Effect of oil extraction methods on walnut oil quality characteristics and the functional properties of walnut protein isolate

Walnut oils were obtained by supercritical carbon dioxide extraction (SCB), cold-pressing (CP), hexane extraction (HE), and subcritical butane extraction (SBE), and walnut protein isolates (WPI) from the walnut cakes were performed. The results indicate that SCB has the highest oil yield for walnut oil, which was 62.72%, and the total content of trace nutrients (total tocopherols, total phytosterols, and total phenolic compounds) in SCB-walnut oil was also the highest at 2186.75 mg/kg, approximately 1.05 times higher than CP-walnut oil and 1.21 times higher than SBE-walnut oil. Meanwhile, the treatment of WPI with SCB results in a decrease in β-Sheet and α-Helix structures and an increase in β-Turn and Random coil structures. Thereby increasing its oil-holding capacity (OHC) and solubility by approximately 1.16 times and 1.27 times compared to CP, respectively. Interestingly, SCB as a green oil production technology, also has good prospects for retaining WPI functionality characteristics.

Valorization of tuberose flower waste through development of therapeutic products using supercritical carbon dioxide extraction and microencapsulation technologies

Tuberose flowers (Calcutta Single variety) valued as ornamentals globally, have short shelf-lives of 8 days at 4 ± 1 °C and are therefore discarded post senescence. Previous investigations from our laboratory have established that a combination treatment using GRAS preservatives [(sucrose (4%) and CaCl2 (0.02%)]-cum-gamma-irradiation (0.02 kGy) could extend its shelf-life to 24 days, when stored at 4 ± 1 °C with concomitant enhancement in the content of its bioactive principle, viz. methyl eugenol. Supercritical carbon dioxide (SC-CO2) extract of the tuberose flower wastes post combination treatment therefore had a higher methyl eugenol content (4.11 ± 0.05 µg/g), vis-à-vis its non-treated counterpart (2.03 ± 0.03 µg/g), and thus significantly higher antioxidant and antimicrobial potencies (MIC values of 1.83 ± 0.02 mg/ml and 1.98 ± 0.03 mg/ml against S. aureus ATCC 25923 strain and MDR strain, respectively). The microencapsulated powder of the extract (MEp) obtained by spray drying was applied for healing of epidermal wounds created on New Zealand white rabbits, post skin irritancy test (wherein no clinical sign of toxicity, redness or swelling was observed). When MEp was applied, accelerated healing occurred which commenced on day 2 and was completed by day 6 vis-à-vis that of the control powder set (without extract) which showed no signs of wound healing. Therefore, the sensorially compromised-senesced tuberose flowers, a rich source of methyl eugenol, has been successfully valorized through utilization of the same in developing a novel topical antibiotic powder against potent skin pathogens.

Investigation of the chemical structure of anti-amyloidogenic constituents extracted from Thamnolia vermicularis

ETHNOPHARMACOLOGICAL RELEVANCE

Thamnolia vermicularis (Sw.) Schaer (T. vermicularis) is known to have therapeutic effects on various diseases in Southwest China. Recent research has highlighted that T. vermicularis may suppress Aβ level and Tau hyperphosphorylation to improve the pathological characteristics of Alzheimer's disease, indicating that it might have the potential to treat Alzheimer's disease.

AIM OF THE STUDY

The objective of this study was to evaluate the inhibitory effect of T. vermicularis on the fibril formation of a typical amyloidogenic protein, hen egg white lysozyme (HEWL), and to identify the effective components that could potentially enable an extract of T. vermicularis to be used in the development of novel therapeutic agents.

MATERIALS AND METHODS

A water extract was prepared from T. vermicularis (TVWE) and its inhibitory effect on amyloid fibrillation in vitro was investigated using thioflavin T and 8-anilinonapthalene-1-sulfonic acid spectrofluorometric analyses. The anti-amyloidogenic components of TVWE were separated and qualitatively analyzed using thin layer chromatography (TLC), supercritical carbon dioxide extraction (SFE-CO₂), and liquid chromatography-mass spectrometry. Finally, the effect of the bioactive components on the structure of HEWL in the early stages of fibrillogenesis was determined by molecular docking simulation.

