Incorporation of antibacterial zein/thymol nanoparticles dispersed using nanobubble technology improves the functional performance of gelatin films

Development and application of mathematical modeling of thymol release from environmental-responsive potato starch active packaging films

Traditional active packaging materials are easily affected by the environment, resulting in their inability to release active substances in specified quantities at specified times and locations. In this study, MCM-41 was used as a thymol (THY) carrier and added to the potato starch (PS) matrix to design an intelligent release active packaging film based on storage microenvironment. MCM-41 encapsulation improved thermal stability of THY. THY-MCM-41 addition significantly improved the tensile strength (TS, 7.18 MPa) of the film (P < 0.05) and endowed the film excellent gas and water barrier protection. THY release was responsive to temperature and relative humidity (RH), and the First-order model better explained the THY release pattern (R2 > 0.980). The THY-MCM-41/PS film exhibited long-term antibacterial effect during 10-day storage due to the sustained release of THY. Additionally, strawberries packaged in the THY-MCM-41/PS film exhibited the best sensory characteristics during 5-day storage (25 °C and 50 % RH). Overall, the present THY-MCM-41/PS film provides a novel alternative for the sustained release of active substances in order to achieve the excellent preservation of goods such as fruits and vegetables.

Synergistic Antimicrobial Hybrid Bio-Surface Formed by Self-Assembled BSA Nanoarchitectures with Chitosan Oligosaccharide

Innovation in green, convenient, and sustainable antimicrobial packaging materials for food is an inevitable trend to address global food waste challenges caused by microbial contamination. In this study, we developed a biogenic, hydrophobic, and antimicrobial protein network coating for food packaging. Experimental results show that disulfide bond breakage can induce the self-assembly of bovine albumin (BSA) into protein networks driven by hydrophobic interactions, and chitosan oligosaccharide (COS) with antimicrobial activity can be stably bound in this network by electrostatic interactions. The inherent antimicrobial activity of COS and the numerous hydrophobic regions on the surface of the BSA-network give the BSA@COS-network significant in vitro antimicrobial ability. More importantly, the BSA@COS-network coating can prolong the onset of spoilage of strawberries in various packaging materials by nearly 3-fold in storage. This study shows how surface functionalization via protein self-assembly is integrated with the biological functioning of natural antibacterial activity for advanced food packaging applications.

Novel Biodegradable Nanoparticulate Chain-End Functionalized Polyhydroxybutyrate-Caffeic Acid with Multifunctionalities for Active Food Coatings

The bioactivities of polyhydroxyalkanoates have been curtailed owing to the lack of bioactive functional groups in their backbones. In this regard, polyhydroxybutyrate (PHB) produced from new locally isolated Bacillus nealsonii ICRI16 was chemically modified for enhancing its functionality, stability as well as solubility. First, PHB was transformed to PHB-diethanolamine (PHB-DEA) by transamination. Subsequently, for the first time, the chain ends of the polymer were substituted by caffeic acid molecules (CafA), generating novel PHB-DEA-CafA. The chemical structure of such a polymer was confirmed by Fourier-transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance (¹H NMR). The modified polyester demonstrated improved thermal behavior compared to PHB-DEA as was shown by thermogravimetric analysis, derivative thermogravimetry, and differential scanning calorimetry analyses. Interestingly, 65% of PHB-DEA-CafA was biodegraded in a clay soil environment after 60 days at 25 °C, while 50% of PHB was degraded within the same period. On another avenue, PHB-DEA-CafA nanoparticles (NPs) were successfully prepared with an impressive mean particle size of 223 ± 0.12 nm and high colloidal stability. The nanoparticulate polyester had powerful antioxidant capacity with an IC₅₀ of 32.2 mg/mL, which was the result of CafA loading in the polymer chain. More importantly, the NPs had a considerable effect on the bacterial behavior of four food pathogens, inhibiting 98 ± 0.12% of Listeria monocytogenes DSM 19094 after 48 h of exposure. Finally, the raw polish sausage coated with NPs had a significantly lower bacterial count of 2.11 ± 0.21 log cfu/g in comparison to other groups. When all these positive features are recognized, the polyester described herein could be considered as a good candidate for commercial active food coatings.