Effect of Various Plasticizers in Different Concentrations on Physical, Thermal, Mechanical, and Structural Properties of Wheat Starch-Based Films

The Optimization of Avocado-Seed-Starch-Based Degradable Plastic Synthesis with a Polylactic Acid (PLA) Blend Using Response Surface Methodology (RSM)

This research improves the strength of plastic using avocado seed starch and PLA. The effect of blending avocado seed starch and PLA was optimized using the RSM approach by using two variables: water absorption and biodegradability. Mixing them using RSM gave the best result: 1.8 g of starch and 3 g of PLA. Degradable plastic has a tensile strength of 10.1 MPa, elongation at a break of 85.8%, and a Young's modulus of 190 MPa. Infrared spectroscopy showed that the plastic had a -OH bond at 3273.20 cm-1, 3502.73 cm-1, and 3647.39 cm-1, a CH2 bond at 2953.52 cm-1, 2945.30 cm-1, and 2902.87 cm-1, a C=C bond at 1631.78 cm-1, and a C-O bond at 1741.72 cm-1. The plastic decomposed in the soil. It was organic and hydrophilic. Thermal tests demonstrated that the plastic can withstand heat well, losing weight at 356.86 °C to 413.64 °C, forming crystals and plastic melts at 159.10 °C-the same as PLA. In the melt flow test, the sample melted before measurement, and was therefore not measurable-process conditions affected it. A water absorption of 5.763% and biodegradation rate of 37.988% were found when the samples were decomposed for 12 days. The starch and PLA fused in the morphology analysis to form a smooth surface. The RSM value was close to 1. The RSM gave the best process parameters.

Biodegradable plastics: mechanisms of degradation and generated bio microplastic impact on soil health

Conventional petroleum-derived polymers are valued for their versatility and are widely used, owing to their characteristics such as cost-effectiveness, diverse physical and chemical qualities, lower molecular weight, and easy processability for large-scale production. However, the extensive accumulation of such plastics leads to serious environmental issues. To combat this existing situation, an alternative lies in the production of bioplastics from natural and renewable sources such as plants, animals, microbes, etc. Bioplastics obtained from renewable sources are compostable and susceptible to degradation caused by microbes hydrolyzing to CO2, CH4, and biomass. Also, certain additives are reinforced into the bioplastic films to improve their physicochemical properties and degradation rate. However, on degradation, the bio-microplastic (BM) produced could have positive as well as negative impact on the soil health. This article thus focuses on the degradation of various fossil based as well as bio based biodegradable plastics such as polyhydroxyalkanoates (PHA), polyhydroxy butyrate (PHB), polylactic acid (PLA), polybutylene succinate (PBS), polycaprolactone (PCL), and polysaccharide derived bioplastics by mechanical, thermal, photodegradation and microbial approaches. The degradation mechanism of each approach has been discussed in detailed for different bioplastics. How the incorporation or reinforcement of various additives in the biodegradable plastics effects their degradation rates has also been discussed. In addition to that, the impact of generated bio-microplastic on physicochemical properties of soil such as pH, bulk density, carbon, nitrogen content etc. and biological properties such as on genome of native soil microbes and on plant nutritional health have been discussed in detailed.

Tapioca-starch-based bionanocomposites with fructose and titanium dioxide for food packaging and fertilization applications

Bionanocomposites offer a promising solution to the plastic waste crisis. Although tapioca starch shows potential as a bioplastic material, it is characterized by low mechanical properties, poor thermal stability, and high water absorption owing to its hydrophilic nature. To increase the flexibility of the material and reduce the transmission rate of oxygen and water vapor, additives such as fructose and titanium dioxide (TiO2) can be incorporated into the material. TiO2 nanoparticles are commonly utilized in agriculture to enhance nutrient release and promote plant growth. In this study, X-ray diffraction analysis revealed that TiO2 reduced crystal size while increasing the crystallinity of bionanocomposites. Fourier-transform infrared spectroscopy analysis revealed an absorption peak at 3397 cm-1, indicating hydrogen bonding between TiO2 and starch-OH groups, and a peak at 773 cm-1, indicating an increase in the intensity of Ti-O-Ti stretching vibrations with the incorporation of TiO2. Water absorption rate results confirmed that TiO2 addition enhanced bionanocomposite resistance to water vapor and moisture, evidenced by increased tensile strength from 0.11 to 0.49 MPa and Young's modulus from 2.48 to 5.26 MPa, as well as decreased elongation at break from 21.46 % to 2.36 % in bionanocomposites with TiO2. Furthermore, with TiO2 addition, the biodegradation rate of the bionanocomposites decreased, which is beneficial for enhancing plant nutrient content.

