Cellulase-assisted release of secoisolariciresinol from extracts of flax (Linum usitatissimum) hulls and whole seeds

Extraction of secoisolariciresinol from seed hulls and whole seeds of flax was improved using an enzymatic step with cellulase R10 from Trichoderma reesei that allowed better yield as compared to β-glucosidase. The cellulase assisted extraction process was further optimised for different parameters such as duration and concentration of hydromethanolic extraction, duration of alkaline hydrolysis, pH, duration and incubation temperature as well as enzyme concentration. Best results were obtained using a method including the following successive steps: 16 h of 70% hydromethanolic extraction, 6 h of 0.1 M sodium hydroxide hydrolysis followed by a 6 h incubation with 1 unit ml⁻¹ of cellulase R10 in 0.1 M citrate–phosphate buffer pH 2.8 at 40 °C. Under these conditions, all forms of the main flax lignan were recovered as the aglycone form, i.e. secoisolariciresinol. Highest yields in secoisolariciresinol diglucoside (SDG) equivalent reached 7.72% of flaxseed hull (cv. Baladin) dry weight and 2.88% of whole seed (cv. Barbara) weight, thus allowing a significant improvement in comparison with published methods.     

Extraction of β-carotenes from palm oil mesocarp using sub-critical R134a

Sub-critical extraction of palm oil from palm mesocarp using R134a solvent was conducted via the dynamic mode to investigate the ability of R134a to extract β-carotene. The yield of palm oil and the solubility of β-carotene were investigated at 40, 60 and 80 °C and pressure range from 45–100 bar. The extracted oil was analysed for β-carotene content using UV–Vis spectrophotometry. The results showed that palm oil yield increased with pressure and temperature. The maximum solubility of β-carotene was obtained at 100 bar and 60 °C while the lowest solubility occurred at 80 bar and 40 °C. The higher concentration of extracted β-carotene ranging from 330–780 ppm as compared to that achieved through conventional palm oil processing indicates that extraction of β-carotene using R134a is viable.     

Functional food oil coloured by pigments extracted from microalgae with supercritical CO2

A functional food oil, rich in fatty acids and antioxidants, coloured with pigments (carotenoids) extracted with supercritical CO₂ from the microalga Chlorella vulgaris, was produced, having in view its use in food industry (namely for derived seafood). The supercritical fluid extraction (SFE) was carried out in order to study the effect of several modifiers (oil mixed with the microalga and ethanol with the supercritical CO₂), the degree of crushing of the microalga and the supercritical fluid flow rate, at a pressure of 300 bar and temperature of 40 °C. Moreover, the microalga pigments were also extracted with acetone and with vegetable oil at room and high temperature. The recovery of carotenoids was 100% with oil at room temperature for 17 h, 70% with oil at 100 °C for 30 min, 69% with supercritical CO₂ at 40 °C and 300 bar. In SFE the degree of crushing strongly influenced the extraction recovery and higher pigment recoveries were obtained with well crushed biomass.     

Application of response surface methodology to optimise supercritical carbon dioxide extraction of essential oil from Cyperus rotundus Linn.

Supercritical fluid extraction with carbon dioxide (SC-CO₂ extraction) was performed to isolate essential oils from the rhizomes of Cyperus rotundus Linn. Effects of temperature, pressure, extraction time, and CO₂ flow rate on the yield of essential oils were investigated by response surface methodology (RSM). The oil yield was represented by a second-order polynomial model using central composite rotatable design (CCRD). The oil yield increased significantly with pressure (p < 0.0001) and CO₂ flow rate (p < 0.01). The maximum oil yield from the response surface equation was predicted to be 1.82% using an extraction temperature of 37.6 °C, pressure of 294.4 bar, extraction time of 119.8 min, and CO₂ flow rate of 20.9 L/h.     

