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ABSTRACT: Use of supercritical carbon dioxide (SC–CO2) for the extraction and fractionation of nutraceuticals offers numerous advantages, avoiding the use of organic solvents
and minimizing the degradation of bioactives. Optimal design of such processes requires fundamental knowledge of not only
the solubility behavior but also physical and transport properties of the SC–CO2 + nutraceutical mixture under high pressure. Determination of such fundamental data is challenging and requires specialized
equipment. Because of the nonpolar nature of SC–CO2, lipid-based nutraceuticals, including specialty oils and carotenoids, can be extracted with neat SC–CO2; however, recovery of phytochemicals like phenolics require the addition of a polar cosolvent. Ethanol is the cosolvent of
choice for nutraceutical applications. Extraction of nutraceuticals from a large number of plant materials has been studied
extensively for the optimization of various processing parameters. Further fractionation of the extracts or various other
mixtures is possible using fractional extraction, fractional separation, or column separation approaches to obtain bioactives
in concentrated form. Supercritical fluid technology offers the flexibility to extract and fractionate nutraceuticals by combining
different techniques and simplifying the overall process compared to conventional technologies, but feasibility of every application
needs to be evaluated on a case-by-case basis. Some applications such as the extraction of specialty oils and recovery of
tocopherols from deodorizer distillate have already reached commercialization level while numerous other promising applications
are under development around the world.
12/2010: pages 353-392;
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ABSTRACT: Dietary fiber reduces the intestinal absorption of nutrients and the blood concentrations of cholesterol and triglycerides.
We wished to test the hypothesis that high-viscosity (HV) and low-viscosity preparations of barley and oat beta-glucan modify the expression of selected genes of lipid-binding proteins in the intestinal mucosa and reduce the intestinal in vitro uptake of lipids.
Five different beta-glucan extracts were separately added to test solutions at concentrations of 0.1-0.5% (wt/wt), and the in vitro intestinal uptake of lipids into the intestine of rats was assessed. An intestinal cell line was used to determine the effect of beta-glucan extracts on the expression of intestinal genes involved in lipid metabolism and fatty acid transport.
All extracts reduced the uptake of 18:2 when the effective resistance of the unstirred water layer was high. When the unstirred layer resistance was low, the HV oat beta-glucan extract reduced jejunal 18:2 uptake, while most extracts reduced ileal 18:2 uptake. Ileal 18:0 uptake was reduced by the HV barley extract, while both jejunal and ileal cholesterol uptakes were reduced by the medium-purity HV barley extract. The inhibitory effect of HV barley beta-glucan on 18:0 and 18:2 uptake was more pronounced at higher fatty acid concentrations. The expression of genes involved in fatty acid synthesis and cholesterol metabolism was down-regulated with the HV beta-glucan extracts. beta-Glucan extracts also reduced intestinal fatty-acid-binding protein and fatty acid transport protein 4 mRNA.
The reduced intestinal fatty acid uptake observed with beta-glucan is associated with inhibition of genes regulating intestinal uptake and synthesis of lipids. The inhibitory effect of beta-glucan on intestinal lipid uptake raises the possibility of their selective use to reduce their intestinal absorption.
The Journal of nutritional biochemistry 09/2009; 21(8):695-701. · 4.29 Impact Factor
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ABSTRACT: The design of a reciprocating dual action piston pump capable of circulating viscous fluids at pressures of up to 34 MPa (5000 psi) and temperatures up to 80 degrees C is described. The piston of this pump is driven by a pair of solenoids energized alternatively by a 12 V direct current power supply controlled by an electronic controller facilitating continuously adjustable flow rates. The body of this seal-less pump is constructed using off-the-shelf parts eliminating the need for custom made parts. Both the electronic controller and the pump can be assembled relatively easily. Pump performance has been evaluated at room temperature (22 degrees C) and atmospheric pressure using liquids with low and moderately high viscosities, such as ethanol and corn oil, respectively. At ambient conditions, the pump delivered continuous flow of ethanol and corn oil at a flow rate of up to 170 and 17 cm3/min, respectively. For pumping viscous fluids comparable to corn oil, an optimum reciprocation frequency was ascertained to maximize flow rate. For low viscosity liquids such as ethanol, a linear relationship between the flow rate and reciprocation frequency was determined up to the maximum reciprocation frequency of the pump. Since its fabrication, the pump has been used in our laboratory for circulating triglycerides in contact with supercritical carbon dioxide at pressures of up to 25 MPa (3600 psi) and temperatures up to 70 degrees C on a daily basis for a total of more than 1500 h of operation functioning trouble free.
