Cellulose isolation and core–shell nanostructures of cellulose nanocrystals from chardonnay grape skins

Unveiling structure and performance of tea-derived cellulose nanocrystals

In this study, cellulose was extracted from black tea residues to produce black tea cellulose nanocrystals (BT-CNCs) using an optimized acid hydrolysis method. The structure and performance of BT-CNCs were evaluated. The results showed that the optimal conditions for acidolysis of BT-CNCs included a sulfuric acid concentration of 64 %, a solid-liquid ratio of 1:18 (w/v), a hydrolysis temperature of 45 °C, and a hydrolysis time of 50 min. The optimization process resulted in a 44.8 % increase in the yield of BT-CNCs, which exhibited a crystallinity of 68.57 % and were characterized by the typical cellulose I structure. The diameters of the particles range from 5 to 45 nm, and they exhibit aggregation behavior. Notably, BT-CNCs demonstrated excellent storage stability, and the Tyndall effect occurred when exposed to a single beam of light. Although the thermal stability of BT-CNCs decreased, their primary thermal degradation temperature remained above 200 °C. The colloidal nature of BT-CNCs was identified as a non-Newtonian fluid with "shear thinning" behavior. This study introduces a novel method to convert tea waste into BT-CNCs, increasing the yield of BT-CNCs and enhancing waste utilization. BT-CNCs hold promise for application in reinforced composites, offering substantial industrial value.

Pickering emulsions stabilized by cellulose nanocrystals extracted from hazelnut shells: Production and stability under different harsh conditions

Cellulose nanocrystals (CNCs) are biodegradable particles that have emerged as promising stabilizers for Pickering emulsions. This study investigated the effectiveness of CNCs in forming the Pickering emulsion from hazelnut shells (HS), an agricultural waste. Following the alkaline and bleaching treatments applied to HS, CNCs were obtained from treated hazelnut shell with acid hydrolysis. The physicochemical characteristics of CNCs were investigated using dynamic light scattering, XRD, FTIR, SEM, and TEM. A high crystalline (69.6 %) CNCs with a spherical shape were obtained. Contact angle and interfacial tension tests were conducted and showed that CNCs had amphiphilic nature. Pickering emulsions were investigated for their size, zeta potential, and stability under varying CNC concentrations. The results showed that when CNCs concentration increased from 0.5 to 2.0 wt%, droplet diameter decreased approximately 1.8 times and zeta potential increased. Creaming was not observed during 28 days of storage in a concentration of 2.0 wt% CNCs. The CNC stabilized emulsions exhibited high stability within a range of pH, temperatures, and salt concentrations. This study demonstrated that CNCs extracted from HS as environmentally friendly and cost-effective materials, could serve as a new stabilizer for Pickering emulsions especially for high temperature and low pH sensitive products such as mayonnaise.

Preparation and Characterization of Soluble Dietary Fiber Edible Packaging Films Reinforced by Nanocellulose from Navel Orange Peel Pomace

The packaging problem with petroleum-based synthetic polymers prompts the development of edible packaging films. The high value-added reuse of navel orange peel pomace, which is rich in bioactive compounds, merited more considerations. Herein, nanocellulose (ONCC) and soluble dietary fiber (OSDF) from navel orange peel pomace are firstly used to prepare dietary fiber-based edible packaging films using a simple physical blend method, and the impact of ONCC on the film's properties is analyzed. Adopting three methods in a step-by-step approach to find the best formula for edible packaging films. The results show that dietary-fiber-based edible packaging films with 4 wt.% ONCC form a network structure, and their crystallinity, maximum pyrolysis temperature, and melting temperature are improved. What's more, dietary-fiber-based edible packaging films have a wide range of potential uses in edible packaging.

Nanoencapsulation of oregano essential oil using cellulose nanocrystals extracted from hazelnut shell to enhance shelf life of fruits: Case study: Pears

This study aimed to investigate the potential application of cellulose nanocrystals (CNCs) extracted from an agricultural waste for encapsulation of oregano essential oil (OEO) and subsequently their use for coating to improve the shelf life of pears as a model. By hydrolyzing hazelnut shell cellulose under the optimum conditions, high crystalline CNCs with a zeta potential of -67.8 ± 4.4 mV and a diameter of 157 ± 10 nm were produced. Different concentrations of OEO (10-50 % w/w) were incorporated into CNCs and characterized using FTIR, XRD, SEM and TEM. OEO containing 50 % CNC with the highest EE and LC was selected for coating. Pears were coated with gluten containing 0.5, 1.5 and 2 % encapsulated OEO (EOEO) and pure OEO and stored for 28 days. Physicochemical, microbial and sensory properties of the pears were examined. Microbial analysis showed that EOEO2% was more effective in controlling microbial growth than controls and pure OEO, and a 1.09 Log reduction in bacterial count was recorded on day 28 of storage when compared to control. It was concluded that CNCs produced from an agricultural waste and loaded on an essential oil could be used to extend the shelf life of pear and potentially other fruits.

