Techniques to extract bioactive compounds from food by-products of plant origin

By-products of plant origin represent an abundant source of bioactive compounds. However, to exploit these resources commercially relevant strategies for their extraction must be developed. This review focuses on the extraction of bioactive compounds from food by-products of plant origin by a number of novel methods, including pressurised liquid extraction and supercritical CO2 extraction. In general supercritical CO2 extraction is most effective for apolar compounds such as carotenoids, while pressurised liquid extraction can be used to extract more polar compounds such as polyphenols. Both techniques are sustainable and green techniques. In addition, pre-treatment of plant by-products by novel non-thermal processing techniques in order to enhance extraction will be highlighted. In general the selection of an appropriate extraction strategy is dependent on the type of compound to be extracted as well as the potential up scaling of the technique.