Variation of composition and functional properties of gum from six Canadian flaxseed (Linum usitatissimum L.) cultivars

Comparison on structure, properties and functions of pomegranate peel soluble dietary fiber extracted by different methods

In this research, the different methods (acid extraction, alkaline extraction and enzymatic extraction) were used to extract soluble dietary fiber (SDF) from pomegranate peel and compared with water extraction. Results revealed that all three extraction methods influenced the structure, physicochemical and functional properties of SDF. Especially, SDF extracted by enzymes (E-SDF) and SDF extracted by alkali (A-SDF) had higher yield (27.30% and 27.17%), molecular weight and thermal stability than SDF extracted by water (W-SDF). Higher oil holding capacity (OHC) was found in SDF extracted by acid (C-SDF) (3.18 g/g), A-SDF (3.18 g/g) and E-SDF (5.36 g/g) compared with W-SDF. In addition, A-SDF showed the smallest particle size, lowest ζ-potential and highest viscosity among the tested samples. E-SDF presented a more porous structure, better glucose adsorption capacity (GAC) and antioxidant activity than C-SDF and A-SDF. To sum up, A-SDF and E-SDF may have great potential to be functional food ingredients in the food industry.

Effects of Ultrasound-Assisted Extraction on Structure and Rheological Properties of Flaxseed Gum

In this study, flaxseed gum (FG) was extracted using hot water extraction and ultrasonic-assisted extraction. The yield, molecular weight distribution, monosaccharide composition, structure, and rheological properties of FG were analyzed. The FG yield (9.18) achieved using ultrasound-assisted extraction (this sample was labeled as UAE) was higher than the yield (7.16) achieved with hot water extraction (this sample was labeled as HWE). The polydispersity, monosaccharide composition, and characteristic absorption peaks of the UAE were similar to that of the HWE. However, the UAE had a lower molecular weight and looser structure than the HWE. Moreover, zeta potential measurements indicated that the UAE exhibited better stability. An analysis of the rheological properties showed that the viscosity of the UAE was lower. Thus, the UAE had an effectively better yield of FG, preliminarily modified structure, and rheological properties, and provided a theoretical basis for its application in food processing.

Effect of Flaxseed Mucilage and Gum Arabic on Probiotic Survival and Quality of Kefir during Cold Storage

This study aimed to assess the survival of probiotic cultures in kefir. Kefir is a fermented dairy product, and in this study we incorporated nutritionally rich flaxseed mucilage and gum arabic as a prebiotic, then monitored for improvement in the the viability of Lactobacillus acidophilus and Bifidobacterium lactis. In addition, some physicochemical variables of kefir were investigated. The addition of flaxseed mucilage and gum arabic significantly (p ˂ 0.05) increased the growth of both Lactobacillus acidophilus and Bifidobacterium lactis compared to the control. Samples enriched with flaxseed mucilage and gum arabic had significantly (p ˂ 0.05) reduced pH and increased viscosity. Flaxseed mucilage and gum arabic significantly (p ˂ 0.05) changed the color parameters L*, a*, and b*. However, as the concentration of flaxseed mucilage increased, the L* value decreased. Moreover, adding flaxseed mucilage and gum arabic into kefir increased (p ˂ 0.05) the protein content. These results showed that flaxseed mucilage and gum arabic could be used to increase the survival of probiotic cultures in kefir without changing its physicochemical properties.

A review of flaxseed lignan and the extraction and refinement of secoisolariciresinol diglucoside

Lignan is a class of diphenolic compounds that arise from the condensation of two phenylpropanoid moieties. Oilseed and cereal crops (e.g., flaxseed, sesame seed, wheat, barley, oats, rye, etc.) are major sources of plant lignan. Methods for commercial isolation of the lignan secoisolariciresinol diglucoside (SDG) are not well reported, as most publications describing the detection, extraction, and enrichment of SDG use methods that have not been optimized for commercial scale lignan recovery. Simply scaling up laboratory methods would require expensive infrastructure to achieve a marketable yield and reproducible product quality. Therefore, establishing standard protocols to produce SDG and its derivatives on an industrial scale is critical to decrease lignan cost and increase market opportunities. This review summarizes the human health benefits of flaxseed lignan consumption, lignan physicochemical properties, and mammalian lignan metabolism, and describes methods for detecting, extracting, and enriching flaxseed lignan. Refining and optimization of these methods could lead to the development of inexpensive lignan sources for application as an ingredient in medicines, dietary supplements, and other healthy ingredients.