RESULTS

TVWE strongly inhibited the ability of HEWL to form an amyloid fibril, yielding an IC₅₀ of 0.018 mg/mL for the inhibition of fibrillogenesis. The chemical constituents in the various TVWE fractions resolved by TLC were qualitatively identified by liquid chromatography-quadrupole/time-of-flight mass spectrometry (LC-Q-TOF-MS). The target components were predicted by reviewing the existing literature on T. vermicularis, in which the components of T. vermicularis, along with three small molecules (molecular weight: 182) were preliminarily identified. Molecular docking simulation showed that these small molecules were bound to the core region of HEWL, affecting its stability. Finally, the active anti-amyloidogenic components were extracted from whole T. vermicularis using SFE-CO₂ and then identified.

CONCLUSION

The potential components of TVWE that could prevent HEWL fibrillogenesis were primarily identified using TLC, LC-Q-TOF-MS, and SFE-CO2. The candidate small-molecule compounds were further predicted by combining the LC-Q-TOF-MS results with molecular docking analysis. The effective components of T. vermicularis were extracted using SFE-CO₂. Together, these methods could constitute a practical strategy for the isolation and identification of anti-amyloidogenic components from a traditional Chinese medicine.

Effect of supercritical carbon dioxide fluid extract from Chrysanthemum indicum Linné on bleomycin-induced pulmonary fibrosis

Background

As a prevalent type of cryptogenic fibrotic disease with high mortality, idiopathic pulmonary fibrosis (IPF) still lacks effective therapeutic drugs. The compounds extracted from buds and flowers of Chrysanthemum indicum Linné with supercritical-carbon dioxide fluid (CI_SCFE) has been confirmed to have antioxidant, anti-inflammatory, and lung-protective effects. This paper aimed to clarify whether CI_SCFE could treat IPF induced by bleomycin (BLM) and elucidate the related mechanisms.

Methods

Rats (Sprague-Dawley, male) were separated into the following groups: normal, model, pirfenidone (50 mg/kg), CI_SCFE-L, −M, and -H (240, 360, and 480 mg/kg/d, i.g., respectively, for 4 weeks). Rats were given BLM (5 mg/kg) via intratracheal installation to establish the IPF model. A549 and MRC-5 cells were stimulated by Wnt-1 to establish a cell model and then treated with CI_SCFE. Haematoxylin-eosin (H&E) and Masson staining were employed to observe lesions in the lung tissues. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot (WB) were performed to observe changes in genes and proteins connected with the Wnt/β-catenin pathway.

Results

CI_SCFE inhibited the proliferation of MRC-5 cells (IC₅₀: 2.723 ± 0.488 μg/mL) and A549 cells (IC₅₀: 2.235 ± 0.229 μg/mL). In rats, A549 cells, and MRC-5 cells, BLM and Wnt-1 obviously induced the protein expression of α-smooth muscle actin (α-SMA), vimentin, type I collagen (collagen-I), and Nu-β-catenin. The mRNA levels of matrix metalloproteinase-3 (MMP-3) and − 9 (MMP-9), two enzymes that degrade and reshape the extracellular matrix (ECM) were also increased while those of tissue inhibitor of metalloproteinase 1 (TIMP-1) were decreased. However, CI_SCFE reversed the effects of BLM and Wnt-1 on the expression pattern of these proteins and genes.

Conclusion

These findings showed that CI_SCFE could inhibit IPF development by activating the Wnt/β-catenin pathway and may serve as a treatment for IPF after further investigation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03409-9.

Response surface methodology to optimize supercritical carbon dioxide extraction of Polygonum cuspidatum

BACKGROUND

Resveratrol and emodin are abundant polyhydroxy compounds that are found in the Chinese traditional medicinal herb Polygonum cuspidatum and widely used due to their excellent antioxidant properties.

OBJECTIVE

This study aimed to obtain the maximum extraction yields of resveratrol and emodin from the P. cuspidatum via green extraction.

METHODS

The extracts were acquired through supercritical carbon dioxide (SC-CO2) extraction with ethanol as cosolvent. The independent variables of the extraction process, namely, temperature (45-55 °C), the pressure (20-30 MPa), and the ethanol content (80 -120 mL/L), were optimized by response surface methodology (RSM).

