Tocol Composition and Supercritical Carbon Dioxide Extraction of Lipids from Barley Pearling Flour

Samples of whole grain and 35% pearling flour of 20 different barley varieties grown in Alberta were analyzed for their lipid contents. Total lipid contents of whole grains were within 1.9% to 3.0% (w/w), whereas those of the 35% pearling flour were 4.3% to 7.9%. Lipids of 35% pearling flour fraction of Tercel barley were extracted using supercritical carbon dioxide (SC‐CO₂) at different pressures (24, 45, and 58 MPa) and temperatures (40 and 60 °C) for 3 h. Lipid recoveries of 73% to 97% were achieved using SC‐CO₂ extraction under different operational conditions. Tocol contents and compositions of whole grain, 35% pearling flour, and SC‐CO₂ extracts were analyzed using HPLC. Tocol content of the whole grain was 53.8 to 124.9 μg/g and that of the pearling flour was 195 to 363 μg/g of flour. The hulless barley varieties were higher in tocols, with waxy, double waxy and Tercel varieties having the highest levels (P < 0.05). The ratios of total tocotrienols to total tocopherols varied within 1.6 to 3.9 range. Tocol concentrations of SC‐CO₂ extract fractions varied from 1171 to 4391 μg/g extract depending on the operational conditions. Barley oil is a good natural source of different tocol isomers rich in tocotrienols.     

Column Fractionation of Canola Oil Deodorizer Distillate Using Supercritical Carbon Dioxide

Semi-continuous column fractionation of canola oil deodorizer distillate using supercritical CO₂ (SCCO₂) was carried out to determine the feasibility of value-added processing of this feed material for the recovery of bioactive components such as sterols and tocopherols and to determine the effect of operating conditions [pressure (20, 25 MPa using a temperature gradient of 70–100 °C), temperature (70, 100 °C) and a linear temperature gradient (70–100 °C at 25 MPa)] on extract yield and separation efficiency. Total extract yield increased significantly (p ≤ 0.05) with pressure, whereas at isobaric conditions (25 MPa) the highest yield was obtained at the lowest temperature tested (70 °C). Fractionation efficiency was reflected in the composition of fractions and was affected by operating conditions. Residue composition was determined by extract yield in addition to selectivity. Use of the thermal gradient (70–100 °C) decreased the content of volatiles, free fatty acids and tocopherols while increasing sterol content significantly (p ≤ 0.05) to a level of 40% (GC area %) in the residue obtained at 25 MPa. The findings indicate the potential of canola oil deodorizer distillate as a source of sterols and warrant further research on the countercurrent column fractionation to improve the separation efficiency.     

Physicochemical properties of leftover egg yolk after livetins removal

Isolation of immunoglobulin Y (IgY) from egg yolk using water-dilution method generates large quantities of leftover pellet as the co-product. Although egg yolk is well known for its great emulsion property, there is a lack of understanding on how livetins removal would affect the emulsion and rheological properties of the pellet. Therefore, the objective of this study was to determine the effect of soluble protein removal on emulsifying and rheological characteristics of the leftover egg yolk. Egg yolk pellet exhibited distinct structural and physicochemical properties after soluble protein removal. Emulsions prepared from pellet were more vulnerable to coalescence instability than that of egg yolk, although both had a similar oil droplet size. Egg yolk displayed a Newtonian behaviour, compared to a shear-thinning behaviour of pellet. Pellet showed a higher apparent viscosity as well as higher viscoelastic moduli than those of egg yolk, probably due to increased hydrogen bond and hydrophobic interactions in the pellet. Therefore, the changes on the emulsion stability and the rheological properties of egg yolk after soluble proteins removal should be considered in food formulation and processing. Further study is needed to improve the emulsion property of pellet for uses in the food industry.     

Lipase-catalysed interesterification between canola oil and fully hydrogenated canola oil in contact with supercritical carbon dioxide

The processing parameters in enzymatic reactions using CO₂-expanded (CX) lipids have strong effects on the physical properties of liquid phase, degree of interesterification, and physicochemical properties of the final reaction products. CX-canola oil and fully hydrogenated canola oil (FHCO) were interesterified using Lipozyme TL IM in a high pressure stirred batch reactor. The effects of immobilised enzyme load, pressure, substrate ratio and reaction time on the formation of mixed triacylglycerols (TG) from trisaturated and triunsaturated TG were investigated. The optimal immobilised enzyme load, pressure, substrate ratio and time for the degree of interesterification to reach the highest equilibrium state were 6% (w/v) of initial substrates, 10 MPa, blend with 30% (w/w) of FHCO and 2 h, respectively. The physicochemical properties of the initial blend and interesterified products with different FHCO ratios obtained at optimal reaction conditions were determined in terms of TG composition, thermal behaviour and solid fat content (SFC). The amounts of saturated and triunsaturated TG decreased while the amounts of mixed TG increased as a result of interesterification. Thus, the interesterified product had a lower melting point, and broader melting and plasticity ranges compared to the initial blends. These findings are important for better understanding of CX-lipid reactions and for optimal formulation of base-stocks of margarine and confectionary fats to meet industry demands.     

