Commercial Wheat Gluten Research Articles

Gelation and dough‐forming properties of canary seed protein concentrate in comparison with commercial soy protein concentrate and vital wheat gluten

AbstractBackground and ObjectivesIn this study, a lab‐scale process was developed to aqueously de‐oil canary seed (yellow and brown‐seeded) flour and derive a protein concentrate. The protein concentrates prepared were evaluated for their gelation and bread dough‐forming properties.FindingsThe aqueous process successfully reduced the oil content in both yellow‐seed and brown‐seed roller‐milled flour. The protein concentrate prepared from yellow‐seed flour and brown‐seed flour had 74.9% and 68.6% purity (dry weight basis), respectively. Proteins showed high resistance to thermal denaturation (peak denaturation at 107°C). It was found that the least gelation concentration of both protein concentrates was 16% (w/w). There were no significant differences in viscoelastic properties and water holding capacity between the protein gels of these two canary seed types and the addition of salt did not noticeably improve these properties. Compared to canary seed, commercial soy protein showed better gelation properties. Both yellow and brown canary seed protein showed a good potential for improving bread dough strength when incorporated into a low‐gluten‐strength wheat flour and was comparable to commercial vital wheat gluten at 1%–3% (w/w) inclusion levels.ConclusionsThe new canary seed protein ingredients prepared by the solvent‐free aqueous‐based process hold good potential for application in food formulation based on their gelation and bread dough‐forming properties.Significance and NoveltyThe gelation and dough‐forming properties of canary seed were not previously studied; therefore, this study provides an insight into those properties for potential food applications for canary seed proteins, which is important for canary seed market diversification as a novel protein source.

Gluten extraction from deoxynivalenol contaminated wheat by wet milling

The wet milling process can be a valuable alternative for deoxynivalenol (DON) contaminated wheat grain, taking advantage of DON water solubility. The present research was conducted on hard red spring wheat (HRSW) and durum wheat (DW) samples contaminated with DON. The wheat samples were dry milled into farina and semolina, which were further subjected to three different small-scale wet milling tests, dough-washing (Martin process), moderately sheared dough-water dispersion (medium shear) process, and highly sheared flour-water dispersion (high shear) process. Gluten samples extracted from all the wet milling processes had DON levels below the limit of quantification (<0.2 mg/kg) because of the high water solubility of DON. Size-exclusion HPLC revealed that gluten samples obtained from medium shear and high shear processes were composed of more unextractable (sonication extractable) glutenin macropolymers and less gliadin fractions than those obtained from the Martin process. This yielded better rheological performance for the gluten samples, so that they were quite similar to the control (commercial wheat gluten), which means the gluten samples exhibited a potential application as food ingredients.

Simple tests as tools for vital wheat gluten evaluation

PurposeThe purpose of this paper is to evaluate the viscoelastic quality of commercial vital wheat glutens from different origins (A and B) through simple tests, and correlate these results with dough rheological parameters measured using more complex equipment (farinograph and extensograph) and with bread quality characteristics (specific volume and crumb firmness) obtained from wheat flour fortified with 7 g/100 g of vital gluten.Design/methodology/approachFor the evaluation of vital gluten quality, two commercial vital wheat gluten named A and B were used. The simple tests performed with these samples were wet and dry gluten contents and index gluten, extensbility test and expansion test. The Pearson correlation was performed among data from dough rheological tests (farinograph and extensograph) and bread quality parameters (specific volume (SV) and crumb firmness) obtained from the fortification of wheat flour with 7 g/100 g of VGA or VGB (previous work, data not shown).FindingsThe simple tests showed differences in the viscoelastic properties of vital gluten A and B; vital gluten A presented higher elasticity and lower extensibility than vital gluten B, and the gluten ball of sample A presented higher SV. By correlation analysis, it was verified that the simple tests studied may be useful to assess the baking performance of commercial vital gluten when this product is added to wheat flour for its fortification. Furthermore, the results indicate the need for more information on vital wheat gluten proteins for its commercialisation and use.Originality/valueThis work is very important, not just for the scientific community, but also for the bakery industry, that requires more information about vital wheat gluten before its use in bread making. As there are great differences in the protein quality of commercial vital wheat glutens and their functionality, the study was developed to solve this problem.

