Effect of processing methods on yacon roots health-promoting compounds and related properties

Background: Yacon roots contain remarkable amounts of prebiotic fructans and rare antioxidant phenolics. Plantbased foods present a short shelf-life. In the case of yacon, fresh storage causes rapid depolymerization of fructans. Therefore, many attempts to extend yacon roots shelf-life have been made over the last years. Scope and approach: This review aims at presenting the effect of processing methods on yacon roots healthpromoting compounds, such as fructooligosaccharides, inulin and phenolics. Additionally, yacon-based products health-promoting properties, such as antioxidant enzymes activity, lipid peroxidation inhibition and other metabolic parameters that reflect intestinal health, are presented. An overview of the impact of processing on health-promoting compounds retention/concentration is shown. Yacon-based products with higher values of health-promoting properties are pointed out. Key findings and conclusions: Innovations have been incorporated in the main methods used for processing yacon along the years, namely drying and blanching, such as the use of vacuum, foam-mat drying, use of salts and acids in the blanching solution, and combination between blanching and drying. Results show that fructan retention was superior when using hot air drying preceded by blanching with salts and acids. Phenolic content in solids was higher when using spray drying. Phenolic content in liquids was higher when using blanching combined with lactobionic acid addition to the juice. In addition, yacon-based products, especially flours, promote intestinal health by means of affecting metabolic parameters like microbial counts, short-chain fatty acids content, antioxidant enzymes expression and postprandial glycemic response.