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SEM images of uncoated cellulose sheets (a and b) and cellulose sheets coated with carnauba wax nano (c and d) and microemulsion (e and f)
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The cellulose sheets used in packaging applications depend on the hydrophilic properties of the cellulose fibers. However, the development of hydrophobic cellulose from new sustainable materials obtained from renewable sources is still poorly reported in the literature. Thus, a green method to obtain hydrophobic curaua cellulose sheets was studied....
Citations
... While they exhibit good mechanical properties, they all suffer from a high affinity to water that limits their barrier properties. In line with the aim for biodegradability, vegetable oils or natural waxes 7 have been considered to solve this issue. They pose sustainable alternative hydrophobization to methods like silanizations or coatings with uorinated synthetic polymers like polyvinylideneuoride. ...
Coating paper with polymers is an efficient way of awarding it with gas-tightness and moisture protection in food packaging applications, but it impedes the recyclability of the both paper and polymer. Cellulose nanocrystals were found to be excellent gas barrier materials, but their hydrophilicity forbids their straightforward application as protective coatings. To introduce hydrophobicity into a CNC coating, this work exploited the capability of cationic CNCs isolated in a one-step treatment with a eutectic medium to stabilize Pickering emulsions in order to include a natural drying oil in a dense layer of CNCs. This way, a hydrophobic coating with improved water vapor barrier properties was achieved.
... This is because most natural waxes are made up of ester groups which can be broken down, unlike the presence of a hydrocarbon chain in the paraffin wax. For hydrophobic paper coatings, many waxes have been explored in the past, such as Carnauba wax [31], Candelilla wax [32], Soy wax [33], and Rice Bran wax [32], which are examples of plant-based wax. On the other hand, Beeswax and Wool wax are insect and animal-based wax, respectively, which have been studied extensively [13,34,35]. ...
In this study, insect waxes (Beeswax and Shellac wax) were spray-coated onto paper, cups, and bowls to achieve
surface hydrophobicity for packaging applications. The thin coatings of wax mixtures with different ratios of
waxes were employed at various annealing temperatures and studied in detail for the thermal, chemical, surface,
and barrier properties of 20 coated papers. SEM confirmed the presence of multi-structured wax particles on the
surface of coated papers only when annealed up to 80 ◦C (at 100 ◦C complete melting of wax particles occurred),
where increasing Shellac wax in the wax mixtures resulted in large aggregates of wax particles on the paper. FTIR
confirmed Beeswax with shorter fatty acid chains, comparing Shellac wax with longer fatty acid chains. Addi-
tionally, DSC confirmed a lower melting point for Beeswax, comparing Shellac wax with the higher melting
point. The robustness of waxes after annealing was evident from the tape and crinkle tests. The spray-coated
paper with insect wax mixture showed good repellency towards different food simulants, such as water, acetic
acid, ethanol, octane, and several food products, as measured using contact angles. Lowered water absorption
was noted for coated pulp-based bowls. The coating also showed self-cleaning or anti-fouling properties.
... However, in the last 10 years, this scenario has changed, and in addition to the contributions to breeding programs, new uses of the germplasm have been explored. Ornamental attributes, plant fibers and bioactive molecules for pharmaceutical purposes have been sought and identified, showing important value aggregation opportunities for the gene pool conserved (Souza et al., 2012, 2014, Sena Neto et al., 2013, Campos et al., 2019, Rodrigues et al., 2000, Paixão et al., 2021, Pereira et al., 2022, Cassago et al., 2022. ...
The Active Pineapple Germplasm Bank (Pineapple AGB) of Embrapa Cassava & Fruits (Embrapa/ CNPMF) has more than 700 accessions under field conditions. As backups, there are copies kept in a greenhouse, with one or two plants per accession, cultivated in plastic pots with commercial substrate. An in vitro gene bank was established in 2003, and during the past few years, several studies have been carried out to improve the in vitro conservation protocol. Currently, about 60% of the AGB’s accessions are preserved by this protocol. Another conservation strategy used is cryopreservation of shoot tips and pollen grains, with well-defined methods. One of the most significant advances in the pineapple germplasm conservation has been the implementation of a quality control system, which enabled to define standard operation procedures (SOP) towards a more efficient and safer germplasm conservation.