Quality characteristics of angel food cake and muffin using lentil protein as egg/milk replacer

Replacement of animal proteins could be interesting for the food industry because it allows long‐term cost savings, among other reasons. Replacing egg/milk protein (50–100 wt%) by lentil protein (LP) was evaluated on angel cake/muffin quality. The replacement did not significantly affect final product volume, neither the muffins nor the angel food cakes. LP did not affect dough formation and contributed to hold crumb structure building an entangled network in both cake products. In addition, angel cakes and muffins containing LP had significantly lower baking loss than the control. Inferior quality for angel cakes and muffins containing LP was observed regarding hardness and chewiness that increased upon storage, compared to the control. For sensory evaluation in angel cakes, appearance of LP formulations showed lower scores than the control, likely due to the change of crumb colour. Other attributes were not significantly impacted by LP presence. For muffins, M‐100‐LPC formulation showed significant differences with the control for most of the attributes, except appearance and flavour. Indeed, consumers preferred muffins with 100% egg/milk protein replacement, which received higher acceptability scores than control. They also appreciated the ‘nutty’ flavour and moisture of angel cake with 50% egg protein replacement. This research suggests that lentil protein can totally or partially substitute egg/milk protein as foam and emulsion stabiliser in cakes, producing products with satisfactory quality.     

Apparent solubility of lycopene and β-carotene in supercritical CO2, CO2 + ethanol and CO2 + canola oil using dynamic extraction of tomatoes

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.     

Kinetic modeling of the glycerolysis reaction for soybean oils in supercritical carbon dioxide media

Production of MAG by glycerolysis is important for food, pharmaceutical, and cosmetic industries. Conducting glycerolysis in supercritical carbon dioxide (SC-CO₂) media has advantages over conventional alkali-catalyzed glycerolysis. However, kinetic data are lacking for such conversions in the presence of SC-CO₂. The objectives of this study were to estimate the rate constants and elucidate the mechanism for the glycerolysis of soybean oil in SC-CO₂ using previously reported data. The data were taken from experiments using soybean oil, glycerol (glycerol/oil molar ratios of 15–25) and water (3–8% w/w) in SC-CO₂ at 20.7–62.1 MPa and 250°C for a 4 h period. Rate constants for the parallel glycerolysis and hydrolysis reactions were estimated for each processing parameter (glycerol/oil, water content, pressure) by minimizing the summed squared error between the values calculated from the experimental data and those obtained from the kinetic model. The results suggested that water and pressure had an effect on rate constants but the glycerol/oil ratio did not. Findings provide the kinetic modeling data necessary for the optimization of supercritical processes involving glycerolysis reactions for the production of MAG from vegetable oils.     

Interactions between meat proteins and barley (Hordeum spp.) β-glucan within a reduced-fat breakfast sausage system

Barley β-glucan, a soluble fibre component with health benefits, has the potential to be used as a fat replacer in meat systems. Interactions between meat proteins and β-glucan gum were examined in reduced-fat (12%, w/w) sausages formulated with β-glucan at 0.3% (w/w) (0.3β-gl) and 0.8% (w/w) (0.8β-gl) levels, as well as high- and reduced-fat controls. Cooking loss results indicated that β-glucan gum held more water in cooked sausages than control gum (carboxymethyl cellulose), due to its ability to form a tighter network within the protein matrix, as shown by scanning electron microscopy. In a raw system, β-glucan gum was not as effective at retaining moisture as a stable protein network, formed by heating. Differential scanning calorimetry results showed that sausages with a higher gum to protein ratio required additional energy for protein denaturation to occur. Findings indicate that β-glucan gum increases the amount of moisture held in a cooked meat protein system, due to the physical entrapment of water, when compared to the high-fat control, but is similar to the reduced-fat formulation with added water.     

Physical and Sensory Characteristics of Reduced-Fat Breakfast Sausages Formulated With Barley β-Glucan

ABSTRACT: Barley β-glucan, a soluble fiber component, with health benefits, has the potential to be used as a fat replacer in meat systems. Reduced-fat (12%, w/w) sausages formulated with β-glucan at 0.3% (w/w) (0.3 β-gl) and 0.8% (w/w) (0.8 β-gl) levels were developed and compared to high-and reduced-fat controls both sensorially and instrumentally. Compression tests showed 0.3 β-gl to be similar ( p > 0.05) to controls. A trained panel found 0.8 β-gl to be less firm ( p ≤ 0.05) than all others, while consumer panelists evaluated 0.3 β-gl sausages to be acceptable. Raw and cooked sausages contained the same amount of β-glucan. Findings suggest that reduced-fat sausages formulated with β-glucan gum could be a valuable addition to a meat product line.     

Barley β-glucan aerogels as a carrier for flax oil via supercritical CO2

Flax oil has important implications in human health, however, it must be protected in food systems to maintain bioactivity and avoid rancidity. Impregnation of active compounds in polymer networks using supercritical CO₂ (SCCO₂) has shown potential for their protection and delivery. Aerogels were formed with barley β-glucan using SCCO₂ drying. Impregnation of flax oil in barley β-glucan aerogels using SCCO₂ was evaluated when oil was added at different stages of the drying process (before, during and after drying) and under static and dynamic processes at different processing times (2, 6 and 8 h), temperatures (40 and 60 °C) and pressures (15 and 30 MPa). Impregnated aerogels were analyzed using Fourier-transform infrared spectrometry and scanning electron microscopy. Addition of oil during the drying process and the use of a dynamic flow regime resulted in the highest loading of aerogels. Oil loading increased with processing time, from 47.79% (lipid as % of total impregnated aerogel mass) after 4 h to 60.96% after 8 h, and with increasing pressure. Aerogel impregnation using SCCO₂ has potential as a delivery vehicle for high-value food grade compounds, including flax oil.