Abstract:

Objective: To investigate the tempering drying characteristics of preserved prunes (Jiayingzi) with different moisture contents under different tempering environments and duration. Method: Physical and chemical analysis and sensory evaluation were conducted to preserved prune samples with different moisture contents after tempering and then hot air drying. Results: All the tempering environment, drying duration and moisture content had marked effects on the drying characteristics of preserved prunes. Prolonged tempering (up to 20 h) and drying time (up to 1.5 h) resulted in efficient improvements of physical and chemical characteristics and sensory quality. Compared to natural, absolute dry and refrigerator environments, air-conditioned environment exhibited the best tempering effect. The air-conditioned and absolute dry environments resulted in the highest recovery of structure and distribution uniformity of moisture. Generally, the longer the time to temper, the higher rising rate of drying velocity. But when tempering time was over 12 h, the drying velocity did not rise significantly. Conclusion: The best tempering conditions are as follows: moisture content of preserved prune samples, 35%; tempering duration, 12 h; and tempering environment, air-conditioned environment.

Key words: preserved prunes, tempering, drying characteristics, sensory analysis, texture profile analysis