RESULTS

These variables extremely affected the yields of resveratrol and emodin. Second-order polynomial mathematical models were developed and applied to predict the optimal extraction conditions (i.e., temperature of 51.8 °C, pressure of 25.34 MPa, and ethanol content of 110.83 mL/L). Under these conditions, confirmatory experiment displayed that the yields of resveratrol and emodin were 2.564 ± 0.121 and 2.804 ± 0.108 mg/g, respectively. High antioxidant properties, strong free radical scavenging ability, and good reducing ability were observed for the extracts.

CONCLUSION

Resveratrol and emodin could be successfully extracted from P. cuspidatum by SC-CO2, and RSM can effective optimize the process.

HIGHLIGHTS

The SC-CO2 extraction of resveratrol and emodin from P. cuspidatum was developed, and RSM was successfully used to optimize the extraction parameters and predict the optimal conditions.

Supercritical carbon dioxide extracts of small cardamom and yellow mustard seeds have fasting hypoglycaemic effects: diabetic rat, predictive iHOMA2 models and molecular docking study

In the present investigation, the supercritical carbon dioxide (SC-CO2) extracts of small cardamom (SC) and yellow mustard (YM) seeds have been investigated for their efficacies in combating type 2 diabetes in streptozotocin-induced Wistar albino rats. Fasting blood glucose (FBG) levels in the rats were monitored on days 8, 15 and 21. On day 15, FBG level reduced appreciably by 31·49 % in rats treated with SC seed extract and by 32·28 % in rats treated with YM seed extract, comparable to metformin (30·70 %) and BGR-34 (a commercial polyherbal drug) (31·81 %) administered rats. Either extract exhibited desirable effects on hepatic glucose-6-phosphatase, glucose-6-phosphate dehydrogenase (G6PD) and catalase activities in controlling diabetes. A molecular docking exercise was conducted to identify specific compounds in the extracts which possessed augmenting effect on G6PD. The results revealed that all the bioactive compounds in the extracts have binding affinities with the enzyme and contributed to the antidiabetic efficacies of the extracts as G6PD augmenters. The effects of the extracts on insulin sensitivity and glucose uptake were investigated using non-invasive modelling by iHOMA2 software. This in vitro approach indicated that extract administration resulted in increased both insulin sensitivity of the liver and glucose uptake in the gut. The findings of the present study attest these SC-CO2 extracts of the spices as safe alternatives of metformin and BGR-34 in combating type 2 diabetes and could be safely subjected to clinical studies. These extracts could also be employed in designing proactive food supplements in mitigating the metabolic disorder.

Chemistry, oxidative stability and bioactivity of oil extracted from Rosa rugosa (Thunb.) seeds by supercritical carbon dioxide

Rosa rugosa Thunb. seed oil (RR) extracted by supercritical CO₂ was investigated. RR chemical composition, radical scavenging effect and oxidative stability were evaluated. RR aqueous emulsions were examined for cell cytotoxicity, proliferation, redox state and migration using mouse embryonic fibroblast Balb/3T3, human dermal fibroblast NHDF cell lines, and on neoplastic cell lines: acute monocytic leukemia THP-1 and lung adenocarcinoma A549. RR total contents of phytosterols, tocopherols, carotenoids and phenolics were 10115.23, 784.16, 40.32 and 10.30 mg/kg, respectively. Rich antioxidant composition of RR was reflected in its high antioxidant activity (2.1 mM/kg Trolox equivalent) as well as oxidative stability (activation energy 105.6 kJ/mol). The RR emulsions led to marked augmentation of the total cell protein content in BALB/3T3 and NHDF cultures, inhibited cancer cell migration and reduced ROS formation. The studied RR oil proved to have a remarkable combination of bioactive compounds and to exert an antioxidative and chemopreventive effects.

Consecutive high-pressure and enzyme assisted fractionation of blackberry (Rubus fruticosus L.) pomace into functional ingredients: Process optimization and product characterization

In this study supercritical carbon dioxide (SFE-CO₂) and pressurized liquid (PLE) extractions were optimized for the recovery of valuable fractions from blackberry pomace. Consecutively applied SFE-CO₂ and PLE at optimized parameters yielded 9.9, 26.3 and 5.1 g/100 g of CO₂, ethanol (EtOH) and water-soluble extracts, respectively. Oil of lipophilic fraction was composed mainly of healthy polyunsaturated fatty acids (linoleic 64.1%, α-linolenic 12.9%), while polar solvents effectively recovered antioxidants (up to 29.1 mg gallic acid and 168.7 mg Trolox equivalents from g pomace). PLE-EtOH extract contained 12.2 mg/g of cyanidin-3-glucoside, while other anthocyanins were detected in significantly lower quantities (0.5-0.7 mg/g). SFE-CO₂ and PLE reduced the antioxidant capacity of starting plant material by 86-93%. In terms of extraction time, solvent consumption, total yields, and phytochemical characteristics, high-pressure fractionation was more efficient for obtaining valuable pomace constituents as compared to conventional and enzyme-assisted extractions.

