Pressurized fluid systems: Phytochemical production from biomass

•Current status of subcritical fluid technology is presented.•The use of pressurized fluids allows phytochemical production from diverse vast biomass.•Optimum phytochemical production is obtained with unique pressurized fluids.•Reaction pathways for the most common model systems in sCW media are presented.•Applications of new pressurized systems are presented.

Pressurized fluids, such as subcritical water, pressurized aqueous ethanol and pressurized aqueous ionic liquids, are considered as environment-friendly solvents that can be used for the production of phytochemicals from a variety of biomasses. Phytochemicals, such as phenolic acids and carbohydrates, have innumerous applications in the food, pharmaceutical and other industries. In this study, the current status of pressurized fluids and production of phytochemicals are presented. Research in our laboratory has focused on the use of pressurized fluids to obtain phytochemicals from potato peel, lentil husk, barley hull, lupin hull, among others to later be used in some applications. Experiments with pressurized fluids were performed using a dynamic flow high-pressure system at different temperatures, pressures, time, static holding time and pH. Results indicated that the total phenolic and carbohydrate contents and antioxidant activity of these biomass systems increased with temperature. The optimum phytochemical production and total antioxidant activity of each biomass were obtained using specific pressurized fluids. For example, the highest carbohydrate extraction from barley hull was obtained using pressurized aqueous ethanol, but this pressurized fluid was not the best for phenolics removal. Then, pure phenolics were used in two applications: enzymatic synthesis of ferulic acid in flaxseed oil in SC-CO2 media and added to milk to retain valuable components using high pressure processing assisted by temperature. Important reaction pathways for specific systems were also discussed. Phytochemical production from selected biomasses using pressurized fluids and its uses in reactive system applications were demonstrated.

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