Conlinin in flaxseed (Linum usitatissimum L.) gum and its contribution to emulsification properties

Novel palm shortening substitute using a combination of rapeseed oil, linseed meal and beta-glucan

This study investigated the potential of a novel sustainable ingredient composed of rapeseed oil, linseed meal and beta-glucan (PALM-ALT) to mimic palm shortening functionality in cake. The combined functional properties of linseed meal and beta-glucan led to stable semi-solid emulsion-gels (20-31 μm oil droplet size, 105-115 Pa.s viscosity and 60-65 Pa yield stress). PALM-ALT contained 25 and 88% less total and saturated fat than palm shortening, whilst PALM-ALT cakes contained 26 and 75% less total and saturated fat than the palm-based control. PALM-ALT cakes matched the flavour profile of the palm-based control, while rapeseed oil cakes tasted more sour and less sweet than the control (p < 0.05). PALM-ALT cakes proved less hard and more cohesive than the control (p < 0.05), with 100% of the consumer panel preferring PALM-ALT formulations. This study demonstrated the unique potential of PALM-ALT as healthier, sustainable and competitive alternative to palm shortening.

Techno-Functions and Safety Concerns of Plant-Based Peptides in Food Matrices

Plant-based peptides (PBPs) benefit functional food development and environmental sustainability. Proteolysis remains the primary method of peptide production because it is a mild and nontoxic technique. However, potential safety concerns still emanate from toxic or allergenic sequences, amino acid racemization, iso-peptide bond formation, Maillard reaction, dose usage, and frequency. The main aim of this review is to investigate the techno-functions of PBPs in food matrices, as well as their safety concerns. The distinctive characteristics of PBPs exhibit their techno-functions for improving food quality and functionality by contributing to several crucial food formulations and processing. The techno-functions of PBPs include solubility, hydrophobicity, bitterness, foaming, oil-binding, and water-holding capacities, which subsequently affect food matrices. The safety and quality of foodstuff containing PBPs depend on the proper source of plant proteins, the selection of processing approaches, and compliance with legal regulations for allergen labeling and safety evaluations. The safety concerns in allergenicity and toxicity were discussed. The conclusion is that food technologists must apply safe limits and consider potential allergenic components generated during the development of food products with PBPs. Therefore, functional food products containing PBPs can be a promising strategy to provide consumers with wholesome health benefits.

Proteomic Profile of Flaxseed (Linum usitatissimum L.) Products as Influenced by Protein Concentration Method and Cultivar

The research is focused on the quantitative evaluation of the flaxseed (Linum usitatissimum L.) proteome at the level of seed cake (SC), fine flour-sieved a fraction below 250 µm (FF)-and protein concentrate (PC). The evaluation was performed on three oilseed flax cultivars (Agriol, Raciol, and Libra) with different levels of α-linolenic acid content using LC-MS/MS (shotgun proteomics) analysis, which was finalized by database searching using the NCBI protein database for Linum usitatissimum and related species. A total of 2560 protein groups (PGs) were identified, and their relative abundance was calculated. A set of 33 quantitatively most significant PGs was selected for further characterization. The selected PGs were divided into four classes-seed storage proteins (11S globulins and conlinins), oleosins, defense- and stress-related proteins, and other major proteins (mainly including enzymes). Seed storage proteins were found to be the most abundant proteins. Specifically, 11S globulins accounted for 41-44% of SC proteins, 40-46% of FF proteins, and 72-84% of PC proteins, depending on the cultivar. Conlinins (2S albumins) were the most abundant in FF, ranging from 10 to 13% (depending on cultivar). The second most important class from the point of relative abundance was oleosins, which were represented in SC and FF in the range of 2.1-3.8%, but only 0.36-1.20% in PC. Surprisingly, a relatively high abundance of chitinase was found in flax products as a protein related to defence and stress reactions.

