Effect of ultrasound pretreatment on physical, bioactive, and antioxidant properties of carrot cubes after centrifugal dewatering

Abstract

Ultrasound-pretreated centrifugal dewatering (UCD) is a novel method for vegetable dewatering process in the central kitchen. In this study, carrot cubes were blanched and dewatered by UCD at various ultrasonic frequencies (0, 20, 30, 45, 80 and 100 kHz). Conventional centrifugal dewatering (CCD) was performed for comparison. At similar centrifugal conditions, the dewatering capacity of UCD was >30% higher than CCD. The retention of β-carotene, phenolic and flavonoid substances also increased by 10–50%. The optimized ultrasonic frequency for UCD processing was 45 kHz. At this optimized condition, the reducing power of carrot cubes was improved by 3.4%. Retention of total phenolics, flavonoids and β-carotene were increased by 33.89%, 48.51% and 26.71%, respectively. Nevertheless, a moderate reduction (25.82%) of hydroxyl radical scavenging capacity was observed for the UCD. Overall, UCD can be used as an alternative improved method of CCD to enhance the dewaterability and quality of carrot.

Highlights

• Ultrasound-pretreated centrifugal dewatering (UCD) improved dewaterability of carrot and retained its nutritional values.

• UCD increased the dehydration rate of carrot by >30% than conventional centrifugal dewatering (CCD).

• The β-carotene, phenolics and flavonoids substances in UCD carrot was 10-50% higher than that of CCD.

• UCD has a positive effect on antioxidant activity of carrot.

Keywords:

• Ultrasonic frequencies
• dewatering
• dewaterability
• physicochemical properties

Additional information

Funding

This work was supported by the National Key R&D Program of China (contract no. 2018YFD0400801).