Isolation and characterization of novel bioplasticizers from rose (Rosa damascena Mill.) petals and its suitability investigation for poly (butylene adipate-co-terephthalate) biofilm applications

The current growing environmental awareness has forced the use of biodegradable plasticizers, which are sustainable and abundant in plant resources. Rose petal plasticizers (RPP) act as an actual substitute for chemical plasticizers in this situation as they are biocompatible and biodegradable. Chemical procedures like amination, alkalization, and surface catalysis are used to extract the natural emollients from rose petals. XRD, FT-IR, and UV studies were used to understand the characteristics of the rose petal plasticizer. Based on the XRD data, the RPP's crystallinity size (CS) and crystallinity index (CI) values were determined to be 9.36 nm and 23.87%, respectively. The surface morphology of the isolated plasticizer is investigated using SEM, EDAX analysis and AFM. RPP surface pores with rough surfaces are visible in SEM images, which make them appropriate for plasticizing novel bioplastics with superior mechanical qualities. The plasticizer's heat degradation behaviour is investigated using thermogravimetric and differential thermogram analysis curves. Following the characterization of the synthesised molecules, the plasticization effect was examined using a biodegradable polymer matrix called poly (butylene adipate-co-terephthalate) (PBAT). The reinforcement interface was also examined using scanning electron microscopy analysis. RPP-reinforced films demonstrated greater flexibility and superior surface compatibility at a 5% loading compared to PBAT-only films. Based on a number of reported features, RPP could be a great plasticizer to address future environmental problems.

Effects of polyol and surfactant plasticisers on lyophilised rice starch wafers for buccal drug delivery

Rice starch is a promising biopolymer for buccal formulations but typical oven drying may promote starch retrogradation that affects mechanical properties. Hence, lyophilisation was proposed here to improve starch product's stability. This study aims to investigate the effects of plasticisers (sorbitol and Tween® 80, T80) on the characteristics and drug release profiles of lyophilised rice starch wafers incorporated with propranolol hydrochloride. The wafers were prepared by lyophilising starch mixture (5%w/v) with plasticiser (0.2 and 0.3 g/g) and drug (10, 20, 30%w/w). Control wafers exhibited loose layers with rough wrinkled surface. Sorbitol resulted in a dense structure with higher puncture strength (PS) but lower water absorption capacity (WAC) while T80 loosened the flakes that reduced PS and increased WAC. Drug inclusion decreased PS and increased WAC of unplasticised wafers. T80-plasticised wafers with drug had a lower PS and higher WAC than sorbitol-plasticised wafers. Particularly, T80-plasticised wafers achieved outstandingly high PS and the lowest WAC at 30%w/w drug. Drug dissolution of wafers relied mainly on the drug crystallinity and WAC at 10 and 30%w/w drug. Plasticisers reduced and increased drug dissolution at 10 and 20%w/w drug, respectively. This study highlights the potential of lyophilisation in preparing rice starch wafers for buccal delivery.

Pullulan-based films impregnated with silver nanoparticles from the Fusarium culmorum strain JTW1 for potential applications in the food industry and medicine