Development and characterization of edible films based on flaxseed gum incorporated with Piper betle extract

There has been a shift from use of petroleum-based plastics, causing serious environmental pollution, towards innovative and biodegradable edible packaging. The present study documents the development of composite edible films based on the flaxseed gum (FSG) modified by the incorporation of betel leaf extract (BLE). The films were assessed for physicochemical, mechanical, morphological, thermal, antimicrobial and structural characteristics. Scanning electron microscopy images indicated that the roughness decreased with an increase in BLE concentration. The water vapor permeability of the FSG-BLE films ranged from 4.68 to 1.59 × 10-9 g s- 1 m- 2 Pa- 1, lower than that of the control sample (6.77 × 10-9 g s- 1 m- 2 Pa- 1). The BLE4 (containing 10 % BLE) films had the highest tensile strength of 32.46 MPa compared to the control sample (21.23 MPa). Similarly, EAB and seal strength of the films incorporated with BLE were ameliorated. X-ray diffraction pattern and FTIR illustrated the shift of amorphous to crystalline behavior and a significant interaction among the BLE and FSG functional groups. Furthermore, the thermal stability of the treated films was not affected significantly however, they showed improved antimicrobial activity with the highest diameter of inhibition zone in the BLE4 sample. This study concluded that the FSG-BLE composite films (BLE4 in particular) can be considered as novel packaging material for food conservation coupled with a potential to enhance the shelf life of perishable food products.

The physicochemical stability and in vivo gastrointestinal digestion of flaxseed milk: Implication of microwave on flaxseed

The current study was to investigate how microwave on flaxseed affected the physicochemical stability and gastrointestinal digestion of oil bodies (OBs) in flaxseed milk. Flaxseed was subjected to moisture adjustment (30-35 wt%, 24 h), and microwave exposure (0-5 min, 700  W). Microwave treatment slightly weakened the physical stability of flaxseed milk indicated by Turbiscan Stability Index, but there were no visual phase separation during 21 days of storage at 4 °C. Upon microwave treatment, OBs experienced the layer-by-layer encapsulation into loose interface embedding by storage protein-gum polysaccharide complex from bulk phase, resulting in lower viscoelasticity of flaxseed milk. The OBs underwent earlier interface collapse and lipolysis during gastrointestinal digestion, followed by synergistic micellar absorption, faster chylomicrons transport within enterocytes of rats fed flaxseed milk. The accumulation of α-linolenic acid and synergistic conversion into docosapentaenoic and docosahexanoic acids in jejunum tissue were achieved accompanied by the interface remodeling of OBs in flaxseed milk.

Protein Fractions from Flaxseed: The Effect of Subsequent Extractions on Composition and Antioxidant Capacity

Flaxseed proteins exhibit functionalities interesting for the food industry, including antioxidant capacity. Antioxidant activity depends on the protein composition and the presence of phenolic compounds extracted with them from the matrix. The research focused on the effect of subsequent protein extractions (water, salt and alkaline) of flaxseed meals (of three cultivars) on the protein fraction composition and its relations to antioxidant capacity. The protein and phenolic profiles and antioxidant functionalities (in antiradical ORAC and emulsion assays) were analysed. Spectroscopic characteristics of the fractions (fluorometric and FT-IR analysis) were also included. Our study has shown the effect of fractionation on the share of proteins at MW from 56-38 kDa (globulin-like) and <15 kDa (albumin-like) in the protein profiles. The highest globulin share was in the alkaline-extracted fractions (AEF) and albumin in the salt-extracted (SEF) ones. SDG (secoisolariciresinol diglucosides) and phenolic acids (p-coumaric and ferulic) were extracted with flaxseed proteins. Their contents were fraction-dependent and the highest in AEF. The concentration of phenolics in AEF corresponded with the highest antiradical capacity (ORAC) compared with the other fractions. However, the SEF showed a higher ability to inhibit oxidation in emulsions than AEF, which could be associated with the higher content of the low MW proteins.

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.

Structural Characterization and Functional Properties of Flaxseed Hydrocolloids and Their Application

Flaxseed is an excellent source of valuable nutrients and is also considered a functional food. There are two types of hydrocolloids in flaxseed: flaxseed gum and proteins. Flaxseed gum exhibits emulsifying and foaming activities or can be used as a thickening and gelling agent. Due to its form of soluble fiber, flaxseed gum is related to many health benefits. Flaxseed proteins have various functional properties based on their physicochemical properties. While albumins possess the emulsion-forming ability, globulins better serve as foaming agents. Flaxseed proteins may also serve as a source of functional peptides with interesting biological and health-related activities. Functional properties and health-related benefits predetermine the application of these hydrocolloids, mainly in the food industry or medicine. Although these properties of flaxseed hydrocolloids have been recently and extensively studied, they are still not widely used on the industrial scale compared to other popular plant gums and proteins. The aim of this review was to present, discuss and highlight the recent discoveries in the structural characteristics and functional and biological properties of these versatile hydrocolloids with respect to factors affecting their characteristics and offer new insights into their potential applications as comparable alternatives to the other natural hydrocolloids or as the sources of novel functional products.