... Further carnauba wax micro and nano-emulsion with ammonium and dimethylpolysiloxane were coated on paper sheets by dip method, resulting in a contact angle of 50° to 75°. It further reduces WVTR by a 3.55 factor [177]. These emerging materials have proven themselves as reliable coating solution. ...
Packaging for liquid products is mainly made from petroleum-based polymers, either rigid or flexible. The multilayer packaging provides small and handy packs available for the common masses. However, an alternative bio-sourced material for liquid products is urgently needed due to the limitation of fossil fuel, restrictions from environmental regulations, and its non-biodegradable nature. Paper is used as a packaging material that mainly provides structural strength to the package with some barrier properties if required after suitable surface treatment. Here we review the use of lignocellulosic pulp to produce paper-based sachets and paper bottles for liquid product packaging, emphasizing the detailed manufacturing process. The barrier properties of various conventional polymers and barriers required by a specific liquid product package are also discussed and detailed, as a barrier is required to increase further or maintain the product’s shelf-life. Current research and new product development at an industrial scale and their materials are critically discussed. Suitable coating materials on paper sheets and paper bottles are detailed, as paper alone cannot be used for liquid products due to wettability in the hydrophilic region and poor barrier properties. The potential of biopolymers like polylactic acid, polyhydroxyalkanoates, and their nanocomposites are further explored to ensure the package’s sustainability compared to conventional polymers. Moreover, the emerging biomaterial such as cellulose fatty ester, cellulose nanopaper, waterborne acrylic emulsion, and natural wax-based dispersion for coating on paper packaging is detailed. Furthermore, the barrier, mechanical properties, and finally, recyclability are a concept taken into account from the design phase onwards.
Graphical Abstract
... 7,11−13 Some studies have shown the potential of PALFs to produce polymer composites, 14−16 nanocomposites, 17−20 electronic devices, 21 and nanopapers by continuous casting with intrinsic mechanical property characteristics. 22,23 A recent study demonstrated the potential of PALFs for the production of hydrophobic cellulose sheets with micro-and nanoemulsions of carnauba wax, 24 aiming to reduce problems caused by high water vapor permeation and hydrophilicity of cellulose fibers. 24−30 The fiber structure has also been explored for water retention and controlled release of fertilizers, such as nitrogen (N), phosphorus (P), and potassium (K), for better development of seeds and seedlings, thus generating plants with greater stem height and number and size of leaves. ...
... For hydrophobization of the cellulose sheet tubes, each functionalized tube was coated with nanoemulsion of carnauba wax using a hand sprayer. For comparative purposes, the sheet tubes without fertilizers were coated with microor nanoemulsion of carnauba based on the results reported by Campos et al. 24 (2019). The micro-and nanoemulsions of carnauba wax were prepared according to the method reported in the literature using carnauba biomass, palm oleic acid (P.A.), ammonium hydroxide (NH 4 OH), and dimethylpolysiloxane (C 2 H 6 OSi) n . ...
... Furthermore, the TGA/DTG curves of fertilized and covered sheets demonstrated less mass loss due to water vaporization between 90 and 120°C. This result indicated that covered sheets with carnauba emulsion presented more hydrophobic character than uncoated sheets reaching a maximum contact angle of 80°, as reported by Campos et al. 24 (2019), which can guarantee greater physical stability of the tubes in a damp soil environment. However, as seen by flame atomic absorption spectroscopy, the hydrophobic character of the sheets after coating did not inhibit the controlled release of nutrients in the aqueous medium. ...
Agricultural products such as seedling tubes are often made of nondegradable petroleum-based polymers. Little progress has been made in developing sustainable and active supports for seedling cultivation that enable acclimatization time reduction of certain seedlings. Thus, the aim of this work was to manufacture multimodal sheet tubes functionalized with fertilizers and hydrophobized with carnauba emulsion for pineapple seedling cultivation. Energy dispersive spectroscopy and flame atomic absorption spectrometry demonstrated the fibers' homogeneous distribution and efficient release of nutrients. As a proof-of-concept, these tubes provided better development of pineapple seedlings in comparison to the control, increasing the number, length, and width of the seedlings' leaves by more than 15%, 40%, and 50%, respectively. The coating with carnauba emulsion guaranteed the physical integrity of sheet tubes in the greenhouse until their planting. These findings may pave the way for a new alternative of sustainable agricultural supports for seedling cultivation.
