Novel Extraction Methods of Anthocyanins from Plums, Plum Products, and By-Products

Abstract

Plums are widely known to be a good source of bioactive phytochemicals, among which are anthocyanins that are mainly found in the peels of red-purple varieties. Plum products, such as juices, jams, prunes, and pomace, resulting from juicing, still contain a significant amount of anthocyanins. But their content and profile vary with an array of factors, including the extraction procedure employed for their isolation and purification. Two types of extraction methods are usually employed to extract anthocyanins from plums, plum products, and by-products: conventional solvent extraction and new non-conventional methods, which can sometimes be paired with the conventional techniques. Solvent extraction is usually performed with methanol and ethanol, but high concentrations and large volumes are needed to obtain yields relevant for industrial use. However, methanol is not generally recognized as safe (GRAS), and extensive research is currently being conducted to develop new, non-conventional methods that are environmentally friendly, rapid, and easy to perform. Two promising novel procedures among these methods are ultrasound- and microwave-assisted extraction methods. Several studies proposed optimized novel extraction methods, including pre-extraction steps, but they are rather scarce and there generally appears to be a lack of consensus. Additionally, the expression of the results is largely unstandardized, which affects the accuracy and precision of the anthocyanins quantification and profile identification.