Linum usitatissimum Delivery over Chitosan Nanobiopolymer: Enhanced Effects on Polycystic Ovary Syndrome Condition.

Herein, chitosan nanoparticle (CHIT) was used as a safe and biocompatible matrix to carry flaxseed (Linum usitatissimum L.) extract (FSE). The number of main features and bio-interface properties of CHIT-FSE were determined by SEM, DLS, FTIR, XRD, TGA, and zeta potential analyses and compared to those of chitosan lacking FSE. A GC-MS analysis was also conducted to reveal the bioactive compounds of FSE. The active anchoring of the FSE phytomolecules over chitosan nanoparticles with enhanced thermal and structural stability was correspondingly verified. Subsequently, the influence of CHIT-FSE, CHIT-TPP, and FSE supplementation was assessed on hormonal and biochemical markers of polycystic ovary syndrome (PCOS) in female rats and compared with untreated and healthy control groups. After 16 days of treatment, CHIT-FSE represented the best performance for controlling the serum levels of the studied biochemical (lipid profile and blood glucose level) and hormonal (insulin, testosterone, luteinizing, and follicle-stimulating hormone) parameters. Considering the negligible therapeutic activity of CHIT-TPP, the enhanced activity of CHIT-FSE compared to only FSE was expounded based on the potent action of chitosan nanoparticles in enhanced stabilization, bioavailability, transport, and permeability of the therapeutically important phytomolecules. As per the results of this investigation, supporting medically important biomolecules over chitosan can enhance their therapeutic effectiveness in controlling PCOS.

Marine biofilm formation on flax fibre reinforced biocomposites.

Artificial reefs represent useful tools to revitalize coastal and ocean ecosystems. Their formulation determines the biofilm formation which is the prerequisite for the colonization process by marine micro- and macroorganisms. In comparison with concrete, biobased polymers offer improved characteristics, including architecture, formulation, rugosity and recycling. This article aims to explore a new scale of artificial reef made of biocomposites reinforced with a high flax fibre (Linum utilatissimum) content (30%). Cellular adhesion and resulting biofilm formation were assessed using two marine microorganisms: Pseudoalteromonas sp. 3J6 and Cylindrotheca closterium. The influence of flax fibre leachates and plastic monomers on the growth of those marine microorganisms were also evaluated. Results indicated that the introduction of flax fibres inside the polymer matrix modified its physicochemical properties thus modulating adhesion and biofilm formation depending on the microorganism. This study gives insights for further developments of novel functionalized artificial reefs made of biocomposites.

Application of seed mucilage as functional biopolymer in meat product processing and preservation.

Meat products consumption is rising globally, but concerns about sustainability, fat content, and shelf life. Synthetic additives and preservatives used for extending the shelf life of meat often carry health and environmental drawbacks. Seed mucilage, natural polysaccharides, possesses unique functional properties like water holding, emulsifying, and film forming, offering potential alternatives in meat processing and preservation. This study explores the application of seed mucilage from diverse sources (e.g., flaxseed, psyllium, basil) in various meat and meat products processing and preservation. Mucilage's water-holding and emulsifying properties can potentially bind fat and decrease the overall lipid content in meat and meat-based products. Moreover, antimicrobial and film-forming properties of mucilage can potentially inhibit microbial growth and reduce oxidation, extending the shelf life. This review emphasizes the advantages of incorporating mucilage into processing and coating strategies for meat and seafood products.

Potential use of extracted flax seed mucilage in the construction of macroporous cryo-scaffolds.

Mucilage is a natural source of polysaccharides that has recently attracted attention for use in biomaterial production. It attracts attention with its easy and fast extraction, biocompatibility, high water retention capacity, and biodegradability. Although there are studies on the characterization of mucilage obtained from different plant sources, the interaction of this polymer with other polymers and its potential to form new biomaterials have not yet been sufficiently investigated. Based on this, in this study, the potential of mucilage extracted from flaxseed for the production of cryogels for tissue engineering applications was demonstrated. Firstly, yield, basic physicochemical properties, morphology, and surface charge-dependent isoelectric point determination studies were carried out for the characterization of the extracted mucilage. The successful preparation of mucilage was evaluated for the construction of cryo-scaffolds and 3D, spongy, and porous structures were obtained in the presence of chitosan and polyvinyl alcohol polymers. A heterogeneous morphology with interconnected macro and micro porosity in the range of approximately 85-115 m pore diameter was exhibited. Due to the high hydrophilic structure of the mucilage, which is attached to the structure with weak hydrogen bonds, the contact angle values of the scaffolds were obtained below 80° and they showed the ability to absorb 1000 times their dry weight in approximately 30 min. As a preliminary optimization study for the evaluation of mucilage in cryogel formation, this work introduced a new construct to be developed as wound dressing scaffold for deep and chronic wounds.

