Influence of Microwave Heating on Food Bioactives

The industrial and domestic use of microwaves has largely increased in the last few decades due to its significant reduction in processing time and energy consumption. Other than for domestic and industrial cooking, microwaves are widely used in the food industry for drying, thawing, tempering and stabilization processes such as blanching, pasteurization and sterilization. Moreover, this technology is also used to assist extraction of bioactive compounds, exploiting the formation of porous structures. In comparison to the traditional thermal treatments, microwave heating shows the ability to retain higher contents of bioactive compounds, higher antioxidant activities, and improve the digestibility of some food products. These benefits are especially due to the short processing times and the almost total lack of water during the treatment, which would lead to bioactives leaching. Enzyme’s deactivation and reduction of anti-nutritional factors also contribute to bioactives retention in microwave-treated foods. Advantages and drawbacks of microwave heating at domestic and industrial level are discussed in this chapter, focusing on the effect of this technology on the retention of bioactive compounds in different food matrices. The efficiency of microwave treatment for extraction of food bioactives is also discussed.