Subcritical water extraction of essential oils and plant oils

Subcritical water extraction is a green technology with interesting advantages in relation to the possibility of processing fresh raw materials to sustainably obtain natural valuable products. The potential of this technology for the aqueous extraction of lipophilic fractions from plant biomass is well known and has recently attracted renewed interest. This review presents an update of the advances on the extraction of two valuable types of lipophilic products, essential oils and vegetal lipids from various plant biomasses. It also emphasizes the effect of process variables as particle size, time, liquid to solid ratio, pressure and temperature as well as the operation tunability to select optimal conditions for different solutes. The optimal operation conditions play a key role to efficiently recover these natural products with potential applications in cosmetic, food, agricultural and pharmaceutical/medical industries

Microwave-assisted extraction of Ulva spp. including a stage of selective coagulation of ulvan stimulated by a bio-ionic liquid

Microwave-assisted hydrothermal processing was proposed to recover high valuable compounds with antioxidant and gelling features from Ulva spp. green seaweed. The influence of the extraction conditions on the solubles, ulvan fraction and residual solid phase was studied to achieve a global valorization of the seaweed. A particular emphasis was placed on the selective coagulation of ulvan stimulated by a bio-ionic liquid during the extraction process. The achieved outcomes indicated that the selected microwave treatment exhibited a notable impact on the phytochemical properties of the soluble extracts, with the highest values of sulfate and protein content at 160 °C, and the highest antioxidant features at 200 °C. The most prominent molecular weight distributions were also identified for systems hydrothermal treated at 160 °C. The ulvan analyses showed that those extracted after microwave treatment at 160 °C showed the highest yields, molecular weight and the strongest gel features from the rheological point of view. The presence of the chloride chlorine during the extraction process favored the ulvan performance and the enhancement of the corresponding viscoelastic properties.Agencia Estatal de Investigación | Ref. RYC2018-024454-IXunta de Galicia | Ref. ED431F 2020/01ED481D-2022/018Financiado para publicación en acceso aberto: Universidade de Vigo/CISU

Evernia prunastri lichen as a source of bioactive glucans with potential for topical applications

Microwave hydrothermal treatment was selected to extract valuable fractions with bioactive and gelling properties from Evernia prunastri lichen with potential for topical applications. The impact of the extraction processing conditions on the soluble extracts, mucilage fraction and residual solid phase was analyzed within a lichen global valorization approach. A particular stress was made on the thermo-rheological and structural characteristics of the extracted glucan and galactomannan polymers, the corresponding gelled matrices, and their cosmetic feasibility. Results revealed that the proposed microwave-assisted treatment showed a relevant influence on the phytochemical features of the aqueous soluble extracts, accounting the major protein content at 120 °C and the enhanced antioxidant and anti-tyrosinase properties at 140 °C. Extracts at 200 °C showed the highest anti-inflammatory (COX-1 and COX-2 inhibition) efficacies. The biopolymer analyses indicated that those recovered after lichen hydrothermal treatment at 160 °C featured a good extraction performance, the highest molecular weight, apparent viscosity, and antiproliferative potential. The thermo-rheological properties of the corresponding matrices formulated at 10 % and 60 or 80 °C exhibited the strongest and most thermo-reversible characteristics, as well as antifreezing feasibility. Another advantage of the selected fractions was the absence of skin irritation according to the in vitro skin irritation assay.Xunta de Galicia | Ref. GRC-ED431C 2022/08Agencia Estatal de Investigación | Ref. RYC2018-024454-IXunta de Galicia | Ref. ED431F 2020/01Xunta de Galicia | Ref. ED481D-2022/018Universidade de Vigo/CISU

Valorisation of Camellia sinensis branches as a raw product with green technology extraction methods

This work deals with the study of tea stalks from pruning debris using environmental friendly extraction technology to offer new healthy properties. In the manufacturing tea industry, tea trees require to be pruned every year and most of their remains are discarded as a waste with no economic value. Microwave aqueous extraction and pressurized hot water extraction process (autohydrolysis) were used to recover bioactive compounds from the tea branches. Operating at a fixed solid: liquid ratio (1:15), the effect of the maximum heating temperatures from 140 to 220 °C was studied. Liquid extracts were analysed for total phenolic, oligosaccharides, protein, mineral and heavy metals content, as well as for antioxidant capacity. The antitumoral possibilities were also determined for selected samples. The obtained results indicated that both processes could be used as an alternative to recover bioactive compounds from tea wastes, although microwave-assisted extraction allowed saving time when compared with autohydrolysis processing. The temperature exhibited a relevant effect on the total phenolic content and antioxidant capacity, decreasing with the microwave treatment and increasing with the autohydrolysis temperature. The obtained extracts could be adequate for incorporation in food and non-food fields.Ministerio de Economía y Competitividad | Ref. IJCI-2016-27535Ministerio de Ciencia, Innovación y Universidades | Ref. RYC2018- 024454-