Insights into digestibility, biological activity, and peptide profiling of flaxseed protein isolates treated by ultrasound coupled with alkali cycling.

This study aims to investigate the effects of ultrasound coupled with alkali cycling on the structural properties, digestion characteristics, biological activity, and peptide profiling of flaxseed protein isolates (FPI). The digestibility of FPI obtained by ultrasound coupled with pH 10/12 cycling (UFPI-10/12) (74.56 % and 79.12 %) was significantly higher than that of native FPI (64.40 %), and UFPI-10 showed higher hydrolysis degree (35.76 %) than FPI (30.65 %) after intestinal digestion. The combined treatment induced transition from α-helix to ß-sheet with an orderly structure. Large FPI aggregates broke down into small-sized FPI particles, which induced the increase of specific surface area of particles. This might expose more cutting sites and contact area with enzymes. Furthermore, UFPI-10 showed high antioxidant activity (29.18 %) and lipid-lowering activity (70.52 %). Peptide profiling revealed that UFPI-10 exhibited a higher proportion of 300-600 Da peptides and significantly higher abundance of antioxidant peptides than native FPI, which might promote its antioxidant activity. Those results suggest that the combined treatment is a promising modification method to improve the digestion characteristics and biological activity of FPI. This work provides new ideas for widespread use of FPI as an active stabilizer in food systems.

Influence of flaxseed-derived diglyceride-based high internal phase Pickering emulsions on the rheological and physicochemical properties of myofibrillar protein gels.

The study aimed to investigate the influence of flaxseed-derived diglyceride-based high internal phase Pickering emulsions (HIPPE) at different levels (0%, 10%, 20%, 30%, 40%, and 50%) on the rheological and physicochemical properties of myofibrillar protein (MPs) gels. The study indicated that with increasing HIPPE levels, there was a significant increase in whiteness while a decrease in water-holding capacity. The gels with 10% HIPPE levels had higher ionic bonds, while those with 40% and 50% HIPPE levels showed higher hydrogen bonds. By increasing HIPPE levels in the formation of MP gels, the T2 relaxation time was found to decrease. Additionally, in all MP gels, G' values were significantly higher than G" values over time. Adding lower contents of HIPPE levels resulted in a more compact microstructure. These findings indicate that flaxseed-derived diglyceride-based HIPPEs could be utilized as fat substitutes in meat products to enhance their nutritional quality.

Investigation on Fermented Milk Quality after the Addition of Flaxseed Mucilage and the Use of Lactobacillus delbrueckii subsp. bulgaricus and Lactiplantibacillus plantarum AG9.