Introduction: Biopolymers, such as pullulan, a natural exopolysaccharide from Aureobasidium pullulans, and their nanocomposites are commonly used in the food, pharmaceutical, and medical industries due to their unique physical and chemical properties. Methods: Pullulan was synthesized by the A. pullulans ATCC 201253 strain. Nanocomposite films based on biosynthesized pullulan were prepared and loaded with different concentrations of silver nanoparticles (AgNPs) synthesized by the Fusarium culmorum strain JTW1. AgNPs were characterized by transmission electron microscopy, Zeta potential measurements, and Fourier-transform infrared spectroscopy. In turn, the produced films were subjected to physico-chemical analyses such as goniometry, UV shielding capacity, attenuated total reflection-Fourier-transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy, and their mechanical and degradation properties were assessed. The antibacterial assays of the nanoparticles and the nanocomposite films against both food-borne and reference pathogens, including Listeria monocytogenes, Salmonella infantis, Salmonella enterica, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae, were performed using standard methods. Results: AgNPs were small (mean 15.1 nm), spherical, and displayed good stability, being coated with protein biomolecules. When used in higher concentrations as an additive to pullulan films, they resulted in reduced hydrophilicity and light transmission for both UV-B and UV-A lights. Moreover, the produced films exhibited a smooth surface. Therefore, it can be concluded that the addition of biogenic AgNPs did not change the morphology and texture of the films compared to the control film. The nanoparticles and nanocomposite films demonstrated remarkable antibacterial activity against both food-borne and reference bacteria. The highest activity of the prepared films was observed against L. monocytogenes. Discussion: The obtained results suggest that the novel nanocomposite films prepared from biosynthesized pullulan and AgNPs can be considered for use in the development of medical products and food packaging. Moreover, this is the first report on pullulan-based nanocomposites with mycogenic AgNPs for such applications.

Development and Characterization of Polylactic Acid (PLA)-Based Nanocomposites Used for Food Packaging

The present study is focused on polylactic acid (PLA) blending with bio nanoadditives, such as Tonsil^® (clay) and Aerosil^®, to obtain nanocomposites for a new generation of food packaging. The basic composition was enhanced using Sorbitan oleate (E494) and Proviplast as plasticizers, increasing the composite samples' stability and their mechanical strength. Four mixtures were prepared: S1 with Tonsil^®; S2 with Aerosil^®; S3 with Aerosil^® + Proviplast; and S4 with Sabosorb. They were complexly characterized by FT-IR spectroscopy, differential scanning calorimetry, mechanical tests on different temperatures, and absorption of the saline solution. FTIR shows a proper embedding of the filler component into the polymer matrix and DSC presents a good stability at the living body temperature for all prepared samples. Micro and nanostructural aspects were evidenced by SEM and AFM microscopy, revealing that S3 has the most compact and uniform filler distribution and S4 has the most irregular one. Thus, S3 evidenced the best diametral tensile strength and S4 evidenced the weakest values. All samples present the best bending strength at 18 °C and fair values at 4 °C, with the best values being obtained for the S1 sample and the worst for S4. The lack of mechanical strength of the S4 sample is compensated by its best resistance at liquid penetration, while S1 is more affected by the liquid infiltrations. Finally, results show that PLA composites are suitable for biodegradable and disposable food packages, and the desired properties could be achieved by proper adjustment of the filler proportions.

Potato Starch-Based Film Incorporated with Tea Polyphenols and Its Application in Fruit Packaging

Effects of tea polyphenols (TP) on the physical properties, barrier properties and functionality of potato starch-based film were determined, while the interaction mechanism between TP and starch in film and the application of this film in fruit packaging were further evaluated. TP exhibited different effects on the physical properties of potato starch-based film, including thickness (0.083 to 0.087 mm), moisture content (9.27% to 9.68%), color (ΔE value: 5.41 to 10.55), light transmittance (51% to 62%), tensile properties and thermal properties, and improved its barrier properties, including water vapor permeability (9.68 to 11.84 × 10-11 g m-1 s-1 Pa-1),oxygen permeability (1.25 to 2.78 × 10-16 g m-1 s-1 Pa-1) and antioxidant activity. According to the determination of wide-angle X-ray diffraction, Fourier transform infrared and scanning electron microscope, TP could interact with starch chains via hydrogen bonds to form non-crystal complexes, thus affecting the cross-linking among starch chains and further changing the microstructure of film. Furthermore, film incorporated with TP could improve the storage quality (including weight and texture) of blueberries, and inhibit the enzymatic browning of fresh-cut bananas during storage. All present results suggested that tea polyphenols had potential to enhance the properties and function of potato starch-based film, and the film exhibited the application prospect in fruit packaging and preservation.