Spray-drying microencapsulation of tea extracts using green starch, alginate or carrageenan as carrier materials

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGTea industry generates many by-products which could be used to produce and incorporate bioactive tea extracts (TE) into nutraceuticals, cosmetics and/or clinical applications. However, sensibility to external factors is a major disadvantage hindering its utilization. This study deals with the implementation and characterization of suitable biopolymer delivery systems based on starch, carrageenan or alginate, as microencapsulation, to stabilize and protect TE through innovative thin-carbohydrate-coated formulations. TE were spray-dried and microencapsulated in recycled carrier materials (alginate, carrageenan or starch). Product yields varied from 55 to 58%. High microencapsulation and loading efficiencies were achieved (60–93% and 65–84%, respectively). Antioxidant capacity varied from 32 to 46 g Trolox/100 g extract, within different carrier-systems; which also showed promising rheological and UV-protective properties when transformed into gels. Total phenolic content, particle-size distribution, HPSEC-analysis, SEM-analysis and FTIR-analysis were also performed. In sum, this paper characterizes and discusses the high potential of these recycled carbohydrate-coated microparticles for future applicationsMinisterio de Ciencia, Innovación y Universidades | Ref. RYC2018-024454-IXunta de Galicia | Ref. ED431F 2020/01Xunta de Galicia | Ref. ED481B 2018/07

A rheological approach of seawater-based natural cosmetics with extracts from sonicated medicinal herbs

An eco-friendly ultrasound assisted extraction of high-valuable compounds from four medicinal herbs such as thyme, sage, lavender and rosemary with their corresponding characterization was studied. A rheological approach of the proposed seawater based personal care products prepared in the presence of these soluble extracts was addressed without jeopardizing their technological aptitude. Results indicated that soluble extracts from thyme exhibited the highest phenolic content and antiradical potential (>30 g gallic acid equivalent/100 g extract, >130 g Trolox equivalent/100 g extract, DPPH - IC50: 0.37 g/L). Color testing showed that seawater-based both body milk and shampoo formulations incorporated with soluble extracts featured light ocher brown systems, achieving the darkest color for those made in the presence of extracts from thyme. Rheological outcomes indicated that the developed matrices with extracts from medicinal herbs exhibited at rest solid-like structure for body milks and liquid-like for shampoos with magnitudes comparable to their synthetic counterparts, being those added with thyme extracts the ones that featured the smoothest viscous profiles. These matrices suggested the enhancement of features for applicability and processing. The proposed cosmetics also showed neither hysteresis nor syneresis for a month stored at room temperature and in the cold.Xunta de Galicia | Ref. EDC431C/2022/08Xunta de Galicia | Ref. ED481D-2022/018Agencia Estatal de Investigación | Ref. RYC2018-024454-IXunta de Galicia | Ref. ED431F 2020/0

Physicochemical evaluation of personal care products Ddeveloped with Chondrus crispus fractions processed by ecofriendly methodologies

Novel personal care products are necessary to cope with the growing market demand for sustainable green products. In this context, this work deals with the formulation and fundamental physicochemical and rheological characterization of different natural personal care products using bioactive fractions from Chondrus crispus red macroalgae extracted under optimized green conditions. Body milks, body oils and shampoos were supplemented with soluble extracts with antioxidant features recovered after hydrothermal (200 °C) and microwave (170 °C)- and ultrasound (80 °C)-assisted extraction of the red macroalgae used as raw material. Formulated products were also compared with those prepared using (±)-α-tocopherol and butylhydroxytoluene standards. Body scrubs were formulated with the remaining solids (<2.25 %) after microwave hydrodiffusion and gravidity treatment of the macroalgae. Results indicated that selected extracts provided personal care products with similar or even better physicochemical, color and viscous features than those supplemented with (±)-α-tocopherol or butylhydroxytoluene commercial antioxidants. Rheological profiles indicated that it is possible to develop personal care products with adequate viscous behavior (102–105 mPa s, at 1 s−1), comparable with their synthetic counterparts. To conclude, the addition of antioxidant extracts led to lower apparent viscosity values suggesting an advantage from the skin applicability point of view, jointly with the absence of both the hysteresis phenomenon and water syneresis of the proposed formulations.Xunta de Galicia | Ref. ED431F 2020/01Ministerio de Ciencia, Innovación y Universidades | Ref. RTI2018-096376-B-I00Ministerio de Ciencia, Innovación y Universidades | Ref. RYC2018-024454-

