Tapioca starch films reinforced with microcrystalline cellulose for potential food packaging application

Development of eco-friendly biofilms by utilizing microcrystalline cellulose extract from banana pseudo-stem

Banana pseudo-stem, often considered as an underutilized plant part was explored as a potential reinforced material to develop an eco-friendly biofilm for food packaging applications. In this study, Microcrystalline cellulose (MCC) was extracted from banana pseudo-stem by alkali and acid hydrolysis treatment. The extracted MCC was used as a reinforced material in different concentrated polyvinyl alcohol (PVA) matrix alone as well as both PVA and Carboxymethyl Cellulose (CMC) matrix to develop biofilm by solvent casting method. The synthesized MCC powder was characterized by scanning electron microscope to ensure its microcrystalline structure and to observe surface morphology. The biofilms composed of MCC, PVA, and CMC were assessed through Fourier-transform infrared spectroscopy (FTIR), mechanical properties, water content, solubility, swelling degree, moisture barrier property (Water Vapor Permeability - WVP), and light barrier property (Light Transmission and Transparency). The FTIR analysis showed the rich bonding between the materials of the biofilms. The film incorporating a combination of PVA, CMC, and MCC (S6) exhibited the highest tensile strength at 26.67 ± 0.152 MPa, making it particularly noteworthy for applications in food packaging. MCC incorporation increased the tensile strength. The WVP content of the films was observed low among the MCC-induced films which is parallel to other findings. The lowest WVP content was showed by 1% concentrated PVA with MCC (S4) (0.223 ± 0.020 10-9 g/Pahm). The WVP content of S6 film was also considerably low. MCC-incorporated films also acted as a good UV barrier. Transmittance of the MCC induced films at UV range were observed on average 38% (S2), 36% (S4) and 6% (S6) which were almost 6% lower than the control films. The S6 film demonstrated the lowest swelling capacity (1.42%) and water content, indicating a significantly low solubility of the film. The film formulated with mixing of PVA, CMC and MCC (S6) was ahead in terms of food packaging characteristics than other films. Also, the outcomes of this study point out that MCC can be a great natural resource for packaging applications and in that regard, banana pseudo-stem proves to be an excellent source for waste utilization.

Organic waste-to-bioplastics: Conversion with eco-friendly technologies and approaches for sustainable environment

Petrochemical-based synthetic plastics poses a threat to humans, wildlife, marine life and the environment. Given the magnitude of eventual depletion of petrochemical sources and global environmental pollution caused by the manufacturing of synthetic plastics such as polyethylene (PET) and polypropylene (PP), it is essential to develop and adopt biopolymers as an environment friendly and cost-effective alternative to synthetic plastics. Research into bioplastics has been gaining traction as a way to create a more sustainable and eco-friendlier environment with a reduced environmental impact. Biodegradable bioplastics can have the same characteristics as traditional plastics while also offering additional benefits due to their low carbon footprint. Therefore, using organic waste from biological origin for bioplastic production not only reduces our reliance on edible feedstock but can also effectively assist with solid waste management. This review aims at providing an in-depth overview on recent developments in bioplastic-producing microorganisms, production procedures from various organic wastes using either pure or mixed microbial cultures (MMCs), microalgae, and chemical extraction methods. Low production yield and production costs are still the major bottlenecks to their deployment at industrial and commercial scale. However, their production and commercialization pose a significant challenge despite such potential. The major constraints are their production in small quantity, poor mechanical strength, lack of facilities and costly feed for industrial-scale production. This review further explores several methods for producing bioplastics with the aim of encouraging researchers and investors to explore ways to utilize these renewable resources in order to commercialize degradable bioplastics. Challenges, future prospects and Life cycle assessment of bioplastics are also highlighted. Utilizing a variety of bioplastics obtained from renewable and cost-effective sources (e.g., organic waste, agro-industrial waste, or microalgae) and determining the pertinent end-of-life option (e.g., composting or anaerobic digestion) may lead towards the right direction that assures the sustainable production of bioplastics.

