Extraction Conditions and Moisture Content of Canola Flakes as Related to Lipid Composition of Supercritical CO2 Extracts

Canola flakes obtained before and after conventional cooking were extracted with supercritical carbon dioxide (SC-CO₂) at 35–75°C and 20.7–62.0 MPa. Moisture content was adjusted to 12.7–42.5% (w/w, moisture-and oil-free basis). Moisture content of residual flakes after extraction was monitored. Amount of extract recovered increased with increasing temperature and pressure, except at 20.7 MPa pressure it decreased with temperature indicating a crossover of the solubility isotherms. Some water was co-extracted with canola oil. Free fatty acid (FFA) concentration of the extracts increased with decreasing pressure due to a decrease in triglyceride (TG) solubility. Oleic and linolenic acids had highest concentrations in the FFA fractions of all extracts. The lowest TG content of extracts was attained at 20.7 MPa and 75°C. The effect of extraction conditions was more pronounced than seed pre-treatments on yield and composition of SC-CO₂ extracts.     

Supercritical CO2 Extraction of Oil and Residual Proteins from Atlantic Mackerel (Scomber scombrus) as Affected by Moisture Content

Lipid composition of supercritical CO₂ (SC-CO₂) extracts, residual oil in muscle and changes in sarcoplasmic proteins after extraction of Atlantic mackerel were characterized. Dehydration of the muscle to 10.2% (w/w) resulted in high oil yield with minimum changes in protein content and composition. Sarcoplasmic protein content of fish muscle following SC-CO₂ treatment was lower than that of original muscles at all moisture levels (3.8–64%, w/w). Analysis of sarcoplasmic proteins by capillary electrophoresis indicated aggregation of low molecular weight proteins during SC-CO₂ extraction. SC-CO₂-extracted muscle also had lighter color than original samples. The SC-CO₂ extraction showed potential to provide high quality oil and protein meal.     

The influence of process parameters on Gas Assisted Mechanical Expression (GAME) of cocoa nibs

It is known that increased cocoa butter yields can be achieved with Gas Assisted Mechanical Expression (GAME) of cocoa nibs when compared to conventional expression of cocoa nibs [Venter, M.J., Willems, P., Kuipers, N.J.M. & de Haan, A.B. (2006). Gas Assisted Mechanical Expression of cocoa butter from cocoa nibs and edible oils from oilseeds. Journal of Supercritical Fluids, 37 (3), 350]. In a hydraulic press the GAME operation consists of a CO₂ dissolution stage, a pressing stage and a depressurisation stage. In this work the influence of the process parameters involved with the pressing stage on the final cocoa butter yield is investigated. All GAME experiments were performed with 10 MPa of CO₂. It is shown that neither the mass of cocoa nibs used, the duration of the pressing stage nor the mechanical pressure profile has a significant influence on the final cocoa butter yield. The moisture content of the nibs determines the behaviour of the solid structure during the pressing stage, thereby determining the cocoa butter yield that can be achieved as well as the speed with which it can be obtained. The maximum yield is obtained at a moisture content of 1.3 wt.% (wet basis). Lower moisture contents result in a faster compression of the cake. It is impossible to recover cocoa butter with GAME at 100 °C when nibs with moisture contents higher than 5.5 wt.% are used due to the extrusion of the cocoa solids through the filter medium. Similar yields were obtained when cocoa liquor and cocoa nibs were used in GAME experiments at the same conditions. Lastly it is shown that higher yields can be achieved when multi-stage GAME is used instead of single stage GAME. An absolute increase in cocoa butter yield of 7–10% was achieved when two-stage GAME was used instead of single stage GAME.Industrial relevanceCocoa butter is used as an ingredient in a number of popular foodstuffs, and continuous efforts are made by industry to improve the current cocoa butter recovery processes. Hydraulic pressing is the most frequently used process for producing high quality cocoa butter from cocoa nibs. In GAME the cocoa nibs are saturated with supercritical carbon dioxide prior to expression. GAME offers increased cocoa butter yields compared to conventional expression of cocoa nibs. The GAME process has been patented for screw presses, but no information is available on the effect different process parameters have on the performance of GAME in hydraulic presses. The objective of this study was to investigate several process parameters and their influence on GAME of cocoa nibs in a hydraulic press in order to enable selection of the optimum process parameters.     