Zirconium Phosphate Assisted Phosphoric Acid Co-Catalyzed Hydrolysis of Lignocellulose for Enhanced Extraction of Nanocellulose

The high mechanical strength, large specific surface area, favorable biocompatibility, and degradability of nanocellulose (CNC) enable it to be a potential alternative to petroleum-based materials. However, the traditional preparation of CNCs requires a large amount of strong acid, which poses a serious challenge to equipment maintenance, waste liquid recycling, and economics. In this study, a solid and easily recoverable zirconium phosphate (ZrP) was used to assist in the phosphoric acid co-catalyzed hydrolysis of lignocellulose for extracting CNCs. Due to the presence of acidic phosphate groups, ZrP has a strong active center with a high catalytic activity. With the assistance of ZrP, the amount of phosphoric acid used in the reaction is significantly reduced, improving the equipment's durability and economic efficiency. The effects of the process conditions investigated were the phosphate acid concentration, reaction temperature, and reaction time on the yield of CNCs. The Box-Behnken design (BBD) method from the response surface methodology (RSM) was applied to investigate and optimize the preparation conditions. The optimized pre-treatment conditions were 49.27% phosphoric acid concentration, 65.38 °C reaction temperature, and 5 h reaction time with a maximal cellulose yield (48.33%). The obtained CNCs show a granular shape with a length of 40~50 nm and a diameter of 20~30 nm, while its high zeta potential (-24.5 mV) make CNCs present a stable dispersion in aqueous media. Moreover, CNCs have a high crystallinity of 78.70% within the crystal type of cellulose Ⅰ. As such, this study may pioneer the horizon for developing a green method for the efficient preparation of CNC, and it is of great significance for CNCs practical production process.

Banana Peel Waste: An Emerging Cellulosic Material to Extract Nanocrystalline Cellulose

Nanocrystalline cellulose (NCC) has gained attention due to its versatile properties such as biocompatibility, sustainability, high aspect ratio, and abundance of -OH groups that favor modifications of NCC. The objective of this paper is to develop NCC by extracting and characterizing NCC prepared from banana peel powder (BPP). BPP was subjected to alkali and bleaching treatment to remove lignin and hemicellulose and then subjected to acid hydrolysis to prepare NCC. Under optimal conditions (200 mL of sulfuric acid 55% v/v at 50 °C for 60 min), the NCC yield was found to be 29.9%. The particle size and zeta potential of the NCC were found to be 209 nm and -43 mV, respectively. Attenuated total reflectance Fourier transform infrared spectroscopy showed successful removal of lignin and hemicellulose from BPP after the alkali treatment, bleaching, and acid hydrolysis. Field emission scanning electron microscopy showed needle-shaped crystals and transmission electron microscopy showed particles in the nano range. X-ray diffraction analysis showed that the crystallinity index of NCC was 64.12% while keeping the cellulose I crystal structure intact. Thermogravimetric analysis showed good stability which paves way for NCC to be explored for various applications. All the parameters evaluated indicated that NCC was successfully prepared from BPP using alkali treatment, bleaching, and acid hydrolysis.

Application of free and immobilized novel bifunctional biocatalyst in biotransformation of recalcitrant lignocellulosic biomass

