超声预处理蓝莓真空冷冻干燥工艺优化及对品质的影响.

[Objectives]The paper aimed to improve the vacuum freeze-drying rate and product quality of blueberries. [Methods]The ultrasound treatment was used as a pretreatment method to study the effects of ultrasound temperature(45, 55, 65, 75 ℃), frequency(45, 80, 100 kHz), power(600, 700, 800, 900, 1 000 W), and time(25, 30, 35, 40 min)on the drying characteristics, texture, color, nutrient retention rate, and antioxidant activity of blueberries. Then a four factors and three levels response surface optimization experiment was conducted using drying rate, anthocyanin content, color, and brittleness as indicators to select the optimal ultrasonic pretreatment process and parameters. [Results]Ultrasound temperature had a significant impact on the anthocyanin content of blueberries(P<0.001). The effect of ultrasound frequency on the drying rate, anthocyanin content, and brittleness of blueberries was significant(P<0.05). The effect of ultrasound power on blueberry brittleness was significant(P<0.05). The effect of ultrasound conditions on the ΔE value of blueberries was not significant(P>0.05). The optimize process conditions for ultrasonic pretreatment of blueberries were obtained as follows:ultrasonic temperature 55 ℃, frequency 80 kHz, power 700 W, and time 30 minutes. Under these conditions, the drying rate of blueberries was 1.69 g·g-1·h-1, anthocyanin content 0.55 mg·g-1, brittleness 2 770.00 g, and ΔE value 6.16. [Conclusions]Ultrasonic pretreatment could improve the quality of blueberry vacuum freeze-drying. The results provide the basis for the research and product development of blueberry vacuum freeze-drying. [ABSTRACT FROM AUTHOR]