Development and characterisation of protein films derived from dried distillers’ grains with solubles and in-process samples

Polymer films were developed utilising proteins extracted from wheat distillers’ dried grains with solubles (DDGS) and in-process samples (wet solids), both by-products of bioethanol production process. Structural characterisation of DDGS and wet solids films indicated a change in the secondary structure of the proteins, reflecting the impact of DDGS production process such as effect of enzyme on protein properties and consequently on the film properties; whereas the developed films exhibited a rough surface with voids. Determination of moisture sensitivity indicated that DDGS films exhibited more hydrophilicity than wet solids films, with the same trend being observed for their water solubility and water uptake. The moisture content and solubility of DDGS films ranged from 10.2–14.2% and 32.3–41.8% respectively whereas those for wet solids’ film ranged from 18.9–19.8% and 23.8–24.2% respectively. The mechanical properties of DDGS and wet solids (ranging from 0.27–0.32 MPa) were comparatively lower than commercial wheat gluten film (0.6 MPa). The poor mechanical properties and high water vapour permeability of DDGS and the wet solids films limit their application as biodegradable packaging materials. However, based on their hydrophilicity, the developed films have potential applications in agriculture and horticulture as controlled release matrices and soil conditioners.

Protein Characteristics that Affect the Quality of Vital Wheat Gluten to be Used in Baking: A Review.

The use of vital wheat gluten in the baking industry and wheat flour mills aims to improve the rheological characteristics of flour considered unsuitable to obtain products such as sliced bread, French bread, high-fiber breads, and other products that require strong flours. To improve characteristics such as flour strength, dough mixing tolerance, and bread volume, vital wheat gluten is added to flour at levels that can vary from 2% to 10% (flour basis), with 5% being a commonly used dosage. However, the vital wheat gluten commercialized in the market has few quality specifications, especially related to the characteristics of the proteins that constitute it and are responsible for the formation of the viscoelastic gluten network. Information on protein quality is important, because variations are observed in the technological quality of vital wheat gluten obtained from different sources, which could be associated to damage caused to proteins during the obtainment process. Several tests, either physical-chemical analyses, or rheological tests, are carried out to establish gluten quality; however, they are sometimes time-consuming and costly. Although these tests give good answers to specify gluten quality, flour mills, and the baking industries require fast and simple tests to evaluate the uses and/or dosage of vital gluten addition to wheat flour. This review covers the concepts, uses, obtainment processes, and quality analysis of vital wheat gluten, as well as simple tests to help identify details about protein quality of commercial vital wheat gluten.

Binding of carbonyl flavours to canola, pea and wheat proteins using GC/MS approach

Interactions of homologous aldehydes (hexanal, heptanal, and octanal) and ketones (2-hexanone, 2-heptanone, and 2-octanone) to salt and alkaline-extracted canola and pea proteins and commercial wheat gluten were studied using GC/MS. Long-chain aldehyde flavours exhibited higher binding affinity, regardless of protein type and isolation method. Salt-extracted canola protein isolates (CPIs) revealed the highest binding capacity to all aldehydes followed by wheat gluten and salt-extracted pea protein isolates (PPIs), while binding of ketone flavours decreased in the order: PPIs>wheat gluten>CPIs. Two aldolisation products, 2-butyl-2-octenal and 2-pentyl-2-nonenal, were detected from the interactions between CPIs with hexanal and heptanal, respectively. Protein thermal behaviour in the presence of these compounds was analysed by differential scanning calorimeter, where decreased ΔH inferred potential conformational changes due to partial denaturation of PPIs. Compared to ketones, aldehyde flavours possessed much higher “unfolding capacity” (lower ΔH), which accounted for their higher binding affinities.

Gluten-Free Diet: Imprudent Dietary Advice for the General Population?

As of April 20, 2012, Amazon.com listed 4,765entriesforthetopic“gluten-free.”AGooglesearchatthesametime for “gluten-free diet” produced more than 4.2 millionresults. The number-one reason consumers cite for buyinggluten-freeproductsisthattheyareperceivedtobehealthierthan their gluten-containing counterparts.

Edible wheat gluten (WG) protein films

Commercial wheat gluten (WG) films, hard wheat gluten films and soft wheat gluten films, plasticized with glycerol have been cast from water–ethanol solutions. The effect of aging on various film properties has been investigated. The films were aged for about 6 months at 50% relative humidity and ~25 °C, and the mechanical (tensile strength and the percentage of elongation at break (E b)), thermal (TG and DSC) and Attenuated Total Reflectance (ATR)-FTIR spectral properties have been studied. Changes in the protein structure were determined by ATR-FTIR spectroscopy. Films from soft WG exhibited the highest E b (508%) and the highest TS (6.33 MPa). The TG analysis results show that the moisture content in all three kinds of WG protein films is about 5%. The absence of the glycerol phase transition in DSC curves implies that there is no separate phase containing glycerol in the WG protein-glycerol films with 40% glycerol.

