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

Unlocking flaxseed oleosomes (oil bodies) potential: Optimal extraction and functional insights through enzymolysis or dehulling treatment

Oleosomes are intracellular vesicles within a phospholipid monolayer membrane and have significant potential for use in various food applications as natural emulsions. Flaxseed, an underexplored yet promising crop, shows promise for oleosome utilization. However, the high mucopolysaccharide content in hulls may pose challenges to the extraction efficiency of natural flaxseed oleosomes (N-FOs). In this study, two pretreatment methods were employed prior to aqueous extraction: enzymatic hydrolysis using a cellulase-pectinase-xylanase cocktail and dehulling. Both pretreatment methods significantly improved the extraction yield, with dehulling flaxseed oleosomes (D-FOs) achieving 51.3 % and enzymatically hydrolyzed flaxseed oleosomes (E-FOs) reaching 53.1 %, representing an increase by a factor of five compared to N-FOs. The average droplet size of E-FOs ranged from 1.5 to 1.7 μm across pH 2.0 to pH 10.0, while the absolute value of the zeta-potential for E-FOs at pH 10.0 was the highest at -39.6 mV. Cryo-SEM imaged that E-FOs and N-FOs exhibited a more complete structure than D-FOs, which might be attributed to the increased electrostatic repulsion generated by flaxseed protein and spatial hindrance of incompletely hydrolyzed polysaccharides. LF-NMR spectra showed shorter T2 values of E-FOBs, confirming increased interactions between residual polysaccharides and oleosomes. The tight and solid-like interfacial film affirmed by the emulsifying activity and rheological results could protect emulsion droplets against flocculation and disproportionation, thus contributing to enhanced emulsification stability. Enzymatic hydrolysis demonstrated a favorable balance between extraction yield and functional properties compared to dehulling or no pretreatment, making it a suitable approach for efficient oleosome extraction from flaxseeds for various plant-based food applications.

Nutritional and antioxidative characterization, antimicrobial and sensorial stability of flaxseed powder supplemented mutton patties

Oxidative stress and microbial growth deteriorate food quality and cause safety risks. Therefore, the present study was investigated to explore the nutritional, sensorial, anti-oxidative and anti-microbial attributes of flaxseed powder (FP) supplemented at 2-8 % (i.e., T1-T4) level in mutton patties. Among extracts, the aqueous flaxseed extracts exhibited the highest total phenolic contents (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) activities i.e., 275 mg GAE/g, 75 % and 57 mg/g, respectively. The results exhibited significant increase (p < 0.05) in protein, and ash contents from 10.7 to 20.6 and 1.3-2.4 (g/100 g) on addition of FP at 2-8 % in mutton patties, respectively. Likewise, the mutton patties exhibited significant (p < 0.05) decrease in pH and thiobarbituric acid reactive substances (TBARS) of T1-T4 from 7.1 to 3.4 and 317-46 than control i.e., 6.64-4.12 and 453.75-563 at 0-16 days. Among color of mutton patties, L ⁎ values decreased from 37 to 25, while, b ⁎ values increased from 10 to 13 on addition of 2-8 % FP in mutton patties at 0-16 days for T1-T4, respectively. A significant decrease (p < 0.05) in total plate counts (TPC), Salmonella and E. coli of mutton patties was recorded in T0-T4 from 4.2 to 2.8, 0.8-0.3, and 2.1-0.3, respectively at 16th day of storage, respectively. Sensory experts rated the T1 (i.e., 2 % FP supplemented mutton patties) owing to their best sensory scores and overall acceptability. Conclusively, owing to better potential of FP in improving the nutritional and microbial quality of mutton patties, the study further suggests its ability to act as a novel functional ingredient of choice in shelf-life extension of other food products.

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.

Anti-Cancer Properties of Flaxseed Proteome

Flaxseed has been recognized as a valuable source of nutrients and bioactive compounds, including proteins that possess various health benefits. In recent years, studies have shown that flaxseed proteins, including albumins, globulins, glutelin, and prolamins, possess anti-cancer properties. These properties are attributed to their ability to inhibit cancer cell proliferation, induce apoptosis, and interfere with cancer cell signaling pathways, ultimately leading to the inhibition of metastasis. Moreover, flaxseed proteins have been reported to modulate cancer cell mechanobiology, leading to changes in cell behavior and reduced cancer cell migration and invasion. This review provides an overview of the anti-cancer properties of flaxseed proteins, with a focus on their potential use in cancer treatment. Additionally, it highlights the need for further research to fully establish the potential of flaxseed proteins in cancer therapy.

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.

Effect of konjac oligo-glucomannan on emulsifying properties of myofibrillar protein

BACKGROUND

The high viscosity of konjac glumannan (KGM) limits its application in meat processing. In this work, the effects of konjac oligo-glucomannan (KOG), as a derivative of KGM, on the emulsifying properties of myofibrillar protein (MP) and the related mechanism were investigated.

RESULTS

It was found that the addition of KOG had no significant effect on the secondary structure of MP, but altered the tertiary conformation of MP, resulting in exposure of tyrosine residues to polar microenvironments and decreased intrinsic fluorescence intensity. In addition, the addition of KOG increased the emulsifying activity of MP, resulting in decreased particle size and improved physical stability of the emulsion. The emulsifying activity of MP reached the maximum value when 1.0 wt% KOG was added. Moreover, the interfacial tension and interfacially adsorbed protein content of MP/KOG emulsions decreased with the increase in KOG concentration.

CONCLUSION

These findings demonstrated that KOG mainly interacted with MP and changed the amphipathy of the KOG-MP at the oil-water interface, forming a stable interface film to improve the emulsifying properties of MP. © 2023 Society of Chemical Industry.

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.