Selective extraction of high-value phenolic compounds from distillation wastewater of basil (Ocimum basilicum L.) by pressurized liquid extraction

Pressurized liquid extraction of glucosinolates from Camelina sativa (L.) Crantz by-products: Process optimization and biological activities of green extract

The cultivation of Camelina sativa (L.) Crantz is rapidly increasing due to oil production resulting in a substantial volume of by-products, which still have an interesting composition in secondary metabolites, especially glucosinolates. Therefore, a green extraction procedure of glucosinolates by Pressurised Liquid Extraction was developed and optimized using a chemometric approach. Furthermore, the glucosinolates were purified by solid phase extraction, and a preliminary study on bioaccessibility and bioavailability study was carried out to evaluate the resistance of the glucosinolates to the digestive process. The application of pressurised liquid extraction to the recovery of glucosinolates from camelina sativa by-product, is a green, automatic, and rapid method, representing a valid alternative to conventional extraction method to obtain ingredients for food industries.

Distillation of essential oils: An innovative technological approach focused on productivity, quality and sustainability

Essential oil (EO) distillation units, which are commonly installed on farms, have difficultly accessing knowledge centers. The apparent simplicity of the process hides unwanted losses and deviations that go undetected and, therefore, not corrected. This article proposes improvements to the process that are based on "4.0" technologies in order to detect and correct two important deficiencies, with an impact on the yield, quality and environmental performance. The first deficiency comprises the steam channels that are formed through green mass (channeling), are well known and are considered normal by EO producers. Without detection and correction, this negatively affects the extraction results. The second is the lack of technology that is able to automatically determine the extraction endpoint. Smart sensing, control, self-configuration and the dynamic determination of improved process parameters make up a set of actions undertaken by a smart extraction plant (50-liter capacity). Nineteen experiments using lemongrass (Cymbopogon citratus) exhibited remarkable 24% and 10% improvements in the yield and quality, respectively. Energy consumption and a more than 50% reduction in the processing complete the set of results achieved. In addition to manufacturing costs and the utilization of capacity, better sustainability indicators are positive consequences of this technological updating.

Hansen Solubility Parameters Applied to the Extraction of Phytochemicals

In many analytical chemical procedures, organic solvents are required to favour a better global yield upon the separation, extraction, or isolation of the target phytochemical analyte. The selection of extraction solvents is generally based on the solubility difference between target analytes and the undesired matrix components, as well as the overall extraction procedure cost and safety. Hansen Solubility Parameters are typically used for this purpose. They are based on the product of three coordinated forces (hydrogen bonds, dispersion, and dipolar forces) calculated for any substance to predict the miscibility of a compound in a pure solvent, in a mixture of solvents, or in non-solvent compounds, saving time and costs on method development based on a scientific understanding of chemical composition and intermolecular interactions. This review summarises how Hansen Solubility Parameters have been incorporated into the classical and emerging (or greener) extraction techniques of phytochemicals as an alternative to trial-and-error approaches, avoiding impractical experimental conditions and resulting in, for example, saving resources and avoiding unnecessary solvent wasting.

From Aloe vera Leaf Waste to the Extracts with Biological Potential: Optimization of the Extractions, Physicochemical Characterization, and Biological Activities

In the study, the optimization of the extraction from Aloe vera leaf waste was performed via varying solid-to-solvent ratio, solvent type, extraction time, and technique (maceration, heat-, ultrasound-, and microwave-assisted extractions-HAE, UAE, and MAE, respectively). The optimal extraction conditions for achieving the highest polyphenol content are a 1:30 ratio, 70% ethanol, and 30 min of HAE. Total flavonoid and protein contents were significantly higher in the extract from MAE, while total condensed tannin content was the highest in HAE. LC-MS analysis quantified 13 anthraquinone and chromone compounds. The variations in the FT-IR spectra of the extracts obtained by different extraction procedures are minor. The influence of extraction conditions on the antioxidant ability of the extracts depended on applied antioxidant assays. The extracts possessed medium inhibition properties against Staphylococcus aureus and weak inhibitory activity against Enterococcus feacalis. The extracts had stimulative effect on HaCaT cell viability. Regarding the extraction yield, there was a significant difference between the used extraction techniques (MAE > HAE > maceration and UAE). The presented study is an initial step in the production of polyphenol-rich extracts from A. vera leaf waste aimed to be used for the potential preparation of pharmaceutical and cosmetic formulations for the skin.