Consortia of bioactives in supercritical carbon dioxide extracts of mustard and small cardamom seeds lower serum cholesterol levels in rats: new leads for hypocholesterolaemic supplements from spices

Melatonin-rich and 1,8-cineole-rich extracts have been successfully obtained from yellow mustard (YM) and small cardamom (SC) seeds, respectively, employing green technology of supercritical CO₂ (SC-CO₂) extraction. Chemical profiling confirmed the presence of melatonin and 1,8-cineole and co-extractants in the respective extracts. Electron paramagnetic resonance spectroscopy attested strong antioxidant activities of the extracts foregoing pan-assay interference compounds involved in spectroscopic analysis. These extracts also exhibited synergistic efficacies greater than unity confirming antioxidant synergy among the co-extracted bioactives therein. To ascertain hypocholesterolaemic efficacies, these extracts were co-administered orally with Triton X (at the pre-optimised dose of 175 mg/kg body weight (BW)) to Wistar albino rats at doses of 550, 175 and 55 mg/kg BW. Serum total cholesterol levels in the rats were monitored on days 3, 7, 15 and 21. On day 21, total cholesterol level reduced appreciably by 49·44 % in rats treated with YM seed extract and by 48·95 % in rats treated with SC seed extract, comparable with atorvastatin-administered rats (51·09 %). Either extract demonstrated inhibitory effects on hepatic 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase activity. A molecular docking exercise identified specific compounds in the extracts which possessed binding affinities comparable with therapeutically used HMG-CoA reductase inhibitors. In silico and in vivo studies concertedly concluded that the consortium of bioactive components in the extracts cannot be considered as invalid metabolic panaceas and therefore these 'green' extracts could be safely subjected to clinical studies as preventive biotherapeutics for hypercholesterolaemia. These extracts could be consumed per se as hypocholesterolaemic supplements or could be ingredients of new spice-based therapeutic foods.

Effect of pressure variation on the efficiency of supercritical fluid extraction of wild carrot (Daucus carota subsp. maritimus) extracts

The present study was conducted to check the comparative qualities of essential oils prepared by hydrodistillation (HD) and supercritical fluid techniques. It constitutes the first attempt to investigate the chemical composition of Daucus carota subsp. maritimus extracts using supercritical fluid technology (SFE) as an environmentally clean innovative method of extraction. The effect of pressure on the nature of extractable substances from wild carrot has been performed at a constant temperature of 50 °C and two different pressures (100 and 300 bar). The experimental results showed that pressure had a significant enhancing effect on the fluid transport properties and therefore on yield values. The extraction yield increases from 1.167 to 2.986% while increasing pressure. The chemical compositions of the essential oils prepared by HD and SFE were analyzed on the basis of gas chromatography-mass spectroscopy (GC-MS). Thus, we noticed that all analyzed samples were enriched in geranyl acetate and β‑bisabolene, and that the quantities of different identified substances were extremely sensitive to the extraction method and to the pressure variation in case of SFE.

CDK2 and Bcl-xL inhibitory mechanisms by docking simulations and anti-tumor activity from piperine enriched supercritical extract