... AA and CNCs were used directly in the preparation of the nanocomposite coatings. The CWN (droplet size: 39.3 ± 0.7 nm; zeta potential: − 40.32 ± 1.0 mV) was prepared as described by Campos et al. [17]. The nanoemulsion was characterized in a previous study performed by our group [15]. ...
This study investigated the effects of bio-nanocomposite coatings developed using arrowroot starch (AA), cellulose nanocrystals (CNC), carnauba wax nanoemulsion (CWN), and Cymbopogon martinii and Mentha spicata essential oils (CEO and MEO, respectively) on the physicochemical, microbiological, bioactive, antioxidant, and aromatic characteristics of strawberries cv. ‘Oso Grande’ in refrigerated storage for 12 days. The coatings improved the shelf life and stability of strawberries, minimizing their weight loss (2.6–3.9 %), as well as changes in color and texture (except for those coated with CEO), titratable acidity, pH, soluble solids, anthocyanins, phenolic compounds, ascorbic acid content, and antioxidant activity compared with uncoated control strawberries. The bio-nanocomposite coatings containing MEO and CEO also exhibited antimicrobial activity, reduced visible fungal deterioration (40–60 %), and reduced microbial load (3.59–4.03 log CFU g⁻¹ for mesophilic aerobic bacteria and 4.45–5.22 log CFU g⁻¹ for fungi and yeast) during storage. They also significantly reduced the severity of decay caused by inoculation with Botrytis cinerea or Rhizopus stolonifer. The coatings altered the volatile profile of the fruits during storage, decreasing aldehyde and alcohol concentrations and increasing ester concentrations. Thus, these bio-nanocomposite coatings, especially those containing MEO, can be used as antimicrobial coating materials to preserve the post-harvest quality of fresh strawberries.
... Nanoemulsion technology has the advantage of precisely controlling the size distribution of nanoparticles (Silva, Cerqueira, & Vicente, 2012). With high-speed and ultrasonic homogenization, the size distribution of wax nanoparticles can be regulated at the nanoscale (1-100 nm) (de Campos et al., 2019;de Castro e Silva et al., 2020). Carnauba wax is a nontoxic natural wax from the leaves of the Copernicia prunifera palm, and its relatively high melting point (82-86 • C) contributes to its usage in bionanocomposites (de Castro e Silva et al., 2020). ...
... Size regulation (1-100 nm) of carnauba wax nanoparticles was expected to influence the barrier properties of starch-based nanocomposite films. Moreover, in contrast to MMT, CNC and SNC, the hydrophobicity of carnauba wax reduced water vapor absorption on the surface of the starch-based film (de Campos et al., 2019). ...
Barrier properties against water vapor and oxygen were critical for starch-based nanocomposite film. In this study, size regulation of carnauba wax nanoparticle was utilized to adjust multi-scale structure of starch-based film, which intended to improve barrier properties. CW70 with 73.8 nm nanoparticle showed less disrupted starch hydrogen bonding, more ordered double helices, higher starch crystallinity and larger size of micro-ordered region compared with other nanocomposites. These changes of multi-scale structure of CW70 led to the lowest relative water vapor permeability (WVP, 0.86) and oxygen permeability (OP, 0.49) among all nanocomposites. Notably, water vapor could form new hydrogen bonding with starch, and the ratio of amorphous region was significantly negative correlated with WVP. Cohesive energy density was the determining factor for OP, and significant negative correlation was found between the size of micro-ordered region and OP. New knowledge from this study will advance the understanding of starch-based nanocomposite film barrier properties.
... Carnauba wax found in carnauba palms, native to Brazil, melts around 90°C. It demonstrates elasticity and deformation resistance and has a relatively lower viscosity, which helps facilitate its application process (Lacerda et al., 2011;de Campos et al., 2019). Wang et al. (2017) fabricated hydrophobic filter paper using carnauba wax/ hexadecyltrimethoxysilane-(HDTMS-) TiO 2 emulsions using alcohol to separate water and diesel. ...
