Microemulsion: a novel alternative technique for edible oil extraction_a mechanistic viewpoint.

Microemulsions, as isotropic, transparent, nano size (<100 nm), and thermodynamically stable dispersions, are potentially capable of being used in food formulations, functional foods, pharmaceuticals, and in many other fields for various purposes, particularly for nano-encapsulation, extraction of bioactive compounds and oils, and as nano-reactors. However, their functionalities, and more importantly their oil extraction capability, strongly depend on, and are determined by, their formulation, molecular structures and the type, ratio and functionality of surfactants and co-surfactants. This review extensively describes microemulsions (definition, fabrication, thermodynamic aspects, and applications), and their various mechanisms of oil extraction (roll-up, snap-off, and solubilization including those by Winsor Types I, II, III, and IV systems). Applications of various food grade (natural or synthetic) and extended surfactants for edible oil extraction are then covered based on these concepts.

Improved Extraction Efficiency and Antioxidant Activity of Defatted Canola Meal Extract Phenolic Compounds Obtained from Air-Fried Seeds.

This study investigated the efficacy of roasting pre-treatment by air frying to enhance the extraction and recovery of the predominant sinapic acid derivatives (SADs) from roasted canola meal and the antioxidant potential of the methanolic extracts. Canola meal was obtained by air frying canola seed at 160, 170, 180 or 190 °C for 5, 10, 15 or 20 min. Oil was extracted using the Soxhlet method, and the de-oiled meal fraction was air-dried. Phenolic compounds were isolated using ultrasound-assisted extraction with 70% (v/v) methanol and then quantified by high-performance liquid chromatography-diode array detection. The antioxidant potential of the defatted meal methanolic extracts was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and metal ion-chelating activity (MIC) assays. The highest total phenolic content of 3.15 mg gallic acid equivalent/g dry weight was recorded in the defatted meal extract from seeds pre-treated with air frying at 190 °C for 15 min. Sinapine, sinapic acid and an unknown compound at a retention time (RT) of 26.6 min were the major sinapates identified in the defatted meal with the highest concentrations of 7572 ± 479.2 µg/g DW, 727 ± 43.45 µg/g DW and 1763 ± 73.5 µg/g DW, respectively, obtained at 160 °C for 5 min. Canolol (151.35 ± 7.65 µg/g DW) was detected after air frying at a temperature of 170 °C for 20 min. The FRAP and MIC correlated positively (r = 0.85) and generally decreased with increased air frying temperature-time conditions. The highest FRAP and MIC values of 0.53 mM and 80% were obtained at 160 °C for 5 and 20 min, respectively. The outcome of this study will contribute new knowledge that could improve the value addition and by-product utilization of canola seeds.

Relationship between nitrogen functionality and wheat flour dough rheology: Extensional and shear approaches.

Nitrogen supplied to wheat crops to increase grain productivity is being scrutinized because of its role in greenhouse gas emissions. Nitrogen affects food quality as well as food security because it increases grain protein content and can change wheat protein composition, both of which affect the rheological properties of dough made from the grain. This review explores the relationship between nitrogen functionality, wheat protein content and the ratio of gliadins to glutenins through critical assessment of recent studies on nitrogen fertilization of wheat. Moreover, by studying how variations in protein content and the gliadins/glutenins ratio affect the shear and extensional rheological properties of the dough, this review elucidates the direct role of nitrogen on wheat flour dough behavior during processing because process operations primarily employ extensional and shear forces. Nitrogen uptake by wheat plants leads to an increase in wheat protein content and changes in the gliadins/glutenins ratio. Confounding factors associated with wheat plant growth and dough preparation make it difficult to definitively separate effects of wheat protein content from effects of wheat protein composition on dough rheology. Nevertheless, in general, higher protein content is associated with larger gliadins/glutenins ratios, resulting in wheat flour doughs that are more extensible.