The Review of scientific instruments 08/2009; 80(7):075104. · 1.52 Impact Factor
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ABSTRACT: Three seeds of Turkish origin, flax, poppy and safflower were analyzed for their proximate, fatty acids, tocols (tocopherols and tocotrienols) and total phenolic composition, and oxidative stability of their oil. The major fatty acid in the flax oil was alpha-linolenic acid, comprising 58.3% of total fatty acids, whereas poppy and safflower oils were rich in linoleic acid at 74.5% and 70.5% level, respectively. The amount of total tocols was 14.6 mg/100g flax, 11.0mg/100g poppy and 12.1mg/100g safflower seed. Flax and poppy oil were rich in gamma-tocopherol as 79.4 mg/100g oil and 30.9 mg/100g oil, respectively, while alpha-tocopherol (44.1g/100g oil) was dominant in safflower oil. Only alpha- and gamma-tocotrienol were found in the oils. Oxidative stability of oils was measured at 110 degrees C at the rate of 20 L/h air flow rate, and poppy oil (5.56 h) was most stabile oil followed by safflower oil (2.87 h) and flax oil (1.57). There were no correlation between oxidative stability and unsaturation degree of fatty acids and tocol levels of the oils. All of the seeds investigated provide a healthy oil profile and may have potential as a source of specialty oils on a commercial scale.
Bioresource Technology 10/2008; 99(14):6354-9. · 4.98 Impact Factor
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ABSTRACT: Canola meal is a potentially valuable protein source. Canola meals extracted with supercritical CO2 (SC-CO2) were compared to pressed meal and meals extracted with hexane. With regard to the chemical composition, the glucosinolate,
phenolic acid, tannin and phosphorus contents were determined in addition to proximate analysis. As for functionality, color,
nitrogen solubility index (NSI), water and fat absorption, emulsifying capacity and stability, and overrun were determined.
Both hexane- and SC-CO2-extracted meals had a higher protein content than the pressed meal. The SC-CO2-extracted meal had lower glucosinolate and higher phosphorus contents than hexane-extracted meal. The phenolic acid contents
of hexane- and SC-CO2-extracted meals were similar, but were higher than those of meals extracted with SC-CO2 + ethanol. The color values of SC-CO2- and hexane-extracted meals were similar and both were brighter than commercial meals (pressed and toasted). The NSI levels
of SC-CO2- and hexane-extracted meals were similar, but three times that of the commercial meal. Both hexane- and SC-CO2-extracted meals had high water holding capacity, oil absorption, emulsifying capacity, emulsion stability and overrun. Canola
meal extracted with SC-CO2 was similar to hexane-extracted meal in terms of both chemical composition and functionality, but was superior to commercial
meals.
Journal of Oil & Fat Industries 06/2008; 85(7):667-675. · 1.77 Impact Factor
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ABSTRACT: Soluble dietary fiber has been shown to attenuate the postprandial rise in blood glucose levels and reduce the risk of type 2 diabetes and cardiovascular disease. This effect seems to be related to its rheological properties including viscosity. We examined the intra-fiber variability between two different processing methods of concentrating beta-glucan from oats (aqueous vs. enzymatic) in relation to the level of viscosity of beta-glucan and its effect on postprandial glycemia in healthy individuals.
In an acute, randomized, double-blind, crossover study, 11 healthy subjects (gender: 5M:6F; age: 34 +/- 5 years; BMI: 23 +/- 0.8 kg/m(2)) were randomly assigned, on three separate occasions, to consume one of three fiber-matched treatments along with a 75 g oral glucose drink. The enzymatically processed beta-glucan (Oat-A) differed from beta-glucan processed through the aqueous method (Oat-B) solely with regard to viscosity. Finger-prick capillary blood samples were obtained at fasting and at 15, 30, 45, 60, 90 and 120 min after the start of the test drink. The viscosities of the fiber drinks were determined (Paar Physica UDS200 viscometer).
Rheological measurements demonstrated that Oat-A had a significantly higher viscosity than Oat-B and control at 5, 15, 30, 60, and 120 min (p < 0.001). The incremental area under the glucose curve (AUC) on Oat-A was 19.6% and 17% lower than that of Oat-B and control, respectively (p < 0.01).
This study shows that processing oat beta-glucan through enzymatic, rather than by aqueous methods, preserves the viscosity and improves postprandial glycemic control.