Preparation and Evaluation of Supercritical Carbon Dioxide Defatted Soybean Flakes

Full-fat soybean flakes were extracted with supercritical carbon dioxide (SC-CO₂) at pressures of 10,600–12,400 psi, temperatures from 80–100°C, and moisture levels of 5–13.5%. Conditions could be selected to produce defatted soybean meals with nitrogen solubility indices greater than 70% and flavor scores greater than 6.5 on a scale of 1 to 10 (1 = strong and 10 = bland). The usual grassy-beany and bitter flavors of hexane-defatted soybean flours were only minimally detectable in the optimally SC-CO₂-extracted materials. Bland, defatted soybean meal prepared by SC-CO₂ extraction was further processed into high-quality protein concentrates and isolates that were stable when stored under adverse conditions.     

Supercritical Carbon Dioxide Extraction of Eugenol from Clove Buds

Isolation of eugenol from dried clove buds (Syzygium aromaticum Linn) of Indian origin was carried out using supercritical carbon dioxide (SC-CO₂) extraction. Optimization of its process parameters such as temperature, pressure and time of extraction has been conducted using response surface methodology. The optimized conditions that provided the optimum yield of eugenol were a sample size of 20 g of clove powder of particle diameter 0.5 mm at a temperature of 60°C and pressure of 250 bar for 90 min extracting time at a flow rate of 2 l?min^?1 of CO₂. Statistical analyses conducted on the extraction parameters concluded that extraction temperature have significant effect on the yield of eugenol, whereas extraction pressure and time do not. The results obtained are in accordance to the basic principle of supercritical fluid phase equilibrium behavior. Solubility of eugenol in SC-CO₂ under different temperature and pressure regimes have been determined experimentally and values were used to construct a correlated Chrastil equation in linear form to allow the prediction of solubility of eugenol in SC-CO₂ under different extraction conditions. Using dimensionless numbers, an empirical correlation was also deduced for characterization of the extraction process of eugenol in SC-CO₂ considering overall fixed bed behavior for clove matrix and mass transfer coefficients in supercritical phases.     

Supercritical CO<Subscript>2</Subscript> extraction in chia oils production: impact of process duration and co-solvent addition

This study was conducted to show impact of supercritical fluid extraction using pure SC-CO₂ or SC-CO₂ enriched by 2, 6, and 10% of acetone, simultaneously varied by the extraction time (1 vs. 5 h), on the quality of chia seed oils. Obtained oils were relatively similar in the fatty acid composition, but they differed in total content of phytochemicals (from 4956 to 6391 mg/kg of oil). Among them, three oils were the most different: oil extracted 1 h with pure SC-CO₂ (the most abundant in squalene, sterols, and tocopherols), oil extracted 5 h with pure SC-CO₂ (the poorest in squalene, polyphenols, and carotenoids, with medium level of sterols and tocopherols) and oil extracted 1 h with SC-CO₂ enriched by 10% acetone (the most abundant in polyphenols and carotenoids). Such unique chia oils can be valuable for special market needs, such as cosmetics, pharmaceuticals, functional food or diet supplement production.     

Supercritical carbon dioxide extraction of lutein from yellow maize (<Emphasis Type="Italic">Zea mays</Emphasis>) 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.     

Supercritical Fluid Extraction of Dry-Milled Corn Germ with Carbon Dioxide

Dry-milled corn germ was extracted with supercritical carbon dioxide (SC-CO₂) at 5,000-8,000 psi and 50°C. CO₂-extracted oil was lower in free fatty acids and refining loss, and was lighter in color when compared with a commercial expeller-milled crude oil. Total unsaponifiable and tocopherol contents were similar for both oil types. The defatted, highly friable flour has a shelf-stable moisture content of 2-3% and good flavor quality. The flour contains 20% protein with good amino acid balance, meeting FAO specifications for food protein supplements. High pressure SC-CO₂ extraction also denatures the proteins, including oxidative enzymes. Peroxidase activity is reduced tenfold in SC-CO₂-extracted flour when compared with hexane-extracted flours. Storage tests for 5 wk at 38°C and for 2 months at 25°C show that flavor quality of untoasted SC-CO₂-defatted germ flour is maintained even under these extreme conditions.     

Extraction of fennel (Foeniculum vulgare Mill.) seeds with supercritical CO2: Comparison with hydrodistillation

Ground fennel (Foeniculum vulgare Mill.) seeds, growing wild in Montenegro, were extracted with supercritical CO₂ (SC-CO₂) at a flow rate of 0.2 kg CO₂/h under varying extraction conditions in order to determine yield, composition and organoleptic characteristics of extract. The extracts obtained were compared to fennel seed oil isolated by hydrodistillation. In the SC-CO₂, extracts as well in the hydrodistilled oil, the major compounds were trans-anethole (68.6–75.0%) and (62.0%), methylchavicol (5.09–9.10%) and (4.90%), fenchone (8.40–14.7%) and (20.3%), respectively. With pressure varying from 80 to 150 bar and temperature varying from 40 to 57 °C, it was found that, for the selected herb material, the optimal conditions of SC-CO₂ extraction (high percentage of trans-anethole, with significant content of fenchone and reduced content of methylchavicol and co-extracted cuticular waxes) are: pressure, 100 bar; temperature, 40 °C; extraction time, 120 min. Organoleptic tests confirmed that hydrodistilled oil possessed a less intense fennel seed aroma than extracts obtained by SC-CO₂.     

