超声波辅助漂烫预处理对太阳能-热泵联合干燥南瓜片品质的影响

研究超声波辅助漂烫预处理方法对太阳能-热泵联合干燥南瓜片品质的影响,以超声波温度、功率、频率和处理时间为单因素,研究其对干燥南瓜片色差、硬度、β-胡萝卜素及抗坏血酸含量的影响。通过正交优化分析获得最优工艺条件,并与传统漂烫预处理进行干燥南瓜品质的对比实验。结果表明,在超声波温度70 ℃、超声波功率为300 W、超声波频率为35 kHz、超声波处理时间为3 min条件下,干燥处理对南瓜片的颜色及营养物质含量的影响最小,色差值为9.95,相比于传统热烫的预处理方法减少61.64%;硬度值为36.61 N;抗坏血酸含量为13.00 mg/100 g,较传统热烫提高41.38%。因此,相比于传统热烫的预处理方法优势依然明显。证明超声波这一物理手段可显著减少南瓜热处理时色泽变化及抗坏血酸等营养物质的流失,超声波辅助漂烫预处理手段可用于南瓜片干燥加工中。

Effect of ultrasonic-assisted blanching pretreatment on the characteristics of solar-heat pump dried pumpkin slices

In order to demonstrate the influence of ultrasonic-assisted blanching pretreatment on the characteristics of solar-heat pump dried pumpkin slices, the effects of ultrasonic temperature, ultrasonic power, frequency and treatment time on the chromatic aberration, hardness, content of β-carotene and ascorbic acid were studied. The optimum technological conditions were obtained by orthogonal optimization analysis and compared with the traditional blanching pretreatment for drying the quality of pumpkin. The results revealed that under the conditions of ultrasonic temperature of 70℃, ultrasonic power of 300 W, ultrasonic frequency of 35 kHz and ultrasonic treatment time of 3 min, drying treatment had the least effect on the color and nutrient content of pumpkin slices. The chromatic aberration was 9.95, compared with traditional blanching, the chromatic aberration decreased by 61.64%. The hardness value was 36.61 N. The content of ascorbic acid was 13.00 mg/100 g, which was 41.38% higher than the traditional blanching treatment. Therefore, the advantages compared to the traditional hot stamping method are still obvious. It was proved that the physical means of ultrasound can significantly reduce the color change of pumpkin heat treatment and the loss of ascorbic acid and other nutrients, and the ultrasonic blanching pretreatment method owned the potential of being applied in the drying process of pumpkin slices.