Improved sustained-release properties of ginger essential oil in a Pickering emulsion system incorporated in sodium alginate film and delayed postharvest senescence of mango fruits

Enhancing the antioxidant properties and compatibility of protein/sodium alginate film by incorporating Zanthoxylum bungeanum essential oil Pickering emulsion

Zanthoxylum bungeanum essential oil (ZBEO) Pickering emulsion was incorporated into rice protein (RP)/sodium alginate (SA)-based film to enhance the antioxidant activity and compatibility. With increasing ZBEO content from 2 % to 4 %, the average size of ZBEO Pickering emulsion ranged from 124.28 to 165.65 nm. The best mechanical property with a tensile strength of 14.56 MPa and hydrophobicity with a water vapor permeability of 2.11 × 10-12 g⋅cm-1⋅s-1⋅Pa-1 of emulsion film were achieved with 0.8 % ZBEO. In addition, the loss of ZBEO in the emulsion films was reduced by 11-14 %. The DPPH radical scavenging activity of emulsion film with 1.2 % ZBEO was 65.54 % in 95 % ethanol. The results of Fourier transform infrared spectroscopy and molecular dynamics simulation showed that electrostatic interactions played a leading role in film formation. Overall, ZBEO Pickering emulsion is an effective method to enhance the antioxidant activity, mechanical strength and hydrophobicity of RP/SA film.

Carboxymethyl cellulose/gelatin film incorporated with eggplant peel waste-derived carbon dots for active fruit packaging applications

Carbon dots (CDs) were derived using eggplant peel by a hydrothermal approach and incorporated into the carboxymethyl cellulose (CMC) and gelatin (Gel) blend to develop sustainable and functional packaging films for fruit preservation. The CD was uniformly dispersed within the CMC/Gel blend to form a dense and continuous film and fashioned a strong interaction with the polymer chain, increasing the tensile strength of the film by 5.0-16.0 %. Also, with the impregnation of CDs, the UV-blocking potential of the CMC/Gel film was greatly improved to the extent of blocking 94.3 % of UV-B and 72.5 % of UV-A, while the water vapor permeability slightly decreased (by 2.7-5.4 %), and the water contact angle of the film marginally expand (by 6.2-19.1 %). The CMC/Gel film with 3 wt% of CD added depicted strong antioxidant efficacy of 100 % against ABTS and 59.1 % against DPPH and displayed strong antibacterial action that inhibited the progress of Listeria monocytogenes and Escherichia coli by 99.8 %. In addition, when table grapes were packaged using a CMC/Gel composite film containing CD and stored at 4 °C for 24 days, the fruits packed with the composite film maintained excellent external quality and extended the shelf life.

Preparation of Fresh-Keeping Paper Using Clove Essential Oil through Pickering Emulsion and Maintaining the Quality of Postharvest Cherry Tomatoes

This study focused on developing a Pickering emulsion fresh-keeping paper that contained clove essential oil (CEO). Cherry tomatoes served as the test material for assessing the preservative efficacy of fresh-keeping paper. The results showed that Pickering emulsion had strong stability. Additionally, the fresh-keeping paper had a good antioxidant activity and sustained-release effect on CEO. In terms of the preservation effect, 0.75 wt% CEO Pickering emulsion paper reduced the decay incidence and weight loss of cherry tomatoes during 12-day storage. Fresh-keeping paper could also play a positive role in protecting the sensory index and color difference of tomatoes. It slowed the decline rate of soluble solid concentration (SSC) and titrable acid (TA). The vitamin C (Vc) and hardness of preserved tomatoes using fresh-keeping paper were maintained at a high level. The paper also inhibited the growth of microorganisms significantly. Therefore, 0.75 wt% CEO Pickering emulsion fresh-keeping paper displayed considerable potential for application in the preservation of postharvest fruits and vegetables. It is a novel fruit and vegetable preservation material worthy of development.

Effect of clove essential oil nanoemulsion on physicochemical and antioxidant properties of chitosan film

This study evaluated the physicochemical and antioxidant properties of clove essential oil (0, 0.2, 0.4, 0.6, 0.8, 1.0 % v/v) nanoemulsion (CEON) loaded chitosan-based films. With the increasing concentrations of the CEON, the thickness, b* and ΔE values of the films increased significantly (P < 0.05), while L* and light transmission dropped noticeably (P < 0.05). The hydrogen bonds formed between the CEON and chitosan could be demonstrated through Fourier-transform infrared spectra, indicating their good compatibility and intermolecular interactions. Furthermore, the added CEON considerably reduced the crystallinity and resulted in a porous structure of the films, as observed through X-ray diffraction plots and scanning electron microscopy images, respectively. This eventually led to a drop in both tensile strength and moisture content of the films. Moreover, the antioxidant properties were significantly enhanced (P < 0.05) with the increase in the amount of clove essential oil (CEO) due to the encapsulation of CEO by the nanoemulsion. Films containing 0.6 % CEO had higher elongation at break, higher water contact angle, lower water solubility, lower water vapor permeability, and lower oxygen permeability than the other films; therefore, such films are promising for application in meat preservation.

Nanoscale Pickering emulsion food preservative films/coatings: Compositions, preparations, influencing factors, and applications

Pickering emulsion (PE) technology effectively addresses the issues of poor compatibility and low retention of hydrophobic active ingredients in food packaging. Nonetheless, it is important to recognize that each stage of the preparation process for PE films/coatings (PEFCs) can significantly influence their functional properties. With the fundamental considerations of environmental friendliness and human safety, this review extensively explores the potential of raw materials for PEFC and introduces the preparation methods of nanoparticles, emulsification technology, and film-forming techniques. The critical factors that impact the performance of PEFC during the preparation process are analyzed to enhance food preservation effectiveness. Moreover, the latest advancements in PE packaging across diverse food applications are summarized, along with prospects for innovative food packaging materials. Finally, the preservation mechanism and application safety have been systematically elucidated. The study revealed that the PEFCs provide structural flexibility, where designable nanoparticles offer unique functional properties for intelligent control over active ingredient release. The selection of the dispersed and continuous phases, along with component proportions, can be customized for specific food characteristics and storage conditions. By employing suitable preparation and emulsification techniques, the stability of the emulsion can be improved, thereby enhancing the effectiveness of the films/coatings in preserving food. Including additional substances broadens the functionality of degradable materials. The PE packaging technology provides a safe and innovative solution for extending the shelf life and enhancing the quality of food products by protecting and releasing active components.