Inorganic Nanocarriers for Encapsulation of Natural Antimicrobial Compounds for Potential Food Packaging Application: A Comparative Study

Quercetin, a Flavonoid with Great Pharmacological Capacity

Quercetin is a flavonoid with a low molecular weight that belongs to the human diet's phenolic phytochemicals and nonenergy constituents. Quercetin has a potent antioxidant capacity, being able to capture reactive oxygen species (ROS), reactive nitrogen species (RNS), and reactive chlorine species (ROC), which act as reducing agents by chelating transition-metal ions. Its structure has five functional hydroxyl groups, which work as electron donors and are responsible for capturing free radicals. In addition to its antioxidant capacity, different pharmacological properties of quercetin have been described, such as carcinostatic properties; antiviral, antihypertensive, and anti-inflammatory properties; the ability to protect low-density lipoprotein (LDL) oxidation, and the ability to inhibit angiogenesis; these are developed in this review.

Utilizing Imine Bonds to Create a Self-Gated Mesoporous Silica Material with Controlled Release and Antimicrobial Properties

In recent years, silica nanomaterials have been widely studied as carriers in the field of antibacterial activity in food. Therefore, it is a promising but challenging proposition to construct responsive antibacterial materials with food safety and controllable release capabilities using silica nanomaterials. In this paper, a pH-responsive self-gated antibacterial material is reported, which uses mesoporous silica nanomaterials as a carrier and achieves self-gating of the antibacterial agent through pH-sensitive imine bonds. This is the first study in the field of food antibacterial materials to achieve self-gating through the chemical bond of the antibacterial material itself. The prepared antibacterial material can effectively sense changes in pH values caused by the growth of foodborne pathogens and choose whether to release antibacterial substances and at what rate. The development of this antibacterial material does not introduce other components, ensuring food safety. In addition, carrying mesoporous silica nanomaterials can also effectively enhance the inhibitory ability of the active substance.

Nanomaterials-Based Wound Dressing for Advanced Management of Infected Wound

The effective prevention and treatment of bacterial infections is imperative to wound repair and the improvement of patient outcomes. In recent years, nanomaterials have been extensively applied in infection control and wound healing due to their special physiochemical and biological properties. Incorporating antibacterial nanomaterials into wound dressing has been associated with improved biosafety and enhanced treatment outcomes compared to naked nanomaterials. In this review, we discuss progress in the application of nanomaterial-based wound dressings for advanced management of infected wounds. Focus is given to antibacterial therapy as well as the all-in-one detection and treatment of bacterial infections. Notably, we highlight progress in the use of nanoparticles with intrinsic antibacterial performances, such as metals and metal oxide nanoparticles that are capable of killing bacteria and reducing the drug-resistance of bacteria through multiple antimicrobial mechanisms. In addition, we discuss nanomaterials that have been proven to be ideal drug carriers for the delivery and release of antimicrobials either in passive or in stimuli-responsive manners. Focus is given to nanomaterials with the ability to kill bacteria based on the photo-triggered heat (photothermal therapy) or ROS (photodynamic therapy), due to their unparalleled advantages in infection control. Moreover, we highlight examples of intelligent nanomaterial-based wound dressings that can detect bacterial infections in-situ while providing timely antibacterial therapy for enhanced management of infected wounds. Finally, we highlight challenges associated with the current nanomaterial-based wound dressings and provide further perspectives for future improvement of wound healing.

A Review of Regulatory Standards and Advances in Essential Oils as Antimicrobials in Foods

As essential oils (EOs) possess GRAS status, there is a strong interest in their application to food preservation. Trends in the food industry suggest consumers are drawn to environmentally friendly alternatives and less synthetic chemical preservatives. Although the use of EOs has increased over the years, adverse effects have limited their use. This review aims to address the regulatory standards for EO usage in food, techniques for delivery of EOs, essential oils commonly used to control pathogens and molds, and advances with new active compounds that overcome sensory effects for meat products, fresh fruits and vegetables, fruit and vegetable juices, seafood, dairy products, and other products. This review will show adverse sensory effects can be overcome in various products by the use of edible coatings containing encapsulated EOs to facilitate the controlled release of EOs. Depending on the method of cooking, the food product has been shown to mask flavors associated with EOs. In addition, using active packaging materials can decrease the diffusion rate of the EOs, thus controlling undesirable flavor characteristics while still preserving or prolonging the shelf life of food. The use of encapsulation in packaging film can control the release of volatile or active ingredients. Further, use of EOs in the vapor phase allows for contact indirectly, and use of nanoemulsion, coating, and film wrap allows for the controlled release of the EOs. Research has also shown that combining EOs can prevent adverse sensory effects. Essential oils continue to serve as a very beneficial way of controlling undesirable microorganisms in food systems.

Controlled Release of Volatile Antimicrobial Compounds from Mesoporous Silica Nanocarriers for Active Food Packaging Applications

Essential oils and their active components have been extensively reported in the literature for their efficient antimicrobial, antioxidant and antifungal properties. However, the sensitivity of these volatile compounds towards heat, oxygen and light limits their usage in real food packaging applications. The encapsulation of these compounds into inorganic nanocarriers, such as nanoclays, has been shown to prolong the release and protect the compounds from harsh processing conditions. Nevertheless, these systems have limited shelf stability, and the release is of limited control. Thus, this study presents a mesoporous silica nanocarrier with a high surface area and well-ordered protective pore structure for loading large amounts of natural active compounds (up to 500 mg/g). The presented loaded nanocarriers are shelf-stable with a very slow initial release which levels out at 50% retention of the encapsulated compounds after 2 months. By the addition of simulated drip-loss from chicken, the release of the compounds is activated and gives an antimicrobial effect, which is demonstrated on the foodborne spoilage bacteria Brochothrixthermosphacta and the potentially pathogenic bacteria Escherichia coli. When the release of the active compounds is activated, a ≥4-log reduction in the growth of B. thermosphacta and a 2-log reduction of E. coli is obtained, after only one hour of incubation. During the same one-hour incubation period the dry nanocarriers gave a negligible inhibitory effect. By using the proposed nanocarrier system, which is activated by the food product itself, increased availability of the natural antimicrobial compounds is expected, with a subsequent controlled antimicrobial effect.