A review of starch-based biocomposites reinforced with plant fibers

Renewable and biodegradable resources have gained increasing attention as promising alternatives to synthetic plastics. Among the diverse raw materials employed in bioplastics production, starch emerges as an attractive, low-cost, and largely available source. However, the inherent properties of starch-based materials often limit their utility across various applications, necessitating strategic modifications to enhance their performance. A common approach to boost these materials involves incorporating natural fillers into biopolymer matrices. Incorporating natural fibers within starch matrices enables the development of biocomposites with improved properties while retaining their renewable and biodegradable characteristics. This review briefly addresses fundamental aspects of starch structure, obtention, and processing, as well as the main pre-treatments of natural fibers and processing methods currently applied to produce starch-based composites. It also highlights the most recent advances in this field, elucidates the effect of the incorporation of fibers on the biocomposite properties, and discusses the critical parameters affecting the synergic combination between starch and fibers.

Green composites based on thermoplastic starch reinforced with micro- and nano-cellulose by melt blending - A review

Starch is a biodegradable biopolymer, a sustainable material that can replace conventional petrochemical-based plastics. However, starch has some limitations, as it must be processed by heating and treated mechanically with a plasticizer to become thermoplastic starch (TPS). Different variables such as mixing speeds, amount, and kind of plasticizers play a vital role in preparing TPS by melting. Despite this, the properties of the TPS are not comparable with those of traditional plastics. To overcome this limitation, microcellulose or nanocellulose is added to TPS by melt mixing, including the extrusion and internal mixing process, which enables large-scale production. This review aims to compile several studies that evaluate the effect of plasticizers, as well as the relevance of incorporating different cellulosic fillers of different dimensions on the properties of TPS obtained by melt mixing. Potential applications of these materials in food packaging, biomedical applications, and other opportunities are also described.

Characterization and qualitative evaluation of cassava starch-chitosan edible food wrap enriched with culinary leaf powders for eco-friendly food packaging applications

Cassava starch-based edible food wraps were prepared by incorporating leaf powder from Indian curry leaf and Malabar bay leaf, reinforced with different (0.2, 0.4, 0.6, 0.8) wt.% of chitosan. Eleven combinations of films were prepared and their sensory acceptability, physical properties, Fourier-transform infrared spectroscopic (FTIR) spectrum, and scanning electron microscopy (SEM) image, were evaluated. The thickness of the films ranged from 0.198  ±  0.12 to 0.372  ±  0.27 mm. Tensile strength was reported to be the highest (40.71  ±  1.21 MPa) in the curry leaf powder incorporated sample. Maximum elongation at break was reported by bay leaf powder incorporated (5.8  ±  1.59%) sample. The Young's modulus values were observed to be increasing along with the concentration of chitosan. Maximum seal strength values were reported by curry leaf powder incorporated film with 0.8% chitosan (2.93  ±  0.22 N/mm). The leaf powder incorporated samples reported a higher flavonoid content compared to the control. The color analysis (L*, a*, b*) of the films was identical to the natural leaf color. The SEM images indicated a rough texture for the leaf powder incorporated films. The FTIR evaluation confirmed the presence of the respective functional groups. The statistical evaluation done by statistical package for social sciences software showed that all the data were significantly different (P ≤ 0.05.). The study demonstrated the potential of incorporation of leaf powder and chitosan to enhance the properties of starch-based edible packaging.

Essential characteristics improvement of metallic nanoparticles loaded carbohydrate polymeric films - A review

Petroleum-based films have contributed immensely to various environmental issues. Developing green-based films from carbohydrate polymers is crucial for addressing the harms encountered. However, some limitations exist on their property, processibility, and applicability that prohibit their processing for further developments. This review discusses the potential carbohydrate polymers and their sources, film preparation methods, such as solvent-casting, tape-casting, extrusion, and thermo-mechanical compressions for green-based films using various biological polymers with their merits and demerits. Research outcomes revealed that the essential characteristics improvement achieved by incorporating different metallic nanoparticles has significantly reformed the properties of biofilms, including crystallization, mechanical stability, thermal stability, barrier function, and antimicrobial activity. The property-enhanced bio-based films made with nanoparticles are potentially interested in replacing fossil-based films in various areas, including food-packaging applications. The review paves a new way for the commercial use of numerous carbohydrate polymers to help maintain a sustainable green environment.

Nano-chitin: Preparation strategies and food biopolymer film reinforcement and applications

Current trends in food packaging systems are toward biodegradable polymer materials, especially the food biopolymer films made from polysaccharides and proteins, but they are limited by mechanical strength and barrier properties. Nano-chitin has great economic value as a highly efficient functional and reinforcing material. The combination of nano-chitin and food biopolymers offers good opportunities to prepare biodegradable packaging films with enhanced physicochemical and functional properties. This review aims to give the latest advances in nano-chitin preparation strategies and its uses in food biopolymer film reinforcement and applications. The first part systematically introduces various preparation methods for nano-chitin, including chitin nanofibers (ChNFs) and chitin nanocrystals (ChNCs). The nano-chitin reinforced biodegradable films based on food biopolymers, such as polysaccharides and proteins, are described in the second part. The last part provides an overview of the current applications of nano-chitin reinforced food biopolymer films in the food industry.