Enzymatic synthesis of cocoa butter analog through interesterification of lard and tristearin in supercritical carbon dioxide by lipase

Substrate oil composition, reaction time, acyl donor, temperature, and pressure affected the triacylglycerol (TG) content of cocoa butter analog during the interesterification reaction catalyzed by lipase in a supercritical carbon dioxide (SC-CO₂) system. Among oil sources used to interact with tristearin, the content of 1(3)-palmitoyl-3(1)-stearoyl-2-monoolein (POS) (P, palmitate; O, oleate; S, stearate) and 1-palmitoyl-2, 3-dioleoylglycerol (POO) in analog was most similar to the corresponding TG content of cocoa butter when analog was prepared with lard. The optimized interesterification reaction using lard and tristearin (at a mole ratio of 1.4) as substrates to produce cocoa butter analog in a SC-CO₂ system was at 17 MPa, 50 °C, pH 9, for 3 h with an immobilized lipase, Lipozyme IM-20, from Mucor miehei. The lyophilized enzyme facilitated the production of cocoa butter analog in anhydrous substrates (a_w 0.33). The yield and melting point of the purified cocoa butter analog by a silica column was 63% and 34.5 °C, respectively, when the analog was produced under optimal conditions.     

Extraction of boldo (Peumus boldus M.) leaves with supercritical CO2 and hot pressurized water

High-activity fractions in boldo leaves were extracted with supercritical CO₂ (SC-CO₂) and hot pressurized water (HPW). Total yield after 3 h of extraction (0.6–3.5%) in low-pressure SC-CO₂ experiments increased with process pressure (60–150 bar) and decreased with temperature (30–60 °C), as expected. The extract obtained with SC-CO₂ at 50 °C and 90 bar contained approximately 50% of essential oil components. In higher pressure experiments with solvent mixtures, the yield increased with pressure (300–450 bar) and modifier concentration (2–10% ethanol), ranging 0.14–1.95 ppm for the alkaloid boldine and 1.8–4.8% for total solids following 1.5 h treatment at 50 °C. Boldine recovery was solubility-controlled, reaching 7.4 ppm after 7-h extraction at 450 bar and 50 °C using an ethanol–SC-CO₂ mixture (5% co-solvent). Boldine solubility and yield decreased when using pure CO₂ at higher pressure (600 bar, 50 °C). The extract yield after 3 h batch-wise HPW extraction increased from 36.9% at 100 °C to 53.2% at 125 °C, and then decreased as temperature was increased to 175 °C. Boldine yield decreased from 26.8 ppm at 100 °C to 0.7 ppm at 125 °C, and was negligible at ⩾150 °C. The essential oil yield increased to a maximum at 110 °C and was negligible at ⩾150 °C also. The ranking of antioxidant potency of various extracts was as follows: HPW at 110 °C > methanol (soxhlet extraction) ≫ high-pressure SC-CO₂ with or without polar co-solvent > low-pressure SC-CO₂.     

A study on parameters of potential cocoa butter analogue synthesis from camel hump by lipase-catalysed interesterification in supercritical CO2 using response surface methodology

A potential cocoa butter analogue was prepared from camel hump fat and tristearin by enzymatic interesterification in supercritical carbon dioxide (SC–CO₂) using immobilised Thermomyces lanuginosus lipase (Lipozyme TL IM) as a biocatalyst. Response surface methodology (RSM) was used to investigate the effects of pressure, temperature, tristearin/camel hump fat ratio, water content, and incubation time on TAG distribution of cocoa butter analogue. The process conditions were optimised by conducting experiments at five different levels. A second order polynomial response surface equation was developed to indicate the effect of variables on TAG distribution of cocoa butter analogue. Overlaid contour plots generated using the response surface equations showed that all TAG components of cocoa butter analogue are significantly affected by the experimental independent variables. The pressure of 10 MPa; temperature of 42 °C; SSS/CHF ratio of 1.15:1; water content of 10% (w/w); and incubation time of 3 h were found to be the optimum conditions to achieve the most similar cocoa butter analogue to the corresponding cocoa butter.     