Supercritical fluid technologies offer an innovative method for food industry and drug discovery from natural sources. The aim of the study is to investigate the anti-tumor activity of piperine rich extract by supercritical fluid (SFE) from black pepper (Piper nigrum). In silico docking simulations predicted anti-tumor molecular mechanism and protein-piperine hydrophobic interactions, showing hydrogen bonds between piperine and residue Ser5 inside the ATP binding site in CDK2. Moreover, piperine interacts with peptide substrate residue Lys8 inside its binding site in Cyclin A molecule. Other predicted interaction showed piperine inside the hydrophobic groove of Bcl-xL. Confirming the docking simulation, in vitro assays with SFE (40 °C/30 MPa) showed cytotoxicity to MCF-7 cells (IC50 = 27.8 ± 6.8 μg/ml) correlated to increased apoptosis. Balb/c mice-bearing Ehrlich Ascites Carcinoma (EAC) group that received the SFE (100 mg/kg/day) showed tumor growth inhibition (60%) and increased mice survival (50%), probably related to cell cycle arrest (G2/M) and increased apoptosis. In vivo treatments with SFE increased the expression of pro-apoptotic proteins (p53 and Bax), inhibited cell cycle proteins (CDK2, Cyclin A) and anti-apoptotic protein (Bcl-xL). Thus, confirming in silico predicted inhibitory interactions. These results clearly showed promising performance of the piperine-rich fraction recovered from black pepper, drawing attention to its use as complementary therapy for cancer.

Supercritical carbon dioxide extraction of lutein from yellow maize (Zea mays) kernels: process optimization based on lutein content, antioxidant activity, and ω-6/ω-3 fatty acid ratio

Yellow maize kernels were subjected to supercritical carbon dioxide (SC-CO2) extraction to obtain a lutein-rich extract with potential nutraceutical properties. SC-CO2 extraction parameters (pressure and temperature) were optimized by employing a full-factorial (32) design of experiments and response surface methodology, based on yield of lutein, antioxidant activity, and ω-6/ω-3 fatty acid ratio of the extracts. A Chrastil equation was also developed for predicting the solubility of lutein in SC-CO2 under different extraction conditions. The optimized extraction condition was obtained at 500 bar, 70 °C for 90 min, at which the extract was found to possess a unique combination of the highest lutein yield (275.00 ± 3.50 μg/g of dry weight), along with a well-balanced ω-6/ω-3 fatty acid ratio (3:1). Moreover, the total phenol content and antioxidant activity were also found to be the highest at this condition. This lutein-rich extract is a promising nutraceutical or dietary supplement in the food industry.

Preparation of acellular scaffold for corneal tissue engineering by supercritical carbon dioxide extraction technology

In this study, we developed a novel method using supercritical carbon dioxide (SCCO₂) to prepare acellular porcine cornea (APC). Under gentle extraction conditions using SCCO₂ technology, hematoxylin and eosin staining showed that cells were completely lysed, and cell debris, including nuclei, was efficiently removed from the porcine cornea. The SCCO₂-treated corneas exhibited intact stromal structures and appropriate mechanical properties. Moreover, no immunological reactions and neovascularization were observed after lamellar keratoplasty in rabbits. All transplanted grafts and animals survived without complications. The transplanted APCs were opaque after the operation but became transparent within 2weeks. Complete re-epithelialization of the transplanted APCs was observed within 4weeks. In conclusion, APCs produced by SCCO₂ extraction technology could be an ideal and useful scaffold for corneal tissue engineering.

STATEMENT OF SIGNIFICANCE

We decellularized the porcine cornea using SCCO₂ extraction technology and investigated the characteristics, mechanical properties, and biocompatibility of the decellularized porcine cornea by lamellar keratoplasty in rabbits. To the best of our knowledge, this is the first report describing the use of SCCO₂ extraction technology for preparation of acellular corneal scaffold. We proved that the cellular components of porcine corneas had been efficiently removed, and the biomechanical properties of the scaffold were well preserved by SCCO₂ extraction technology. SCCO₂-treated corneas maintained optical transparency and exhibited appropriate strength to withstand surgical procedures. In vivo, the transplanted corneas showed no evidence of immunological reactions and exhibited good biocompatibility and long-term stability. Our results suggested that the APCs developed by SCCO₂ extraction technology could be an ideal and useful scaffold for corneal replacement and corneal tissue engineering.

Supercritical CO2 extraction of candlenut oil: process optimization using Taguchi orthogonal array and physicochemical properties of the oil

A series of experiments was conducted to determine optimum conditions for supercritical carbon dioxide extraction of candlenut oil. A Taguchi experimental design with L9 orthogonal array (four factors in three levels) was employed to evaluate the effects of pressure of 25-35 MPa, temperature of 40-60 °C, CO2 flow rate of 10-20 g/min and particle size of 0.3-0.8 mm on oil solubility. The obtained results showed that increase in particle size, pressure and temperature improved the oil solubility. The supercritical carbon dioxide extraction at optimized parameters resulted in oil yield extraction of 61.4% at solubility of 9.6 g oil/kg CO2. The obtained candlenut oil from supercritical carbon dioxide extraction has better oil quality than oil which was extracted by Soxhlet extraction using n-hexane. The oil contains high unsaturated oil (linoleic acid and linolenic acid), which have many beneficial effects on human health.

