Novel approaches based on ultrasound for spray drying of food and bioactive compounds

Abstract

Ultrasound assisted spray drying has been extensively used in the food and pharmaceutical industries for increasing the stability of variety of compounds involved in different applications, especially for drying sensitive compounds in the case of pharmaceutical industries. The use of ultrasonic spray drying has shown promising results in pharmaceutical sector though the application in food industries is still in the development stage possibly due to the absence of suitable designs, lower throughput values, and scale of operations. Considering these aspects, the current review focuses on the analysis of ultrasound-assisted spray drying for the food products and bioactive compounds so as to provide a better perception for the use in food processing industries. A detailed study into the diverse application of ultrasound in spray drying for encapsulation, microsphere generation, etc. in food industry and the enhancement into such applications using ultrasonic nozzle has been presented. Along with this, guidelines for the operating conditions involved in ultrasonic atomization for suitable applications with desired outputs and a detailed comparison with other nozzles have also been presented. Several advantages of ultrasonic spray drying over conventional method such as better size distribution, no nozzle clogging, lower velocity atomization, etc. have also been discussed. The low velocity spray generation using ultrasonic atomizers eliminates the requisite for large drying chambers thus, contributing to the compact designs. Overall, it has been clearly demonstrated that ultrasound offers lots of promise for improving the operations mainly with reduced processing times, enhanced production rates, and product quality.

Keywords:

• Food products and bioactive compounds
• ultrasound
• spray drying
• encapsulation
• microspheres