BACKGROUND: Flaxseed mucilage (FSM) is one of the healthy components of flaxseed. FSM is an example of a material that can be used in the food, cosmetic, and pharmaceutical industries due to its rheological properties. FSM consists mainly of two polysaccharides, arabinoxylan, and rhamnogalacturonan I, and it also contains protein components and minerals. The prospect of using FSM in food is due to its gelling, water binding, emulsifying, and foaming properties. In addition, valuable natural sources of phenolic compounds such as lignans, phenolic acids, flavonoids, phenylpropanoids, and tannins are partially extracted from flaxseed in FSM. These antioxidant components have pharmacological properties, including anti-diabetic, anti-hypertensive, immunomodulatory, anti-inflammatory and neuroprotective properties. A combination of FSM and lactobacilli in dairy foods can improve their functional properties. This study aimed to develop dairy products by adding of FSM and using two lactic acid bacteria (LAB). FSM (0.2%) was used as an ingredient to improve both the texture and antioxidant properties of the product. METHODS: Skim milk was fermented with 0.2% flaxseed mucilage using Lactobacillus delbrueckii subs. bulgaricus and the probiotic Lactiplantibacillus plantarum AG9. The finished fermented milk products were stored at 4 °C for 14 days. Quantitative chemical, textural, and antioxidant analyses were carried out. RESULTS: Adding 0.2% FSM to the dairy product stimulated the synthesis of lactic acid. FSM increased the viscosity and water-holding capacity of L. bulgaricus or L. bulgaricus/L. plantarum AG9 fermented milk products. Combining these starter strains with FSM promoted the formation of a hard, elastic, resilient casein matrix in the product. When only L. plantarum AG9 was used for the fermentation, the dairy product had a high syneresis and a low viscosity and firmness; such a product is inferior in textural characteristics to the variant with commercial L. bulgaricus. The addition of FSM improved the textural properties of this variant. The use of L. plantarum AG9 and FSM makes it possible to obtain a fermented milk product with the highest content of polyphenolic compounds, which have the highest antioxidant properties and stimulate lipase and α-glucosidase inhibitor synthesis. Combining of L. bulgaricus and L. plantarum AG9 in the starter (20% of the total mass of the starter) and adding of 0.2% FSM is the optimal combination for obtaining a dairy product with high textural and antioxidant properties. CONCLUSIONS: The physicochemical properties (viscosity, syneresis, water holding capacity, texture) and antioxidant properties of fermented milk were improved. In the future, as part of the work to investigate the functional properties of dairy products with FSM, studies will be conducted using in in vivo models.

Impact of flaxseed gum on the aggregate structure, pasting properties, and rheological behavior of waxy rice starch.

This study examines the effects of flaxseed gum (FG) on the aggregate structure, pasting and rheological properties of waxy rice starch (WRS). Results display an increase in the ordered molecular structure (R1047/1024), relative crystallinity (RC), compactness (α), and microphase heterogeneity (ε, density degree of nanoaggregates, from 3.52 to 4.23) for WRS-FG complexes. These suggested FG facilitated the development of more organized molecular and crystalline structures of WRS, accompanied by the formation of ordered nanoaggregates with higher density (i.e., nano-aggregation structure). Also, FG addition resulted in the formation of enhanced gel network structure characterized by thicker layer walls and more uniform pores. These structural transformations contributed to a rise in gelatinization temperature (To, from 56.90 °C to 62.10 °C) and enthalpy (ΔH), as well as alterations in paste viscosities (PV, from 1285.00 mPa·s to 1734.00 mPa·s), and the rigidity of network structure (e.g., decreased loss tangent). These results indicate that FG could effectively regulate the techno-functional properties of WRS by rationally controlling the starch intrinsic structures of starch. And this study may improve the pasting and gelling properties of starch, thus driving the development of high-quality starchy foods and prolonging their shelf life, especially for glutinous rice flour products.

Comprehensive analysis of oxidative stability and nutritional values of germinated linseed and sunflower seed oil.

Germination of seeds is known to affect the nutritional composition of cold-pressed oils. This study focused on the effects of germination on the antioxidants and oxidative stability of linseed and sunflower seed oil. As hypothesized, germination led to increased antioxidant activities and tocopherol, chlorophyll and carotenoid content. Analysis revealed a 37.2 ± 3.5-fold and 11.6 ± 1.5-fold increase in polyphenol content in linseed and sunflower seed oil from germinated seeds, respectively. Using LC-HRMS/MS, profiles with up to 69 polyphenolic substances were identified in germinated seed oils for the first time. Germination promoted lipid hydrolysis, as evidenced by NMR, with overall significant decreases in triacylglycerol content leading to increased diacylglycerol and free fatty acid values. Rancimat measurements predicted a 4.10 ± 0.52-fold longer shelf-life for germinated linseed oil. This study successfully demonstrated the potential of germination to develop PUFA-rich oils with enhanced antioxidant capacity and oxidative stability.

On the rheological and sensory properties of a novel natural salivary substitute.