Development of nanocellulose fiber reinforced starch biopolymer composites: a review

In the last few years, there are rising numbers for environmental waste due to factors such as plastic based food packaging that really need to get enough attention in order to prevent the issue from becoming worse and bringing disaster to society. Thus, the uses of plastic composite materials need to be reduced and need to be replaced with materials that are natural and have low degradation to preserve nature. Based on the statistics for the global, the production of plastic has been roughly calculated for passing 400 million metric tons every year and has a high probability of approaching the value of 500 million metric tons at the year of 2025 and this issue needs to be counteracted as soon as possible. Due to that, the increasing number for recent development of natural biopolymer, as an example starch, has been investigated as the substitution for the non-biodegradable biopolymer. Besides, among all biodegradable polymers, starch has been considered as promising substitution polymer due to its renewability, easy availability, and biodegradability. Apart from that, by the reinforcement from the nanocellulose, starch fiber has an increasing in terms of mechanical, barrier and thermal properties. In this review paper, we will be discussing the up-to-date development of nanocellulose fiber reinforced starch biopolymer composites throughout this century.

Accelerated Shelf-Life and Stability Testing of Hydrolyzed Corn Starch Films

Nonbiodegradable food packaging films are made from plastics such as polyethylene and polypropylene, which can take hundreds of years to decompose and create environmental hazards. On the other hand, biodegradable food packaging films are made from renewable materials such as corn starch or cellulose, that degrade within a few weeks or months and prove to be more sustainable and environmentally friendly. In this work, we used corn starch hydrolyzed (CSH) with α-amylase to prepare a film with biodegradable properties. The film was tested for 60 days at different accelerated temperatures and relative humidity (RH), 13 ± 2 °C and 65 ± 5% RH, 23 ± 2 °C and 45 ± 5% RH, and 33 ± 2 °C and 30 ± 5% RH, to test its durability and stability. Soil biodegradation of the CSH film was evaluated by visual appearance, microscopic observation, weight loss, scanning electron microscopy (SEM), and Fourier-transformed infrared spectroscopy (FTIR) every 6 days. The film was found to have strong hygroscopic properties and was able to last up to 10 months if it is maintained at 20 ± 5 °C and 45 ± 5% RH. After the biodegradability test for at least 30 days, the film showed a significantly higher weight loss rate and microbial activity on the surface of the film, which indicates that the film is biodegradable. The present work recommends biodegradable CSH films as an excellent environmentally friendly choice for dried foods packaging, due to their good shelf life at room temperature, which is beneficial when shipping and storing products, but these films are not suitable for foods with high moisture content.

Production of Thermoplastic Starch-Aloe vera Gel Film with High Tensile Strength and Improved Water Solubility

Biodegradable film packaging made from thermoplastic starch (TPS) has low mechanical performance and high water solubility, which is incomparable with synthetic films. In this work, Aloe vera (AV) gel and plasticized soluble potato starch were utilised to improve the mechanical stability and water solubility of TPS. Dried starch was mixed with glycerol and different AV gel concentrations (0% to 50%). The TPS + 50% AV gel (30 g TPS + 15 g AV gel) showed the best improvement compared to TPS alone. When compared to similar TPS films with AV gel added, this film is stronger and dissolves better in water. Mechanical qualities improved the tensile strength and Young's modulus of the TPS film, with 1.03 MPa to 9.14 MPa and 51.92 MPa to 769.00 MPa, respectively. This was supported by the improvement of TPS water solubility from 57.44% to 46.6% and also by the increase in decomposition temperature of the TPS. This promises better heat resistance. The crystallinity percentage increase to 24.26% suggested that the formation of hydrogen bonding between TPS and AV gel enhanced crosslinking in the polymeric structure. By adding AV gel, the TPS polymeric structure is improved and can be used as a biodegradable food-packaging film.