Association of asparagine concentration in wheat with cultivar, location, fertilizer, and their interaction.

The need to produce wheat with low asparagine concentration is of great importance as a measure to mitigate acrylamide concentration in wheat-based products. The association of asparagine concentration in Canadian bread wheat with cultivar, growing location, fertilizer and their interaction were investigated. Wheat cultivars (8) were grown in 2 locations under 4 fertilizer treatments in triplicate (which consisted of two nitrogen rates (90 or 120 lbs/acre) with or without 15 lbs sulphur per acre). The asparagine concentration ranged from 168.9 to 1050 µg/g and was significantly affected by cultivar, location, and their interaction but not fertilizer treatment. Location and cultivar were responsible for 80% and 14% of the variation, respectively. Some cultivars were not affected by location and maintained their low asparagine accumulation trait. Thus, breeding strategies should aim to identify cultivars that are low asparagine accumulating and are stable across different growing environments.

Characterization of the ergometric properties of commercial bioactive dairy peptides.

The thermodynamic properties of bioactive peptides provide insights into their functional behavior and their biological efficacy. We conducted precise analyses of the density, the ultrasonic velocity and the relative attenuation of serial dilutions of three commercial dairy peptides prepared by enzymatic methods. From these we determined the partial specific volume and the partial specific adiabatic compressibility coefficient for the peptides. At concentrations greater than ~2.5 â€‹mg â€‹mL-1, the apparent values for specific volume and adiabatic compressibility were constant, differing between the three peptides at ±3% for specific volume and ±70% for compressibility. Both specific volume and adiabatic compressibility were highly dependent on concentration, indicating the importance of precise low concentration measurements to obtain correct values for these thermodynamic parameters. From these parameters it was apparent that restructuring of water molecules around the peptides (and their associated counterions) led to compact solutes that were also incompressible. These thermodynamic analyses are critical for understanding how the properties and the beneficial effects of bioactive peptides are influenced by their chemical environment.

Role of NaCl level on the handling and water mobility in dough prepared from four wheat cultivars.

In bread, NaCl plays a number of roles including improving flavor, functionality, dough handling, and prevention of sticky dough. Its reduction can create significant processing challenges. As such, the dough handling properties for four wheat cultivars (Pembina, Roblin, McKenzie, and Harvest) were investigated as a function of NaCl (0-4%) level. In terms of dough rheology, both cultivar and NaCl level were significant factors. The maximum deformation (Jmax ) in the dough decreased with increasing NaCl levels, indicating that the gluten network became stronger so that it was able to resist the imposed stress. For extensibility, increasing the levels of NaCl resulted in increased resistance to extension for all cultivars. Dough stickiness was shown to be both cultivar and salt level dependent, with weaker cultivars showing higher stickiness. Findings for water association indicated that with the addition of NaCl there was less free water among the different cultivars and an increase in the water associated with the starch-fraction. Dough morphology measurements supported rheology trends; the stronger dough producing cultivars created more elongated protein polymers with a unidirectional network whereas the weaker cultivars created porous multidirectional networks. Overall, Pembina and Roblin formed stronger gluten networks than McKenzie and Harvest, however, the effect of NaCl level was shown to be cultivar dependent. Findings indicate that careful cultivar selection will help mitigate challenges in dough handling within a reduced NaCl environment.

The effects of sodium reduction on the gas phase of bread doughs using synchrotron X-ray microtomography.

