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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 β‐glucosidase activity has found wide application in preparing bioactive aglycone. RESULTS: LAB strains with good β‐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 β‐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 β‐glucosidase production L. plantarum could be potentially applied in preparing flax lignan ingredients and fermented flaxseed. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Pulsed field ablation is a novel approach to treating 33.5 million patients with atrial fibrillation and offers a tissue‐specific advantage over conventional radiofrequency ablation and cryoablation. However, for complex structural targets in the heart, current electrodes often damage non‐target areas due to inaccurate ablation and have to employ electrical pulses with amplitudes of several kilovolts. Herein, materials and designs of a catheter‐integrated microelectrode and sensors that can be used for high‐precision and low‐voltage pulsed field ablation through minimally invasive operation on a large animal model, is reported. The device with a new electrode configuration supports point‐by‐point ablation with a width of 3.8 mm (≈1/10 that of a typical ablation electrode) for individual lesions at the voltage of 300 V (an order of magnitude reduction compared to the current state‐of‐the‐art). More impressively, the integrated catheter allows for pulsed field ablation on the large animal heart through minimally invasive surgery and blocks the electrical conduction pathway on the heart, which is the key to treating atrial fibrillation. This catheter‐integrated device will enhance the efficiency and safety of pulsed field ablation, especially for complex cardiac structures, thus facilitating its move to the clinic. [ABSTRACT FROM AUTHOR]

Semidried salted tilapia was fermented and prepared byMonascus(Monascus ankaandMonascus purpureus). The sample was restored at 25°C to undergo the preservation test. The color value, total volatile base nitrogen (TVB-N) value, ammoniacal nitrogen content, acid value, and peroxide value were measured on a daily basis for 24 days. Results showed thatMonascuscontributed to inhibiting the growth of microorganisms and delayed the advent of decomposition. Meanwhile, they could keep the lipids from oxidation and rancidity, which helped the semidried tilapia achieve a satisfying color. The preservation test and the bacterial colony culture test on physicochemical and microbiological indexes under 25°C showed thatMonascusfermentation could inhibit the growth of other microorganisms, improved the quality of semidried tilapia, and extended shelf life. [ABSTRACT FROM PUBLISHER]

A new approach for determination of glycidyl fatty acid esters (GDEs) based on ¹H nuclear magnetic resonance (¹H NMR) spectroscopy was developed. The ¹H NMR spectra of the GDE standards were prepared and characterized. The quantification formula was then deduced from the characteristic signals of two epoxy methylene (CH2) protons at chemical shifts 2.56 and 2.76 ppm. Tests on repeatability, reproducibility, and recovery were conducted and proved the reliability of the quantification method. This method was extended to GDEs mixed with oil matrices composed of different acylglycerols (GREs). The weighted average factor fw is introduced to calculate the fatty acid composition based on the stoichiometric proportion of the lipid component and its esterification degree. With the fatty acid composition determined, the molar percentage obtained from ¹H NMR can be converted to the weight percentage. This method is an analytical model for the determination of GDEs, with advantages such as easy operation and high accuracy. [ABSTRACT FROM AUTHOR]

Human intestinal microbiota plays a crucial role in converting secoisolariciresinol diglucoside, a lignan found in flaxseed, to enterodiol, which has a range of health benefits: antioxidative, antitumor, and estrogenic/anti-estrogenic effects. Given the high secoisolariciresinol diglucoside content in flaxseed cake, this study investigated the potential of co-fermenting flaxseed cake with fermented soybean product to isolate bacterial strains that effectively convert secoisolariciresinol diglucoside to enterodiol in a controlled environment (in vitro). The co-fermentation process with stinky tofu microbiota significantly altered the lignan, generating 12 intermediate lignan metabolites as identified by targeted metabolomics. One particular promising strain, ZB26, demonstrated an impressive ability to convert secoisolariciresinol diglucoside. It achieved a conversion rate of 87.42 ± 0.33%, with secoisolariciresinol and enterodiol generation rates of 94.22 ± 0.51% and 2.91 ± 0.03%, respectively. Further optimization revealed, under specific conditions (0.5 mM secoisolariciresinol diglucoside, pH 8, 30 °C for 3 days), ZB26 could convert an even higher percentage (97.75 ± 0.05%) of the secoisolariciresinol diglucoside to generate secoisolariciresinol (103.02 ± 0.16%) and enterodiol (3.18 ± 0.31%). These findings suggest that the identified strains ZB26 have promising potential for developing functional foods and ingredients enriched with lignans. [Display omitted] • Flaxseed cake and fermented tofu were co-fermented for strain screening. • Five Strains of Enterococcus converting flax lignan to enterodiol were isolated. • The metabolic pathway of flax lignans to enterodiol via strain ZB-26 is proposed. [ABSTRACT FROM AUTHOR]

1H NMR spectrum of palm oil. [ABSTRACT FROM AUTHOR]