Extraction of microalgae derived lipids with supercritical carbon dioxide in an industrial relevant pilot plant

Microalgae are capable of producing up to 70% w/w triglycerides with respect to their dry cell weight. Since microalgae utilize the greenhouse gas CO₂, they can be cultivated on marginal lands and grow up to ten times faster than terrestrial plants, the generation of algae oils is a promising option for the development of sustainable bioprocesses, that are of interest for the chemical lubricant, cosmetic and food industry. For the first time we have carried out the optimization of supercritical carbon dioxide (SCCO₂) mediated lipid extraction from biomass of the microalgae Scenedesmus obliquus and Scenedesmus obtusiusculus under industrrially relevant conditions. All experiments were carried out in an industrial pilot plant setting, according to current ATEX directives, with batch sizes up to 1.3 kg. Different combinations of pressure (7–80 MPa), temperature (20–200 °C) and CO₂ to biomass ratio (20–200) have been tested on the dried biomass. The most efficient conditions were found to be 12 MPa pressure, a temperature of 20 °C and a CO₂ to biomass ratio of 100, resulting in a high extraction efficiency of up to 92%. Since the optimized CO₂ extraction still yields a crude triglyceride product that contains various algae derived contaminants, such as chlorophyll and carotenoids, a very effective and scalable purification procedure, based on cost efficient bentonite based adsorbers, was devised. In addition to the sequential extraction and purification procedure, we present a consolidated online-bleaching procedure for algae derived oils that is realized within the supercritical CO₂ extraction plant.

Phytochemical composition of fractions isolated from ten Salvia species by supercritical carbon dioxide and pressurized liquid extraction methods

Ten Salvia species, S. amplexicaulis, S. austriaca, S. forsskaolii S. glutinosa, S. nemorosa, S. officinalis, S. pratensis, S. sclarea, S. stepposa and S. verticillata were fractionated using supercritical carbon dioxide and pressurized liquid (ethanol and water) extractions. Fifteen phytochemicals were identified using commercial standards (some other compounds were identified tentatively), 11 of them were quantified by ultra high pressure chromatography (UPLC) with quadruple and time-of-flight mass spectrometry (Q/TOF, TQ-S). Lipophilic CO₂ extracts were rich in tocopherols (2.36-10.07mg/g), while rosmarinic acid was dominating compound (up to 30mg/g) in ethanolic extracts. Apigenin-7-O-β-d-glucuronide, caffeic and carnosic acids were quantitatively important phytochemicals in the majority other Salvia spp. Antioxidatively active constituents were determined by using on-line high-performance liquid chromatography (HPLC) analysis combined with 2,2'-diphenyl-1-picrylhydrazyl (DPPH) assay (HPLC-DPPH). Development of high pressure isolation process and comprehensive characterisation of phytochemicals in Salvia spp. may serve for their wider applications in functional foods and nutraceuticals.

Simultaneous quantification of vitamin E, γ-oryzanols and xanthophylls from rice bran essences extracted by supercritical CO2

Since the nutrition value of rice is diminished during rice processing, technology that can preserve and sustain functional compounds is necessary. In this study, supercritical carbon dioxide (SC-CO2) extraction was optimized for operational conditions (time, temperature, pressure and modifier) to extract vitamin E, γ-oryzanols and xanthophylls from rice bran. The simultaneous quantification of the compounds was developed using high-performance liquid chromatography with diode array and fluorescence detectors. Central composite design and respond surface methodology were applied to achieve optimum extraction conditions. The optimized conditions were 60min, 43°C, 5420psi with 10% ethanol as a modifier. Pigmented rice bran extracts contained greater amounts of functional phytochemicals than non-pigmented rice bran extracts (0.68, 1410, and non-detectable μg/g compared with 16.65, 2480, and 0.10μg/g of vitamin E, γ-oryzanols and xanthophylls in pigmented and non-pigmented ones, respectively). SC-CO2 extraction with modifier would be promising for preparation of phytochemical essences for therapeutic purpose.