Mechanical Properties and Network Structure of Wheat Gluten Foams

This Article reports the influence of the protein network structure on the mechanical properties of foams produced from commercial wheat gluten using freeze-drying. Foams were produced from alkaline aqueous solutions at various gluten concentrations with or without glycerol, modified with bacterial cellulose nanosized fibers, or both. The results showed that 20 wt % glycerol was sufficient for plasticization, yielding foams with low modulus and high strain recovery. It was found that when fibers were mixed into the foams, a small but insignificant increase in elastic modulus was achieved, and the foam structure became more homogeneous. SEM indicated that the compatibility between the fibers and the matrix was good, with fibers acting as bridges in the cell walls. IR spectroscopy and SE-HPLC revealed a relatively low degree of aggregation, which was highest in the presence of glycerol. Confocal laser scanning microscopy revealed distinct differences in HMW-glutenin subunits and gliadin distributions for all of the different samples.

Quality of shear fractionated wheat gluten – Comparison to commercial vital wheat gluten

The functional properties of gluten obtained with a shear-induced separation process, recently proposed by Peighambardoust et al. (2008), are compared with a commercially available vital wheat gluten. Two tests were performed. First, a relatively strong wheat flour, Soissons, was enriched with gluten protein. The resulting dough was then evaluated on its kneading performance. Second, a weak flour, Kolibri, was enriched to evaluate the baking properties. The wheat flour enriched with gluten protein obtained via the shear-induced separation process (SCG) showed comparable to improved gluten functionality relative to commercial available vital wheat gluten protein (CVWG). The differences in functionality cannot be directly related to the composition as analyzed with SE-HPLC, because the composition of the gluten materials was rather comparable. The differences in functionality may therefore be related to the different drying techniques used or to the inherent mildness of the shear-induced separation technique.

Impact of sourdough, yeast and gluten on small and large deformation rheological profiles of durum wheat bread doughs

The impact of percentage of sourdough (SD) addition and presence of yeast (Y) and/or commercial wheat gluten (G) -added singly and in binary combination- on both small and large deformation rheological performance and viscometric profile of durum wheat bread doughs was considered. Eight distinctive rheological dough features were identified as able/capable to clearly differentiate soured bread doughs made with semolina:remilled semolina rate of 80:20 into defined functional quality groups. The presence of added commercial wheat gluten provided firmer, more elastic and more extensible doughs with slightly lower viscometric profile. Simultaneous presence of yeast/sourdough and yeast/gluten modulate single effects of sourdough on the durum wheat bread dough mechanical properties. Several relationships were found between fundamental and empirical rheological properties and within viscometric features of soured semolina doughs.

GLUTEN EXTRACTED FROM FRESH PASTA BY‐PRODUCT: PHYSICOCHEMICAL PROPERTIES AND POTENTIAL USE IN BREAD MAKING

ABSTRACT The chemical, functional, rheological and structural properties of gluten extracted from fresh durum wheat pasta by‐product (PG) were studied and compared with those of the commercial soft wheat gluten (CG). PG had lower starch and fat contents, lower adhesiveness and higher emulsifying and foaming stabilities than CG, whereas CG had higher foaming capacity, cohesiveness and chewiness. CG gave also a more open matrix surface morphology than PG. The glutens did not show a significant difference of their protein content, water absorption, hardness and springiness. They showed also similar dynamic rheological behaviors (G′, G″ and tan δ) at low frequencies (&lt;4 Hz). In addition, PG and CG can be used in the bread‐baking process since addition (2%, flour basis) to dough characterized by a low bread‐making quality improved significantly its strength (W) and its elasticity‐to‐extensibility ratio (P/L).PRACTICAL APPLICATIONSThe pasta by‐product could be considered as an excellent source of gluten and may be used as an improver in bread making. This hypothesis is supported by determining the functional and rheological properties of the gluten extracted from fresh pasta by‐product. Furthermore, addition of 2% of this gluten to low bread‐making quality wheat flour leads to an improvement of the dough alveographic characteristics (W and P/L) and an increase in bread volume by 46%.