Comparative Composition Structure and Selected Techno-Functional Elucidation of Flaxseed Protein Fractions

This study aimed to comparatively elucidate the composition structure and techno-functionality of flaxseed protein isolate (FPI), globulin (FG), and albumin (FA) fractions. The results showed that FA possessed smaller particle dimensions and superior protein solubility compared to that of FG (p < 0.05) due to the lower molecular weight and hydrophobicity. FA and FG manifested lamellar structure and nearly spherical morphology, respectively, whereas FPI exhibited small lamellar strip structure packed by the blurring spheres. The Far-UV CD, FTIR spectrum, and intrinsic fluorescence confirmed more flexible conformation of FA than that of FG, followed by FPI. The preferential retention of free phenolic acids was observed for FA, leading to excellent antioxidant activities compared with that of FG in FPI (p < 0.05). FA contributed to the foaming properties of FPI, relying on the earlier interfacial adsorption and higher viscoelastic properties. FA displayed favorable emulsifying capacity but inferior stability due to the limited interfacial adsorption and deformation, as well as loose/porous interface. By comparison, an interlayer anchoring but no direct interface coating was observed for lipid droplets constructed by FG, thereby leading to preferable emulsion stability. However, FPI produced lipid droplets with dense interface owing to the effective migration of FA and FG from bulk phase, concomitant with the easy flocculation and coalescence. Thus, the techno-functionality of flaxseed protein could be tailed by modulating the retention of albumin fraction and specific phenolic acids.

Food Puree for Seniors: The Effects of XanFlax as a New Thickener on Physicochemical and Antioxidant Properties

With the increasing number of older adults, the elderly-friendly food market has been rapidly growing. The physicochemical and antioxidant properties of soymilk-based banana-blueberry-puree with and without flaxseed-based (XanFlax) and xanthan-gum-based (brand G) thickeners were compared as a potential senior food. Samples included a control, three treatments with XanFlax (1%, 3%, and 5%), and three treatments with brand G (1.35%, 2.7%, and 5.4%). The physicochemical (color, sugar, salinity, pH, viscosity, and hardness) and antioxidant properties [DPPH, ABTS, reducing power (RP), and total polyphenol content (TPC)] were compared. The chromaticity values (L*, a*, and b*) and pHs were similar among all treatments and the control, but the salinity of brand G showed statistical differences (p < 0.05). All samples met the Korean Industrial Standards for senior foods in terms of viscosity and hardness, while samples with brand G were harder and more viscous than those with XanFlax and the control (p < 0.001). XanFlax samples had greater ABTS radical scavenging activities than the control and brand G samples (p < 0.001). Although, the developed puree can be a possible senior food product without the addition of thickeners, XanFlax might be applied as a non-xanthan gum-based viscosity thickener with antioxidant functions for senior-friendly foods.

Bioactive peptides derived from plant origin by-products: Biological activities and techno-functional utilizations in food developments - A review

Agro-industrial by-products containing considerable amounts of protein (10-50%) such as soybean meal, rice bran and coconut pulp are promising bioactive peptide sources with annual disposal rate of 800 million tons in the world. More recently, plant by-products rich in protein content have been studied under various prisms that include recovery techniques, peptide production methods, determination of technological benefits and functional properties, and their applications in foods. The researches in bioactive peptides provide evidence over the techno-functional properties and the health benefits are highly dependent upon their amino acid sequences, molecular weights, conformations and surface properties. Research findings compared bioactive properties of the obtained peptides with respect to their amino acid sequences and also reported that hydrophobic/hydrophilic properties have direct effect on both functional and health effects. In addition, the resultant properties of the peptides could be affected by the conducted extraction method (alkaline, enzymatic, ultrasound assisted, microwave assisted, etc.), extraction solvent, precipitation and purification techniques and even by the final drying process (spray, freeze, vacuum, etc.) which may alter molecular weights, conformations and surface properties. Latest studies have investigated solubility, emulsifying, foaming, water/oil holding capacity and surface properties and also antioxidant, antimicrobial, anticarcinogenic, hypocholesterolemic, antihypertensive, immunomodulatory and opioid activities of bioactive peptides obtained from plant by-products. Moreover, the application of the bioactive peptides into different food formulations has been a recent trend of functional food development. These bioactive peptides' bitter taste and toxicity are possible challenges in some cases that need to be resolved before their wider utilization.