Effects of supercritical CO2 fluid parameters on chemical composition and yield of carotenoids extracted from pumpkin

Pumpkin is a traditional food that is grown extensively worldwide and is believed to be beneficial to human health due to its high contents of carotenoids. The carotenoids in pumpkin were extracted by organic solvents and by supercritical carbon dioxide (SC-CO₂), and then they were identified, quantified, and compared. β-carotene (31 to 40 g per 100 g of total carotenoids) was the predominate carotenoid in pumpkin. Lutein and lycopene contents were much higher in SC-CO₂ extracts than those in organic solvent extract. Cis-β-carotene increased by more than two times in the SC-CO₂ extracts, even at a relatively low temperature of 40 °C, over those in the solvent extracts, indicating both enhanced solubility and isomerization from trans- to cis-β-carotene. The influences of modifier (10 mL/100 mL), temperature (40-70 °C), and pressure (25-35 MPa) of SC-CO₂ extraction on the change of carotenoid yields were also investigated. The highest yield (109.6 μg/g) was obtained at 70 °C and 35 MPa, with a 73.7% recovery. Selective extraction could be achieved by adjusting the temperature and pressure. Higher proportions of all-trans-β-carotene extracts were achieved at 40 °C under both 25 MPa and 35 MPa conditions. In order to extract more cis-isomers, a higher temperature of 70 °C was preferred.     

Optimizing conditions for anthocyanins extraction from purple sweet potato using response surface methodology (RSM)

Optimization for purple sweet potato (Ipomoea batatas (L.) Lam) anthocyanins (PSPAs) extraction was investigated using response surface methodology in this paper. PSPAs were extracted using acid-ethanol at different extraction temperature (40-80 °C), time (60-120 min) and solid-liquid ratio (1:15-1:30). The combined effects of extraction conditions on PSPAs yield and color attributes (expressed as L*, C* and H) were studied using a three-level three-factor Box-Behnken design. The results showed that The highest yield (158 mg/100 g dw) of PSPAs were reached at the temperature 80 °C, extraction time 60 min, and solid-liquid ratio 1:32. PSPAs yield indicated a high and significant correlation with L^* (P<0.05; r=−0.961) and it was significantly affected by extraction temperature (P<0.01) and solid-liquid ratio (P<0.05).     

Study of alcoholic and aqueous extraction of pequi (Caryocar brasiliense Camb.) natural antioxidants and extracts concentration by nanofiltration

Pequi (Caryocar brasilense Camb.) is a typical Brazilian fruit, rich in polyphenols and carotenoids. The present work studied aqueous and alcoholic pequi extraction, in bench scale, evaluating time and temperature variation influence on polyphenols and carotenoids recovery. For the extraction best conditions (25 °C within 1 h for aqueous extract and 40 °C within 24 h for alcoholic extract), a residue reextraction was carried out, which has increased compounds recovery from fruit material. The final extract (a mixture of the first and second extract) was submitted to a concentration step by nanofiltration (in a stirred cell with a temperature of 25 °C and a pressure of 800 kPa). For alcoholic extract, the rejection towards bioactive compounds was small (around 10% for carotenoids and 15% for polyphenols). For aqueous extract, nanofiltration showed a high efficiency to concentrate the polyphenols and carotenoids (with retention coefficient around 100% and 97%, respectively).     

Extraction of phenolics and essential oil from dried sage (Salvia officinalis) using ethanol–water mixtures

Effects of particle size, temperature, contact time, solvent-to-sage ratio and the ethanol–water ratio on the extraction of the active compounds rosmarinic acid, carnosic compounds and essential oil from dried sage (Salvia officinalis) were studied. Optimal extraction conditions giving highest yield of all three active compounds were particle diameter 1 mm, extraction temperature 40 °C, solvent-to-sage ratio of 6:1 and 55–75 wt% ethanol for up to 3 h. This gave an extract equivalent to 14.9% of dry sage, containing 6.9% rosmarinic acid (55% recovery), 10.6% carnosic compounds (75% recovery) and 7.3% essential oil (42% recovery). Scale up of the process by a factor of 100 demonstrated that the optimised laboratory scale process can be carried out without any loss of efficiency at an industrial scale.     

A comparative analysis of lipid and carotenoid composition of the gonads of Anthocidaris crassispina, Diadema setosum and Salmacis sphaeroides

In this study, sea urchins Anthocidaris crassispina, Diadema setosum and Salmacis sphaeroides inhabiting the coastal area of Hong Kong were collected and their gonadal biochemical compositions determined and compared for the first time. The proximate nutritional composition of all species exhibited an order of lipid > protein > carbohydrate. Neutral lipid was the major lipid constituent, accounting for over 80% of the total lipid. The major fatty acids in neutral lipid fraction of the three urchins were C14:0, C16:0, C16:1 (n-7), C18:1 (n-7) and C20:5 (n-3), whereas those in the polar lipid fraction were C16:0, C16:4 (n-4), C20:4 (n-6) and C20:5 (n-3). The dominant carotenoid was echinenone, which accounted for 81.7%, 56.7% and 68.5% of the total carotenoids in A. crassispina, D. setosum and S. sphaeroides, respectively.     

