Preparation of black cumin seed oil Pickering nanoemulsion with enhanced stability and antioxidant potential using nanocrystalline cellulose from oil palm empty fruit bunch

Preparation and functionalization of cellulose nanofibers using a naturally occurring acid and their application in stabilizing linseed oil/water Pickering emulsions

Finding efficient and environmental-friendly methods to produce and chemically modify cellulose nanofibers (CNFs) remains a challenge. In this study, lactic acid (LA) treatment followed by microfluidization was employed for the isolation and functionalization of CNFs. Small amounts of HCl (0.01, 0.1, and 0.2 M) were used alongside LA to intensify cellulose hydrolysis. FTIR spectroscopy and solid-state 13C NMR confirmed the successful functionalization of CNFs with lactyl groups during isolation, while SEM, AFM, and rheological tests revealed that the addition of HCl governed the fibers' sizes and morphology. Notably, the treatment with LA and 0.2 M HCl resulted in a more efficient defibrillation, yielding smaller nanofibers sizes (62 nm) as compared to the treatment with LA or HCl alone (90 and 108 nm, respectively). The aqueous suspension of CNFs treated with LA and 0.2 M HCl showed the highest viscosity and storage modulus. LA-modified CNFs were tested as stabilizers for linseed oil/water (50/50 v/v) emulsions. Owing to the lactyl groups grafted on their surface and higher aspect ratio, CNFs produced with 0.1 and 0.2 M HCl led to emulsions with increased stability (a creaming index increase of only 3 % and 1 %, respectively, in 30 days) and smaller droplets sizes of 23.4 ± 1.2 and 35.5 ± 0.5 μm, respectively. The results showed that LA-modified CNFs are promising stabilizers for Pickering emulsions.

Cinnamaldehyde-enriched Pickering emulsions stabilized by modified cellulose I and II nanocrystals recycled from maple leaves for shrimp preservation

The utilization of biomass waste has attracted much interest, but such attention hasn't been paid to the abundant fallen maple leaves in Canada. Herein, we aim to obtain cellulose nanocrystals (CNCs) from maple leaves and explore their potential applications as sustainable stabilizers of Pickering emulsions for the preservation of food products with complicated structures. The results reveal that two types of CNCs were extracted from maple leaves at different alkaline conditions. Octenyl succinic anhydride was selected to modify rod-like CNCs, and the CNC-stabilized oil-in-water Pickering emulsions showed excellent stability. Cinnamaldehyde, a model antibacterial compound, was incorporated in the Pickering emulsions, which exhibited the improved storage stability and sustained antibacterial capacity towards both Gram-positive and Gram-negative bacteria. Shrimp was chosen as an example that has complicated surface structure and is hard to disinfect, and the CNC-stabilized Pickering emulsions could be easily sprayed on the surface of shrimp to inhibit the proliferation of bacteria and inactivate the psychrophilic bacteria responsible for shrimp spoilage at refrigerated condition, so as to preserve the quality of shrimp. Therefore, the current work suggests the possibility to utilize fallen maple leaves as a promising source of CNCs and the applications of CNC-stabilized Pickering emulsions in seafood preservation.

Characterization of coconut milk waste nanocellulose based curcumin-enriched Pickering nanoemulsion and its application in a blended beverage of defatted coconut milk and pineapple juice

In this study, we aimed to develop a blended beverage enriched with curcumin. The curcumin was incorporated within a Pickering nanoemulsion that was stabilized with nanocellulose. The nanocellulose was synthesized from coconut milk waste residue using 38 %-42 % sulfuric acid (AC) and 5 and 10 min ultrasound (UL) separately and in combination (ACU). While combined treatment showed an increase in particle size with ultrasonication time, PDI was observed to decrease. ACU with 10 min ultrasonication was further used at 0.05 %, 0.1 %, 0.2 %, and 0.3 % for stabilization of curcumin enriched Pickering nanoemulsion. The curcumin in Pickering nanoemulsion fabricated with 0.1 % of nanocellulose with an average particle size and PDI value of 259.6 nm and 0.284, respectively was found to be the most stable as compared to other Pickering nanoemulsions at different pH levels and temperatures. RP-HPLC analysis revealed that with 0.1 % of nanocellulose, the Pickering nanoemulsion was most stable at 2 pH and 63 °C temperatures. The in vitro release of curcumin from Pickering nanoemulsion added to a blended beverage in intestinal phase was 51.58 %, which was higher than the stomach phase (38.19 %). The outcomes clearly showed Pickering nanoemulsion to be a promising carrier for curcumin encapsulation in beverage.