The Effect of Roasting on the Protein Profile and Antiradical Capacity of Flaxseed Meal

Roasting is more and more often used as a pre-treatment of flaxseeds. However, the process can influence flaxseed proteins that may be crucial for their properties. The aim of this research was to study changes in the electrophoretic protein profile (SDS-PAGE) and the antiradical capacity of flaxseed meals after roasting. The roasting temperature (160, 180, and 200 °C) and flaxseed cultivars (golden and brown seed) were factors including in the study. The free (F-MRP) and bound-to-protein (B-MRP) Maillard reaction products were also analyzed. The most significant changes in the SDS-PAGE protein profiles of roasted seeds of each of the tested flax cultivars were observed for the 13 kDa protein fraction (decrease) and for the 19 kDa and 17 kDa fractions (increase). The research revealed a significant correlation between the roasting temperature and B-MRP content, and changes in the percentage share of those three protein fractions. The antiradical capacity of roasted flaxseeds decreased, as compared with untreated seeds. After roasting at 200 °C the antiradical capacity of flaxseeds improved slightly, probably due to the MRP formation, but it was still significantly lower than that of the raw seeds. The research provides novel information about key protein fractions that seem to be important changing during heat treatment.

Characterization and enhanced functionality of nanoparticles based on linseed protein and linseed gum biocomplexes

The formation, characterization, and functionality of hybrid nanoparticles based on linseed bio-macromolecules extracted as linseed protein (LP) and linseed gum (LG) from the remaining meal after oil extraction were investigated. The assembly of bioparticles at different protein to polysaccharide ratios as a function of pH was characterized in terms of absorbance measurements, dynamic light scattering and surface charge. The wettability of the assembled particles as well as the plain LP and LG was also determined. By increasing the LG proportion in the bioparticles, both the size of the particles and their contact angle tended to decrease, whereas their zeta potential became more negative over the whole studied pH range. The formed negatively charged particles at pH 3 with a 50:50 LP to LG ratio and a size of approximately 300 nm were selected and their functional properties (solubility, emulsifying and foaming properties) were compared to the individual biopolymers. The interaction between LG and LP was found to modify the functional properties of native LP especially at and around its isoelectric point. The LP-LG particles could be useful for stabilizing plant-based emulsions and foams.

Rheology and soft tribology of thickened dispersions aiming the development of oropharyngeal dysphagia-oriented products

Dysphagia is a swallowing disorder that mainly affects elderly but can be minimized by thickening of liquid foods. Flaxseed gum (FG) was studied as a potential alternative thickener for dysphagia patients in comparison to commercial thickeners based on xanthan gum (XG) and modified starch (MS). Rheological and tribological responses of biopolymer-based thickening solutions (0.75–3% w/w) incorporated in different food matrices (water, orange-flavoured soy juice and skim milk) were recorded and correlated. In general, the increase in gums concentration led to increases in viscosity, viscoelastic properties and lubricating capacity. An opposite behavior was observed for the MS-based products, since an increase in concentration led to a lower increase in viscosity and viscoelastic properties but caused a decrease in the lubricating capacity. These results indicated that associating tribology to rheology is crucial to further define formulations with pleasant swallowing characteristics.

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Modified starch-based (MS) has lower thickening and lubricant capacities than gums.

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Higher MS concentrations increased viscosity, while decreased lubrication.

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Flaxseed gum & xanthan-based solutions are better thickeners and lubricants than MS.