Chemical Composition and Rheological Properties of Seed Mucilages of Various Yellow- and Brown-Seeded Flax (Linum usitatissimum L.) Cultivars

When seeds sown in the soil become wet, their hulls secrete viscous matter that can retain water and thus support germination. Flaxseed mucilage (FSM) is an example of such a material and is attractive for food, cosmetic, and pharmaceutical applications due to its suitable rheological properties. FSM consists mainly of two polysaccharides, namely, arabinoxylan and rhamnogalacturonan I, and it also contains some proteins, minerals, and phenolic compounds. The genotype and the year of the flax harvest can significantly affect the composition and functional properties of FSM. In this work, FSM samples were isolated from flax seeds of different cultivars and harvest years, and their structural and rheological properties were compared using statistical methods. The samples showed significant variability in composition and rheological properties depending on the cultivar and storage time. It was found that the ratio of two polysaccharide fractions and the contribution of less-prevalent proteins are important factors determining the rheological parameters of FSM, characterizing the shear-thinning, thixotropic, and dynamic viscoelastic behavior of this material in aqueous solutions. The yield strength and the hysteresis loop were found to be associated with the contribution of the pectin fraction, which included homogalacturonan and rhamnogalacturonan I. In contrast, the shear-thinning and especially the dynamic viscoelastic properties depended on the arabinoxylan content. Proteins also affected the viscoelastic properties and maintained the elastic component of FSM in the solution. The above structural and rheological characteristics should be taken into account when considering effective applications for this material.

Rheological and tribological nature of flaxseed gum influenced by concentration and temperature and its application as a coating agent for potato chips

Influence of different concentrations (0.5, 1.0, 2.0, and 3.0% w/v) and temperatures (4, 25, 50, and 75°C) on particle size distribution (PSD) and rheological and tribological characteristics of flaxseed gum (FSG) solutions was investigated. Besides, FSG dispersions (0.5, 1.0, and 2.0% w/v) were used as edible coating and their influence on the quality parameters (oil uptake, moisture loss, texture, and sensory properties) of fried potato chips was studied. All FSG dispersions revealed shear-thinning nature and viscous properties (as G″ > G') that were more dominant at higher concentrations and lower temperatures. The power-law model presented a good fit in demonstrating the flow behavior of FSG dispersions. Concentration was the variable that affected the tribology of FSG dispersions, while temperature had little effect on the tribology. Particle size distribution was increased with the increasing concentration of FSG. FSG dispersions as an edible coating effectively reduced the moisture loss, oil uptake, and hardness properties of potato chips. Practical Application Profiling the influence of concentration and temperature on the rheology and tribology of flaxseed gum is particularly valuable during food processing. The results predict the physical properties of coated potato chips that can support the potential application of flaxseed gum as a coating agent. Today's consumers prefer healthier food products with low caloric, higher fiber content, functional properties, and sensory qualities. Food industries can use FSG as a low-cost natural coating material in terms of economic benefits, consumer acceptance, and providing an inordinate potential both for its protective effect and carrying functional compounds such as antioxidants in their coating matrix.

Comparative structural and techno-functional elucidation of full-fat and defatted flaxseed extracts: implication of atmospheric pressure plasma jet

BACKGROUND

The relatively inferior techno-functionality of flaxseed protein/polysaccharide complexes, especially regarding emulsifying and antioxidant activities, has partially limited their implication in the health food system. The present study aimed to investigate the effects of an atmospheric pressure plasma jet (APPJ) on the physicochemical, structural and selected techno-functional properties of flaxseed extracts.