Effects of supercritical fluid extraction parameters on lycopene yield and antioxidant activity

The effects of various parameters of supercritical carbon dioxide (SC-CO₂) fluid extractions of tomato skins on the extraction yields and antioxidant activities of lycopene-rich extracts were investigated. A Box–Behnken design was applied to study the effects of three independent variables (temperature ranging from 40 to 100 °C, pressure ranging from 20 to 40 MPa, and flow rate ranging from 1.0 to 2.0 mL/min) on lycopene yield. The model showed good agreement with the experimental results, by the coefficient of determination (r² = 0.9834). Temperature, pressure, and the quadratic term for the temperature of SC-CO₂ extraction were large significantly positive factors affecting lycopene yield (P < 0.05). The maximum total lycopene content of 31.25 μg/g of raw tomato was extracted at the highest temperature of 100 °C, 40 MPa and 1.5 mL/min. TEAC assay was applied to assess the antioxidant activity of lycopene-rich extracts from SC-CO₂ fluid extraction. The effects of SC-CO₂ fluid extraction parameters on the antioxidant activities of the extracts differed with the yield. For each unit of lycopene extract, the antioxidant activity level was constant below 70 °C, but then gradually decreased above 70 °C due to isomerization occurring as a result of the higher temperature. The ratio of all-trans-lycopene to the cis-isomers changed from 1.70 to 1.32 when the operating temperature was adjusted from 40 to 100 °C, indicating an increased bioavailability due to the generation of the cis-isomers. No significant effects of pressure or flow rate of SC-CO₂ fluid extraction on the antioxidant activity were observed.     

Pressurized liquids as an alternative process to antioxidant carotenoids' extraction from Haematococcus pluvialis microalgae

In this work, extraction of antioxidant carotenoids from Haematococcus pluvialis microalga, has been studied combining pressurized liquid extraction (PLE), using hexane and ethanol as extracting solvents, and analytical techniques such as thin layer chromatography (TLC) and HPLC with DAD. The effect of the extraction temperature (50, 100, 150 and 200 °C) and the polarity of the solvent have been studied in terms of in vitro antioxidant activity and chemical composition considering two different morphological cells (green vegetative cells and red cysts). Results demonstrate that the extraction temperature had a positive influence in the extraction yield while its effect in the antioxidant activity was negative, lowering the activity of the extracts with an increase of the extraction temperature. The best yields were obtained with ethanol at the higher extraction temperature while the best antioxidant activity was also achieved using ethanol but at lower temperatures. Chemical composition was determined by TLC and HPLC with DAD. Several compounds were identified in the samples and concentration of astaxanthin was obtained. Results pointed out that the extracts contained different carotenoids in both, the green and the red phase, and that depending on its contribution a stronger antioxidant activity would be expected.     

Kinetic modeling of spice extraction from S. aromaticum and C. cassia

A mathematical model was developed for the extracts obtained from Syzygium aromaticum and Cinnamomum cassia with different particle size, solvent–solid ratios on extraction yield. Different particle sizes in the range of 2.8 mm to ?0.5 mm were employed and maximum extraction efficiency was achieved with particles of size ?0.5 mm. Among the solvent–solid ratios (20:1, 30:1, 40:1 and 50:1) ratio of 50:1 showed higher extraction yield. In the extraction kinetics, higher effective diffusivity value of 36.01 × 10⁻¹⁰ m²/s for S. aromaticum and 26.78 × 10⁻¹⁰ m²/s for C. cassia were achieved. Antioxidant values were determined and extracts prepared from ethanol showed higher scavenging activities for S. aromaticum and C. cassia as 78% and 85% respectively. Maximum phenolic content of 1.6 and 12.4 mg GAE/g of sample were achieved for S. aromaticum and C. cassia by hexane and water respectively.     