Flaxseed gum: Extraction, bioactive composition, structural characterization, and its potential antioxidant activity

Flaxseed gum (FSG) is a heteropolysaccharide consist of neutral and acidic components that makes up approximately 8% of seed mass. FSG was extracted from mixture of brown and golden varieties of flaxseeds by hot water extraction method. The molecular weight distribution, monosaccharide analysis, chemical composition, and surface morphology of FSG were scrutinized in the current study to get a better insight regarding this important polysaccharide. The average molecular weight was recorded as 1,322 kDa with a polydispersity ratio of 1.6 for Mw/Mn and 2.4 for Mn/Mz. High-performance liquid chromatography (HPLC) screening revealed that extracted FSG was comprised of rhamnose, arabinose, mannose, glucose, fucose, xylose, galactose, glucosamine, glucuronic acid, and galacturonic acid, of which mannose and glucosamine have not been reported previously. The antioxidant activities of FSG measured as DPPH, ABTS, reducing power, and total antioxidant activity clearly demonstrated the antioxidant potency of FSG. Fourier-transform infrared spectroscopy (FTIR) and the Nuclear magnetic resonance (NMR) (¹ H, ¹³ C) s pectra ratified the presence of functional groups typical for polysaccharide. PRACTICAL APPLICATIONS: Flaxseed gum is a natural carbohydrate polymar. This study provides useful information regarding antioxidant potential, chemical, and structural characterization of FSG. The availability of a gum is fully characterized with bioactive composition, structural features, and antioxidant potential provides a toolset for the practical application in the food or drug industry.

Recovery of high value-added protein from enzyme-assisted aqueous extraction (EAE) of soybeans by dead-end ultrafiltration

The skim fraction (SF) obtained from enzyme-assisted aqueous extraction (EAE) of soybeans is a by-product with high protein content of up to 60.67%. As such, it is of great interest to develop an efficient method to recover protein from this fraction. In this study, the potential of dead-end ultrafiltration (UF) in recovering skim protein extracted with different proteases was evaluated. Two polyethersulfone (PES) membranes with molecular weight cutoffs (MWCO) of 3 kDa and 5 kDa were utilized. Results revealed that the membrane with the MWCO of 5 kDa exhibited better filtration efficiency, since higher permeate flux values and lower impurity rejections were observed. Compared with Flavourzyme and Protex 7L, Alcalase 2.4L and Protex 6L exhibited stronger hydrolyzing ability, resulting in higher filtration fluxes but lower protein rejection coefficients. The recovered protein showed comparable amino acid profile to SPC, while with significantly reduced levels of trypsin inhibitors and phytate (p < 0.05), indicating high quality of the recovered protein. Overall, UF can be applicable to recover high value-added protein from EAE of soybeans and remove undesired components from the resulting protein products.

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.

Flaxseed gum in combination with lemongrass essential oil as an effective edible coating for ready-to-eat pomegranate arils

Flaxseed gum (FSG) in combination with lemongrass essential oil (LGEO) was investigated for coating of ready-to-eat pomegranate arils. FSG was used at 0.3% and 0.6% concentrations and with both concentrations LGEO was incorporated at levels of 0ppm, 200ppm, 500ppm and 800ppm. Changes in headspace gases, physicochemical, microbiological and sensory attributes of pomegranate arils stored at 5°C were studied on different days of analysis during the 12day storage period. Coatings containing LGEO were effective in reducing total plate count and yeast and mold populations. Increasing LGEO concentrations in the coatings resulted in more decline in microbial populations. Reduced weight loss occurred in coated samples as compared to uncoated (control) sample. Coated samples showed a gradual decrease in ripening index in contrast with control where a significantly higher decline was observed. Total soluble solids, pH and titratable acidity significantly varied over the storage period. Color change (ΔE) for control increased steeply over the storage time in comparison to coated samples. Furthermore, chroma decreased while as hue angle increased over time.

Effect of extraction temperature on composition, structure and functional properties of flaxseed gum

Flaxseed gum (FG) was extracted at four different temperatures (30, 50, 70 and 90°C). Chemical composition and structural features of FG extracted at different temperatures were investigated to determine the effect of temperature. Content of acidic monosaccharides and denatured protein increased with increasing FG extraction temperature. The ratio of neutral to acidic monosaccharides decreased from 6.7 to 5.7 as the extraction temperature was increased from 30 to 90°C. Physiochemical and functional properties, including zeta-potential, surface morphology, emulsifying activity index (EAI) and emulsion stability index (ESI), water absorption capacity (WAC) and fat absorption capacity (FAC) of FG samples, were also investigated as a function of extraction temperature. EAI and WAC of FG samples reduced significantly with rise in extraction temperature. Our study suggests that FG extracted at different temperatures may be specifically targeted for different applications, such as for emulsification or gel formation in food systems.