Optimization of Basic Ingredient Combination for Sandwich Cookie Filling Using Response Surface Methodology

An optimum formulation for a cookie sweet cream filling was selected using response surface methodology (RSM). The formulation included corn starch, powdered sugar, unflavored gelatin, cocoa butter, and distilled water. The effects of the amount of starch (0–30 %), sugar (40–70 %), gelatin solution (5/55 g water) (0–12 %), and cocoa butter (18–30 %) on the water activity and the textural characteristics (firmness, elasticity, relaxation time, adhesiveness, and cohesiveness) of cookie fillings were investigated. Significant regression models, which explained the effects of different percentages of these ingredients on all response variables, were determined. Based on the results, the formulation for the production of a cookie filling with acceptable water activity value and desired texture qualities was obtained by incorporating 23.16 % corn starch, 46.84 % powdered sugar, 0.87 % gelatin solution, and 29.13 % cocoa butter.     

In Situ Ultrasonic Characterization of Cocoa Butter Using a Chirp

Differences between tempered and untempered cocoa butter were investigated by an ultrasonic signal “chirp” generated by contact transducers. Polarized light microscopy and powder X-ray diffraction were used to characterize the morphology and polymorphism of tempered and untempered cocoa butter, whereas pulsed nuclear magnetic resonance was used to determine the amount of crystalline solids present. Ultrasonic wave velocity and attenuation data were collected simultaneously throughout the 5-h crystallization process for cocoa butter. Ultrasonic velocity and attenuation changed at the different solid fat contents (SFC): 4, 8, and 11 %. Untempered cocoa butter showed an attenuation of 3 dB/cm at 1.7 MHz and 4 % SFC, whereas tempered cocoa butter showed an attenuation of 4.5 dB/cm at 1.7 MHz and 4 % SFC. At 3 MHz, the attenuation was 2 dB/cm for untempered and 6 dB/cm for tempered cocoa butter. Under these conditions (4 % SFC, 3 MHz), the chirp wave of tempered sample showed a phase angle change of 0.5 rad, whereas the untempered sample showed ?0.5 rad relative to the canola oil that was taken as 0. The study suggests that an ultrasonic chirp can be effectively used to detect differences between tempered and untempered cocoa butter when measuring attenuation and ultrasonic wave phase angle changes as a function of frequency. The in-line characterization of chocolate “temper” using such nondestructive ultrasonic measurements could be applied to industrial chocolate manufacturing.     

An Improved Ultrasonic-Assisted Extraction Method by Optimizing the Ultrasonic Frequency for Enhancing the Extraction Efficiency of Lycopene from Tomatoes

In order to assess the optimization of the ultrasonic frequency in a range of 18–146 kHz for extracting lycopene from tomatoes and evaluate its influence on the extraction efficiency, an improved ultrasonic-assisted extraction (IUAE) method was proposed by using a novel ultrasonic extraction and detection system, in which the ultrasonic frequency information could be converted to intuitive waveforms that are easily identified by eyes. Additionally, to improve the extraction yield of lycopene, in this work, the optimization of various process parameters by ultrasonic treatment, including extraction time, solvent/material ratio, extraction temperature, and ultrasonic power for improving the yield of lycopene were investigated. These results indicated that all of the considered parameters had effected on the yield of lycopene significantly, and the optimum extraction conditions were as follows: extraction time duration 20 min; ratio of solvent to material 2:1; extraction temperature 25 °C; ultrasonic power 200 W; ultrasonic frequency 46–48 kHz. In comparison with other extraction methods, such as conventional solvent extraction (CSE), supercritical fluid extraction (SFE), supercritical carbon dioxide co-extraction (SC-CO₂), and existing UAE, the IUAE method achieved a far more extraction yield, a reduction of extraction time, and a smaller amount of solvent at lower temperature, which showed a great promising prospect in the extraction and separation of natural products.     

Roasted Peanuts and Peanut Butter Quality are Affected by Supercritical Fluid Extraction

Roasted peanuts were extracted using supercritical CO₂ (413.6 bar, 50–60° for 0, 2 or 4 hr). Peanuts were evaluated for shatter, tristimulus color, shear-compression force, moisture, lipid content, and sensory attributes. Extracted nuts were prepared into peanut butter and evaluated for color, relative torque resistance ratio, and sensory attributes. Lipid content decreased from 51.6 to 40.6% during 4 hr extraction. SFE increased shatter, shear-compression force, and Hunter L-value, but decreased hue angle, roasted aroma intensity, moistness of mass, fracturability, and roasted flavor intensity of peanuts. SFE increased the relative torque resistance ratio, and adhesiveness of peanut butter but had little effect upon flavor. SFE may be useful to reduce peanut contaminants and lipids to produce value-added peanut products.     