Extraction of Cuminum cyminum essential oil by combination technology of organic solvent with low boiling point and steam distillation

Extraction of essential oil from Cuminum cyminum seeds using a combination of organic solvent with low boiling point and steam distillation was explored. The effect of different parameters, such as particle size (40, 60, 80 mesh), temperature (°C) 10, 15, 20 and extraction time (3, 5, 8 h), on the extraction yield was investigated using three-level orthogonal array design. The experimental results showed that the temperature had the largest effect on the yield of the extract (oleoresin), followed by extraction time and particle size. The optimum parameters, such as temperature, particle size, and extraction time were in turn 20 °C, 80 mesh, and 8 h. Essential oil of C. cyminum seeds obtained by supercritical fluid extraction (SFE), hydrodistillation (HD), combination technology of organic solvent with low boiling point and steam distillation (OS-SD) were further analysed by gas chromatographic/mass spectrometric detection to compare the extraction methods. Forty-five compounds in the C. cyminum essential oil were identified, showing that the composition of the extraction by different methods was mostly similar, whereas relative concentration of the identified compounds was apparently different. General characteristics of the C. cyminum essential oil obtained by different methods were further compared, and OS-SD was considered as the optimum process among the three processes to obtain C. cyminum essential oil for high quality, simple technology and low cost.     

Response surface optimisation of aqueous enzymatic oil extraction from bayberry (Myrica rubra) kernels

Aqueous enzymatic extraction (AEE) of oil from Myrica rubra kernels was performed. The four AEE parameters namely mixed enzyme (cellulose/neutral protease = 1/2, w/w) amount, liquid/solid ratio, extraction time, and temperature, were optimised by response surface methodology. The statistical analysis indicated that the enzyme amount, liquid/solid ratio, time, and the quadratics of liquid/solid ratio, and enzyme amount, as well as the interactions between time and temperature, showed significant effects on oil yield. The optimal extraction conditions for oil yield were mixed enzyme amount, liquid/solid ratio, time, temperature as 3.17% (w/w), 4.91 ml/g, 4 h and 51.6 °C. Under the optimum conditions, the experimental oil extraction yield was 31.15%. The GC–MS analysis showed that the oil was abundant in the unsaturated fatty acids (9-octadecenoic acid and 9,12-octadecadienoic acid accounting for more than 80%), and the AEE was more efficient method to extract polyunsaturated fatty acid than the organic solvent process.     

Optimisation of supercritical fluid extraction of flavonoids from Pueraria lobata

Supercritical carbon dioxide extraction was employed to extract flavonoids from Pueraria lobata. The optimal conditions for flavonoid extraction were determined by response surface methodology. Box–Behnken design was applied to evaluate the effects of three independent variables (pressure, temperature and co-solvent amount) on the flavonoid yield of P. lobata. Correlation analysis of the mathematical-regression model indicated that a quadratic polynomial model could be employed to optimise the supercritical carbon dioxide extraction of flavonoids. From response surface plots, pressure, temperature and co-solvent amount exhibited independent and interactive effects on the extraction of flavonoids. The optimal conditions to obtain the highest flavonoid yield of P. lobata were a pressure of 20.04 MPa, a temperature of 50.24 °C and a co-solvent amount of 181.24 ml. Under these optimal conditions, the experimental values agreed with the predicted values, using analysis of variance, indicating a high goodness of fit of the model used and the success of response surface methodology for optimising supercritical carbon dioxide extraction of flavonoids from P. lobata.     

Application of response surface methodology to optimise extraction of flavonoids from fructus sophorae

Response surface methodology (RSM) based on a central composite design (CCD) was applied to optimise the extraction conditions for flavonoids from fructus sophorae with advantages in terms of resisting flavonoids during the whole process and maximising of extraction yield. Three aglycon forms of the flavonoids, namely, quercetin, kaempferol and isorhamnetin were quantified by high-performance liquid chromatography with ultraviolet detection (HPLC-UV) to estimate extraction yield. The combined effects of independent variables were studied and the optimal extraction conditions were obtained as ethanol concentration, 74.47%; solid–liquid ratio, 17.99 ml/g; temperature, 89.13 °C; and extraction time, 2.10 h. The reliability of the method was confirmed by recovery experiments, performed under optimal conditions. Recoveries indicated that flavonoids resisted the extraction conditions. The experimental extraction yield under optimal conditions was found to be 10.459%, which was well matched with the predicted values of 10.461%.     