Journal of the American College of Nutrition 12/2007; 26(6):639-44. · 2.29 Impact Factor
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Jennifer Snart,
Rodrigo Bibiloni,
Teresa Grayson,
Christophe Lay,
Haiyan Zhang,
Gwen E Allison,
Julie K Laverdiere, Feral Temelli,
Thavaratnam Vasanthan,
Rhonda Bell,
Gerald W Tannock
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ABSTRACT: BBn (BioBreeding) rats were fed casein-based diets supplemented with barley flour, oatmeal flour, cellulose, or barley beta-glucans of high [HV] or low viscosity [LV] in order to measure the prebiotic effects of these different sources of dietary fiber. The dietary impact on the composition of the cecal microbiota was determined by the generation of denaturing gradient gel electrophoresis (DGGE) profiles of PCR-amplified 16S rRNA gene sequences. The DGGE profiles produced from the cecal microbiota of rats within each dietary group were similar, but consensus profiles generated from pooled bacterial DNAs showed differences between rat groups. Animals fed HV glucans (HV-fed rats) had DGGE consensus profiles that were 30% dissimilar from those of the other rat groups. A 16S rRNA gene fragment that was more conspicuous in the profiles of HV-fed animals than in those of cellulose-fed rats had sequence identity with Lactobacillus acidophilus. Measurements of L. acidophilus rRNA abundance (DNA-RNA hybridization), the preparation of cloned 16S rRNA gene libraries, and the enumeration of Lactobacillus cells (fluorescent in situ hybridization) showed that lactobacilli formed a greater proportion of the cecal microbiota in HV-fed rats. In vitro experiments confirmed that some lactobacilli utilize oligosaccharides (degree of polymerization, 3 or 4) present in beta-glucan hydrolysates. The results of this study have relevance to the use of purified beta-glucan products as dietary supplements for human consumption.
Applied and Environmental Microbiology 04/2006; 72(3):1925-31. · 3.83 Impact Factor
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ABSTRACT: Echinacea has been known for its immunostimulatory activity, and its alkylamide components have been linked to such biological activity. Consequently, alkylamides in Echinacea angustifolia were extracted using supercritical carbon dioxide from fresh and dried roots at 45-60 degrees C and 34-55 MPa, and the alkylamide yield in the extracts was determined. The yield of alkylamides from fresh roots increased with temperature yet decreased with pressure, whereas the yield from air-dried roots (moisture content 8.4%) increased with both temperature and pressure. Freeze-drying of the roots to a moisture content of 4.9% did not result in any further increase in the yield compared to that of air-dried roots. Alkylamide yield of the ground dried roots extract was the highest (p < or = 0.05) among those from fresh, ground and unground E. angustifolia roots. Supercritical fluid extraction therefore shows potential for the recovery of alkylamides from dried Echinacea roots.
Journal of Agricultural and Food Chemistry 07/2002; 50(14):3947-53. · 2.82 Impact Factor
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ABSTRACT: Mixed linkage beta-glucan is a cell wall component of cereal grains such as oat and barley. A number of nutritional studies have demonstrated a link between the regular consumption of foods containing cereal beta-glucan at physiologically effective concentrations and a reduced risk of chronic health problems. However, since beta-glucan exists in lower concentrations in grains, its incorporation into regular foods at physiologically effective levels without compromising the sensory attributes of foods has been a problem. Therefore, industry interest has been growing to produce beta-glucan concentrates. This article reviews the different types of dry and wet technologies available for concentration of cereal beta-glucan with a focus on commercial scale processing and their impact on the physicochemical properties of beta-glucan.
Food Research International.
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ABSTRACT: Carotenoids such as β-carotene are gaining interest in the food industry due to their nutritional and antioxidant properties. Understanding the solubility behavior of carotenoids in supercritical CO2 (SC CO2) is fundamental for any industrial supercritical process application and design. Solubility of β-carotene was measured in both a binary and a multicomponent complex system. Solubility of β-carotene in the binary system was measured using a quartz crystal microbalance technique at temperatures of 40 and 50 °C and pressures ranging from 120 to 200 bar. Solubility of β-carotene in the multicomponent complex system was determined from dynamic extraction experiments using a laboratory-scale supercritical extraction system. Carotenoids were extracted from freeze-dried carrots with SC CO2 at temperatures of 40 and 50 °C and pressures ranging from 120 to 327 bar. β-Carotene solubility values for the binary system measured herein and reported in the literature are of the order of 10−7 mole fraction while the solubility values for the multicomponent complex system (β-carotene extracted from carrots with SC CO2) under the same conditions are 5–10 times smaller. Solubility in both systems increased with temperature and pressure. The difference in the solubility values obtained using both systems is mainly due to the matrix effects of the multicomponent complex system such as the cell structure and the interactions of β-carotene with other components such as carbohydrates in the carrot matrix.
The Journal of Supercritical Fluids.