RESULTS

The results obtained showed that the full-fat and defatted flaxseed extract solutions (5 mg mL^-1 ) displayed a sustainable decline in pH (-54.06%, -48.80%, P < 0.05) and zeta potential values (-29.42%, -44.28%, P < 0.05), but a gradual increase in particle sizes, as visualised by an optical microscope, during 0-120 s of APPJ treatment. Moreover, the APPJ led to initial decrease but subsequent increase in protein carbonyls and secondary lipid oxidation products, and concurrently changed the spatial conformation and microstructure of flaxseed extracts, as indicated by endogenous fluorescence properties and scanning electron microscopy (SEM). Additionally, the protein subunit remodeling and gum polysaccharides depolymerization were different for full-fat and defatted flaxseed extracts after 30 s of APPJ exposure. Importantly, the emulsifying and antioxidant activities of defatted flaxseed extract were particularly improved, as assessed by cyro-SEM and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity following 15-30 s of APPJ treatment, as a result of the changing interactions between protein and gum polysaccharides, as well as the release of specific phenolic compounds.

CONCLUSION

APPJ could serve as a promising strategy for tailoring the specific techno-functionality of flaxseed extracts based on mild structural modification. © 2021 Society of Chemical Industry.

Role of Flaxseed Gum and Whey Protein Microparticles in Formulating Low-Fat Model Mayonnaises

Flaxseed gum (FG) and whey protein microparticles (WPMs) were used to substitute fats in model mayonnaises. WPMs were prepared by grinding the heat-set whey protein gel containing 10 mM CaCl₂ into small particles (10–20 µm). Then, 3 × 4 low-fat model mayonnaises were prepared by varying FG (0.3, 0.6, 0.9 wt%) and WPM (0, 8, 16, 24 wt%) concentrations. The effect of the addition of FG and WPMs on rheology, instrumental texture and sensory texture and their correlations were investigated. The results showed that all samples exhibited shear thinning behavior and ‘weak gel’ properties. Although both FG and WPMs enhanced rheological (e.g., viscosity and storage modulus) and textural properties (e.g., hardness, consistency, adhesiveness, cohesiveness) and kinetic stability, this enhancement was dominated by FG. FG and WPMs affected bulk properties through different mechanisms, (i.e., active filler and entangled polysaccharide networks). Panellists evaluated sensory texture in three stages: extra-oral, intra-oral and after-feel. Likewise, FG dominated sensory texture of model mayonnaises. With increasing FG concentration, sensory scores for creaminess and mouth-coating increased, whereas those of firmness, fluidity and spreadability decreased. Creaminess had a linear negative correlation with firmness, fluidity and spreadability (R² > 0.985), while it had a linear positive correlation with mouth-coating (R² > 0.97). A linear positive correlation (R² > 0.975) was established between creaminess and viscosity at different shear rates/instrumental texture parameters. This study highlights the synergistic role of FG and WPMs in developing low-fat mayonnaises.

Variations in the structural and functional properties of flaxseed gum from six different flaxseed cultivars

Although flaxseed gum (FG) has been widely studied, the differences in its structure and function with respect to various flaxseed cultivars remain unclear. In this study, our objective was to examine the differences between FG samples obtained from different flaxseed cultivars based on their structural and functional properties. Specifically, FG samples from the different cultivars were extracted via hot water extraction followed by ethanol precipitation. Thereafter, they were analyzed via zeta potential measurements, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), and scanning electron microscopy (SEM). The results demonstrated that the different cultivars showed significantly different FG yields (p < .05; range, 5.83%-7.36%). Further, the FTIR spectra of the FG samples were slightly different but showed typical polysaccharide absorption peaks. Furthermore, the XRD patterns obtained predominantly showed an amorphous region and a small crystalline region, while the SEM images obtained at 1,000× magnification revealed that the samples had smooth and irregular surfaces, with a scaly structure. However, at 20,000× magnification, the FG samples showed slight structural differences. Additionally, the zeta potentials of the FG samples (range, -19.4 to -30.6 mV; p < .05) were cultivar-dependent and indicated the presence of negatively charged macromolecules. This implies that the FG samples from the different cultivars show diverse structural properties. Our findings not only provide useful information regarding FG samples extracted from different cultivars but also serve as a theoretical basis for the application of FG in food processing.

