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Background Probiotics are defined as microorganisms that can exert health benefits for the host. Among the recognized probiotics, Lactobacillus paracasei are one of the most frequently used probiotics in humans. The L. paracasei strain M11-4, isolated from fermented rice, which could ferment soymilk within a short curd time, and fermented soymilk presented high viability, acceptable flavor and antioxidant activity, which revealed that the strain maybe have a potential antioxidant value. Therefore, it is necessary to further explore the antioxidant activity of L. paracasei strain M11-4. Results The radical scavenging activities, lipid peroxidation inhibition, and reducing power of L. paracasei M11-4 were the highest in the fermentation culture without cells, while the activities of other antioxidant enzymes of L. paracasei M11-4 were high in the cell-free extract and bacterial suspension. Moreover, L. paracasei M11-4 exerted its antioxidant effect by upregulating the gene expression of its antioxidant enzymes, thioredoxin (Trx) and glutathione (GSH) systems when hydrogen peroxide (H2 O2 ) existed. Supplementation of rats with L. paracasei M11-4 effectively alleviated D-galactose-induced oxidative damage in the liver and serum and prevented D-galactose-induced changes to intestinal microbiota. Supplementation with L. paracasei M11-4 also reduced the elevated expression of Trx and GSH system genes induced by D-galactose. Conclusion L. paracasei M11-4 has good antioxidant properties both in vitro and in vivo and the antioxidant mechanism of it was studied at the molecular level. This article is protected by copyright. All rights reserved.

In this study, an active antibacterial packaging film was developed by coating a polyethylene terephthalate/polyvinylidene chloride/retort casting polypropylene (PPR) plastic multilayer film with plantaricin BM‐1 and chitosan. The characteristics of the active packaging film and its antibacterial effect for chilled meat preservation were evaluated. Our results indicated that the barrier properties against oxygen were improved significantly and the tensile strength and the elongation at break were changed slightly. The active plantaricin film significantly (P

Lactobacillus plantarum BM-1 isolated from a traditionally fermented Chinese meat product was found to produce a novel bacteriocin that is active against a wide range of gram-positive and gram-negative bacteria. Production of the bacteriocin BM-1 started early in the exponential phase and its maximum activity (5120 AU/mL) was recorded early during the stationary phase (16 hr). Bacteriocin BM-1 is sensitive to proteolytic enzymes but stable in the pH range of 2.0–10.0 and heat-resistant (15 min at 121°C). This bacteriocin was purified through pH-mediated cell adsorption–desorption and cation-exchange chromatography on an SP Sepharose Fast Flow column. The molecular weight of the purified bacteriocin BM-1 was determined to be 4638.142 Da by electrospray ionization Fourier transform mass spectrometry. Furthermore, the N-terminal amino acid sequence was obtained through automated Edman degradation and found to comprise the following 15 amino acid residues: H2N-Lys-Tyr-Tyr-Gly-Asn-Gly-Val-Tyr-Val-Gly-Lys-His-Ser-Cys-Ser. Comparison of this sequence with that of other bacteriocins revealed that bacteriocin BM-1 contains the consensus YGNGV amino acid motif near the N-terminus. Based on its physicochemical characteristics, molecular weight, and N-terminal amino acid sequence, plantaricin BM-1 is a novel class IIa bacteriocin.