Globally, the bakery industry has a target of reducing sodium content in bread products. However, removing salt results in changes in the quality of bread through effects on dough's gas phase during the breadmaking process. Using synchrotron X-ray microtomography, the objective of this study was to investigate how sodium reduction induced changes in the gas phase parameters (i.e., gas volume fraction, bubble size distribution (BSD) and its time evolution) of non-yeasted doughs made from a wide range of formulations (i.e., wheat cultivar and water content) prepared with different mixing times. As salt content was reduced, a lower gas volume was retained in the dough by the end of mixing. Less gas bubbles were also retained if doughs were prepared from a stronger wheat cultivar, higher water content, and/or mixed for a shorter time. Rates of change in the median (R0) and the width (ε) of the fitted lognormal radius dependence of bubble volume fraction [BVF(R)] indicated that reduced sodium content permitted disproportionation to proceed more rapidly. Higher water content or longer mixing time also resulted in faster disproportionation, indicating that water content and mixing time can be manipulated as a means of increasing bubble stability against disproportionation during low-sodium breadmaking. An examination of relative changes in dough's gas phase parameters arising from sodium reduction demonstrated that wheat cultivar, water content and mixing time all affected dough's tolerance to sodium reduction. Therefore, attainment of good bread crumb cell structure in low-sodium bread formulas is a function of salt's effects on dough rheology in addition to its effect on yeast activity, so that dough formulation and mixing conditions also need to be considered.

Effect of salts from the lyotropic series on the handling properties of dough prepared from two hard red spring wheat cultivars of differing quality.

The influence of select salts from the lyotropic series (NH4Cl, KCl, NaCl, MgCl2, CaCl2, and MgSO4) on the rheology and stickiness of dough prepared from a strong (Pembina) and a weak (Harvest) hard red spring wheat flour were examined at a 1 and 2% salt levels, with water mobility and water association with different dough components also being assessed at the 1% salt level. Overall, Pembina was found to develop stronger gluten networks that were more resilient than those of Harvest as evident from a lower tan δ and less compliance during shear creep recovery rheology. However, the effect of salt-type differed based on cultivar. Pembina showed lower dough stickiness than Harvest in all cases. NH4Cl decreased dough stickiness the most for both cultivars. The use of alternative salts affected the association of water with the starch-fraction and gluten-fraction in doughs, and this effect was cultivar-dependent.

Interesterification of Soybean Oil with Propylene Glycol in Supercritical Carbon Dioxide and Analysis by NMR Spectroscopy.

The time course study of high monoester mixtures from soybean oil (HMMS) synthesis, as healthier alternatives to trans food products, in a supercritical CO2 (SCCO2) medium with and without enzyme, was investigated. Phosphorous nuclear magnetic resonance (31P-NMR) was used to quantify the absolute amount of partially esterified acylglycerols (PEGs). Carbon NMR was utilized to determine the type and position of the fatty acids (FAs) of HMMS. Enzyme and time significantly influenced the synthesis of 1-monoglycerides (1-MGs), 2-MGs, and 1,2-diglycerides (1,2-DGs) in this alcoholysis of soybean oil with 1,2-propanediol, based on high catalytic activity and operational stability of Novozym 435 in SCCO2 during short reaction time. Results suggest that 4 h is a suitable reaction time for this lipase-catalyzed interesterification (LIE) system for the synthesis of 2-MGs with a yield of 20%. The highest polyunsaturated fatty acid (PUFA) (65%) in the triglyceride (TG) of HMMS was produced after 4 h of reaction. After 6 h of reaction, a high level (20%) of saturated fatty acids (SFAs) was found in the TGs of HMMS, which were distributed between the sn-2 (5%) and sn-1, 3 (15%) positions.

Microemulsion as nanoreactor for lutein extraction: Optimization for ultrasound pretreatment.