Modification of Crude Canola Lecithin for Food Use

Crude canola lecithin was fractionated by removal of neutral lipids with acetone followed by ethanol extraction with or without supercritical carbon dioxide (SC-CO₂). Two extraction steus of 60 min each at 35°C with 500 mL acetone were optimum for maximum yield of acetone solubles and maximum phospholipid (PL) concentration (66.7%) in the acetone insoluble (AI) fraction. AI were separated into 26.5% ethanol soluble and 68.7% ethanol insoluble fractions. PL concentration in the extract increased with increasing amounts of ethanol used. Yields were low for SC-CO₂/ethanol extraction, of which extracts from 55.2 MPa/ 70°C contained 32% PL (83% phosphatidyl choline).     

Extraction of alkylresorcinols from wheat bran with supercritical CO2

The supercritical fluid extraction (SFE) of wheat bran alkylresorcinols has been studied. Extractions were carried out at 40.0 MPa. The effect of particle size, static extraction pretreatment with supercritical CO₂ (SC-CO₂) and extraction temperature on the extraction kinetics was investigated. The extraction yield increased as the particle size decreased and with temperature. Extraction curves present a faster and linear initial extraction period followed by a slower extraction period. Based on these results the approximate mathematical model of Sovová was successfully applied to describe the extraction curves. The total content of alkylresorcinols was determined and compared with the alkylresorcinol content obtained by conventional organic solvent extraction. Due to the amphiphilic nature of these resorcinolic lipids, the extraction yield was higher for polar organic solvents than for SC-CO₂. Characterization of supercritical extracts was also performed by determining the fatty acid composition and antioxidant activity.     

Monitoring Tempered Dark Chocolate Using Ultrasonic Spectrometry

Ultrasonic spectrometry was used to distinguish between properly tempered and untempered commercial dark chocolate. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to characterize the polymorphic state of tempered and untempered chocolate, results that were correlated to those of ultrasonic spectrometry. Four different kinds of dark chocolate samples with different amounts of sugar (7.5–50 %), fat (30–50 %), and cocoa mass (70–90 %) were subjected to two different tempering protocols. The tempering was achieved using cocoa butter seeds under static cooling from 50 to 14 °C. The ultrasonic generator and analyzer SIA-7 (V.N. Instruments) was used to monitor the crystallization process. The instrument generated a chirp signal with a bandwidth of 0.5 to 3 MHz and was set to work in a four-pathway configuration with two transducers and a center frequency of 2.25 MHz. Spectrometric analysis was carried out with chocolate samples containing 2, 4, and 6 % solid fat content (SFC). The SFC was obtained from DSC measurements. Ultrasonic signals for attenuation, reflection, and velocity were compared between tempered and untempered chocolates. It was shown that seed-tempered chocolate with 30 % sugar and 47.5 % fat attenuated 2.5 MHz of ultrasonic waves by 0.8, 1.7, and 2.0 dB/cm at 2, 4, and 6 % SFC, respectively. On the other hand, untempered chocolate attenuated the ultrasound signal by 3.5, 3.6, and 4.3 dB/cm. Furthermore, it was found that ultrasound reflection signals were stronger and ultrasonic velocity was higher in chocolates with high sugar content.     

Antioxidant-Rich Extract from Dehydrated Seabuckthorn Berries by Supercritical Carbon Dioxide Extraction

Seabuckthorn (Hippophae rhamnoides L.) berry oil having high nutraceutical, cosmeceutical, and therapeutic activity has been extracted from dried seabuckthorn (SBT) whole berry powder using supercritical carbon dioxide (SC-CO₂), a green process for extraction of bioactives. The SC-CO₂ process was optimized using Box?CBehnken design. Three SC-CO₂ parameters namely extracting pressure, extracting temperature, and time of extraction were examined. The optimal SC-CO₂ conditions were determined, and the quadratic response surfaces were drawn from the mathematical models. A maximum recovery of 85.12% tocopherol, 71.73% carotene, and an EC₅₀ of 29.02?mg/ml (from DPPH assay) was obtained after SC-CO₂ extraction at 44?°C, 345?bar, and run time of 80?min. Use of methanol as an entrainer at 30% v/w of SBT berry at optimized conditions further increased the extraction efficiency and the potency. This extract can be used for varied nutraceutical, cosmeceutical, and pharmaceutical applications.