Preparation and characterization of foxtail millet bran oil using subcritical propane and supercritical carbon dioxide extraction

The foxtail millet (Setaria italica Beauv) bran oil was extracted with traditional solvent extraction (SE), supercritical carbon dioxide extraction (SCE) and subcritical propane extraction (SPE) and analyzed the yield, physicochemical property, fatty acid profile, tocopherol composition, oil oxidative stability in this study. The yields of foxtail millet bran oil by SE, SCE and SPE were 17.14 %, 19.65 %, 21.79 % of raw material weight (corresponded to 75.54 %, 86.60 %, 96.03 % of the total amount of the oil measured by using Soxhlet extraction), respectively. The effect of the extraction methods on the physicochemical properties (peroxide value, saponification value and color) was significant while the difference in fatty acid profile was negligible based on GC analysis. The major components of vitamin E in the obtained oils were identified as α- and β-tocopherols by HPLC, and SPE was superior to SE and SCE in the extraction of tocopherols. In Rancimat test, the oil obtained by SPE showed the highest oil oxidative stability, which could attribute to its high tocopherol content and low peroxide value. In view of oil quality, SPE employed smaller times and lower pressures compared to SE and SCE. SPE was a suitable and selective method for the extraction of the foxtail millet bran oil.

Effect of drying and co-matrix addition on the yield and quality of supercritical CO₂ extracted pumpkin (Cucurbita moschata Duch.) oil

In this work a process for obtaining high vitamin E and carotenoid yields by supercritical carbon dioxide (SC-CO₂) extraction from pumpkin (Cucurbita moschata Duch.) is described. The results show that the use of a vacuum oven-dried [residual moisture (∼8%)] and milled (70 mesh sieve) pumpkin flesh matrix increased SC-CO₂ extraction yields of total vitamin E and carotenoids of ∼12.0- and ∼8.5-fold, respectively, with respect to the use of a freeze-dried and milled flesh matrix. The addition of milled (35 mesh) pumpkin seeds as co-matrix (1:1, w/w) allowed a further ∼1.6-fold increase in carotenoid yield, besides to a valuable enrichment of the extracted oil in vitamin E (274 mg/100 g oil) and polyunsaturated fatty acids. These findings encourage further studies in order to scale up the process for possible industrial production of high quality bioactive ingredients from pumpkin useful in functional food or cosmeceutical formulation.

Optimization of supercritical fluid extraction and HPLC identification of wedelolactone from Wedelia calendulacea by orthogonal array design

The purpose of this work is to provide a complete study of the influence of operational parameters of the supercritical carbon dioxide assisted extraction (SC CO2E) on yield of wedelolactone from Wedelia calendulacea Less., and to find an optimal combination of factors that maximize the wedelolactone yield. In order to determine the optimal combination of the four factors viz. operating pressure, temperature, modifier concentration and extraction time, a Taguchi experimental design approach was used: four variables (three levels) in L9 orthogonal array. Wedelolactone content was determined using validated HPLC methodology. Optimum extraction conditions were found to be as follows: extraction pressure, 25 MPa; temperature, 40 °C; modifier concentration, 10% and extraction time, 90 min. Optimum extraction conditions demonstrated wedelolactone yield of 8.01 ± 0.34 mg/100 g W. calendulacea Less. Pressure, temperature and time showed significant (p < 0.05) effect on the wedelolactone yield. The supercritical carbon dioxide extraction showed higher selectivity than the conventional Soxhlet assisted extraction method.

Fatty acid profile, oxidative stability and toxicological safety of bayberry kernel oil

The fatty acid profile, oxidative stability and toxicological safety of bayberry (Myrica rubra Sieb. et Zucc.) kernel oil (BKO) extracted by supercritical carbon dioxide (SC-CO₂) and solvent of diethyl ether were assessed. Fatty acid profile was determined by gas chromatography, oxidative stability by placing the sample of 25g in a blast oven at 50±1°C to accelerate oxidation and toxicological safety by bacterial reverse mutation (Ames test) and acute oral toxicity in mice. The results demonstrated that in comparison to lard and rapeseed oil, the peroxide values of BKO were higher but the acid values were similar during the incubation test. The Ames test demonstrated no mutagenicity and no obvious acute toxicity were observed, suggesting that the BKO has potential as a novel edible oil.