The role of gluten in a sugar-snap cookie system: A model approach based on gluten–starch blends

The cookie making properties of dough made from blends of commercial wheat starch and gluten were determined. Higher gluten levels decreased dough piece weight, its density, stickiness and hardness. The largest spread was obtained when no gluten was added. However, this resulted in cookies of unacceptable structure. Higher gluten contents increased spread onset time, decreased cookie spread but generally had little impact on set time while additional water lowered spread onset time and likewise had no statistically significant impact on set time. The results showed that the final cookie diameter is quite dependent on the spread onset time which itself depends on the amount of water available to the non-gluten constituents in the system. Size-exclusion high performance liquid chromatography showed that during baking, proteins aggregated. This indicated that during the process the added gluten acquired the necessary mobility for interaction. However, because increasing levels of gluten increasingly decreased the relative level of water available to itself, and because the set time, and, hence, the set temperature, did not depend on the gluten level, we concluded that cookie dough setting was not determined by an ‘apparent’ glass transition. Furthermore, more protein aggregation went hand in hand with less spread.

Role of Chain Entanglements in the Electrospinning of Wheat Protein-Poly(Vinyl Alcohol) Blends

The aim of this investigation was to determine if the rapid solvent removal evaporation that occurs during electrospinning enabled the gluten protein and poly(vinyl alcohol) (PVOH) chains to remain at least partially entangled in the final product. Natural and synthetic biopolymer blends are known to phase separate in the melt. Differential scanning calorimetry (DSC) was used to test our hypothesis, which we achieved by systematically comparing the thermal profiles of the nonwoven fibrous sheets comprising: 1) 100% commercial wheat gluten, 2) 100% PVOH, and 3) the (75/25) wheat gluten/PVOH blend. The DSC scans of the two PVOH-containing, nonwoven fibrous sheets exhibited differences in the characteristics and positions of the melting peaks (Tm) of the PVOH crystalline phase, while the DSC scans of the nonwoven fibrous sheets comprising either 100% commercial wheat gluten or the wheat gluten/PVOH blend yielded neither a measurable glass transition temperature (Tg) nor a Tm. Energy dispersive spectroscopy (EDS) was used to compare the elemental compositions of the individual fibers with the compositions of the spherical domains found in the nonwoven fibrous mats. These scans revealed that the mineral matter found in commercial wheat gluten (roughly 1% by weight) had phase-separated from the bulk gluten protein as a result of electrospinning.

Occurrence of the Free and Peptide Forms of Pyroglutamic Acid in Plasma from the Portal Blood of Rats That Had Ingested a Wheat Gluten Hydrolysate Containing Pyroglutamyl Peptides

In order to determine pyroglutamic acid levels in plasma, we developed a method based on precolumn derivatization of the carboxyl group of pyroglutamic acid with 2-nitrophenylhydrazine. Eight-week-old male SD strain rats were administered 200 mg of an acidic peptide fraction obtained from a commercial wheat gluten hydrolysate containing 0.63 mmol/g pyroglutamyl peptide. After administration, significant amounts of free pyroglutamic acid were observed in the ethanol-soluble fraction of the plasma from the portal vein. In addition, pyroglutamate aminopeptidase digestion of the ethanol-soluble fraction liberated significant amounts of pyroglutamic acid, which indicated the presence of the pyroglutamyl peptide. The presence of the pyroglutamyl peptide in the plasma was further confirmed by size exclusion chromatography. The levels of free and peptide forms of pyroglutamic acid increased significantly and reached a maximum (approximately 40 nmol/mL) at 15 and 30 min after administration, respectively.

Characterization of Biodegradable Films Obtained from Cysteine-Mediated Polymerized Gliadins

This study focuses on the effect exerted by interchain disulfide bonds on the functional properties of films made from gliadins when cross-linked with cysteine. Gliadins were extracted from commercial wheat gluten with 70% aqueous ethanol, and cysteine was added to the film-forming solution to promote cross-linking between protein chains. The formation of interchain disulfide bonds was assessed by SDS-PAGE analysis. Gliadin films treated with cysteine maintain their integrity in water and become less extensible while their tensile strength increases as a consequence of the development of a more rigid network. The glass transition temperature of cross-linked films shifts to slightly higher values. The plasticizing effects of glycerol and moisture are also demonstrated. The mechanical behavior of cysteine-cross-linked gliadin films was compared to that of polymeric glutenins. Cross-linked gliadins displayed tensile strength values similar to those of glutenin films but achieved slightly lower elongation values. Cysteine-cross-linked gliadin films present the advantage that they are ethanol soluble, facilitating film fabrication or their application as a coating for food or for any other film or surface.

