Utilization of Plant-Based Agricultural Waste by Subcritical Water Treatment

Abstract

The application of subcritical water treatments to valorize cer tain plant-based agricultural waste is reviewed with a focus on the extraction of phenolic compounds and the production of oligosaccharides. Phenolic compounds can be ef ficiently extracted by raising the temperature to an optimal value; however, many phenolic compounds are decomposed at high temperatures. Nevertheless, some degradation products of phenolic compounds also show high antioxidant activity. The conversion of polysaccharides from plant-based agricultural waste into smaller polysaccharides or oligosaccharides may be an alternative method for the preparation of ingredients with health benefits.

Compressed fluids and phytochemical profiling tools to obtain and characterize antiviral and anti-inflammatory compounds from natural sources

“…In this case, the temperature is more important than pressure to promote the depolymerization of the polysaccharides and favor their solubility due to the reduction of their molecular weight. The range of temperatures for recovery of polysaccharides vary between 120 to 250 o C depending on the type and source of biomass [47], while pressure is kept around 10 MPa when dealing with SWE.…”

Physical and chemical properties, antioxidant capacity, and total phenolic content of xyloglucan component in tamarind ( Tamarindus indica ) seed extracted using subcritical water

“…Subcritical water is defined as hot water at a temperature ranging between 100 and 374°C under high pressure to maintain water in the liquid state (Pourali, Asghari, & Yoshida, ). Subcritical water has been widely used for extraction, hydrolysis, and conversion of carbohydrates in low‐value biomass into useful compounds (Khuwijitjaru, ). Khuwijitjaru, Watsanit, and Adachi () used subcritical water treatment to hydrolyze polysaccharide from coconut meal to obtain a manno‐oligosaccharide and found that high extraction temperature (230°C) and short treatment time (<3 min) tended to provide high amounts of carbohydrate with greater mannose contents.…”