The prevalence of xerostomia, the sensation of dry mouth, is estimated at 20 % in the general population and up to 50 % in older adults. Saliva plays different roles during bolus formation: lubrication, mixing, coating, hydration, dissolution, and comminution of food particles. This study proposes and tests artificial saliva formulations mimicking human saliva rheological and sensory perceptions. Shear and extensional rheology were assessed to select the type of formulation closest to saliva rheological characteristics. After evaluating three alternative sources, an extract simulating saliva rheology was produced from flax seeds. Friction coefficient and rheological properties, such as flow curves, relaxation times, and Trouton ratios, were compared favorably with human saliva. The sensory evaluation demonstrated that flaxseed extracts induce perceived mouth hydration, slipperiness, and adhesion exceeding that of human saliva. The flaxseed extract proposed in this can i) be used to study in vitro food oral processing and ii) pave the way to novel natural salivary substitutes to alleviate the symptoms of xerostomia.

Exploration of the Lipid Profile of Edible Oleaginous Microgreens by Mass Spectrometry-Based Lipidomics.

The spreading awareness of the health benefits associated with the consumption of plant-based foods is fueling the market of innovative vegetable products, including microgreens, recognized as a promising source of bioactive compounds. To evaluate the potential of oleaginous plant microgreens as a source of bioactive fatty acids, gas chromatography-mass spectrometry was exploited to characterize the total fatty acid content of five microgreens, namely, chia, flax, soy, sunflower, and rapeseed (canola). Chia and flax microgreens appeared as interesting sources of α-linolenic acid (ALA), with total concentrations of 2.6 and 2.9 g/100 g of dried weight (DW), respectively. Based on these amounts, approximately 15% of the ALA daily intake recommended by the European Food Safety Authority can be provided by 100 g of the corresponding fresh products. Flow injection analysis with high-resolution Fourier transform single and tandem mass spectrometry enabled a semi-quantitative profiling of triacylglycerols (TGs) and sterol esters (SEs) in the examined microgreen crops, confirming their role as additional sources of fatty acids like ALA and linoleic acid (LA), along with glycerophospholipids. The highest amounts of TGs and SEs were observed in rapeseed and sunflower microgreens (ca. 50 and 4-5 µmol/g of DW, respectively), followed by flax (ca. 20 and 3 µmol/g DW). TG 54:9, 54:8, and 54:7 prevailed in the case of flax and chia, whereas TG 54:3, 54:4, and 54:5 were the most abundant TGs in the case of rapeseed. ß-Sitosteryl linoleate and linolenate were generally prevailing in the SE profiles, although campesteryl oleate, linoleate, and linolenate exhibited a comparable amount in the case of rapeseed microgreens.

Valorization of Red Beetroot (Beta vulgaris L.) Pomace Combined with Golden Linseed (Lini semen) for the Development of Vegetable Crispbreads as Gluten-Free Snacks Rich in Bioactive Compounds.

This work aimed to develop gluten-free snacks such as crispbread based on beetroot pomace (Beta vulgaris L.) and golden linseed (Lini semen). Beetroot is attracting more and more consumer attention because of its nutritional and health properties. The use of beet pomace contributes to waste management. Linseed, known as a superfood with many health-promoting properties, was used to produce crispbreads as an alternative to cereals, which are allergens. Beetroot pomace and whole or ground linseed were used in different proportions to produce crispbread snacks. Chemical and physical analyses were performed including water activity, dry matter, betalains, and polyphenols content, as well as Fourier transform infrared spectroscopy (FTIR). A sensory evaluation and microstructure observations were also performed. The obtained snacks were characterized by low water activity (0.290-0.395) and a high dry matter content (93.43-97.53%), which ensures their microbiological stability and enables longer storage. Beetroot pomace provided betalains-red (14.59-51.44 mg betanin/100 g d.m.) and yellow dyes (50.02-171.12 mg betanin/100 g d.m.)-while using linseed enriched the product with polyphenols (730-948 mg chlorogenic acid/100 g d.m.). FTIR analysis showed the presence of functional groups such as the following: -OH, -C-O, -COOH, and -NH. The most desired overall consumer acceptability was achieved for snacks containing 50% beetroot pomace and 50% linseed seeds. The obtained results confirmed that beetroot pomace combined with linseed can be used in the production of vegetable crispbread snacks.

