocyanin contents, antioxidant activities, and sensory characteristics of the final products. IRFD-IRD could reduce 11.36–22.73% of the drying time and 9.99–24.87% of the energy consumption in comparison of IRFD alone. IRFD (3 h)-IRD samples had smaller total color difference than that of IRFD samples. Odor, bulk density, and hardness as well as sensory characteristics of IRFD (3 h)-IRD samples were similar to those of IRFD samples. Furthermore, IRFD (3 h)-IRD and IRFD samples possessed similar retention of bioactive compounds as well as antioxidant activities. Combined IRFD (3 h)-IRD is a promising technique for the processing of rose-flavored yogurt melts. The combined drying method significantly reduced the drying time and energy consumption without affecting the final product quality.