In the present study, the capability of microemulsion technique, as a novel technique for synchronous extraction and solubilization of lipophilic compounds, on lutein extraction from marigold petals was investigated. Under the optimized sonication (amplitude 100%, 120 s, 25°C), the extraction efficiency increased (85%) using SDS:ethanol (1:2)-based ME. Moreover, sonication led to smaller droplets (12-163 nm) with favorable thermodynamic stability. In addition, the developed MEs showed higher thermal and especially UV stability in comparison to organic solvent extracts which were fainted with first-order kinetics. It was also found that co-surfactant could be eliminated from formulation on the expense of the optimized sonication, was valuable output form industrial point of view. These findings revealed the high potential of ultrasound technique on the extraction and solubilization of lutein by ME technique which can be directly utilized in lutein-enriched functional foods and beverages. PRACTICAL APPLICATIONS: From applicability point of view, the solvent extracted compounds cannot be easily dissolved in food or pharmaceutical systems that are mostly hydrophilic. Therefore, microemulsions (MEs), as green and environmentally friendly food-grade systems, due to their potential capability for simultaneous extraction and solubilization of carotenoids are of great interest. Therefore, the present study confirmed the practical ability of MEs in lutein extraction and protection. All in all, the developed lutein MEs with high lutein extraction capacity and superior lutein chemical stability against thermal treatment and especially UV radiation is an original finding which allows design of new functional foods and could be potentially useful for enriching foods, pharmaceuticals, nutraceuticals, and supplement formulation.

Effect of enzymatic crosslinking on the handling properties of dough as a function of NaCl levels for CWRS varieties, Pembina and Harvest.

The effects of transglutaminase (TG) and glucose oxidase (GO) on the handling properties of model bread dough were examined at both normal (2% wt. by flour) and reduced (1% wt.) sodium chloride (NaCl) levels using two Canada Western Red Spring (CWRS) cultivars; Pembina and Harvest. The reduction of NaCl level had negative effects on dough rheology and stickiness, however, the inclusion of GO (0.001 and 0.01% by flour weight) or TG (only at the 0.5% by flour weight inclusion) was able to improve dough strength and reduce stickiness. GO appeared to be more effective than TG (at 0.01%) at equivalent concentrations for improving dough-handling properties. Flour cultivar had significant effects; Harvest flour (weaker) was more impacted by salt reduction and enzyme inclusion compared to Pembina flour (stronger). Crosslinking assays showed significant differences in glutenin macropolymer (GMP) content in dough prepared with GO, and dough prepared with different flours. Additionally, significantly fewer free thiol groups were found in dough produced with GO compared to dough without any enzymes and those with TG. GO appears to have potential for use as a bread improver to reduce stickiness and improve the strength of bread dough produced at lower salt concentrations, especially for dough prepared with weaker flour cultivars.

Ultrasonic Characterization of Amyloid-Like Ovalbumin Aggregation.

Thermal processing conditions, pH, and salt content affect the formation of egg white ovalbumin amyloid, which was investigated using high-precision measurements of ultrasonic velocity and attenuation. These were related to fluorescence and particle size measurements. Fluorescence changes indicated the formation of amyloid-like aggregates that was enhanced by increasing time-temperature treatments. The ultrasonic velocity of ovalbumin after heating at neutral pH (60 min at 70 or 80 °C) was lower than that of unheated ovalbumin, whereas the attenuation was higher. The decrease in the velocity represents increased compressibility associated with a change in the compactness of the protein, whereas changes in attenuation are due to protein conformational changes. Heating ramp studies revealed transitions at approximately 58 and 73 °C. During heating at a constant temperature, the ultrasonic velocity decreased slowly with increasing heating time, indicating an increase in ovalbumin compressibility. It is suggested that the obtained amyloid-like ovalbumin aggregates contain a compact core surrounded by loosely packed protein segments.

Relation between ultrasonic properties, rheology and baking quality for bread doughs of widely differing formulation.

BACKGROUND: The objective was to evaluate whether an ultrasonic reflectance technique has predictive capacity for breadmaking performance of doughs made under a wide range of formulation conditions. Two flours of contrasting dough strength augmented with different levels of ingredients (inulin, oil, emulsifier or salt) were used to produce different bread doughs with a wide range of properties. Breadmaking performance was evaluated by conventional large-strain rheological tests on the dough and by assessment of loaf quality. The ultrasound tests were performed with a broadband reflectance technique in the frequency range of 0.3-6 MHz. RESULTS: Principal component analysis showed that ultrasonic attenuation and phase velocity at frequencies between 0.3 and 3 MHz are good predictors for rheological and bread scoring characteristics. CONCLUSIONS: Ultrasonic parameters had predictive capacity for breadmaking performance for a wide range of dough formulations. Lower frequency attenuation coefficients correlated well with conventional quality indices of both the dough and the bread. © 2016 Society of Chemical Industry.