Herein, an innovative, green, and practical biocatalyst was developed using conjugation of a novel bifunctional mannanase/xylanase biocatalyst (PersiManXyn1) to the modified cellulose nanocrystals (CNCs). Firstly, PersiManXyn1 was multi-stage in-silico screened from rumen macrobiota, and then cloned, expressed, and purified. Next, CNCs were synthesized from sugar beet pulp using enzymatic and acid hydrolysis processes, and then Fe₃O₄ NPs were anchored on their surface to produce magnetic CNCs (MCNCs). This hybrid was modified by dopamine providing DA/MCNCs nano-carrier. The bifunctional PersiManXyn1 demonstrated the superior hydrolysis activity on corn cob compared with the monofunctional xylanase enzyme (PersiXyn2). Moreover, the immobilization of PersiManXyn1 on the nano-carrier resulted in an improvement of the thermal stability, kinetic parameters (K_cat), and storage stability of the enzyme. Incorporation of the Fe₃O₄ NPs on the CNCs made magnetic nano-carrier with high magnetization value (25.8 emu/g) which exhibited rapid response toward the external magnetic fields. Hence, the immobilized biocatalyst could be easily separated from the products by a magnet, and reused up to 8 cycles with maintaining more than 50% of its original activity. The immobilized PersiManXyn1 generated 22.2%, 38.7%, and 35.1% more reducing sugars after 168 h hydrolysis of the sugar beet pulp, coffee waste, and rice straw, respectively, compared to the free enzyme. Based on the results, immobilization of the bifunctional PersiManXyn1 exhibited the superb performance of the enzyme to improve the conversion of the lignocellulosic wastes into high value products and develop the cost-competition biomass operations.

The Food-Materials Nexus: Next Generation Bioplastics and Advanced Materials from Agri-Food Residues

The most recent strategies available for upcycling agri-food losses and waste (FLW) into functional bioplastics and advanced materials are reviewed and the valorization of food residuals are put in perspective, adding to the water-food-energy nexus. Low value or underutilized biomass, biocolloids, water-soluble biopolymers, polymerizable monomers, and nutrients are introduced as feasible building blocks for biotechnological conversion into bioplastics. The latter are demonstrated for their incorporation in multifunctional packaging, biomedical devices, sensors, actuators, and energy conversion and storage devices, contributing to the valorization efforts within the future circular bioeconomy. Strategies are introduced to effectively synthesize, deconstruct and reassemble or engineer FLW-derived monomeric, polymeric, and colloidal building blocks. Multifunctional bioplastics are introduced considering the structural, chemical, physical as well as the accessibility of FLW precursors. Processing techniques are analyzed within the fields of polymer chemistry and physics. The prospects of FLW streams and biomass surplus, considering their availability, interactions with water and thermal stability, are critically discussed in a near-future scenario that is expected to lead to next-generation bioplastics and advanced materials.

Preparation and Surface Functionalization of Carboxylated Cellulose Nanocrystals

In recent years, cellulose nanocrystals (CNCs) have emerged as a leading biomass-based nanomaterial owing to their unique functional properties and sustainable resourcing. Sulfated cellulose nanocrystals (sCNCs), produced by sulfuric acid-assisted hydrolysis of cellulose, is currently the predominant form of this class of nanomaterial; its utilization leads the way in terms of CNC commercialization activities and industrial applications. The functional properties, including high crystallinity, colloidal stability, and uniform nanoscale dimensions, can also be attained through carboxylated cellulose nanocrystals (cCNCs). Herein, we review recent progress in methods and feedstock materials for producing cCNCs, describe their functional properties, and discuss the initial successes in their applications. Comparisons are made to sCNCs to highlight some of the inherent advantages that cCNCs may possess in similar applications.

Immobilization of enzyme cocktails on dopamine functionalized magnetic cellulose nanocrystals to enhance sugar bioconversion: A biomass reusing loop

A combined enzymatic treatment/acid hydrolysis technique was utilized to synthesize cellulose nanocrystals (CNCs) from sugar beet pulp. CNCs were functionalized with magnetite nanoparticles and dopamine making a versatile nano-carrier (DA/Fe₃O₄NPs@CNCs) for covalent enzyme immobilization. Oxygene/amine functionalities, high magnetization value, and specific surface area of DA/Fe₃O₄NPs@CNCs made it a reusable and green candidate for conjugation to hydrolytic enzyme cocktails (three cellulases, two hemicellulases, and their combinations) to prepare an innovative and practical nano-biocatalyst for biomass conversion. The conjugated enzymes showed an enhanced optimum temperature (∼ 10 °C), improved thermal stability, and shifted optimum pH toward alkaline pHs. Covalent attachment could successfully suppress the enzyme leaching and provide easy recovery/reuse of the nano-biocatalyst up to 10 cycles, with > 50% of initial activity. Application of the nano-biocatalyst in hydrolysis of rice straw and sugar beet pulp showed an increase (20-76%) in the yield of fermentable sugars compared to the free enzyme cocktails.