Valorisation, Green Extraction Development, and Metabolomic Analysis of Wild Artichoke By-Product Using Pressurised Liquid Extraction UPLC-HRMS and Multivariate Data Analysis

Valorisation of food by-products has recently attracted considerable attention due to the opportunities to improve the economic and environmental sustainability of the food production chain. Large quantities of non-edible parts of the artichoke plant (Cynara cardunculus L.) comprising leaves, stems, roots, bracts, and seeds are discarded annually during industrial processing. These by-products contain many phytochemicals such as dietary fibres, phenolic acids, and flavonoids, whereby the most challenging issue concerns about the recovery of high-added value components from these by-products. The aim of this work is to develop a novel valorisation strategy for the sustainable utilisation of artichoke leaves' waste, combining green pressurised-liquid extraction (PLE), spectrophotometric assays and UPLC-HRMS phytochemical characterization, to obtain bioactive-rich extract with high antioxidant capacity. Multivariate analysis of the major selected metabolites was used to compare different solvent extraction used in PLE.

Plant Secondary Metabolites: An Opportunity for Circular Economy

Moving toward a more sustainable development, a pivotal role is played by circular economy and a smarter waste management. Industrial wastes from plants offer a wide spectrum of possibilities for their valorization, still being enriched in high added-value molecules, such as secondary metabolites (SMs). The current review provides an overview of the most common SM classes (chemical structures, classification, biological activities) present in different plant waste/by-products and their potential use in various fields. A bibliographic survey was carried out, taking into account 99 research articles (from 2006 to 2020), summarizing all the information about waste type, its plant source, industrial sector of provenience, contained SMs, reported bioactivities, and proposals for its valorization. This survey highlighted that a great deal of the current publications are focused on the exploitation of plant wastes in human healthcare and food (including cosmetic, pharmaceutical, nutraceutical and food additives). However, as summarized in this review, plant SMs also possess an enormous potential for further uses. Accordingly, an increasing number of investigations on neglected plant matrices and their use in areas such as veterinary science or agriculture are expected, considering also the need to implement "greener" practices in the latter sector.

Selective extraction of bioactive compounds from plants using recent extraction techniques: A review

Plant extraction has existed for a long time and is still of interest. Due to technological improvements, it is now possible to obtain extracts with higher yields. While global yield is a major parameter because it assesses the extraction performance, it can be of interest to focus on the extraction of particular compounds (specific metabolites) to enrich the sample and to avoid the extraction of unwanted ones, for instance the primary metabolites (carbohydrates, triacylglycerols). The objective then is to improve extraction selectivity is then considered. In solid-liquid extraction, which is often called maceration, the solvent has a major impact on selectivity. Its polarity has a direct influence on the solutes extracted, related to the chemical structure of the compounds, and modelling compound/solvent interactions by using various polarity or interaction scales is a great challenge to favor the choice of the appropriate extracting liquid. Technical advances have allowed the development of recent, and sometimes green, extraction techniques, such as Microwave-Assisted Extraction (MAE), Ultrasound-Assisted Extraction (UAE), Pressurized Liquid Extraction (PLE) and Supercritical Fluid Extraction (SFE). This review focuses on the specificity of these recent techniques and the influence of their physical parameters (i.e. pressure, intensity, etc.). In addition to the solvent selection, which is of prime interest, the physical parameters applied by the different techniques influence the extraction results in different ways. Besides, SFE is a versatile and green technique suitable to achieve selectivity for some compounds. Due to its properties, SC-CO₂ allows tailoring conditions to improve the selectivity.

A sustainable approach for the extraction of cholesterol-lowering compounds from an olive by-product based on CO2-expanded ethyl acetate

Olive (Olea europaea) processing results in large amounts of by-products that contain valuable molecules such as phenolic compounds and phytosterols. These molecules have demonstrated to reduce blood cholesterol levels. This work proposes the development of a method to obtain simultaneously phenolic compounds and phytosterols from the olive stone using CO₂-expanded liquid extraction. Hansen solubility parameters were employed for the theoretical prediction of the most suitable bio-based solvent to extract target compounds. The Box-Behnken experimental design was employed to select the optimal conditions of pressure (8-25 MPa), the molar fraction of CO₂ in ethyl acetate (0.15-0.55), and the temperature (40-80 °C). Extracts showing the highest and the lowest reductions of micellar cholesterol solubility capacity were analyzed by gas chromatography coupled to mass spectrometry to find out the compounds responsible for this activity. Different phenolic compounds, free fatty acids, and phytosterols were identified in the extracts. β-Sitosterol and, especially, tyrosol and hydroxytyrosol were the compounds that primarily contributed to the reduction of micellar cholesterol solubility capacity.