Determination of Bioactive Compound Kynurenic Acid in Linum usitatissimum L.

Kynurenic acid (KYNA) is a bioactive compound exhibiting multiple actions and positive effects on human health due to its antioxidant, anti-inflammatory and neuroprotective properties. KYNA has been found to have a beneficial effect on wound healing and the prevention of scarring. Despite notable progress in the research focused on KYNA observed during the last 10 years, KYNA's presence in flax (Linum usitatissimum L.) has not been proven to date. In the present study, parts of flax plants were analysed for KYNA synthesis. Moreover, eight different cultivars of flax seeds were tested for the presence of KYNA, resulting in a maximum of 0.432 µg/g FW in the seeds of the cultivar Jan. The level of KYNA was also tested in the stems and roots of two selected flax cultivars: an oily cultivar (Linola) and a fibrous cultivar (Nike). The exposure of plants to the KYNA precursors tryptophan and kynurenine resulted in higher levels of KYNA accumulation in flax shoots and roots. Thus, the obtained results indicate that KYNA might be synthesized in flax. The highest amount of KYNA (295.9 µg/g dry weight [DW]) was detected in flax roots derived from plants grown in tissue cultures supplemented with tryptophan. A spectroscopic analysis of KYNA was performed using the FTIR/ATR method. It was found that, in tested samples, the characteristic KYNA vibration bands overlap with the bands corresponding to the vibrations of biopolymers (especially pectin and cellulose) present in flax plants and fibres.

In vitro degradation and antibacterial activity of bacterial cellulose deposited flax fabric reinforced with polylactic acid and polyhydroxybutyrate.

The objective of this study was to prepare biocomposites through the solution casting method followed by compression moulding in which bacterial cellulose (BC) deposited flax fabric (FF) produced through fermentation is coated with minimal amount of polylactic acid (PLA) and polyhydroxybutyrate (PHB). Biocomposites incorporated with 60 % of PLA or PHB (% w/w) show enhanced tensile strength. Cross-sectional morphology showed good superficial interaction of these biopolymers with fibres of FF thereby filling up the gaps present between the fibres. The tensile strength of biocomposites at 60 % PLA and 60 % PHB improved from 37.97 MPa (i.e., BC deposited FF produced in presence of honey) to 67.17 MPa and 56.26 MPa, respectively. Further, 0.25 % of nalidixic acid (NA) (% w/w) and 6 % of oleic acid (OA) (% w/w) incorporation into the biocomposites imparted prolonged antibacterial activity against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The in vitro cytotoxicity of biocomposites was determined using L929 mouse fibroblast cells. The 3-(4,5-cime- thylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide cytotoxicity tests showed that the PHB derived biocomposites along with antibacterial compounds in it were non-toxic. In vitro degradation of biocomposites was measured for up to 8 weeks in the mimicked physiological environment that showed a gradual rate of degradation over the period.

Shaping sustainable pathways: Enhancing mechanical properties of biocomposite through tannic acid treatment of flax fabrics.

Biocomposites developed using natural fibers serve as a sustainable alternative to synthetic composite materials. However, narrowing the performance gap between synthetic composites and biocomposites requires serious efforts. A promising approach is the modification of natural fibers using various chemical treatments. This paper investigates the potential of tannic acid (TA) treatment as a sustainable approach to enhance mechanical performance and reduce moisture absorption of flax fabric-reinforced biocomposites. The methodology involves the treatment of flax woven fabric with tannic acid, a naturally occurring polyphenolic compound, followed by the fabrication of biocomposite using a green epoxy matrix. The variables studied during treatment are TA concentration and processing time. Characterization of untreated and treated flax fabric and its composites was done using various analytical techniques such as FTIR spectroscopy, moisture absorption and mechanical testing (tensile strength, flexural strength, and impact resistance). FTIR spectroscopy of TA-treated flax confirmed attachment of aromatic rings and carbon double bond formation, thus serving for properties enhancement. The mechanical characterization of composites showed that properties are enhanced up to an optimum limit of concentration and processing time i.e., 1 % concentration and 30 min of processing. Moisture absorption of the TA-treated composite also reduced significantly as compared to untreated composites. These findings contribute towards the advancement in sustainable biocomposites and pave the way for their utilization in various applications.