Green synthesized iron nanoparticles as highly efficient fenton-like catalyst for degradation of dyes

Iron nanoparticles (Fe NPs) were synthesized herein through a simple and eco-friendly method using FeCl₃ and aqueous plant extract (dimocarpus longan, DL). Compared with Fe NPs prepared via traditional chemical methods, this biogenetic DL-Fe NPs demonstrates higher catalytic activity in Fenton-like reaction to degrade methyl orange (MO) in a wide pH range. It's worth noting that the DL-Fe NPs manifest a superior stability even after storage for at least 28 days. Systematic characterizations indicate that the active biomolecules from plant extract significantly contribute to the superior performance of DL-Fe NPs, by facilitating the dye molecules to be adsorbed on the surfaces of DL-Fe NPs, and providing a stable acid environment for the Fenton-like catalytic reaction. The kinetics study demonstrates this removal process conforms to the pseudo first-order model with the reaction activation energy of 41.6 kJ/mol. Moreover, various typical dyes including congo red, malachite green, methylene blue, eosin-Y and rhodamine B can be dramatically degraded by this DL-Fe NPs with a satisfactory removal efficiency.

Starch nanocrystals as the particle emulsifier to stabilize caprylic/capric triglycerides-in-water emulsions

Starch nanocrystals (SNCs) grafted with octenyl succinic anhydride (OSA) were used to stabilize caprylic/capric triglycerides (GTCC)-in-water emulsions. The morphology and viscoelasticity of emulsions were studied in terms of particle loadings and degrees of substitution (DSs). It is found that the emulsifying capacities of SNCs increase with increased DSs. Both the pristine SNC and modified ones can be well used to stabilize emulsions, whereas the emulsification follows different mechanisms. The platelet-like structure of SNCs, together with its improved amphiphilicity after surface treatments, are important to the formation and evolution of droplet clusters. The deformation and relaxation of those clusters result in weak flow overshoots and strong thixotropy in different shear flow fields, which favor storage and applications of GTCC-in-water emulsions as hydrocolloids. The mechanisms were then discussed in terms of rigidity of SNC and relaxations of clusters. This work proposes a promising application of SNC in food and cosmetic industries.

Nanocellulose Production: Exploring the Enzymatic Route and Residues of Pulp and Paper Industry

Increasing environmental and sustainability concerns, caused by current population growth, has promoted a raising utilization of renewable bio-resources for the production of materials and energy. Recently, nanocellulose (NC) has been receiving great attention due to its many attractive features such as non-toxic nature, biocompatibility, and biodegradability, associated with its mechanical properties and those related to its nanoscale, emerging as a promising material in many sectors, namely packaging, regenerative medicine, and electronics, among others. Nanofibers and nanocrystals, derived from cellulose sources, have been mainly produced by mechanical and chemical treatments; however, the use of cellulases to obtain NC attracted much attention due to their environmentally friendly character. This review presents an overview of general concepts in NC production. Especial emphasis is given to enzymatic hydrolysis processes using cellulases and the utilization of pulp and paper industry residues. Integrated process for the production of NC and other high-value products through enzymatic hydrolysis is also approached. Major challenges found in this context are discussed along with its properties, potential application, and future perspectives of the use of enzymatic hydrolysis as a pretreatment in the scale-up of NC production.

Morphological, chemical and thermal analysis of cellulose nanocrystals extracted from bamboo fibre

This work investigates the extraction of cellulose nanocrystals (CNC) from bamboo fibre as an alternative approach to utilize the waste bamboo fibre. In this study, bamboo fibre was subjected to acid hydrolysis for efficient isolation of CNC from bamboo fibre. The extracted CNC's were morphologically, characterized via Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM). The energy Dispersive X-rays (EDX) provided the elemental composition of the prepared CNC's and X-ray diffractometer (XRD) exhibited their crystallinity. The physiochemical analysis was done via Fourier Transform Infrared (FTIR); and their thermal analysis was revealed by Thermogravimetric Analysis (TGA) and Differential scanning calorimetry (DSC). As from their morphological investigations, rod like structures of CNC's were observed under SEM analysis with higher carbon content as demonstrated by EDX, while needle shaped CNC's were observed from TEM and AFM studies. Acid hydrolysis for 45 min resulted into higher degree of crystallinity and higher yield of CNC's about 86.96% and 22% respectively. Owing to higher quality of CNC's obtained as a result of efficient and modified techniques, these can find potential usage in nanocomposites for biomedical and food packaging application.