Myxospermy Evolution in Brassicaceae: A Highly Complex and Diverse Trait with Arabidopsis as an Uncommon Model

The ability to extrude mucilage upon seed imbibition (myxospermy) occurs in several Angiosperm taxonomic groups, but its ancestral nature or evolutionary convergence origin remains misunderstood. We investigated seed mucilage evolution in the Brassicaceae family with comparison to the knowledge accumulated in Arabidopsis thaliana. The myxospermy occurrence was evaluated in 27 Brassicaceae species. Phenotyping included mucilage secretory cell morphology and topochemistry to highlight subtle myxospermy traits. In parallel, computational biology was driven on the one hundred genes constituting the so-called A. thaliana mucilage secretory cell toolbox to confront their sequence conservation to the observed phenotypes. Mucilage secretory cells show high morphology diversity; the three studied Arabidopsis species had a specific extrusion modality compared to the other studied Brassicaceae species. Orthologous genes from the A. thaliana mucilage secretory cell toolbox were mostly found in all studied species without correlation with the occurrence of myxospermy or even more sub-cellular traits. Seed mucilage may be an ancestral feature of the Brassicaceae family. It consists of highly diverse subtle traits, probably underlined by several genes not yet characterized in A. thaliana or by species-specific genes. Therefore, A. thaliana is probably not a sufficient reference for future myxospermy evo-devo studies.

Seed mucilage evolution: Diverse molecular mechanisms generate versatile ecological functions for particular environments

Plant myxodiasporous species have the ability to release a polysaccharidic mucilage upon imbibition of the seed (myxospermy) or the fruit (myxocarpy). This is a widespread capacity in angiosperms providing multiple ecological functions including higher germination efficiency under environmental stresses. It is unclear whether myxodiaspory has one or multiple evolutionary origins and why it was supposedly lost in several species. Here, we summarize recent advances on three main aspects of myxodiaspory. (a) It represents a combination of highly diverse traits at different levels of observation, ranging from the dual tissular origin of mucilage secretory cells to diverse mucilage polysaccharidic composition and ultrastructural organization. (b) An asymmetrical selection pressure is exerted on myxospermy-related genes that were first identified in Arabidopsis thaliana. The A. thaliana and the flax intra-species mucilage variants show that myxospermy is a fast-evolving trait due to high polymorphism in a few genes directly acting on mucilage establishment. In A. thaliana, these actors are downstream of a master regulatory complex and an original phylogenetic overview provided here illustrates that this complex has sequentially evolved after the common ancestor of seed plants and was fully established in the common ancestor of the rosid clade. (c) Newly identified myxodiaspory ecological functions indicate new perspectives such as soil microorganism control and plant establishment support.

Influence of different extraction techniques on recovery, purity, antioxidant activities, and microstructure of flaxseed gum

Four extraction techniques (that is, hot water extraction [HWE], alkaline-acidic extraction [AAE], ultrasound assisted extraction [UAE], and microwave assisted extraction [MAE]) were compared for flaxseed gum extraction and their influence on the yield, purity, structural characterization (monosaccharide composition, molecular weight distribution, and microstructure by transmission electron microscope), and antioxidant activity (in terms of scavenging ability of 2,2-diphenyl-1-picrylhydrazyl [DPPH], 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid [ABTS], and reducing power) was investigated. The HWE achieved higher yield (8.96%) than UAE (7.84%) followed by MAE (7.01%) and AAE (6.44%). Moreover, the four flaxseed gum (FSG) samples exhibited the identical monosaccharide composition, but slight difference was observed in the content, whereas the molecular weight ratios exhibited significant difference. All samples displayed concentration-dependent manner for all antioxidant assays. UAE-FSG showed significant higher scavenging ability on DPPH free radical, ABTS free radical, reducing power, and β-carotene bleaching assay followed by HWE-FSG, MAE-FSG, and AAE-FSG. Overall results showed that UAE was favorable to the purity of FSG, whereas HWE was more advantageous to improve the extraction yield and facile as it requires no special equipment. PRACTICAL APPLICATION: Extraction methods directly affect the recovery and purity of the extracted compound. Thus, this study could help in selection of appropriate extraction method for FSG. The results suggested that FSG possesses potential healthcare application in food industry because of their nutrition composition and antioxidant activities, and thus, it can be used for formulation of functional food as a natural antioxidant agent.