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ABSTRACT: The viscosity and solubility of β-glucan in muffins have been shown to be reduced by certain storage conditions, though the effect of storage on bread fortified with barley β-glucan concentrate has not been investigated. Therefore, this study investigated the effect of storage temperature and time (23 °C for 1, 4, and 7 d, 4 °C for 4, 7, and 14 d, and -20 °C for 1, 2, 4, and 8 wk) on the solubility and viscosity of β-glucan upon incorporation into bread at levels corresponding to 0 or 1.5 g β-glucan/serving, with or without vital gluten addition. The firmness and moisture content of bread following each storage treatment were also evaluated. The highest moisture and lowest firmness values were found in fresh bread, though these parameters were still maintained at appreciable levels upon room temperature storage of the 1.5 g β-glucan/serving bread with added gluten and at either room temperature or frozen storage for the 1.5 g β-glucan/serving bread for 4 d. If it is desirable to store bread for 7 d or more, frozen storage should be utilized in order to best maintain bread moisture and firmness levels. It is recommended that β-glucan-fortified bread be consumed fresh for greatest β-glucan solubility and viscosity, though β-glucan solubility of approximately 40% is still achievable upon frozen storage of the bread for up to 2 wk. It is still unclear, however, as to what extent of reductions in the solubility and viscosity of β-glucan would lower its physiological effectiveness. PRACTICAL APPLICATION: Previous research has demonstrated that solubility and thus viscosity of β-glucan, which is an important property associated with its health benefits can be impacted by different storage conditions applied to some bakery products, like muffins. This study demonstrates the extent of changes in the solubility and viscosity of β-glucan incorporated into bread. Therefore, storage time and temperature should be optimized to minimize changes in β-glucan for maintaining its efficacy for its health benefits.
Journal of Food Science 76(1):C1-7. · 1.66 Impact Factor
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ABSTRACT: Glycerolysis–hydrolysis reactions to produce monoacylglycerol (MAG) and diacylglycerol (DAG) used in the production of functional foods and nutraceuticals were conducted in supercritical carbon dioxide (SC-CO2) media to elucidate the reaction kinetics, provide the reaction mechanism and assess the potential catalytic agent involved. Reactions were conducted in an electrically heated, magnetically stirred autoclave at 250 °C, 10–30 MPa, anhydrous glycerol/canola oil molar ratio of 34:1 and initial water content of 0 to 8% (w/w). Reactions were also conducted in supercritical nitrogen at 250 °C, 10 MPa, and 8% (w/w) initial water. Samples were collected as a function of time and the concentrations of MAG, DAG, free fatty acids (FFA) and triacylglycerol (TAG) were obtained using thin layer chromatography–flame ionization detection. The maximum rate of MAG formation at 20 MPa was significantly higher (p ≤ 0.05) than that at 30 MPa, but similar (p > 0.05) to that at 10 MPa; a finding that has economical impact because a pressure of 10 MPa can be reached without the use of a high-pressure pump. Rates of MAG formation in SC-CO2 and -N2 media were similar (p > 0.05) thereby demonstrating that SC-CO2 does not contribute to catalysis. The maximum rate of MAG production at 10 MPa was significantly higher (p ≤ 0.001) for reaction with 4% (w/w) initial water compared with anhydrous reactions and was significantly lower (p ≤ 0.05) compared to that of reaction with 8% (w/w) initial water. Although this study was unable to identify the catalytic reagent, it did show that water played an important role. Reactions were carried out up to 14 h and equilibrium was reached at 9 h. The average equilibrium composition (mol%) obtained at 9–10 h for the reactions conducted at 10–30 MPa with 4–8% (w/w) water was 66–71% MAG, 13–15% DAG, 13–17% FFA and 0–1% TAG. A MAG concentration of >65% is higher than that obtained in conventional glycerolysis where the concentration of MAG generally does not exceed 58%. Such findings not only demonstrate improved yields but also lead to a better understanding of the complex mechanisms of simultaneous glycerolysis–hydrolysis reactions and are critical for optimal process design targeting the MAG and DAG products.
The Journal of Supercritical Fluids.
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ABSTRACT: New vapor pressure data for phenolic compounds (caffeic acid, ferulic acid, and p- and o-coumaric acids) were experimentally obtained and compared to values predicted by a group contribution method. A gas–liquid chromatography method was used to experimentally determine the vapor pressure since this method is reliable, reproducible and rapid. These vapor pressure data were then used to predict second cross virial coefficients of phenolic compounds in supercritical carbon dioxide (SC CO2) using a method based on the residual chemical potential in terms of the virial coefficients and fluctuation theory. The solubility results obtained by this method were compared to those from two other correlations based on the regular solution theory and Chrastil equation. Good agreement was obtained with the correlations when compared to the experimental literature data on the solubility of phenolic compounds in SC CO2.