Synthesis and structure of carboxymethylcellulose with a high degree of substitution derived from waste disposable paper cups

The cost of the cellulose derived from some raw materials was high. In addition, the dispersion of the cellulose with special shape and a low degree of substitution (DS) in water-soluble polymers was poor. To resolve this problem, cellulose was separated from waste disposable paper cups (WDPC) and then the carboxymethylcellulose (CMC) was synthesized by etherification. Under the optimized conditions (the etherification temperature of 70 ℃, the etherification time of 1.5 h, the monochloroacetic acid mass (C₂H₃ClO₂) of 7 g), the DS of CMC was as high as 1.21. As-prepared CMC showed ribbon and rod-like shapes with a diameter of 25-50 μm. In addition, they exhibited an excellent thermal stability. Compared with other CMC, we could infer that as-prepared CMC in this paper will have potential applications in flexible composites and functional materials.

Waste paper: An underutilized but promising source for nanocellulose mining

Nanocellulose has achieved an inimitable place and value in nano-materials research sector. Promising and exclusive physical, chemical and biological properties of nanocellulose make it an attractive and ideal material for various high end-user applications. Conventionally, the base material for nanocellulose i.e. cellulose is being extracted from various lignocellulosic raw materials (like wood, agro-industrial-residues, etc.) using pulping followed by bleaching sequences. As an alternate to lignocellulosic raw materials, waste paper also showed potential as a competent raw material due to its abundant availability and high cellulosic content (60-70%) with comparatively less hemicelluloses (10-20%) and lignin (5-10%) without any harsh treatments. The production yields of nanocellulose were reported to vary from 1.5% to 64% depending upon the waste papers and treatments given. The diameters of these nanocelluloses were reported in the range of 2-100 nm and crystallinity range around 54-95%. Thermal degradation of waste paper nanocellulose was varied from 187 °C to 371 °C. Although these properties are comparable with the nanocellulose obtained from lignocellulosic raw materials, yet waste paper is an underutilized source for nanocellulose preparation due to its ordinary fate of recycling, dumping and incineration. In the sight of necessity and possibility of waste paper utilization, this article reviews the outcomes of research carried out for preparation of nanocellulose using waste paper as a source of cellulose. There is a need of sincere investigation to convert this valuable waste to wealth i.e. waste papers to nanocellulose, which will be helpful in solid waste management to protect environment in economical way.

Magnetic nanocomposite based on polyacrylic acid and carboxylated cellulose nanocrystal for the removal of cationic dye

The development of safe and cost-effective methods for the treatment of dye polluted wastewater has been a great concern among researchers. Herein, we developed a nanocomposite (M3D–PAA–CCN) based on polyacrylic acid (PAA) crosslinked with magnetic 3D crosslinkers (M3D) and carboxylated cellulose nanocrystals (CCN), for the removal of cationic dyes from aqueous solutions. Acrylic-functionalized Fe₃O₄ nanoparticles were covalently linked to the polymer chains via the form of the 3D crosslinker to introduce magnetic properties into the as-synthesized nanocomposite. The addition of highly dispersive CCN reduced the gel-like properties of the nanocomposite and instead incorporated a diffusive nature, which was more desirable for adsorbents. The surface morphology of the nanocomposite was analyzed by FESEM and the size of the nanocomposite particles was found to be in the range of 60–90 nm. The chemical functionalities and compositions were determined by XPS, FTIR, and EDX analyses whereas TGA confirmed the thermal stability of M3D–PAA–CCN. The maximum adsorption capacity of the M3D–PAA–CCN (332 mg g⁻¹) was measured higher than that of M3D–PAA (114 mg g⁻¹) to a cationic methylene blue (MB) dye indicating the significant contribution of CCN. The adsorption capacity of the as-synthesized M3D–PAA–CCN was found to be highly pH-dependent and the adsorption capacity increased with the increase of pH owing to the greater negative charge as indicated by the higher zeta potential. The adsorption kinetics of MB on the composites was found to follow the pseudo-second-order model. The adsorption capacity was also investigated as a function of concentration to figure out the adsorption mechanism using Langmuir and Freundlich isotherm models. The Langmuir model fitted the adsorption process better as suggested by the relatively smaller nonlinear chi-square value obtained from the fitting parameters.

A low-cost, highly efficient, and recyclable magnetic nanocomposite has been developed from polyacrylic acid and carboxylated cellulose nanocrystals for the removal of cationic dyes from the wastewater.