A review on the conversion of cassava wastes into value-added products towards a sustainable environment

The solid and liquid wastes generated from cassava-based industries are organic and acidic in nature, which leads to various global concerns-primarily global warming and biodiversity loss. But the conversion of these wastes into value-added products associated with environmental pollution control contributes to sustainable development. Generally, the thermochemical process such as pyrolysis and gasification and biochemical processes such as anaerobic digestion have been applied for the conversion of cassava waste into value-added products. This review addresses the valorization of cassava wastes, which fulfill almost all needs of the hour, such as energy (biofuel), wastewater treatment (adsorbents), bioplastics, starch nanoparticles, organic acid production, and antimicrobial agents. The major aim of this paper is to analyze and provide the disclosure of the efficiency of cassava-based industrial waste as a source to minimize the problem associated with conventional fossil fuels and through which mitigate the impact of global warming and climate change. Furthermore, recent research and achievements in the valorization of cassava waste have been highlighted.

Kinetics and Adsorption Equilibrium in the Removal of Azo-Anionic Dyes by Modified Cellulose

This study introduces a new and bio-friendly adsorbent based on natural and cetyltrimethylammonium chloride (CTAC)-modified adsorbent prepared from wheat straw residues for the removal of Congo red (CR) and tartrazine azo-anionic dyes from aqueous solution. The adsorbent was characterized by thermogravimetric analysis (TGA), calorimetric differential (DSC), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX), and pH point of zero charge (pHPZC) techniques. It was found that decreasing the adsorbent dose and increasing the initial concentration favors the removal of tartrazine and Congo red. Tartrazine adsorption capacities were 2.31 mg/g for the cellulose extracted from wheat residues (WC) and 18.85 mg/g for the modified wheat residue cellulose (MWC) for tartrazine as well as 18.5 mg/g for WC and 19.92 for MWC during Congo red (CR) adsorption, respectively. Increasing the initial and decreasing the adsorbent dose concentration favored the adsorption process. From time effect analysis, it was found that the equilibrium time was reached at 120 min when modified wheat cellulose was used and at 480 min when wheat cellulose was used. The kinetics of adsorption were described by pseudo-second-order in all cases with R2 > 0.95. The obtained data equilibrium from this research was well-fitted by the Freundlich isotherm model.

Overview of Bioplastic Introduction and Its Applications in Product Packaging

Each year, more than 330 million tons of plastic are produced worldwide. The main consumers of plastics are the packaging (40%), building (20%) and automotive (8%) industries, as well as for the manufacture of household appliances. The vast majority of industrial plastics are not biodegradable and, therefore, create environmental problems due to the increase in the amount of solid waste. Studies have been conducted to produce biodegradable materials such as bioplastics to overcome this environmental problem. Bioplastics are defined as materials that are bio-based, biodegradable, or both; they can provide excellent biodegradability and can be used to help alleviate environmental problems. Therefore, this article presents an overview of the introduction of bioplastic materials and classifications, and a comprehensive review of their drawbacks and areas of importance, including basic and applied research, as well as biopolymer mixtures and biocomposites developed in the last decade. At the same time, this article provides insights into the development of bioplastics research to meet the needs of many industries, especially in the packaging industry in Malaysia. This review paper also focuses generally on bioplastic packaging applications such as food and beverage, healthcare, cosmetics, etc.

The effects of dual modification on functional, microstructural, and thermal properties of tapioca starch

The aim of this study was to investigate the effects of dual modification on the functional, microstructural, and thermal properties of tapioca starch. Tapioca starch was first hydrolyzed by 0.14 M HCl for 0, 6, 12, 18, and 24 hr and then hydroxypropylated by adding 0%, 10%, 20%, and 30% (v/w) propylene oxide. The degree of hydroxypropylation, solubility, water absorption, rheological, thermal, and microstructure characterization of dually modified tapioca starch was determined. Hydroxypropylation did not cause any considerable changes in the starch granular size and shape of tapioca starch. Acid hydrolysis disrupts the starch granules, and the starches with smaller sizes were produced. The degree of molar substitution (DS) of dual modified starches ranged from 0.118 to 0.270. The dual modified starches significantly had higher solubility than native starch (p < .05). Hydrolysis of starches with acid decreases swelling power while hydroxypropylation increases the swelling power. The results also showed lower gelatinization (To, Tp, Tc, and ΔH) and pasting parameters (the peak and final viscosity, peak time, and pasting temperature) for the dual modified starches than other treatments. In summary, this study showed that dually modified tapioca starch has potential application in dip molding and coating.