Current advances of nanocellulose application in biomedical field

Nanocellulose (NC) is a natural fiber that can be extracted in fibrils or crystals form from different natural sources, including plants, bacteria, and algae. In recent years, nanocellulose has emerged as a sustainable biomaterial for various medicinal applications including drug delivery systems, wound healing, tissue engineering, and antimicrobial treatment due to its biocompatibility, low cytotoxicity, and exceptional water holding capacity for cell immobilization. Many antimicrobial products can be produced due to the chemical functionality of nanocellulose, such disposable antibacterial smart masks for healthcare use. This article discusses comprehensively three types of nanocellulose: cellulose nanocrystals (CNC), cellulose nanofibrils (CNF), and bacterial nanocellulose (BNC) in view of their structural and functional properties, extraction methods, and the distinctive biomedical applications based on the recently published work. On top of that, the biosafety profile and the future perspectives of nanocellulose-based biomaterials have been further discussed in this review.

Harnessing Nature's Ingenuity: A Comprehensive Exploration of Nanocellulose from Production to Cutting-Edge Applications in Engineering and Sciences

Primary material supply is the heart of engineering and sciences. The depletion of natural resources and an increase in the human population by a billion in 13 to 15 years pose a critical concern regarding the sustainability of these materials; therefore, functionalizing renewable materials, such as nanocellulose, by possibly exploiting their properties for various practical applications, has been undertaken worldwide. Nanocellulose has emerged as a dominant green natural material with attractive and tailorable physicochemical properties, is renewable and sustainable, and shows biocompatibility and tunable surface properties. Nanocellulose is derived from cellulose, the most abundant polymer in nature with the remarkable properties of nanomaterials. This article provides a comprehensive overview of the methods used for nanocellulose preparation, structure-property and structure-property correlations, and the application of nanocellulose and its nanocomposite materials. This article differentiates the classification of nanocellulose, provides a brief account of the production methods that have been developed for isolating nanocellulose, highlights a range of unique properties of nanocellulose that have been extracted from different kinds of experiments and studies, and elaborates on nanocellulose potential applications in various areas. The present review is anticipated to provide the readers with the progress and knowledge related to nanocellulose. Pushing the boundaries of nanocellulose further into cutting-edge applications will be of particular interest in the future, especially as cost-effective commercial sources of nanocellulose continue to emerge.

Food-Grade Oil-in-Water (O/W) Pickering Emulsions Stabilized by Agri-Food Byproduct Particles

In recent years, emulsions stabilized by solid particles (known as Pickering emulsions) have gained considerable attention due to their excellent stability and for being environmentally friendly compared to the emulsions stabilized by synthetic surfactants. In this context, edible Pickering stabilizers from agri-food byproducts have attracted much interest because of their noteworthy benefits, such as easy preparation, excellent biocompatibility, and unique interfacial properties. Consequently, different food-grade particles have been reported in recent publications with distinct raw materials and preparation methods. Moreover, emulsions stabilized by solid particles can be applied in a wide range of industrial fields, such as food, biomedicine, cosmetics, and fine chemical synthesis. Therefore, this review aims to provide a comprehensive overview of Pickering emulsions stabilized by a diverse range of edible solid particles, specifically agri-food byproducts, including legumes, oil seeds, and fruit byproducts. Moreover, this review summarizes some aspects related to the factors that influence the stabilization and physicochemical properties of Pickering emulsions. In addition, the current research trends in applications of edible Pickering emulsions are documented. Consequently, this review will detail the latest progress and new trends in the field of edible Pickering emulsions for readers.

Acetylated lignin from oil palm empty fruit bunches and its electrospun nanofibres with PVA: Potential carbon fibre precursor