A Comprehensive Review of the Development of Carbohydrate Macromolecules and Copper Oxide Nanocomposite Films in Food Nanopackaging

Background. Food nanopackaging helps maintain food quality against physical, chemical, and storage instability factors. Copper oxide nanoparticles (CuONPs) can improve biopolymers’ mechanical features and barrier properties. This will lead to antimicrobial and antioxidant activities in food packaging to extend the shelf life. Scope and Approach. Edible coatings based on carbohydrate biopolymers have improved the quality of packaging. Several studies have addressed the role of carbohydrate biopolymers and incorporated nanoparticles to enhance food packets’ quality as active nanopackaging. Combined with nanoparticles, these biopolymers create film coatings with an excellent barrier property against transmissions of gases such as O2 and CO2. Key Findings and Conclusions. This review describes the CuO-biopolymer composites, including chitosan, agar, cellulose, carboxymethylcellulose, cellulose nanowhiskers, carrageenan, alginate, starch, and polylactic acid, as food packaging films. Here, we reviewed different fabrication techniques of CuO biocomposites and the impact of CuONPs on the physical, mechanical, barrier, thermal stability, antioxidant, and antimicrobial properties of carbohydrate-based films.

The Emerging Role of Ionic Liquid-Based Approaches for Enhanced Skin Permeation of Bioactive Molecules: A Snapshot of the Past Couple of Years

Topical and transdermal delivery systems are of undeniable significance and ubiquity in healthcare, to facilitate the delivery of active pharmaceutical ingredients, respectively, onto or across the skin to enter systemic circulation. From ancient ointments and potions to modern micro/nanotechnological devices, a variety of approaches has been explored over the ages to improve the skin permeation of diverse medicines and cosmetics. Amongst the latest investigational dermal permeation enhancers, ionic liquids have been gaining momentum, and recent years have been prolific in this regard. As such, this review offers an outline of current methods for enhancing percutaneous permeation, highlighting selected reports where ionic liquid-based approaches have been investigated for this purpose. Future perspectives on use of ionic liquids for topical delivery of bioactive peptides are also presented.

Natural Clay as a Low-Cost Adsorbent for Crystal Violet Dye Removal and Antimicrobial Activity

This investigation aimed at evaluating the efficiency of micro and nanoclays as a low-cost material for the removal of crystal violet (CV) dye from an aqueous solution. The impacts of various factors (contact time, pH, adsorbent dosage, temperature, initial dye concentration) on the adsorption process have been taken into consideration. Six micro and nanoclay samples were obtained by treating clay materials collected from different locations in the Albaha region, Saudi Arabia. Out of the six tested micro and nanoclays materials, two (NCQ1 and NCQ3) were selected based on the highest adsorption efficiency for complete experimentation. The morphology and structure of the selected micro and nanoclay adsorbents were characterized by various techniques: SEM-EDX, FTIR, XRF, XRD, and ICP-MS. The XRF showed that the main oxides of both nanoclays were SiO₂, Al₂O₃, Fe₂O₃, K₂O, CaO, and MgO, and the rest were impurities. All the parameters affecting the adsorption of CV dye were optimized in a batch system, and the optimized working conditions were an equilibrium time of 120 min, a dose of 30 mg, a temperature of 25 °C, and an initial CV concentration of 400 mg/L. The equilibrium data were tested using nonlinear isotherm and kinetic models, which showed that the Freundlich isotherm and pseudo-second-order kinetics gave the best fit with the experimental data, indicating a physico-chemical interaction occurred between the CV dye and both selected micro and nanoclay surfaces. The maximum adsorption capacities of NCQ1 and NCQ3 adsorbents were 206.73 and 203.66 mg/g, respectively, at 25 °C. The thermodynamic factors revealed that the CV dye adsorption of both micro and nanoclays was spontaneous and showed an exothermic process. Therefore, the examined natural micro and nanoclays adsorbents are promising effective adsorbents for the elimination of CV dye from an aqueous environment.

Essential oils as natural antimicrobials applied in meat and meat products-a review

Meat and meat products are highly susceptible to the growth of micro-organism and foodborne pathogens that leads to severe economic loss and health hazards. High consumption and a considerable waste of meat and meat products result in the demand for safe and efficient preservation methods. Instead of synthetic additives, the use of natural preservative materials represents an interest. Essential oils (EOs), as the all-natural and green-label trend attributing to remarkable biological potency, have been adopted for controlling the safety and quality of meat products. Some EOs, such as thyme, cinnamon, rosemary, and garlic, showed a strong antimicrobial activity individually and in combination. To eliminate or reduce the organoleptic defects of EOs in practical application, EOs encapsulation in wall materials can improve the stability and antimicrobial ability of EOs in meat products. In this review, meat deteriorations, antimicrobial capacity (components, effectiveness, and interactions), and mechanisms of EOs are reviewed, as well as the demonstration of using encapsulation for masking intense aroma and conducting control release is presented. The use of EOs individually or in combination and encapsulated applications of EOs in meat and meat products are also discussed.