Recovery of Anthocyanins from Hibiscus sabdariffa L. Using a Combination of Supercritical Carbon Dioxide Extraction and Subcritical Water Extraction

Abstract

Anthocyanins are one of the bioactive compounds in roselle that has many medicinal proposes. Anthocyanins are placed in the inner part of the roselle; therefore, combinations of two methods were applied to extract the anthocyanins. The first stage is employing supercritical carbon dioxide (ScCO2) to break the particle surface or outer layer of the roselle based on the total phenolic compounds (TPC) recovery, and the second step was to apply subcritical water extraction (SWE) for the extraction of anthocyanins. The objective is to determine the best conditions to obtain high yields of total anthocyanins compounds (TAC) from the roselle (Hibiscus sabdariffa) by employing a combination of ScCO2 and SWE. The optimal conditions of ScCO2 (first stage) were 19.13 MPa, 60 °C, and 4.31 mL/min, yielding 18.20%, and 80.34 mg/100 g TPC, respectively. The optimum conditions of SWE (second stage) were 9.48 MPa, 137 °C, and 6.14 mL/min, yielding 86.11% and 1224.61 mg/100 g TAC, respectively. The application of integrated ScCO2 and SWE proved successful in achieving high anthocyanins production and yield as compared to previous extraction methods. This approach may be used to extract the roselle with a greater anthocyanin’s concentration than the prior method.

Towards a greener future: Bioactive compounds extraction from shrimp shells using eco‐friendly techniques

“…"> Enhanced solubility : According to Putra et al (2022), when water is subjected to subcritical heating, its density diminishes, resulting in an augmentation of its solvent capacity. The increased solubility of compounds, especially those that are hydrophilic and polar in nature, is of significant importance in the extraction procedure (Rizkiyah et al, 2023). The enhanced capacity of water to establish hydrogen bonds and solubilize a diverse array of substances becomes increasingly evident, facilitating its infiltration into the structure of shrimp exoskeletons and the solvation of certain biological functions. …”

“…Compound recovery: After the bioactive compounds have been dissolved and transferred into the solvent phase, the pressure is rapidly decreased, facilitating the reversion of water to its liquid form. The change in pressure induces the precipitation of the dissolved compounds from the aqueous solution, leading to the formation of a concentrated extract (Rizkiyah et al, 2022).…”

“…T A B L E 1 Parameters of supercritical carbon dioxide influence on the yield and valuable compounds recovery.ParameterEffect on yield and recovery Explanation ReferencePressureIncreased pressure leads to an increase in yieldIncreased pressure has been seen to boost the solubility of substancesIdham et al (2021) Temperature The achievement of maximum yield recovery is facilitated by the optimization of temperature conditions Elevated temperatures have the potential to induce the breakdown of compounds Sodeifian et al (2022) CO 2 flow rate An increase in flow rates has the potential to enhance the overall yield Enhanced mass transfer may be achieved by increased flow velocity Masghati and Ghoreishi (2018) Co-solvent The augmentation of co-solvent concentration has the potential to improve the overall yield in some instances The addition of a co-solvent has the potential to enhance the solubility Putra, Yustisia, et al (2023) Particle size The use of smaller particles has the potential to enhance the overall yield The augmentation of surface area promotes the process of extraction Putra, Rizkiyah, Aziz, et al (2023) Extraction time Extended extraction durations have the potential to result in increased yield A longer duration of extraction facilitates enhanced diffusion of compounds Arumugham et al (2022)Matrix pretreatmentThe use of matrix pretreatment has the potential to enhance yieldThe enhancement of chemical release is facilitated by the disruption of cell wallsRizkiyah et al (2023) …”

Enzyme-assisted ultrasonic extraction of total flavonoids and extraction polysaccharides in residue from Abelmoschus manihot (L)

“…The corresponding extraction and separation are also developing. With people's attention to environmental protection, the extraction of natural bioactive ingredients is seeking green environmental protection methods [8] , especially in the cosmetic, food and pharmaceutical industries, increasing request for the natural products of sustainable and environmentally responsible manner [9] . Some plants, herbs and fruits are often extracted with unique active ingredients, there are still a variety of valuable bioactive components in the residues, which are neglected and abandoned, resulting in a large waste of resources [10] , and recycling of valuable bioactive components in the residues is very much in line with the requirements of green and sustainable development [11] .…”