Microwave assisted extraction advantages are widely recognised. However, its implementation at an industrial scale is restricted due to microwave limitations. In this work, a microwave pretreatment is proposed as an easy scale-up alternative. The double effect of this pretreatment on extraction yield and on product richness is assessed. Microwaves accelerate the extraction kinetics of most compounds, but their effect on polyphenols is more pronounced than in other substances (like sugars and fibres). The differentiated kinetic rates are exploited to improve the polyphenol richness of the final dry product. By selecting the appropriate operating conditions, polyphenol yield was increased a 57% and, simultaneously, dry product richness was enhanced a 32%. Especially remarkable was the anthocyanin extraction boost, in which the anthocyanin content in the final dry product was 85% higher than the one obtained without the microwave pretreatment. Antioxidant assays also demonstrate an improvement in extracts cellular bioactivity, as 83% and 133% more active extracts were obtained.
Figure 1: Process schema
The whole work can be found at: http://www.sciencedirect.com/science/article/pii/S0960308517301220