The Role of Structure and Interactions in Thermoplastic Starch-Nanocellulose Composites

Composite films were fabricated by using cellulose nanocrystals (CNCs) as reinforcement up to 50 wt% in thermoplastic starch (TPS). Structure and interactions were modified by using different types (glycerol and sorbitol) and different amounts (30 and 40%) of plasticizers. The structure of the composites was characterized by visible spectroscopy, Haze index measurements, and scanning electron microscopy. Tensile properties were determined by tensile testing, and the effect of CNC content on vapor permeability was investigated. Although all composite films are transparent and can hardly be distinguished by human eyes, the addition of CNCs somewhat decreases the transmittance of the films. This can be related to the increased light scattering of the films, which is caused by the aggregation of nanocrystals, leading to the formation of micron-sized particles. Nevertheless, strength is enhanced by CNCs, mostly in the composite series prepared with 30% sorbitol. Additionally, the relatively high water vapor permeability of TPS is considerably decreased by the incorporation of at least 20 wt% CNCs. Reinforcement is determined mostly by the competitive interactions among starch, nanocellulose, and plasticizer molecules. The aging of the films is caused by the additional water uptake from the atmosphere and the retrogradation of starch.

Valorization of Rice Straw into Cellulose Microfibers for the Reinforcement of Thermoplastic Corn Starch Films

In the present study, agro-food waste derived rice straw (RS) was valorized into cellulose microfibers (CMFs) using a green process of combined ultrasound and heating treatments and were thereafter used to improve the physical properties of thermoplastic starch films (TPS). Mechanical defibrillation of the fibers gave rise to CMFs with cumulative frequencies of length and diameters below 200 and 5–15 µm, respectively. The resultant CMFs were successfully incorporated at, 1, 3, and 5 wt% into TPS by melt mixing and also starch was subjected to dry heating (DH) modification to yield TPS modified by dry heating (TPSDH). The resultant materials were finally shaped into films by thermo-compression and characterized. It was observed that both DH modification and fiber incorporation at 3 and 5 wt% loadings interfered with the starch gelatinization, leading to non-gelatinized starch granules in the biopolymer matrix. Thermo-compressed films prepared with both types of starches and reinforced with 3 wt% CMFs were more rigid (percentage increases of ~215% for TPS and ~207% for the TPSDH), more resistant to break (~100% for TPS and ~60% for TPSDH), but also less extensible (~53% for TPS and ~78% for TPSDH). The incorporation of CMFs into the TPS matrix at the highest contents also promoted a decrease in water vapor (~15%) and oxygen permeabilities (~30%). Finally, all the TPS composite films showed low changes in terms of optical properties and equilibrium moisture, being less soluble in water than the TPSDH films.

Characterization of Anthocyanin Associated Purple Sweet Potato Starch and Peel-Based pH Indicator Films

In food packaging, smart indicator films based on natural resources have greatly attracted researchers to minimize the environmental issues as well as to satisfy consumer preferences for food safety. In this research, pH-sensitive films were prepared using purple-fleshed sweet potato starch (SPS) and sweet potato peel (SPP). Two categories of the film (i) SPS and (ii) SPS/SPP, were fabricated via solvent casting technique, incorporating different concentrations of commercial purple sweet potato anthocyanin (CA) at 0%, 1%, 1.5%, and 2% (w/v) and the physicochemical, mechanical, thermal, and morphological properties of the films were investigated. The thickness, water solubility, and swelling degree of the films increased with the increment of CA, whereas there were no significant changes in the water content (WC) of the films. Water vapor permeability (WVP) was decreased for SPS films while statistically similar for SPS/SPP films. The addition of CA reduced the tensile strength (TS) and tensile modulus (TM) yet increased the elongation at break (EaB) of the films as compared to films without CA. The FTIR results confirmed the immobilization of anthocyanin into the film. In SEM images, roughness in the surfaces of the CA-associated films was observed. A reduction of thermal stability was found for the films with anthocyanin except for the SPS/SPP CA 2% film. Furthermore, the CA-associated films showed a remarkable color response when subjected to pH buffers (pH 1 to 12) and successfully monitored chicken freshness. The fastest color migration was observed in acidic conditions when the films were immersed into aqueous, acidic, low fat, and fatty food simulants. The findings of this work demonstrated that the developed pH indicator films have the potential to be implemented as smart packaging to monitor food freshness and quality for safe consumption.

