Chitosan–green tea extract powder composite pouches for extending the shelf life of raw meat

Effects of eugenol on physicochemical properties of sturgeon skin collagen-chitosan composite membrane

In this study, a series of collagen-chitosan-eugenol (CO-CS-Eu) flow-casting composite films were prepared using collagen from sturgeon skin, chitosan, and eugenol. The physicochemical properties, mechanical properties, microstructure, as well as antioxidant and antimicrobial activities of the composite membranes were investigated by various characterization techniques. The findings revealed that the inclusion of eugenol augmented the thickness of the film, darkened its color, reduced the transparency, and enhanced the ultraviolet light-blocking capabilities, with the physicochemical properties of the CO-CS-0.25%Eu film being notably favorable. Eugenol generates increasingly intricate matrices that disperse within the system, thereby modifying the optical properties of the material. Furthermore, the tensile strength of the film decreased from 70.97 to 20.32 MPa, indicating that eugenol enhances the fluidity and ductility of the film. Added eugenol also exhibited structural impact by loosening the film cross-section and decreasing its density. The Fourier transform infrared spectroscopy results revealed the occurrence of several intermolecular interactions among collagen, chitosan, and eugenol. Moreover, the incorporation of eugenol bolstered the antioxidant and antimicrobial capabilities of the composite film. This is primarily attributed to the abundant phenolic/hydroxyl groups present in eugenol, which can react with free radicals by forming phenoxy groups and neutralizing hydroxyl groups. Consequently, inclusion of eugenol substantially enhances the freshness retention performance of the composite film. PRACTICAL APPLICATION: ● The CO-CS-Eu film utilizes collagen from sturgeon skin, improving the use of sturgeon resources.● Different concentrations of eugenol altered its synergistic effect with chitosan.● The CO-CS-Eu film is composed of natural products with safe and edible properties.

Nanopriming-mediated memory imprints reduce salt toxicity in wheat seedlings by modulating physiobiochemical attributes

BACKGROUND

Around the globe, salinity is one of the serious environmental stresses which negatively affect rapid seed germination, uniform seedling establishment and plant developments restricting sustainable agricultural productivity. In recent years, the concepts of sustainable agriculture and cleaner production strategy have emphasized the introduction of greener agrochemicals using biocompatible and natural sources to maximize crop yield with minimum ecotoxicological effects. Over the last decade, the emergence of nanotechnology as a forefront of interdisciplinary science has introduced nanomaterials as fast-acting plant growth-promoting agents.

RESULTS

Herein, we report the preparation of nanocomposite using chitosan and green tea (CS-GTE NC) as an ecofriendly nanopriming agent to elicit salt stress tolerance through priming imprints. The CS-GTE NC-primed (0.02, 0.04 and 0.06%), hydroprimed and non-primed (control) wheat seeds were germinated under normal and salt stress (150 mM NaCl) conditions. The seedlings developed from aforesaid seeds were used for physiological, biochemical and germination studies. The priming treatments increased protein contents (10-12%), photosynthetic pigments (Chl a (4-6%), Chl b (34-36%), Total Chl (7-14%) and upregulated the machinery of antioxidants (CAT (26-42%), POD (22-43%)) in wheat seedlings under stress conditions. It also reduced MDA contents (65-75%) and regulated ROS production resulting in improved membrane stability. The priming-mediated alterations in biochemical attributes resulted in improved final germination (20-22%), vigor (4-11%) and germination index (6-13%) under both conditions. It reduced mean germination time significantly, establishing the stress-insulating role of the nanocomposite. The improvement of germination parameters validated the stimulation of priming memory in composite-treated seeds.

CONCLUSION

Pre-treatment of seeds with nanocomposite enables them to counter salinity at the seedling development stage by means of priming memory warranting sustainable plant growth and high crop productivity.

Safety achievement and shelf-life prolongation of poultry breast meats by polylactic acid active packaging and gamma-irradiation

Active packaging incorporated with volatile oils is a promising technology to extend the shelf-life of perishable food. Therefore, the present work aimed at producing composite pouches based on polylactic acid incorporated with a mixture of lemongrass and cumin essential oils (PLA/mix oil). The effect on the shelf-life of fresh poultry breasts was determined on samples packaged in the PLA/mix oil alone and in combination with gamma-irradiation, and stored under refrigeration through microbiological, physicochemical, and sensorial analyses. The effect of active packaging and gamma-irradiation on artificially inoculated foodborne bacteria (Escherichia coli O157:H7 ATCC 25922, Salmonella Enteritidis, Listeria monocytogenes ATCC 35152) in poultry breasts was evaluated. When compared to control, poultry breast samples packaged in the PLA/mix oil and irradiated at 4 kGy alone decreased microbial count, maintained colour and pH values, and increased TBARS index at a lower rate, thus extended the shelf-life by 21 and 14 d, respectively. However, the combination of PLA/mix oil and gamma-irradiation at 2 kGy (PLA/mix oil + 2 kGy) was more effective in decreasing all microbial counts and extending the shelf-life by more than 28 d. Initial load of S. Enteritidis, E. coli, and L. monocytogenes inoculated in poultry breasts decreased by 3.03, 2.98, and 3.19 log CFU/g, respectively, after 3 d of storage in PLA/mix oil packaging, while the combination between PLA/mix oil and gamma-irradiation at 2 kGy (PLA/mix oil + 2 kGy) caused a synergistic impact with an increase in radiosensitivity of S. Enteritidis, E. coli, and L. monocytogenes by 3.53, 4.47, and 4.23 log CFU/g, respectively, after one day of storage as compared to the control. Active packaging (PLA/mix oil) alone and in combination with gamma-irradiation can be considered an innovative technology that could have a major effect on the prolongation of shelf-life and safety of poultry breast meats. Moreover, this new technology represents a promising alternative to commercial and unsustainable plastic films.

A review of multilayer and composite films and coatings for active biodegradable packaging

Active biodegradable packaging are being developed from biodegradable biopolymers which may solve the environmental problems caused by petroleum-based materials (plastics), as well as improving the shelf life, quality, nutritional profile, and safety of packaged food. The functional performance of active ingredients in biodegradable packaging can be extended by controlling their release profiles. This can be achieved by incorporating active ingredients in sandwich-structured packaging including multilayer and composite packaging. In multilayer materials, the release profile can be controlled by altering the type, structure, and thickness of the different layers. In composite materials, the release profile can be manipulated by altering the interactions of active ingredients with the surrounding biopolymer matrix. This article reviews the preparation, properties, and applications of multilayer and composite packaging for controlling the release of active ingredients. Besides, the basic theory of controlled release is also elaborated, including diffusion, swelling, and biodegradation. Mathematical models are presented to describe and predict the controlled release of active ingredients from thin films, which may help researchers design packaging materials with improved functional performance.