The electrospinning of acetylated lignin/polyvinyl alcohol (PVA) nanofibres was carried out to expand the application of lignin materials obtained from oil palm empty fruit bunches (OPEFB). Lignin was isolated by the steam explosion method and subsequently precipitated using H₂SO₄. Acetylated lignin was produced by mixing acetic anhydride and pyridine at a 2:1 v/v ratio. Following the acetylation process, FTIR analysis showed the absorption of the C=O carbonyl group at wavenumber 1714.6 cm^-1. The chemical structures of isolated and acetylated lignin were established using ¹H NMR spectral analysis, and XRD examination demonstrated their amorphous character. The electrospinning process of acetylated lignin and PVA solution was then carried out at 15 kV voltage, 0.8 mL/h flow rate, and 12 cm distance between the needle and collector. The sample exhibited electrical conductivity of 443 μS/cm and viscosity of 2.8 × 10^-3 Pa s. The morphology analysis showed that there were more beads on the surface of lignin/PVA nanofibres than acetylated lignin/PVA nanofibres. In addition, acetylated lignin/PVA nanofibre was more stable than lignin/PVA. The G-band of carbonized material increased with the presence of lignin. The works presented suggest the potential of using waste materials such as OPEFB as a suitable precursor for the preparation of carbon fibre.

The Use of Corn Stover-Derived Nanocellulose as a Stabilizer of Oil-in-Water Emulsion

Agricultural byproducts such as corn stover are widely available sources for preparation of nanocellulose, which is an emerging green chemical with versatile applications. In this study, corn stover-derived nanocellulose was prepared via bleaching, alkaline treatment, 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) oxidation, and ultrasonication. The as-prepared TEMPO-oxidized cellulose nanofibril (TEMPO-CNF) was characterized by transmission electron microscopy, UV-Vis spectrophotometry, rheometry, and zeta potential measurement. Droplet size, phase behavior, and thermodynamic stability of TEMPO-CNF stabilized oil-in-water emulsions were investigated. Results show that TEMPO-CNF with a width of 4 nm, length of 353 nm, and surface charge of 1.48 mmol/g COO^- can be prepared from corn stover. In addition, TEMPO-CNF can be used as an emulsion stabilizer for lemongrass essential oil loaded oil-in-water emulsion. This study is among the first to report that TEMPO-CNF improved the freeze-thaw stability of oil-in-water emulsions stabilized by small molecular weight surfactants (e.g., Tween 80).

Recent developments in industrial applications of nanoemulsions

Nanotechnology is being utilized in various industries to increase the quality, safety, shelf-life, and functional performance of commercial products. Nanoemulsions are thermodynamically unstable colloidal dispersions that consist of at least two immiscible liquids (typically oil and water), as well as various stabilizers (including emulsifiers, texture modifiers, ripening inhibitors, and weighting agents). They have unique properties that make them particularly suitable for some applications, including their small droplet size, high surface area, good physical stability, rapid digestibility, and high bioavailability. This article reviews recent developments in the formulation, fabrication, functional performance, and gastrointestinal fate of nanoemulsions suitable for use in the pharmaceutical, cosmetic, nutraceutical, and food industries, as well as providing an overview of regulatory and health concerns. Nanoemulsion-based delivery systems can enhance the water-dispersibility, stability, and bioavailability of hydrophobic bioactive compounds. Nevertheless, they must be carefully formulated to obtain the required functional attributes. In particular, the concentration, size, charge, and physical properties of the nano-droplets must be taken into consideration for each specific application. Before launching a nanoscale product onto the market, determination of physicochemical characteristics of nanoparticles and their potential health and environmental risks should be evaluated. In addition, legal, consumer, and economic factors must also be considered when creating these systems.

Nanocarriers for Sustainable Active Packaging: An Overview during and Post COVID-19

Lockdown has been installed due to the fast spread of COVID-19, and several challenges have occurred. Active packaging was considered a sustainable option for mitigating risks to food systems during COVID-19. Biopolymeric-based active packaging incorporating the release of active compounds with antimicrobial and antioxidant activity represents an innovative solution for increasing shelf life and maintaining food quality during transportation from producers to consumers. However, food packaging requires certain physical, chemical, and mechanical performances, which biopolymers such as proteins, polysaccharides, and lipids have not satisfied. In addition, active compounds have low stability and can easily burst when added directly into biopolymeric materials. Due to these drawbacks, encapsulation into lipid-based, polymeric-based, and nanoclay-based nanocarriers has currently captured increased interest. Nanocarriers can protect and control the release of active compounds and can enhance the performance of biopolymeric matrices. The aim of this manuscript is to provide an overview regarding the benefits of released active compound-loaded nanocarriers in developing sustainable biopolymeric-based active packaging with antimicrobial and antioxidant properties. Nanocarriers improve physical, chemical, and mechanical properties of the biopolymeric matrix and increase the bioactivity of released active compounds. Furthermore, challenges during the COVID-19 pandemic and a brief post-COVID-19 scenario were also mentioned.