Effect of thermal treatments on functional properties of edible films made from wheat gluten fractions

The effect of thermal treatments on selected properties of films based on gliadins and glutenins prepared from commercial wheat gluten was studied. Gliadin- and glutenin-rich films were heat cured at 40, 55, 70, 85, 95 and 115 °C for 24 h. The effect of heat curing on moisture content, colour, total soluble matter in water, water vapour permeability, tensile strength and elongation at breakpoint of the films was evaluated. Mechanical and water barrier properties of films changed sharply in the range of 55–75 °C. Films became stronger and less extensible with lower water vapour permeability. No changes in the equilibrium moisture content at 50% relative humidity of films associated with thermal treatments were observed. From 70 °C, gliadin films kept their integrity in water whereas film disintegration was observed in other cases. Films became darker with a yellow-brown coloration with the increase of temperature treatment; so in order to preserve the film appearance temperature no higher than 70–75 °C for gliadin and glutenin, respectively, will be recommendable. Thermal treatment can effectively be applied to optimize the use and application of gliadin- and glutenin-rich films.

Effect of cross-linking using aldehydes on properties of glutenin-rich films

The effect of cross-linking agents glutaraldehyde (GTA), glyoxal (GLY) and formaldehyde (FA) on relevant properties of films based on a glutenin-rich fraction from commercial wheat gluten was studied. The gliadin-rich fraction was separated from glutenin-rich fraction using 70% (v/v) aqueous ethanol solution. The 70% ethanol-insoluble fraction (glutenin-rich fraction) was dispersed in 50% (v/v) aqueous ethanol at 40 °C and pH 5. GTA, GLY or FA was added in concentrations of 2, 4 and 8% (g/100 g dry protein) to the film-forming solution. Glycerol was used as plasticizer. Films were cast and dried at 23 °C and 40% RH (relative humidity) for 10 h. Mechanical and water vapour barrier properties, color, water sorption isotherms and glass transition temperature of control and cross-linked films were evaluated. Water vapour permeability values decreased by around 30% when FA, GTA or GLY were incorporated. The highest tensile strength values were obtained using FA, followed by GTA and GLY. Glass transition temperature of cross-linked films shifts to slightly higher values when cross-linking agents were used. Films treated with GTA and GLY were darker with a yellowish color. Addition of concentrations up to 2% of cross-linker did not modify the properties of the films. Water sorption behaviour of control and cross-linked films did not differ.

Development and characterization of biodegradable films made from wheat gluten protein fractions.

Gliadins and glutenins were extracted from commercial wheat gluten on the basis of their extractability in ethanol and used to produce film-forming solutions. Films cast using these gliadin- and glutenin-rich solutions were characterized. Glycerol was used as a plasticizer, and its effect on the films was also studied. Films obtained from the glutenin fraction presented higher tensile strength values and lower elongation at break and water vapor permeability values than gliadin films. Gliadin films disintegrated when immersed in water. The GAB isotherm model was used to describe the equilibrium moisture sorption of the films. The glycerol concentration largely modified mechanical and water vapor barrier properties of both film types.

Ambiguous Impact of Wheat Gluten Proteins on the Colloidal Haze of Wheat Beers

Laboratory-scale brews were prepared from barley malt with various addition levels of commercial wheat gluten. These were calculated to range from 0 to 150% of the amount of gluten in a typical wheat beer mash (60% barley malt and 40% unmalted wheat). Nephelometric permanent haze readings of the experimental beers showed an increase of the haze intensity with the increasing gluten levels, reaching a maximum of 50 EBC haze units at the gluten level corresponding to the wheat gluten level in a mash based on 88% barley malt and 12% wheat. At higher gluten levels, the haze intensity declined to values lower than 1 EBC haze unit. In contrast, the polyphenol levels of centrifuged beers decreased continuously with increasing gluten additions. Total polyphenol, total flavanoid, and simple flavanoid levels decreased by as much as 17, 23, and 21%, respectively. Haze intensities of laboratory-scale beers brewed with variable levels of two wheat varieties with different protein levels were higher for 5% wheat inclusion than for the reference all-malt beer. However, at higher wheat levels (from 10% onward), the haze intensity decreased continuously to 1 EBC haze unit at 40% wheat. Beer brewed with low-protein (12.6%) wheat contained systematically more permanent haze than did beer brewed with high-protein (14.7%) wheat. It was concluded that wheat gluten proteins interact with polyphenols, resulting in the formation of a haze or precipitate depending on the gluten concentration.