Effect of subcritical water processing on the extraction of compounds, composition, and functional properties of asparagus by‐product

The aim of this study was to submit the asparagus by‐product to the subcritical water treatment, evaluating the extraction of antioxidants compounds (AC) and total reducing sugars (TRS), as well as, the composition and technological properties of the residual material. The effects of temperature (100–160 °C) and pressure (100–200 bar) on extraction were evaluated, for total extraction time of 120 min. The results showed that the increase in temperature favored the removal of AC and this variable did not cause modification of most of the compounds identified by mass spectra analysis. The highest removal of AC was observed up to 30 min. The increase in temperature decreased the TRS content. The pressure did not affect the extraction of sugars and AC in the conditions evaluated. The treatment was efficient for the modification of the physico‐chemical composition and technological properties of residual material, reducing the TRS content and improving the ratio of soluble fiber to insoluble fiber. PRACTICAL APPLICATIONS: Asparagus by‐product can be an interesting source of nutrients, like dietary fiber and antioxidant compounds. To maximize the antioxidant yield obtained from this by‐product, it can be used the subcritical water extraction (SWE) that is considered a green solvent. Besides this, the SWE promotes the concentration of dietary fibers of the treated material, due to the sugars removal, and improves the functional properties, which can facilitate the utilization of this material in the development of new food products.