Effects of polysiloxanes with different molecular weights on in vitro cytotoxicity and properties of polyurethane/cotton–cellulose nanofiber nanocomposite films

A series of polyurethane/cotton–cellulose nanofiber nanocomposite films are manufactured using amino-terminated polydimethylsiloxane, polycarbonate diol, isophorone diisocyanate, and dispersed cotton–cellulose nanofibers.

Preparation and characterization of cellulose nanocrystal extracted from Calotropis procera biomass

Calotropis procera fiber (CPF) is the fruit fiber of C. procera and belongs to a typical cellulosic fiber. In this study, Calotropis procera fiber (CPF) was first purified in the pretreatment process including delignification and bleaching before the isolation of cellulose nanocrystal. Chemical composition of Calotropis procera fiber was determined according to TAPPI standard method. It was composed of 64.0 wt% cellulose, 19.5 wt% hemicelluloses, and 9.7 wt% of lignin. The morphology of the Calotropis procera fiber and fiber after each pretreatment process was also investigated. Cellulose nanocrystal was extracted by classical sulfuric acid hydrolysis of the pretreated Calotropis procera fiber. TEM and SEM were used to analyze the morphologies of the obtained CNC. The crystallinity, thermal stability and suspension stability of the CNC were also investigated. The interesting results proved that this under-utilized biomass could be exploited as a new source of cellulose raw material for the production of cellulose nanocrystal.

Recycling of viscose yarn waste through one-step extraction of nanocellulose

Textile manufacturing industries generate large amounts of viscose yarn waste (VW) that causes serious environmental pollution. In this study, VW was used as raw material to successfully extract nanocellulose (NC) in a facile one-step extraction process, without any pretreatment. Different hydrolysis reaction times (5-60 min) were employed, and the extracted material was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning and transmission electron microscopies, atomic force microscopy, and thermogravimetric analysis. Interestingly, it was possible to obtain NC in only 5 min of reaction without any pretreatment and with an increase of 50% in the crystallinity, which was attributed to the pretreatments VW undergone in textile industry that swell cellulose chains and make them more accessible to further reactions. The higher crystallinity index was observed after 30 min of reaction (87%), and through microscopy, it was verified that the morphology of the VW was completely changed to irregular nanoparticles with average size of 42 nm. The obtained NC showed interesting properties to be used in several potential applications, including stabilization of oil/water Pickering emulsions. These results indicate that VW is an attractive source to obtain NC, making the extraction of NC from VW a value-added alternative to recycle this textile waste.

Dietary fibre from berry-processing waste and its impact on bread structure: a review

The structure and function of by-products of berry-processing industries are reviewed, with particular attention to dietary fibre (DF) and its effects in food products. The complex chemical composition and physicochemical characteristics of DF have been investigated and strategies for extraction of specific fractions that provide tailored technological and physiological functionality have been reviewed. The aim of this review is to describe in detail the structural composition and isolation methods of dietary fibre derived from berry by-products, and to explore their potential functionality in foods. The goal is to introduce DF from berry waste streams into the food chain, for which bread is a major vehicle. However, the appeal of bread lies in its aerated structure, for which DF is generally detrimental. The technological influence of DF on the formation and stabilization of the aerated structure of bread is therefore reviewed, in order to understand how to incorporate DF into bread while maintaining palatability. The aerated structure of bread is stabilized by two mechanisms: the gluten matrix and the liquid film surrounding bubbles. Incorporating DF successfully into bread requires understanding its interactions with both of these mechanisms. DF fractions from berries offer superior nutritional value compared to cereal fibre, potentially with less damage to bread structure, due to the higher proportion of soluble fibre. By-products from berry-processing industries could be used as a source of technologically and nutritionally distinctive DF to fabricate foods with enhanced nutritional value. © 2019 Society of Chemical Industry.

