Search Results (6)

This study aimed to investigate the mechanism underlying the synergistic antimicrobial effect of ferulic acid (FA) and ε-polylysine hydrochloride (PL) on Shewanella putrefaciens (S. putrefaciens) and their application on crayfish (Procambarus clarkii). The treatment with FA and PL exhibited a strong synergistic inhibitory effect against S. putrefaciens. The combination of 1/4 Minimum Inhibitory Concentration (MIC) FA and 1/4 MIC PL was the most effective, damaging the cell structure and inhibiting the growth of S. putrefaciens. Plasma-activated water (PAW) can induce microbial inactivation through physical action. In addition, treatments with FA, PL, PAW, PAW-FA, PAW-PL, and PAW + PL-FA substantially decreased total viable counts (TVCs), total volatile base nitrogen (TVB-N), the thiobarbituric acid value (TBA), and the juice loss rate of crayfish, with FA-PL showing the best effect. This study confirmed the antimicrobial efficacy of PL, FA, and PAW, indicating their potential as effective preservatives for controlling spoilage in freshwater crustaceans. Full article

Fresh wet vermicelli is highly susceptible to microbial contamination during storage as a result of its high moisture content and rich nutrients, which leads to spoilage and deterioration. In addition to exerting a great impact on the quality of the product, this results in significant economic losses and potential food safety risks. This work aimed to identify spoilage microorganisms via traditional culturing methods and molecular biology techniques. The effects of environmental factors such as temperature and pH on the growth and development of the dominant spoilage fungi were investigated, and the inhibitory effects of both chemical (potassium sorbate) and natural antimicrobial agents (chitooligosaccharides, chitosan, tea polyphenols, citric acid, and ε-polylysine hydrochloride) were evaluated. The results indicated that Penicillium crustosum was the major spoilage microorganism in fresh wet vermicelli, whose optimal growth temperature and pH was 28 °C and 7, respectively. While conidial germination began at 7 h, hyphal formation was only observed after 12 h. Moreover, the findings suggest that both natural and chemical antimicrobial agents can effectively inhibit the growth of P. crustosum, with ε-polylysine hydrochloride being the strongest antimicrobial agent. Overall, the findings of this study provide a scientific foundation for improving the preservation of fresh wet vermicelli, which is of great significance for extending its shelf life and enhancing food safety. Full article

The quality modification of chilled, raw conditioned mutton (RCM) after storage significantly impacts consumer preferences, making shelf-life extension and quality preservation crucial. This study evaluated the effects of sodium diacetate (SDA), sodium dehydroacetate (DHA-S), ε-polylysine hydrochloride (PLH), and nisin on RCM quality and bacterial community at concentrations of 3.0, 0.50, 0.30, and 0.50 g/kg, respectively. Major spoilage bacteria were isolated, and the inhibitory effects of these preservatives were studied, leading to the development of compound preservatives. TVC increased significantly during RCM preparation, with continuous increases in TVC and TVB-N levels throughout storage, reaching spoilage thresholds by day 5. Bacterial diversity decreased markedly, with Brochothrix and Pseudomonas dominating. SDA effectively inhibited TVC proliferation and TVB-N formation, maintaining bacterial diversity and reducing Brochothrix and Pseudomonas abundance while promoting the growth of lactic acid bacteria. Five spoilage bacteria strains were isolated, including Serratia liquefaciens B2107-1, a potent meat spoilage bacterium under refrigeration. PLH and SDA demonstrated significant inhibitory activity against this bacterium, with minimum inhibitory concentrations (MICs) of 0.175 and 0.400 mg/mL, respectively. Combining PLH and SDA at 1MIC + 3MIC exhibited a synergistic antimicrobial effect, maintaining RCM quality with reduced SDA usage. These findings demonstrate the significant potential of these preservatives in chilled, raw meat products. Full article

Crab roe sauce (CRS) is prone to spoilage due to microbial contamination. Therefore, this study aimed to investigate the inhibitory effects and mechanisms of a mixed bio-preservative (0.025% ε-polylysine hydrochloride (ε-PL) + 0.01% nisin (NS) + 0.01% tea polyphenols (TPs)) on the specific spoilage bacteria (SSB) in CRS. First, the SSB in CRS were isolated and identified by 16S rRNA sequencing. Two isolates were selected as representative strains based on their enzymatic spoilage potential and spoilage capability in CRS. By comparing the inhibition zones, ε-PL, NS, and TPs were selected from five conventional bio-preservatives (ε-PL, NS, TPs, grape seed extract (GSE), and rosemary extract (RE)) to prepare the mixed bio-preservative. The results showed that the minimum inhibitory concentration (MIC) of the mixed bio-preservative against Bacillus pumilus and Bacillus subtilis was 56.3 µg/mL. The growth curves and cell viability tests revealed that the mixed bio-preservative reduced the viability of both strains. The conductivity, alkaline phosphatase activity, and nucleic acid and soluble protein leakage indicated that the mixed bio-preservative disrupted the integrity of the cell walls and membranes of the two isolates in a concentration-dependent manner. Scanning electron microscopy further confirmed the damage to the cell membranes of the two isolates by the mixed bio-preservative. Overall, the mixed bio-preservative exhibited excellently inhibitory effects on the SSB and could be a promising method for the preservation of CRS. Full article

Coating preservation has a remarkable effect on the preservation of aquatic products. This work prepared a composite coating using konjac glucomannan (KGM) as the film-forming matrix and ε-polylysine hydrochloride (ε-PL) and ferulic acid (FA) as the preservative. Three types of treated sea bass (KGM, KGM-ε-PL, and KGM-ε-PL-FA) and untreated sea bass were stored at 4 °C for 20 days to compare freshness changes under different treatment conditions. The results showed that the surface color and texture of sea bass in refrigerated storage changed dramatically and deteriorated as storage time increased. The composite coating treatment was significantly different from the control group. Using Gas-phase ion migration spectrometry (GC-IMS) technology, 32 volatile compounds, such as aldehydes, alcohols, and ketones, were found in fillets during flavor quality analysis. The composite coating can successfully inhibit the formation of odor compounds such as 2-nonenone, isoamyl alcohol monomer, ammonia, and trimethylamine, delaying the deterioration of fish and improving freshness. Among them, KGM-ε-PL-FA composite coating has the most remarkable preservation performance, which significantly inhibits the occurrence of rotten odor, and has a potential application prospect in the field of food preservation. Full article

In this study, two types of antibacterial montmorillonites (Mt) were prepared using a facile method. The Mt modified with ε-polylysine hydrochloride (ε-PL) was named PL-Mt, while the Mt dually modified with dioctadecyl dimethylammonium chloride (D1821) and ε-PL was named PL-OMt. The results of the X-ray diffraction, Fourier-transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) of the PL-Mt indicated that 30% ε-PL was the most suitable amount for intercalating the Mt. The particle size and distribution of the ε-PL in the solution demonstrated that the Mt d-value could not be further increased owing to the increasing ε-PL diameter. The result of the X-ray diffraction of PL-OMt displayed that ultrasonic treatment at 600 W facilitated ε-PL to intercalate into the OMt interlayer space. The PL-OMt prepared with ultrasonic treatment at 600 W exhibited antibacterial activity against Escherichia coli and Bacillus subtilis superior to that of the PL-OMt prepared with higher-power ultrasonic treatment. Thus, the addition of 30% ε-PL based on the dry Mt mass is the most suitable ratio for preparing PL-Mt, while ultrasonic treatment at 600 W is the most suitable for preparing PL-OMt. These findings may expand the application fields of ε-PL. Full article