Flaxseed Gum Solution Functional Properties

Flaxseed gum (FG) is a by-product of flax (Linum usitatissimum L.) meal production that is useful as a food thickener, emulsifier, and foaming agent. FG is typically recovered by hot-water extraction from flaxseed hull or whole seed. However, FG includes complex polymer structures that contain bioactive compounds. Therefore, extraction temperature can play an important role in determining its functional properties, solution appearance, and solution stability during storage. These characteristics of FG, including FG quality, determine its commercial value and utility. In this study, FG solution functional properties and storage stability were investigated for solutions prepared at 70 and 98 °C. Solutions of FG prepared at 98 °C had lower initial viscosity than solutions extracted at 70 °C; though the viscosity of these solutions was more stable during storage. Solutions prepared by extraction at both tested temperatures exhibited similar tolerance to 0.1 mol/L salt addition and freeze-thaw cycles. Moreover, the higher extraction temperature produced a FG solution with superior foaming and emulsification properties, and these properties were more stable with storage. Foams and emulsions produced from FG extracted at higher temperatures also had better stability. FG extracted at 98 °C displayed improved stability and consistent viscosity, foamability, and emulsification properties in comparison to solutions prepared at 70 °C. Therefore, the FG solution extracted at 98 °C had more stable properties and, potentially, higher commercial value. This result indicates that FG performance as a commercial food additive can influence food product quality.

Ionic strength and hydrogen bonding effects on whey protein isolate-flaxseed gum coacervate rheology

Whey protein isolate (WPI) was mixed with anionic flaxseed (Linum usitatissimum L.) gum (FG), and phase transition during coacervate formation was monitored. Effects of ionic strength and hydrogen bonding on coacervation of WPI-FG system and corresponding rheological properties were investigated. During coacervate formation, structural transitions were confirmed by both turbidimetry and confocal laser scanning microscopy. Increasing ionic strength with sodium chloride (50 mM) decreased optical density (600 nm) at pHmax. Correspondingly, pHc and pHϕ1 decreased from pH 5.4 to 4.8 and from 5.0 to 4.6, respectively, while pHϕ2 increased from pH 1.8 to 2.4. Sodium chloride suppressed biopolymer electrostatic interactions and reduced coacervate formation. Adding urea (100 mM) shifted pHϕ1, pHmax, and pHϕ2 from 4.8, 3.8, and 1.8 to 5.0, 4.0, and 2.2, respectively, while pHc was unaffected. Optical density (600 nm) at pHmax (0.536) was lower than that of control in the absence of urea (0.617). This confirmed the role of hydrogen bonding during coacervate formation in the biopolymer system composed of WPI and FG. Dynamic shear behavior and viscoelasticity of collected coacervates were measured, and both shear-thinning behavior and gel-like properties were observed. Addition of sodium chloride and urea reduced ionic strength and hydrogen bonding, resulting in decreased WPI-FG coacervate dynamic viscosity and viscoelasticity. The disturbed charge balance contributed to a loosely packed structure of coacervates which were less affected by altered hydrogen bonding. Findings obtained here will help to predict flaxseed gum behavior in protein-based foods.