Optimizing the extraction process of natural antioxidants from chardonnay grape marc using microwave-assisted extraction

The aim of this work was to extract phenolic compounds from Chardonnay grape marc employing a microwave-assisted extraction (MAE). Firstly, the effect of solvent concentration (30-60%), solid mass (1.0-2.0 g) and extraction time (5-15 min) on the recovery of phenolic content and antioxidant capacity was evaluated using a response surface methodology (RSM). The optimal parameters found by RSM were 48% ethanol for the solvent content, 10 min for the extraction time, and 1.77 g for the solid mass. The extraction was carried out at room temperature to increase scaling-up opportunities at industrial level. It was found that the phenolic profile was mainly composed of flavanols, such as procyanidins, catechin and epicatechin. Furthermore, the polyphenols obtained by MAE showed a DPPH· inhibition value of 87 ± 5% and the total phenolic content was 1.21 ± 0.04 mg GAE/mL. Finally, it was observed that the degradation temperature of the extract (≈ 200 °C) was above the temperature commonly used for the manufacture of protein films by thermo-mechanical processes. This highlights the potential use of this extract as a bioactive additive in protein film forming formulations for food and pharmaceutical applications.

Effect of template type on the preparation of the emeraldine salt form of polyaniline (PANI-ES) with horseradish peroxidase isoenzyme C (HRPC) and hydrogen peroxide

Horseradish peroxidase isoenzyme C (HRPC) is often used as catalyst for the preparation of the conductive emeraldine salt form of polyaniline (PANI-ES) from aniline and hydrogen peroxide (H₂O₂) in the presence of anionic templates in aqueous solution. Here, a direct comparison of three types of soft templates was made, (i) the sodium salt of sulfonated polystyrene (SPS), (ii) micelles from sodium dodecylbenzenesulfonate (SDBS), and (iii) vesicles from either a 1 : 1 molar mixture of SDBS and decanoic acid or from AOT (sodium bis(2-ethylhexyl)sulfosuccinate). Based on UV/vis/NIR, EPR and Raman spectroscopy measurements all three types of templates are similarly suitable, with advantages of the two vesicle systems in terms of aniline conversion degree and radical content in the final PANI-ES product. First experiments with sulfated cellulose nanocrystals (CNCs) indicate that they are promising rigid templates for the preparation of electroconductive PANI-ES-coated cellulose materials or devices.

Different types of templates consisting of sulfonate or sulfate groups were compared for the horseradish peroxidase/H₂O₂-catalysed synthesis of the emeraldine salt form of polyaniline from aniline at pH = 4.3.

A review on processing techniques of bast fibers nanocellulose and its polylactic acid (PLA) nanocomposites

The utilization of nanocellulose has increasingly gained attentions from various research fields, especially the field of polymer nanocomposites owing to the growing environmental hazardous of petroleum based fiber products. Meanwhile, the searching of alternative cellulose sources from different plants has become the interests for producing nanocellulose with varying characterizations that expectedly suit in specific field of applications. In this content the long and strong bast fibers from plant species was gradually getting its remarkable position in the field of nanocellulose extraction and nanocomposites fabrications. This review article intended to present an overview of the chemical structure of cellulose, different types of nanocellulose, bast fibers compositions, structure, polylactic acid (PLA) and the most probable processing techniques on the developments of nanocellulose from different bast fibers especially jute, kenaf, hemp, flax, ramie and roselle and its nanocomposites. This article however more focused on the fabrication of PLA based nanocomposites due to its high firmness, biodegradability and sustainability properties in developed products towards the environment. Along with this it also explored a couple of issues to improve the processing techniques of bast fibers nanocellulose and its reinforcement in the PLA biopolymer as final products.

Recent Advances in Nanocellulose Composites with Polymers: A Guide for Choosing Partners and How to Incorporate Them

In recent years, the research on nanocellulose composites with polymers has made significant contributions to the development of functional and sustainable materials. This review outlines the chemistry of the interaction between the nanocellulose and the polymer matrix, along with the extent of the reinforcement in their nanocomposites. In order to fabricate well-defined nanocomposites, the type of nanomaterial and the selection of the polymer matrix are always crucial from the viewpoint of polymer⁻filler compatibility for the desired reinforcement and specific application. In this review, recent articles on polymer/nanocellulose composites were taken into account to provide a clear understanding on how to use the surface functionalities of nanocellulose and to choose the polymer matrix in order to produce the nanocomposite. Here, we considered cellulose nanocrystal (CNC) and cellulose nanofiber (CNF) as the nanocellulosic materials. A brief discussion on their synthesis and properties was also incorporated. This review, overall, is a guide to help in designing polymer/nanocellulose composites through the utilization of nanocellulose properties and the selection of functional polymers, paving the way to specific polymer⁻filler interaction.

