CHAPTER 12. Continuous Microwave-assisted Isoflavone Extraction

Abstract

This Chapter is dedicated to discussing a new technology that can be deployed for continuous extraction of isoflavones (from soybeans or other source). It starts by briefly discussing the benefits of isoflavones (which are otherwise described in more detail in other Chapters of this Book), then lists a brief overview of other extraction methods. An important section of the Introduction is dedicated to explaining in more details the mechanisms of microwave heating in general, and how these mechanisms can be used to our advantage to design more efficient and higher performing extraction systems. A description of a low-cost continuous microwave system is also provided, but the reader needs to keep in mind that any modifications and customization of off-the-shelf microwave systems needs to be performed with the outmost attention and only by personnel highly qualified for such work. The many safety issues related to microwave systems and their operation are not provided here in detail, and the reader is highly encouraged to familiarize himself with those. Once designed and tested for safety, a typical operation of the system is provided, with the different steps required to extract and quantify the isoflavones being listed in the appropriate order. Some of the most significant research results are then described and discussed, including yields for oil and individual isoflavones, time and temperature comparisons, and a brief discussion related to the extraction kinetics. The Chapter is finished with a brief outline of the major advantages of the continuous microwave extraction system, and a short review of the major research findings.