A two-step method of cyclolinopeptide (linusorb) preparation from flaxseed cake via dry-screening.

Linusorbs (LO), cyclolinopeptides, are a group of cyclic hydrophobic peptides and considered a valuable by-product of flaxseed oil due to numerous health benefits. Currently applied acetone or methanol extraction could contaminate the feedstocks for further food-grade application. Using flaxseed cake as feedstock, this study established a practical method for preparing LO from pressed cake. Firstly, LO composition of 15 flaxseed cultivars was analyzed. Next, cold-pressed cake was milled and screened mechanically. The kernel and hull fractions were separated based on the disparity of their mechanical strength. Monitored by hyperspectral fluorescence, the LO-enriched kernel fraction separated from cold-pressed flaxseed cake was further used as feedstock for LO production. After ethanol extraction, partition, and precipitation, LOs were extracted from cold-pressed flaxseed cake with a purity of 91.4%. The proposed method could serve as feasible flaxseed cake valorization strategy and enable the preparation of other polar compounds such as flax lignan and mucilage.

Anti-inflammatory effect of lignans from flaxseed after fermentation by lactiplantibacillus plantarum SCB0151 in vitro.

Lignan, a beneficial constituent of Flaxseed (Linum usitatissimum L.) showed great interest in researchers because of its multiple functional properties. Nonetheless, a challenge arises due to the glycosidic structure of lignans, which the gut epithelium cannot readily absorb. Therefore, we screened 18 strains of Lactiplantibacillus plantarum, Lacticaseibacillus casei, Lactobacillus acidophilus, Lacticaseibacillus rhamnosus, Pediococcus pentosaceus, Pediococcus acidilactici, and Enterococcus durans to remove glycosides from flaxseed lignan extract enzymatically. Among our findings, Lactiplantibacillus plantarum SCB0151 showed the highest activity of ß-glucosidase (8.91 ± 0.04 U/mL) and higher transformed efficiency of Secoisolariciresinol (SECO) (8.21 ± 0.13%). The conversion rate of Secoisolariciresinol diglucoside (SDG) and the generation rate of SECO was 58.30 ± 3.78% and 32.13 ± 2.78%, respectively, under the optimized conditions. According to the LC-HRMSMS analysis, SECO (68.55 ± 6.57 µM), Ferulic acid (FA) (32.12 ± 2.50 µM), and Coumaric acid (CA) (79.60 ± 6.21 µM) were identified in the biotransformation products (TP) of flaxseed lignan extract. Results revealed that the TP exhibited a more pronounced anti-inflammatory effect than the flaxseed lignan extract. SECO, FA, and CA demonstrated a more inhibitory effect on NO than that of SDG. The expression of iNOS and COX-2 was significantly suppressed by TP treatment in LPS-induced Raw264.7 cells. The secretion of IL-6, IL-2, and IL-1ß decreased by 87.09 ± 0.99%, 45.40 ± 0.87%, and 53.18 ± 0.83%, respectively, at 60 µg/mL of TP treatment. Given these data, the bioavailability of flaxseed lignan extract and its anti-inflammatory effect were significantly enhanced by Lactiplantibacillus plantarum SCB0151, which provided a novel approach to commercializing flaxseed lignan extract for functional food.

Non-oxidized and oxidized flaxseed orbitides differently induce HepG2 cell apoptosis: involvement of cellular uptake and membrane death receptor DR4.

