High Concentrate Flavonoids Extract from Citrus Pomace Using Enzymatic and Deep Eutectic Solvents Extraction

A review of green solvents for the extraction and separation of bioactive ingredients from natural products

Bioactive substances from natural products are good resources from the pharmaceutical and food industries. Conventional organic solvents are widely used for extracting and separating bioactive substances. Recently, various environmentally friendly solvents have been developed and applied in the separation field to replace conventional organic solvents. This review focuses on environmentally friendly solvents for the extraction and separation technologies that meet the requirements of green chemistry. The classifications, applications, influencing factors, and mechanisms involved in the extraction processes using these green solvents are also discussed. Green solvent-based extraction systems are promising alternatives to traditional organic solvents. Green solvents are mild and non-destructive to the active compounds during their application and have negligible effects on the ecosystem when discharged. The use of green solvents for the extraction and separation of active ingredients in natural products is attracting attention because of their low environmental impact and sustainability.

Sustainable strategies to obtain bioactive compounds from citrus peels by supercritical fluid extraction, ultrasound-assisted extraction, and natural deep eutectic solvents

This work proposes a sustainable sequential extraction of bioactive terpenoids and phenolic compounds from grapefruit, lime, and lemon peels using supercritical CO2 extraction (SC-CO2) and ultrasound-assisted extraction (UAE) with natural deep eutectic solvents (NaDES). NaDES screening demonstrated that Choline Chloride:Tartaric acid (1:2) for grapefruit and lemon peels, and Choline Chloride:Glycerol (1:2) for lime peels with 50% water yielded the highest phenolic contents. Cryogenic grinding (CR) and SC-CO2 pretreatments before UAE-NaDES did not improve phenolic recovery compared to direct UAE-NaDES. Pretreatments reduced particle size and increased surface tension, lowering UAE-NaDES efficiency. The direct UAE-NaDES extracts showed the highest phenolic diversity, with naringin in grapefruit and hesperidin in lime and lemon peels as the major compounds identified by HPLC-QTOF-MS. However, SC-CO2 obtained before UAE-NaDES presented higher anticholinergic capacity and a rich terpenoid profile identified by GC-Q-MS. Results demonstrate the potential of this sequential strategy for a more holistic exploitation of citrus peels.

Physical field-assisted deep eutectic solvent processing: A green and water-saving extraction and separation technology

Extraction of organic and bioactive compounds from plant materials with the traditional organic solvents aided by water or oil bath heating is not sustainable, because it consumes a lot of energy, time, water/oil, solvents, and results in lower yield. This review discusses deep eutectic solvent (DES) as a green solvent, physical field technology (PFT) as a water-saving and green technology, and how the coupling of PFT (ultrasound [US], microwave [MW], infrared [IR]) to DES will improve the yield and quality of protein, polysaccharides, polyphenols, pectin, and terpenoids extracted from plant materials. Ultrasonication increases DES extraction efficiency via cavitation dislodgement and pores creation. IR coupling to DES enhances the extraction yield of polyphenols and the antioxidant and antiradical activity. MW improves DES extraction yield, reduces energy consumption, operational cost, and compound degradation, and is inferred to be the greenest technology.

Advances in Extracting Bioactive Compounds from Food and Agricultural Waste and By-Products Using Natural Deep Eutectic Solvents: A Circular Economy Perspective

Due to the urgent need for a transition to sustainable, zero-waste green technology, the extraction of bioactives from food and agricultural by-products and waste has garnered increasing interest. Traditional extraction techniques often involve using organic solvents, which are associated with environmental and health risks. Natural deep eutectic solvents (NADESs) have emerged as a promising green alternative, offering advantages such as low toxicity, biodegradability, and the ability to dissolve a wide range of biomolecules. This review provides a comprehensive overview of recent trends in the application of NADESs for extracting bioactive compounds from sustainable sources. The review explains the composition and principles of preparation and highlights various applications of NADESs in extracting different classes of bioactive compounds, emphasizing their potential to revolutionize extraction processes. By summarizing the latest advancements and trends, this review aims to support research and industrial applications of NADESs, promoting more sustainable and efficient extraction methods in the food and agricultural sectors.

Deep eutectic solvent extraction of myricetin and antioxidant properties

In this study, a response surface method (RSM) was used to optimise the ultrasonic-assisted deep eutectic solvent (DES) extraction of myricetin from myricetin leaves. The results demonstrated that the DES-5 (choline chloride-oxalic acid) system exhibited better extraction results than the other seven DESs prepared. The optimum extraction conditions for myricetin were a DES-5 system with 19% water content of DES, a liquid-to-solid ratio of 37 : 1 mL g-1, an extraction time of 45 min, and an extraction temperature of 72 °C. Under these conditions, the extraction amount of myricetin was 22.47 mg g-1. To optimise the extraction process, the crude myricetin extract was purified, and the optimal conditions were as follows: an AB-8 macroporous adsorption resin was used with an anhydrous ethanol desorption agent. The adsorption rate was 1 BV per h (bed volume per hour), the desorption rate was 1 BV per h, and the desorption capacity was 2 BV (bed volume). The antioxidant properties of the myricetin were also investigated. The results demonstrated that, with an increase in concentration, the scavenging rates of DPPH and ˙OH free radicals increased. Compared to Vc, myricetin had a better scavenging ability for DPPH free radicals, whereas purified myricetin had a better antioxidant effect. At the same concentration, the radical-scavenging rate of the ˙OH radical was slightly higher in myricetin purified by the macroporous adsorption resin than in Vc, and that of the unpurified myricetin was the smallest. Myricetin was purified using a macroporous adsorption resin to improve its antioxidant properties.

Simultaneously efficient dissolution and structural modification of chrysanthemum pectin: Targeting at proliferation of Bacteroides

Pectic polysaccharide is a bioactive ingredient in Chrysanthemum morifolium Ramat. 'Hangbaiju' (CMH), but the high proportion of HG domain limited its use as a prebiotic. In this study, hot water, cellulase-assisted, medium-temperature alkali, and deep eutectic solvent extraction strategies were firstly used to extract pectin from CMH (CMHP). CMHP obtained by cellulase-assisted extraction had high purity and strong ability to promote the proliferation of Bacteroides and mixed probiotics. However, 4 extraction strategies led to general high proportion of HG domain in CMHPs. To further enhance the dissolution and prebiotic potential of CMHP, pectinase was used alone and combined with cellulase. The key factor for the optimal extraction was enzymolysis by cellulase and pectinase in a mass ratio of 3:1 at 1 % (w/w) dosage. The optimal CMHP had high yield (15.15 %), high content of total sugar, and Bacteroides proliferative activity superior to inulin, which was probably due to the cooperation of complex enzyme on the destruction of cell wall and pectin structural modification for raised RG-I domain (80.30 %) with relatively high degree of branching and moderate HG domain. This study provided a green strategy for extraction of RG-I enriched prebiotic pectin from plants.