Impact of Pressure Reduction Rate on the Quality of Steamed Stuffed Bun

Effects of three pressure reduction rates (PRR) of ۱۰۳ Pa s-۱, ۱۹۷ Pa s-۱, and ۳۴۷ Pa s-۱ on temperature distribution and variation, moisture content, and sensory quality of steamed stuffed buns were investigated after vacuum cooling. The distributions and variations of surface temperatures were determined by the thermal infrared imaging method. The temperature profiles presented significant differences in the average cooling rates of the different parts, depending on the PRR. Results showed that the greatest mass loss of ۸.۱% and the shortest cooling time of ۲۸۸ seconds were found with the quickest PRR of ۳۴۷ Pa s-۱, while the least mass loss of ۵.۹۶% and the longest cooling time of ۹۵۵ seconds were observed in the case of the slowest PRR of ۱۰۳ Pa s-۱. The pressure reduction rates had little influence on the changes of moisture contents in the crumb and stuffing. The sensory quality scores of vacuum-cooled buns at ۱۰۳ and ۱۹۷ Pa s-۱ were higher than those at ۳۴۷ Pa s-۱.