BACKGROUND: Flaxseed orbitides have health-promoting properties, particularly potent anti-cancer activity. However, flaxseed orbitides containing a methionine structure, such as [1-9-NαC]-linusorb B2 (CLB), are easily oxidized to sulfoxide ([1-9-NαC],[1-Rs,Ss-MetO]-linusorb-B2 (CLC)) and sulfone ([1-9-NαC], [1-MetO]-linusorb B2 (CLK)), with CLC having less anti-cancer ability than CLB. It is unclear why oxidized flaxseed orbitides are less effective against cancer than non-oxidized flaxseed orbitide. RESULTS: Non-oxidized ([1-9-NαC]-linusorb-B3 (CLA) and CLB) and oxidized (CLC and CLK) flaxseed orbitides were found to significantly upregulate the levels of pro-apoptotic proteins, including Bax/Bcl-2, CytoC, caspase-3, and caspase-8, in a dose-dependent manner, with non-oxidized flaxseed orbitides being more effective than oxidized flaxseed orbitides. Mechanically, the cellular absorption of non-oxidized flaxseed orbitides was higher than that of oxidized flaxseed orbitides. Moreover, the significant fluorescence quenching of DR4 protein by flaxseed orbitides (especially non-oxidized orbitides) indicated the formation of a DR4-orbitide complex. Molecular docking demonstrated that non-oxidized orbitides could easily dock into the active cavity of DR4 protein. Further blocking DR4 significantly reduced the ability of non-oxidized flaxseed orbitides to stimulate caspase-3 expression, whereas oxidized flaxseed orbitides retained this ability. CONCLUSION: Non-oxidized flaxseed orbitides are more effective against cancer than oxidized flaxseed orbitides due to higher cellular uptake and activation of the DR4-mediated death receptor signaling pathway. © 2024 Society of Chemical Industry.

Stability of tryptophan-containing LOs in flaxseed oil and their response towards γ-tocopherol.

Linusorbs (LOs), significantly influence oil quality and sensory properties of flaxseed oil. Trp-containing LOs exhibit distinct oxidative behavior when γ-tocopherol (γ-T) is present. Polar fractions of crude flaxseed oil were stripped via silica absorption, and reintroduced (LO and γ-T) separately into the oil matrix to investigate their interaction during storage. Compared with crude oil, LOs account for 18.49% reduction of p-anisidine value, while LOs with γ-T contributed to most of the endogenous antioxidant effect in crude oil. γ-T was found to suppress oxidation of Trp-containing LO at early stage (Met form), while facilitate oxidation while at their mid-stage (MetO form, Methionine sulfoxide). In vitro oxidation shows that CLD more likely cleaved into peptide fragments, while few products retain intact ring structures. LC-MS/MS analysis and silicon simulation revealed proximity between MetO and Trp residues, facilitating inter- or intra-molecular reactions and ring structure rupture. Remarkably, the presence of γ-T facilitate these phenomena.

A comparative study on flaxseed lignan biotransformation through resting cell catalysis and microbial fermentation by ß-glucosidase production Lactiplantibacillus plantarum.

BACKGROUND: Flax lignan has attracted much attention because of its potential bioactivities. However, the bioavailability of secoisolariciresinol diglucoside (SDG), the main lignan in flaxseed, depends on the bioconversion by the colon bacteria. Lactic acid bacteria (LAB) with ß-glucosidase activity has found wide application in preparing bioactive aglycone. RESULTS: LAB strains with good ß-glucosidase activity were isolated from fermented tofu. Their bioconversion of flax lignan extract was investigated by resting cell catalysis and microbial fermentation, and the metabolism of SDG by Lactiplantibacillus plantarum C5 following fermentation was characterized by widely targeted metabolomics. Five L. plantarum strains producing ß-glucosidase with broad substrate specificity were isolated and identified, and they all can transform SDG into secoisolariciresinol (SECO). L. plantarum C5 resting cell reached a maximum SDG conversion of 49.19 ± 3.75%, and SECO generation of 21.49 ± 1.32% (0.215 ± 0.013 mm) at an SDG substrate concentration of 1 mM and 0.477 ± 0.003 mm SECO was produced at 4 mm within 24 h. Although sixteen flax lignan metabolites were identified following the fermentation of SDG extract by L. plantarum C5, among them, four were produced following the fermentation: SECO, demethyl-SECO, demethyl-dehydroxy-SECO and isolariciresinol. Moreover, seven lignans increased significantly. CONCLUSION: Fermentation significantly increased the profile and level of flax lignan metabolites, and the resting cell catalysis benefits from higher bioconversion efficiency and more straightforward product separation. Resting cell catalysis and microbial fermentation of flax lignan extract by the isolated ß-glucosidase production L. plantarum could be potentially applied in preparing flax lignan ingredients and fermented flaxseed. © 2024 Society of Chemical Industry.