Recent Strategies in Preparation of Cellulose Nanocrystals and Cellulose Nanofibrils Derived from Raw Cellulose Materials

The recent strategies in preparation of cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) were described. CNCs and CNFs are two types of nanocelluloses (NCs), and they possess various superior properties, such as large specific surface area, high tensile strength and stiffness, low density, and low thermal expansion coefficient. Due to various applications in biomedical engineering, food, sensor, packaging, and so on, there are many studies conducted on CNCs and CNFs. In this review, various methods of preparation of CNCs and CNFs are summarized, including mechanical, chemical, and biological methods. The methods of pretreatment of cellulose are described in view of the benefits to fibrillation.

A design optimization study on synthesized nanocrystalline cellulose, evaluation and surface modification as a potential biomaterial for prospective biomedical applications

In the present study, nanocrystalline cellulose (NCC) was prepared via acid hydrolysis and synthesis parameters were optimized via response surface modelling with a determined maximum NCC yield of 43.8%. The optimized NCC sample was subsequently surface modified via epichlorohydrin-mediated amination forming aminated nanocrystalline cellulose (A-NCC) with an amine content calculated as 1500μmol/g. The average particle size and zeta potential were determined 100nm and 325nm for NCC and A-NCC, respectively. Structural properties were analyzed by FTIR, TEM and XRD techniques. The obtained A-NCC as final product depicted a pKa value of 10.86±0.07 demonstrating favourable protonation of amine groups at physiological pH allowing the material to be suitable for prospective application in drug delivery and tissue engineering.

Cellulose nanocrystals from grape pomace: Production, properties and cytotoxicity assessment

Cellulose nanocrystals (CNCs) were obtained from grape pomace through chemical and physical pretreatments. Bleached cellulose pulp was subjected to acid hydrolysis (AH) for 30 or 60 min and an ultrasound treatment to obtain CNCs (AH_30S and AH_60S). Compositional analyses of untreated (UGP) and pretreated (PGP) grape pomace showed the effectiveness of pretreatment in removing non-cellulosic components, recovering 80.1% cellulose in PGP (compared to 19.3% of UGP). Scanning and transmission electron microscopies were used to evaluate the CNCs morphology. AH in combination with ultrasound treatment led to needle-shaped structures and apparently more dispersed suspensions. Crystallinity index and thermal stability were studied by X-ray diffraction and thermogravimetric analysis, respectively. The AH_60S sample presented high aspect ratio, crystallinity and thermal stability. CNCs toxicity was evaluated by exposing Caco-2 cells to CNCs suspension and evaluating their viability. Results showed that CNCs are non-toxic, opening the opportunity for their use on food and pharmaceutical applications.

Cellulose nanocrystals from passion fruit peels waste as antibiotic drug carrier

Due to its excellent chemical and physical properties, cellulose nanocrystals (CNC) possess many potential advanced functional applications. In this study, CNC was extracted from natural product by hydrolyzing cellulose segment of passionfruit peels using sulphuric acid solution. The capability of CNC as drug carrier was tested toward tetracycline antibiotic. The drug loading processes were carried out at various pH (3-7) with the optimum uptake of tetracycline achieved at pH 3. The in vitro release of tetracycline drug was carried out in phosphoric buffer medium with two different pH conditions at 37°C. The highest release of tetracycline (82.21%) was achieved at pH 7.2, while the lowest one (25.1%) was achieved at pH 2.1, where the release pattern follow a second order kinetic model. This study highlight the potential application of CNC derived from natural resources as drug carrier without harmful chemical excipients that comply with health safety, biocompatible, biodegradable.

Solution blow spun nanocomposites of poly(lactic acid)/cellulose nanocrystals from Eucalyptus kraft pulp

Cellulose nanocrystals (CNCs) were extracted from Eucalyptus kraft pulp by sulfuric acid hydrolysis, and esterified with maleic anhydride (CNC_MA). The incorporation of sulfate ester groups on the cellulose surface resulted in higher stability of the nanoparticles in aqueous suspensions and lower thermal stability. Then, PLA/CNC and PLA/CNC_MA nanocomposites were successfully obtained by solution blow spinning (SBS) using dimethyl carbonate (DMC) as solvent. CNC and CNC_MA indicated to be acting both as nucleating agents or growth inhibitors of PLA crystal and tends to favor the formation of PLA crystals of higher stability. A fraction of the nanocrystals indicate to be exposed on the surface of the PLA fibers, since the hydrophilicity of the composite films increased significantly. Such composites may have potential application as filtering membranes or adsorbents.