The effects of nano-zinc oxide morphology on functional and antibacterial properties of tapioca starch bionanocomposite

The purpose of this study was to evaluate the effect of nano-zinc oxide (ZnO-N) morphology on the functional and antimicrobial properties of tapioca starch films. For this reason, nanosphere (ZnO-ns), nanorod (ZnO-nr), and nanoparticle of ZnO (ZnO-np) at 0.5%, 1.0%, and 2.0% were added to the starch film. Then, physicochemical, mechanical, and barrier properties were evaluated. Also, UV-visible and Fourier transform infrared spectroscopy (FTIR) spectra and antibacterial activity of prepared nanocomposite films against Escherichia coli were examined. The results revealed that the ZnO-ns had the most effects on mechanical, physicochemical, and barrier properties. The highest values of the tensile strength (14.15 MPa) and Young's modulus (32.74 MPa) and the lowest values of elongation at break (10.40%) were obtained in the films containing 2% of ZnO nanosphere. In terms of UV transmission, ZnO-nr showed the most significant impact morphology. FTIR spectra indicated that interactions for all morphologies were physical interaction, and there are no chemical reactions between starch structure and nanoparticles. The antibacterial effect of the ZnO-ns was higher than that of other morphologies. In summary, ZnO-ns was the best morphology for using ZnO-N in starch-based nanocomposite films.

Preparation, characterization and its potential applications in Isoniazid drug delivery of porous microcrystalline cellulose from banana pseudostem fibers

Banana pseudostem, a cellulose-rich by-product, is regarded as an important agricultural waste during the process of banana production. Microcrystalline cellulose was successfully prepared from banana pseudostem using acid hydrolysis method. Microcrystalline cellulose was characterized through various techniques such as XRD, TGA, SEM, FTIR and antioxidant activity to explore the possible applications in the pharmaceutical industries especially as a drug delivery vehicle. The investigation revealed that the derived microcrystalline cellulose is non-aggregated, short rods with high crystallinity index 67% and stable up to 347 °C. FTIR spectroscopy showed that hydrolysis treatments are efficient for the removal of lignin and hemicellulose content. Microcrystalline cellulose exhibited good antioxidant activity 90.29% at 100 μg/ml. In vitro studies for the drug release were carried out in simulated intestinal fluid (SIF) using Isoniazid drug. The study proves that microcrystalline cellulose can be directly obtained from banana pseudostem which is not only beneficial to reduce the cost of traditional microcrystalline cellulose but is also conducive to the value-added utilization of the pseudostem.

Effects of nanocellulose fiber and thymol on mechanical, thermal, and barrier properties of corn starch films

This study explores the preparation of corn starch (CS) films incorporated with nanocellulose fiber (NCF) and different concentrations of thymol (0.1, 0.3, and 0.5% weight of thymol/volume of solution (% w/v)) via the solvent casting method. The resulting films were characterized by the functional chemistry, crystallinity, morphology, mechanical, thermal, and barrier properties. The Fourier transform infrared spectroscopy analysis confirmed the presence of intermolecular hydrogen bonding between the thymol and starch, as well as the thymol and glycerol, via hydroxyl groups of glycerol, starch, and thymol. The film crystallinity decreased with increasing concentration of thymol. The addition of NCF at 1.5% weight of starch increased the tensile strength (TS) and Young's Modulus (YM), but decreased the elongation at break (EAB), oxygen permeability, and water vapor permeability of the CS films. The thermal stability of the CS films was also improved with the addition of NCF. The addition of thymol to the CS/NCF bio-nanocomposite films decreased the TS and YM, respectively but increased the EAB due to the plasticizing effect of thymol. The addition of thymol also improved the thermal stability but reduced the barrier properties of the films. The effects on the mechanical, thermal, and barrier properties were more pronounced at higher concentrations of thymol. In conclusion, the inclusion of both NCF and thymol led to the improvement of the flexibility and thermal stability of the CS films.