Chickpea Cultivar Selection to Produce Aquafaba with Superior Emulsion Properties

Aquafaba (AQ), a viscous by-product solution produced during cooking chickpea or other legumes in water, is increasingly being used as an egg replacement due to its ability to form foams and emulsions. The objectives of our work were to select a chickpea cultivar that produces AQ with superior emulsion properties, and to investigate the impact of chickpea seed physicochemical properties and hydration kinetics on the properties of AQ-based emulsions. AQ from a Kabuli type chickpea cultivar (CDC Leader) had the greatest emulsion capacity (1.10 ± 0.04 m²/g) and stability (71.9 ± 0.8%). There were no correlations observed between AQ emulsion properties and chickpea seed proximate compositions. Meanwhile, AQ emulsion properties were negatively correlated with AQ yield and moisture content, indicating that AQ with higher dry-matter content displayed better emulsion properties. In conclusion, the emulsification properties of aquafaba are greatly influenced by the chickpea genotype, and AQ from the CDC Leader chickpea produced the most stable food oil emulsions.

Characterization of mucilages extracted from different flaxseed (Linum usitatissiumum L.) cultivars: A heteropolysaccharide with desirable functional and rheological properties

Flaxseed mucilage is composed of water soluble heteropolysaccharides of high molecular weight representing about 3 to 9% of the total seed. In the present study mucilages were extracted from six Indian flaxseed cultivars and their chemical, functional, microstructural and rheological properties were investigated. The extracted mucilages differed significantly (P < 0.05) in their yield (5.56-6.54%), ash (4.80-7.23%), protein (7.68-12.33%), pentose (0.48-0.80 mg/ml) and total sugar (1.58-3.06 mg/ml) contents. Copper (18.87-148.08 mg/kg) and zinc (15.43-53.43 mg/kg) were found to be the most abundant minerals in mucilages. "LC-2023" cv. mucilage exhibited lower values for lead, chromium and cadmium. The mucilage solutions exhibited high foaming (>40%) and solubility (64.5-69.15% at 80 °C) characteristics. Rheological data revealed shear rate dependent behaviour of aqueous mucilage solutions irrespective of cultivar type and concentration used. Frequency sweep tests demonstrated that at high frequency range investigated, storage modulus was higher than loss modulus thereby suggesting viscoelastic fluid behaviour of flaxseed mucilage. All mucilages exhibited endothermic as well exothermic transitions with high decomposition onset temperatures. Mucilage is of special research interest owing to its desirable functional properties, so the outcomes of the present study could be used to identify cultivars for producing mucilages for a desired end use.

Novel Flaxseed Gum Nanocomposites Are Slow Release Iron Supplements

Nanocomposites, based on iron salts and soluble flaxseed gum (FG), were prepared as potential treatments of iron deficiency anemia (IDA). FG was extracted, characterized, and formulated into iron-loading nanocomposites via ion-exchange against FeCl₃, Fe₂(SO₄)₃, FeCl₂, and FeSO₄·7H₂O. FG-iron nanocomposites preparation condition was optimized, and physicochemical properties of the nanocomposites were investigated. In vitro release kinetics of iron in simulated gastric fluid (SGF) was also evaluated. FG heteropolysaccharide, consisting of rhamnose (33.73%), arabinose (24.35%), xylose (14.23%), glucose (4.54%), and galactose (23.15%) monosaccharides, linked together via varieties of glycosidic bonds, was a good recipient for both ferric and ferrous irons under screened conditions (i.e., 80 °C, 2 h, I/G = 1:2). Iron loaded contents in the nanocomposites prepared from FG-FeCl₃, FG-Fe₂(SO₄)₃, FG-FeCl₂, and FG-FeSO₄·7H₂O were 25.51%, 10.36%, 5.83%, and 22.83%, respectively. Iron in these nanocomposites was mostly in a bound state, especially in FG-FeCl₃, due to chelation forming bonds between iron and polysaccharide hydroxyl or carboxyl groups and formed stable polysaccharide-iron crystal network structures. Free iron ions were effectively removed by ethanol treatments. Because of chelation, the nanocomposites delayed iron release in SGF and the release kinetics were consistent with Korsmeyer-Peppas model. This indicates that such complexes might reduce side effects of free iron in human stomach. Altogether, this study indicates that these synthetic FG-iron nanocomposites might be developed as novel iron supplements for iron deficiency, in which FG-FeCl₃ is considered as the best option.