Intensification and biorefinery approaches for the valorization of kitchen wastes – A review

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGKitchen wastes (KW) are post-consumption residues from household and food service sector, heterogenous in composition and highly variable depending on the particular origin, which are often treated as municipal. There is a need to improve the management of these continuously produced and worldwidely available resources and their valorization into novel and commercially interesting products will aid in the development of bioeconomy. The successful implementation of such approach requires cooperation between academia, industrial stakeholders, public and private institutions, based on the different dimensions, including social, economic, ecologic and technological involved. This review aims at presenting a survey of technological aspects, regarding current and potential management strategies of KW, following either a single or multiproduct processing according to the biorefineries scheme. Emphasis is given to intensification tools, designed to enhance process efficiency

Characterization of the antiproliferative activity of Sargassum muticum low and high molecular weight polysaccharide fractions

The extract obtained by pressurized hot water extraction from Sargassum muticum, to recover the bioactive compound known as fucoidan, was fractionated using membranes of 100, 50, 30, 10, and 5 kDa, obtaining five retentates and the final permeate. These fractions were characterized for phloroglucinol content, protein content, sulfate content, and trolox equivalent antioxidant capacity (TEAC); apart from oligosaccharides, FTIR and molar mass distribution were also evaluated. Retentates of 100 and 50 kDa showed higher values for phloroglucinol, TEAC, and sulfate content. The rheology of the alginate fraction was also evaluated. Regarding the potential antitumoral activity, all fractions were assessed in MCF-7 cells using a metabolic activity assay based on the reduction of a tetrazolium compound, the most efficient being R100 and R50. Based on the results, these fractions were compared with commercial fucoidans at the same concentrations, and similar results were found. In addition, synergistic cytotoxic effects using two drugs commonly used in breast cancer, cis-Platinum (cis-Pt) and 5-fluorouracil (5-FU), were tested in combination with R100 and R50. Promising results were obtained when the retentate and the drugs were mixed, showing an improvement in the cytotoxicity induced by the chemotherapy.Xunta de Galicia | Ref. ED481D-2022-018Xunta de Galicia | Ref. ED481A-2018/294Agencia Estatal de Investigación | Ref. RYC2018-024454-IXunta de Galicia | Ref. ED431F 2020/01Xunta de Galicia | Ref. ED431C-2020/02Xunta de Galicia | Ref. ED431C-2022/0

Green extraction of antioxidant fractions from Humulus lupulus varieties and microparticle production via spray-drying

The formulation of polymeric microparticles to encapsulate bioactive compounds from two hop varieties (Nugget and Perle) using sequential green extraction processes was performed. The technologies used were ultrasound-assisted extraction (UAE) and pressurized hot water (PHW) extraction. Liquid phases were analyzed for total phenolic content (~2%), antioxidant activity (IC50, DPPH: 3.68 (Nugget); 4.46 (Perle) g/L, TEAC (~4–5%), FRAP (~2–3%), and reducing power (~4%)), protein content (~1%), oligosaccharide content (~45%), and for structural features. The fractions obtained from UAE were selected to continue with the drying process, achieving the maximum yield at 120 °C (Perle) and 130 °C (Nugget) (~77%). Based on these results, the formulation of polymeric microparticles using mannitol as the carrier was performed with these fractions. The production yield (~65%), particle size distribution (Perle: 250–750 µm and Nugget: ~100 µm), and rheological features (30–70 mPa s at 0.1 s−1) were the parameters evaluated. The UAE extracts from hop samples processed using a sustainable aqueous treatment allowed the formulation of microparticles with a suitable yield, and morphological and viscosity properties adequate for potential food and non-food applications.Agencia Estatal de Investigación | Ref. RYC2018‐024454‐IXunta de Galicia | Ref. ED431F 2020/01Xunta de Galicia | Ref. ED481D‐2022‐01