Sustainable and cost-effective approach for the synthesis of lignin-containing cellulose nanocrystals from oil palm empty fruit bunch

Cellulose nanocrystals (CNC) have received great research attention since the last few decades due to their extraordinary properties and wide range of applications. In this study, a sustainable and cost-effective method for the synthesis of lignin-containing cellulose nanocrystals (LCNC) from oil palm empty fruit bunch (EFB) is presented. This method is able to retain the lignin in EFB and manifest the properties of lignin. The proposed synthesis process is simpler than the conventional method of producing lignin-coated CNC by first removing the lignin to synthesize CNC followed by the re-coating of lignin on the structure. The samples of LCNC were characterized by transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy and water contact angle analysis. In addition, by altering the acid concentration during acid hydrolysis process (53% - 60% H₂SO₄), both surface hydrophobicity (66.0° - 75.1°) and length of LCNC (467 nm-177 nm) can be altered wherein a higher concentration of acid resulted in a greater contact angle and a shorter length of LCNC. Cost and energy analysis deduced that the proposed synthesis method saved about 62% of the total material cost and 80% less energy as compared to the synthesis of lignin-coated CNC.

Coffee silverskin and starch-rich potato washing slurries as raw materials for elastic, antioxidant, and UV-protective biobased films

Food processing wastes together with the perishable foodstuff loss promote environmental and societal concerns. Food byproducts can have value as a source of functional molecules for developing active packaging without food waste, under a circular economy. Nevertheless, the often-associated extraction/chemical processes compromise the sustainability of food byproducts reusability. In this work, coffee silverskin (CS) and starch, recovered from coffee roasting and potato industries, respectively, were together gelatinized to form in-situ films. Targeting to fit with the food application requirements, it is important to understand the influence of crude CS amount (1%, 5%, and 10% w/w of dry starch weight) on potato starch-based film properties. CS conferred a brownish coloration to the films, maintaining their transparency. The films colour intensity, antioxidant activity, and water tolerance were directly related with the CS dosage. Moreover, as high the CS amount, higher the elasticity, stretchability, and UV radiation absorption of the pristine films. These data emphasized that CS molecules extracted during gelatinization prevented the starch-starch hydrogen bonding and conferred functional and barrier properties. Overall, adding crude CS during potato starch gelatinization revealed to be an efficient strategy to tune the performance of potato starch-based films, opening an opportunity for valorising coffee roasting and potato byproducts.

Sandwich panel biocomposite of thermoplastic corn starch and bacterial cellulose

Inadequate disposition and long period for degradation of Petroleum-derived polymers promote damages in the environment, which could be minimized by the use of biodegradable polymers such as starch and cellulose. Films of thermoplastic corn starch (TPS) and bacterial cellulose (BC) were used to produce sandwich panel biocomposite. RXD, SEM and FTIR were used to verify the transformation of TPS from native corn starch. TPS/BC is flexible and transparent, but it is less transparent that TPS and BC due to its multilayer format. TPS/BC presented similar thermal events to TPS and BC samples and thermal stability similar to TPS. The FTIR spectrum of the TPS/BC showed bands observed in the BC and TPS spectra. BC, TPS and TPS/BC showed faster water absorption in the initial stage reaching a stability at about 50 h and presenting Fickian behavior. TPS/BC showed lower water absorption and a good adhesion between the phases observed by SEM images, which can be associated to hydrogen interactions in the interface improving mechanical properties. TPS/BC showed an increase of about 3.6 times in the tensile strength compared to TPS, indicating that BC is a good reinforcement for TPS.

Development of chia seed (Salvia hispanica) mucilage films plasticized with polyol mixtures: Mechanical and barrier properties

Food packaging is one of the main contributors to the high rates of environmental contamination; therefore, interest has emerged on the use of biopolymers as alternative materials to replace conventional food packaging. Chia seed (Salvia hispanica) is recognized by having a high content of a polysaccharide called mucilage. The aim of this study was to evaluate the feasibility using of chia seed mucilage (CSM) and a polyol mixture containing glycerol and sorbitol for the development of films. CSM films with higher sorbitol content showed superior tensile strength (3.23 N/mm²) and lower water vapor permeability (1.3*10^-9 g/m*s*Pa), but had poor flexibility compared to other treatments. Conversely, high glycerol content showed high elongation at break (67.55%) and solubility (22.75%), but poor water vapor permeability and tensile strength. Film formulations were optimized implementing a factorial design according to response surface methodology. Raman spectra analysis showed shifts from 854 to 872 cm^-1 and 1061 to 1076 cm^-1, β (CCO) modes, indicating an increase in hydrogen bonding, responsible for the high tensile strength and decreased water vapor permeability observed in this study. The optimum conditions of polyol concentration were 1.3 g of glycerol and 2.0 g of sorbitol per g of CSM. Based on these results, chia seed mucilage can successfully be used to develop biofilms with potential to be used in drug delivery and edible food coating applications.