Application of carbon dioxide in subcritical state (LCO2) for extraction/fractionation of carotenoids from red paprika

Carbon dioxide, as a liquid (LCO₂) in subcritical state, was applied for extraction of carotenoids from ground paprika. The increasing polarity of LCO₂ with the decrease of its temperature enabled fractionation of pigments according to their increasing polarity. The main constituents of the fractions of +6 °C and −6 °C were triacylglycerols (TAGs) including a small concentration of β-carotene. At −16 °C, more polar pigments (capsorubin, capsanthin, zeaxanthin) and their fatty acid (FA) esters were extracted. The pre-concentration ratio of carotenoids in the fraction at -16 °C was 17.2 with respect to Fraction at +6 °C.     

Optimization of supercritical carbon dioxide extraction of sea buckthorn (Hippophaë thamnoides L.) oil using response surface methodology

Response surface methodology (RSM) was employed to optimize the conditions of supercritical CO₂ extraction of the whole berry oil from sea buckthorn. The effects of pressure, temperature, CO₂ flow rate and extraction time on the yield of oil, vitamin E and carotenoids were investigated. Results showed that the data were adequately fitted into three second-order polynomial models. The independent variables, the quadratics of pressure and extraction time, the interactions between pressure and temperature, pressure and extraction time, temperature and extraction time, as well as flow rate and extraction time had a significant effect on the yield of the oil, vitamin E or carotenoids. It was predicted that the optimum extraction conditions within the experimental ranges would be the extraction pressure of 27.6 MPa and temperature of 34.5 °C with flow rate of 17.0 L/h and extraction time of 82.0 min. Under such parameters, the yields of oil, vitamin E and carotenoids were predicted to be 208.0 g/kg, 288.7 mg/kg and 620.0 mg/kg dry sea buckthorn berry, respectively. Monounsaturated fatty acids were predominant in the whole berry oil, accounting for over 62% of the total fatty acids.     

Laws of flaxseed mucilage extraction

This study examined the application of few-stages aqueous extraction of mucilage from whole flaxseed. Key processing conditions included temperature (40-100 °C), duration (0-60 min), seed to water ratio (1 to 5-30) and mixer rotational speed (0-240 revolutions per minute). It was found, that mucilage extraction from flaxseed is appropriate to carry out without swelling. The maximum yield of flaxseed mucilage was obtained at 80 ± 2 °C with seed to water ratio of 1 to 25. The equation, which described equilibrium solid yield during the extraction depending on the phases’ ratio and the temperature, was found. The equation of solid yield depending on duration and mixer rotational speed under the temperature of 80 ± 2 °C and the seed to water ratio of 1 to 25 was determined. It was showed, that the use of stirring is not expedient for the intensifying the process. The rational duration of extraction under the selected parameters was 30 ± 1 min. To increase the solid content in the extract the few-stages extraction was applied. The three-stage countercurrent extraction of flaxseed mucilage from whole seeds under the temperature of 80 ± 2 °C, the seed to water ratio of 1 to 25, the duration of each stage of 30 ± 1 min was established to receive flaxseed mucilage extract with content of solids from 0.70 to 0.72%, i.e. to extract from 98.3 to 99.1% of mucilage from flaxseed.     

Chia seeds: Microstructure, mucilage extraction and hydration

Microstructural features of the chia seeds (Salvia hispanica L.) were studied by light and scanning electron microscopy. The study reports the effect of temperature (4-80 °C), pH (4-8) and seed:water ratio (1:20 and 1:40) on extraction of the mucilage of chia seeds and the effect of temperature (20-80 °C), pH (3-9) and ionic strength (0-1%) on hydration of the extracted mucilage. The mucilage was localized in cellular structures in the first three layers of the seed coat and upon full hydration filaments (mucilage fibers) became apparent and conformed to a transparent “capsule” attached to the seed. During extraction, temperature and seed:water ratio were found to have a significant effect on yield. Hydration of the extracted mucilage was significantly increased at high pH values, and was higher when salt concentration decreased, being maximal when the temperature reached values close to 80 °C.