Due to the inherent hydrophilic nature and porosity of the paper fibers, hydrophobic polymeric materials, waxes, and inorganic fillers have been widely utilized as coatings and fillers, respectively, on a fiber-based substrate. Coatings also impart oxygen, aroma, and oil barrier properties desirable for food packaging applications. In addition, coatings improve the functional properties and characteristics of paper, including reduced water absorbance, enhanced surface finish, gloss finish, printability, readability, dimensional stability of the substrate, and antimicrobial performance. Such functional properties are highly desirable for consumer packaging applications. However, such coatings may limit the repulpability, recyclability, biodegradability, and compostability of paper and paperboard. In addition, the contamination of the substrate by-product also limits the recyclability of the fiber-based substrates, and the paper, paperboard, or corrugated material ends up in landfill sites. This review focuses on bioderived, biodegradable, compostable, and functional organic, inorganic, and hybrid hydrophobic coatings, which promote the circular economy by improving the repulpability or reduces carbon footprints.
... The hydrophobic surface provides waterproof and self-cleaning functions for plants [25,26], which provides a novel strategy for preparing CRF that employs biological wax to modify the physical and chemical properties of the polyacrylate coating surface for polyacrylate-coated fertilizer. Biological wax is a mixture of hydrophobic compounds derived from plant cuticles, seed coatings, or insects' secretion [27], and Carnauba wax (CW), derived from the leaves of the Copernicus tree [28], not only has strong hydrophobic ability, but also has good performance in adhesion and friction resistance compared with other biological waxes. It is mainly composed of about 80% long-chain wax esters and the remaining 20% is composed of fatty acids, fatty alcohols, and hydrocarbons [29,30]. ...
Benefitting from the special structure of the leaf cuticle layer, plants have natural hydrophobicity and anti-fouling abilities. Inspired by the leaf surface structure, a biomimetic modification strategy was raised to improve the surface hydrophobicity of polyacrylate coating for controlled release fertilizer. Double-layer (polyacrylate and carnauba wax) coated fertilizer was obtained after biomimetic modification. The quality of controlled release fertilizer modified with the carnauba wax was greatly enhanced, and the coating material was effectively saved. The surface appearance of polyacrylate-coated fertilizer was improved for the surface blemish was repaired by the loaded carnauba wax. The characterizations by Fourier transform infrared spectroscopy indicated that the hydrogen bonds were formed between the water-based polyacrylate membrane and the carnauba wax layers. By optimizing the content of polyacrylate and carnauba wax, the release duration of the fertilizer was effectively prolonged, which was improved from 1 month to more than 2 months after the biomimetic modification. Therefore, biological wax as an environmentally-friendly natural material that has showed a broad potential in the application of coated controlled release fertilizer.
... Curcumin incorporation as a bioactive agent in functional-edible-films or -coatings has attracted interest because of the potential health benefits (Figure 4). Substantial in vitro studies have been carried out using curcumin in edible films, exhibiting an increase in their antioxidant properties (Table 1) [21,36,44,[91][92][93]. Roy and Rhim et al. [44] reported that the incorporation of curcumin in poly(lactic acid)-based films increased the antioxidant activity evaluated by the DPPH and ABTS methods from 1.8% and 3.1 to 76.6% and 94.7%, respectively, by the addition of 1.5% curcumin by weight. ...
Edible packaging has been developed as a biodegradable and non-toxic alternative to traditional petroleum-based food packaging. Biopolymeric edible films, in addition to their passive protective function, may also play a bioactive role as vehicles for bioactive compounds of importance to human health. In recent years, a new generation of edible food packaging has been developed to incorporate ingredients with functional potential that have beneficial effects on consumer health. Curcumin, a bioactive compound widely used as a natural dye obtained from turmeric rhizomes (Curcuma longa L.), has a broad spectrum of beneficial properties for human health, such as anti-inflammatory, anti-hypertensive, antioxidant, anti-cancer, and other activities. To demonstrate these properties, curcumin has been explored as a bioactive agent for the development of bioactive packaging, which can be referred to as functional packaging and used in food. The aim of this review was to describe the current and potential research on the development of functional-edible-films incorporating curcumin for applications such as food packaging.