The Journal of Supercritical Fluids.
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ABSTRACT: Oat and barley β-glucans were isolated from their respective concentrates that were prepared through a novel technology, containing total phosphorus at 0.920 and 0.170%, w/w, respectively. The highest purity of oat and barley β-glucans achieved was 97 and 90%, w/w (db), respectively. Purified oat and barley β-glucans contained 21.8 and 54.1%, w/w, respectively, of the total phosphorus present in the corresponding β-glucan concentrates. On a weight basis, the total phosphorus content in purified oat and barley β-glucans was 0.201 (degree of substitution (DS)=0.011) and 0.092% (DS=0.005), respectively. 31P NMR of both types of β-glucans showed the presence of inner C-6 carbon bound phosphomonoesters and an unknown form of phosphorus, possibly phospholipids and/or phosphoproteins. In addition to these phosphorus forms, barley β-glucan sample contained pyrophosphate for which the origin was unknown. Although a substantial amount of phytate phosphorus (0.745 and 0.103%, w/w, for oat and barley, respectively) was present in both types of β-glucan concentrates, this form of phosphorus was absent in the purified β-glucan as evidenced by 31P NMR data. Aqueous extractability of oat β-glucan from purified sample at 37 °C was 6.6-fold higher than that of barley β-glucan at the same temperature. This may partly be attributed to the presence of more (46%) negatively charged phosphorus substitution in oat β-glucan than in barley.
Food Hydrocolloids.
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ABSTRACT: Lycopene and β-carotene were extracted from freeze-dried tomatoes (skin + pulp) with pure SC CO2 and SC CO2 + 5% w/w co-solvent at 40 °C, 400 bar and flow rates of 0.5 and 1.2 L/min. The apparent solubility of lycopene and β-carotene in the multicomponent complex system was determined from dynamic extraction experiments using a laboratory-scale supercritical extraction system. Solubility of pure lycopene and β-carotene in SC CO2 (binary system) was reported in the literature to be of the order of 10−6 mole fraction. The apparent solubility of lycopene extracted from tomatoes with SC CO2 (multicomponent complex system) under the same conditions was almost one order of magnitude smaller. The apparent solubility obtained using oil as a co-solvent was higher than that obtained with ethanol as a co-solvent or pure SC CO2. The differences in solubility are mainly due to the polarity of the co-solvent and the impact of the tomato matrix in the multicomponent complex system.
Journal of Food Engineering.
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ABSTRACT: The effect of barley β-glucan (BG) on the growth of two yogurt starter cultures (SCs) each consisting of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus was investigated. Model yogurt systems were prepared with or without the incorporation of barley BG and lactose to mimic natural levels in milk and allowed to ferment for 8 h at 42 °C. The fermentation efficacy of the SCs was monitored through pH measurements. Samples were collected and analyzed for pH and viscosity at 0, 2, 4, and 8 h. Viscosity was determined using a rotational viscometer at shear rates of 1.29–129 s−1 and 20 °C. The pH measurements indicated no adverse effect on the growth of SCs as the acidification process was consistent with normal pH development, but viscosity measurements suggested that BG was depolymerized by SCs when lactose became a limiting nutrient during fermentation.
International Dairy Journal.
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ABSTRACT: Volatile flavour composition of cooked chicken (CB), beef (BB) and pork (PB) by-product blends was investigated using gas chromatography–mass spectrometry (GC–MS) and the results were compared with those for cooked chicken white muscles (CM), beef shoulder muscles (BM) and pork shoulder muscles (PM), respectively. The total volatile flavour concentration of CB (4828 μg/kg sample) was three times higher than that observed for CM (1604 μg/kg sample). In BB and PB, the total volatile concentration was lower than that observed for their muscle counterparts. Aldehydes, alcohols and nitrogen- and/or sulphur-containing compounds dominated the volatile flavour profiles of CM, BM and PM while a marked dominance of alcohols was evident for CB and BB. The concentration of aldehydes in BB and PB was lower by about 66 and 70%, respectively, than that evident for the corresponding cooked muscles. The difference between the concentration of aldehydes in CM and CB was ∼7%. These differences between the volatile flavour profiles of cooked muscle samples and the corresponding by-product blends may be attributed to the compositional differences in aroma precursors in the samples. This study demonstrated that the volatile flavour compounds in cooked meat by-products are recoverable, but a careful blending of different by-products of a particular species in appropriate proportions may be necessary to generate an aroma similar to that of the respective cooked muscles.
Food Research International.
