Application of bi-layers active gelatin films for sliced dried-cured Coppa conservation

Nisin variants: What makes them different and unique?

Nisin A is a lantibiotic bacteriocin typically produced by strains of Lactococcus lactis. This bacteriocin has been approved as a natural food preservative since the late 1980 s and shows antimicrobial activity against a range of food-borne spoilage and pathogenic microorganisms. The therapeutic potential of nisin A has also been explored increasingly both in human and veterinary medicine. Nisin has been shown to be effective in treating bovine mastitis, dental caries, cancer, and skin infections. Recently, it was demonstrated that nisin has an affinity for the same receptor used by SARS-CoV-2 to enter human cells and was proposed as a blocker of the viral infection. Several nisin variants produced by distinct bacterial strains or modified by bioengineering have been described since the discovery of nisin A. These variants present modifications in the peptide structure, biosynthesis, mode of action, and spectrum of activity. Given the importance of nisin for industrial and therapeutic applications, the objective of this study was to describe the characteristics of the nisin variants, highlighting the main differences between these molecules and their potential applications. This review will be useful to researchers interested in studying the specifics of nisin A and its variants.

Improving the Properties of Gelatin-Based Films by Incorporation of "Pitanga" Leaf Extract and Crystalline Nanocellulose

Biopolymer-based films can be activated by the incorporation of active compounds into their matrix. Plant extracts are rich in phenolic compounds, which have antimicrobial and/or antioxidant properties. The aim of this study was to produce gelatin-based active films and nanocomposite films incorporated with "pitanga" (Eugenia uniflora L.) leaf extract (PLE) and/or crystalline nanocellulose extracted from soybean straw (CN), and to study the physicochemical, functional, microstructural, thermal, UV/Vis light barrier, and antioxidant properties of these materials. PLE enhanced some film properties, such as tensile strength (from 30.2 MPa to 40.6 MPa), elastic modulus (from 9.3 MPa to 11.3 MPa), the UV/Vis light barrier, and antioxidant activity, in addition to affecting the microstructural, surface, and color properties. These improvements were even more significant in nanocomposites simultaneously containing PLE and CN (59.5 MPa for tensile strength and 15.1 MPa for elastic modulus), and these composites also had lower moisture content (12.2% compared to 13.5-14.4% for other treatments) and solubility in water (from 48.9% to 44.1%). These improvements may be the result of interactions that occur between PLE's polyphenols and gelatin, mainly in the presence of CN, probably due to the formation of a stable PLE-CN-gelatin complex. These results are relevant for the food packaging sector, as the activated nanocomposite films exhibited enhanced active, barrier, and mechanical properties due to the presence of PLE and CN, in addition to being entirely produced with sustainable components from natural and renewable sources.

Effects of ginger essential oil on physicochemical and structural properties of agar‑sodium alginate bilayer film and its application to beef refrigeration

To maintain the freshness of meat products, an agar‑sodium alginate (AS) bilayer antibacterial film incorporated with ginger essential oil (GEO) was developed. The effect of GEO at different concentrations (1%, 2%, 3% and 4% v/v) on the physical properties, micro-structure and antibacterial activity closely related to AS film's application to beef refrigeration was extensively studied. In addition, the effects of AS bilayer active film on refrigeration quality and shelf life of beef were systematically evaluated. The porous structure and number of oil droplets became more obvious with the increase of GEO amount in AS film. The incorporation and increase of GEO could delay the lipid oxidation and protein decomposition of beef, reduce the total counts of the tested microorganisms (total viable bacteria, psychrotrophic bacteria, Escherichia coli, Staphylococcus aureus, yeast, and mold) in meat samples. Compared with commercial polyethylene (PE) packaging, the accumulation of basic compounds from the degradation of beef protein as well as the microbial contamination was obviously improved, which could extend the comprehensive shelf life of beef by 4-6 days. Consequently, AS bilayer films incorporated with GEO, especially GEO at 4.0% (v/v) GEO concentration can be developed to be an antibacterial active packaging material for beef refrigeration.

Identification and In Silico Simulation on Inhibitory Platelet-Activating Factor Acetyl Hydrolase Peptides from Dry-Cured Pork Coppa

The unique processing technology of dry-cured meat products leads to strong proteolysis, which produces numerous peptides. The purpose of this investigation was the systematic isolation, purification, and identification of potentially cardioprotective bioactive peptides from dry-cured pork coppa during processing. According to the results of anti-platelet-activating factor acetyl hydrolase activity and radical scavenging ability in vitro, the inhibitory effect of M1F2 in purified fractions on cardiovascular inflammation was higher than that of M2F2. The peptide of M1F2 was identified by nano-liquid chromatography–tandem mass spectrometry. A total of 30 peptides were identified. Based on bioinformatics methods, including in silico analysis and molecular docking, LTDKPFL, VEAPPAKVP, KVPVPAPK, IPVPKK, and PIKRSP were identified as the most promising potential platelet-activating factor acetyl hydrolase inhibitory peptides. Overall, bioactive peptides produced during dry-cured pork coppa processing demonstrate positive effects on human health.