Separation process characteristics of phenolic compounds from organic purple‐fleshed sweet potatoes (Ipomoea batatas L.) leaves using macroporous resins

Abstract Current trends have been noticed in to study of unedible parts of food as sources of phytochemicals or as ingredients in order to develop new uses for discarded materials and to promote sustainability. This study aimed to evaluate the performance of six macroporous resins (XAD 16, XAD 7HP, XAD 2, XAD 4, DAX 8, and XAD 1180 N) in purification of phenolic compounds from organic purple‐fleshed sweet potatoes. Static adsorption and desorption showed that XAD16 and XAD7HP had the highest adsorption and desorption ratio and recovery yield. The process temperature did not affect the adsorption capacity of XAD16. However, XAD7HP showed higher adsorption capacity when performed at 30°C, compared with 40 and 50°C. The process of equilibrium adsorption isotherms for phenolics was better described using Freundlich isotherm model. Dynamic adsorption process on XAD7HP resin showed that phenolic compounds in the water extracts of leaves started to break through after 4.5 bed volumes of extract was loaded. The purification of phytochemicals using adsorption is an alternative to replace organic solvents and provide a safety process for industrial application. Practical Applications Recently, phenolic compounds have been explored due to their significant biological and antioxidant properties; phenolic compounds are also related to decreasing the risk of cardiovascular diseases, cancer, oxidative stress, diabetes, fatness, cancer, and several degenerative diseases. In addition, there is the potential use of phenolic compounds such as anthocyanin as safe colorimetric pH indicators in innovative packaging due to the relationship between levels of pH and anthocyanin colors. Therefore, using advanced processing technologies, phenolic compound purification can be essential for many applications related to food safety, quality, nutrition, and food waste. Furthermore, purified phenolic compounds can be used as raw materials in the pharmaceutical area and food industries.