Ultrasound as a tool to study bubbles in dough and dough mechanical properties: A review.

Investigation of dough mechanical properties using low-intensity ultrasound is now reasonably well established. In this review, an introduction to the fundamentals of ultrasound propagation in non-scattering and in scattering media is followed by several examples of how low-intensity ultrasound is used as a research tool for exploring the bubble size distribution in breadmaking dough and evaluating dough's mechanical properties. Utilization of ultrasonic techniques for quantitative assessments of bubbly dough structure and characterization of dough mechanical properties as affected by dough formulation are pointed out.

Effect of pretreatments and endo-1,4-ß-xylanase hydrolysis of canola meal and mustard bran for production of oligosaccharides.

Alkali/acid-pretreated canola meal and mustard bran were subjected to endo-1,4-ß-xylanase (T. longibrachiatum) hydrolysis for oligosaccharide production. Pretreatments significantly (α = 0.05) increased the relative content of pentose sugars, especially in alkali-pretreated canola meal (∼44 %) and mustard bran (∼72 %). The amounts of pentosan (g/100 g) in acid- and alkali-pretreated canola meal were 7.50 and 8.21 and in corresponding mustard bran were 8.67 and 10.39, respectively. These pretreated substrates produced a pentose content (g/100 g) of 2.10 ± 0.14 (18 h) and 2.95 ± 0.10 (24 h), respectively, during hydrolysis. As per UPLC-MS data, the main oligosaccharides in the hydrolyzates of alkali-pretreated substrates are xylo-glucuronic acid and xylobiose. The release of total phenolics of the hydrolyzates increased until 18 h irrespective of the type of substrate or pretreatment. Hydrolyzates of acid-pretreated substrates indicated more total antioxidant activity than alkali-pretreated substrates, attributed to its high phenolic content. The study suggests the potential of canola meal and mustard bran for the production of oligosaccharides, wherein the use of various combinations of cell-wall-degrading enzymes and its optimization may result in a better yield, with simultaneous production of endogenous phenolics.

Phase behaviour of casein micelles and barley beta-glucan polymer molecules in dietary fibre-enriched dairy systems.

Enrichment of colloidal dairy systems with dietary fibre frequently causes quality defects because of phase separation. We investigate phase separation in skimmed milk enriched with Glucagel (a commercial product made from barley that is predominantly comprised of the polysaccharide ß-glucan). The driving force for phase separation was depletion flocculation of casein micelles in the presence of molecules of the polysaccharide. Depending on the volume fraction of casein micelles and the concentration of Glucagel, the stable system phase separated either as a transient gel or as a sedimented system. The rate at which phase separation progressed also depended on the volume fraction of casein micelles and the concentration of Glucagel. To confirm the role of depletion flocculation in the phase separation process, enzymatic reduction in the molecular weight of ß-glucan was shown to limit the range of attraction between micelles and allow the stable phase to exist at a higher ß-glucan concentration for any given volume fraction of casein micelles. These phase diagrams will be useful to dairy product manufacturers striving to improve the nutrient profile of their products while avoiding product quality impairment.

Influence of positional correlations on the propagation of waves in a complex medium with polydisperse resonant scatterers.

We present experimental results on a model system for studying wave propagation in a complex medium exhibiting low-frequency resonances. These experiments enable us to investigate a fundamental question that is relevant for many materials, such as metamaterials, where low-frequency scattering resonances strongly influence the effective medium properties. This question concerns the effect of correlations in the positions of the scatterers on the coupling between their resonances, and hence on wave transport through the medium. To examine this question experimentally, we measure the effective medium wavenumber of acoustic waves in a sample made of bubbles embedded in an elastic matrix over a frequency range that includes the resonance frequency of the bubbles. The effective medium is highly dispersive, showing peaks in the attenuation and the phase velocity as functions of the frequency, which cannot be accurately described using the independent scattering approximation (ISA). This discrepancy may be explained by the effects of the positional correlations of the scatterers, which we show to be dependent on the size of the scatterers. We propose a self-consistent approach for taking this "polydisperse correlation" into account and show that our model better describes the experimental results than the ISA.

Use of a pressuremeter to measure the kinetics of carbon dioxide evolution in chemically leavened wheat flour dough.

Among a number of impediments to a wider use of chemical leavening agents in bakery applications is the lack of standardized instrumentation capable of providing information on the rates of CO2 production from chemical leaveners in a format that is meaningful to both the technologist (i.e., the dough rate of reaction or DRR) and the researcher (e.g., in terms of fundamental unitskmol CO2 per kg of dough per s). This paper presents an original methodology to carry out the DRR test using a commercial pressuremeter, the Gassmart apparatus, and to model the kinetics of CO2 evolution of chemically leavened dough. Lean formula doughs were leavened at 27 and 39 degrees C with four chemical leavening systems containing sodium bicarbonate and one of four leavening acids, sodium acid pyrophosphate 40 (SAPP), adipic acid (ADA), potassium acid tartrate (KAT), and glucono-delta-lactone (GDL). Chemical kinetics theory was used to gain an insight into the reaction mechanisms responsible for the evolution of carbon dioxide from the leaveners. A first-order reaction kinetics model was found to be suitable for describing the neutralizing properties of GDL and ADA leavening systems, whereas a first-order reaction kinetics model for irreversible parallel reactions better described the leavening properties of the acidic salts KAT and SAPP.

Sound velocity and attenuation in bubbly gels measured by transmission experiments.

Measurements of the phase velocity and attenuation of sound in concentrated samples of bubbly gels are presented. Hair gel was used as a matrix material to obtain well characterized distributions of bubbles. Ultrasonic measurements were conducted over a large range of frequencies, including the resonance frequencies of the bubbles. Surprisingly good agreement with Foldy's prediction was found, even for monodisperse samples at resonance frequencies, up to volume fraction of 1%. Beyond this concentration, the effects of high-order multiple scattering were observed. These results support the feasability of ultrasonic techniques to investigate the size distribution of bubbles in a weak gel or liquid.

Comparison of ultrasonic velocities in dispersive and nondispersive food materials.

Ultrasonic techniques are increasingly being used to evaluate the properties of food materials. Interpretation of the structure and dynamics on the basis of measured ultrasonic parameters requires rigorous definition of ultrasonic parameters such as velocity, especially since many food materials can display considerable dispersive behavior (changes in velocity with frequency). Agar gel (2% w/v) and agar gel (2% w/v) with a regular array of bubbles (8% volume fraction) were chosen as nondispersive and dispersive materials, respectively. Frequency and time domain techniques were used to analyze velocities. Signal, phase, and group velocities were identical in the agar gel and were indistinguishable from those of water (1500 m s(-1)), indicating the predominant effect of the bulk modulus of the water they contain on the longitudinal modulus of the gel. In contrast, the inclusion of the bubbles in the agar gel led to strongly dispersive behavior, with group velocities varying by 1000 m s(-1) above and below the 1500 m s(-1) of the agar gel without bubbles, depending on frequency. The addition of bubbles also led to strong attenuation in the agar gel with a peak occurring at a frequency associated with a band gap arising from destructive interference of sound waves. The results show that care must be taken when comparing ultrasonic parameters derived from experiments on food materials performed at different frequencies or with different ultrasonic techniques.