Cassava Starch Films Containing Quinoa Starch Nanocrystals: Physical and Surface Properties

Gem-like starch granules engineered with different crystalline starches

The retrogradation property endows starch molecules with the unique ability to self-assemble crystals after encountering damage, which can restore the internal double helix structure to a limited extent. We devise a simple set of steps to grow perfect crystals of uniform size with different crystal systems in a given growth environment by first customizing the crystal seeds through enzymatic modification, and then exploiting the spontaneous recrystallization of starch. Optical microscopy confirmed the formation of gem-like starch granules (GSGs) in starches with 24.3 %-28.1 % amylose content, while no GSGs appeared in any of the other contents. FITR and XRD pattern revealed a shift in the double helix arrangement within the crystals, and the resultant change in starch crystal type from A-type to B-type provided theoretical support for the production of tetragonal, tetragonal, and hexagonal crystal systems. This work may provide a promising approach to the development of novel starch-based food/drug carriers.

Enhancing Cassava Starch Bioplastics with Vismia guianensis Alcoholic Extract: Characterization with Potential Applications

This work investigates the incorporation of Vismia guianensis alcoholic extract (EAVG) into cassava starch, with the aim of improving its bioplastic properties. Cassava starch was dissolved into distilled water and doped with 0.2%, 0.5%, and 1.0% EAVG under a temperature controlled at the gelatinization point (∼70 °C) and then cast to form bioplastics. The resulting samples were characterized via attenuated total reflectance/Fourier transform infrared spectroscopy (ATR/FTIR), thermogravimetric and differential thermal analysis (TGA-DTA), X-ray diffraction (XRD), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), atomic force microscopy (AFM), and mechanical essays, providing insights into chemical composition, thermal stability, crystallinity, surface morphology, and mechanical properties. The results demonstrated that EAVG played an effective role, enhancing the flexibility and stability of the bioplastic with potential use in biomedical applications. Moreover, the results also showed significant improvements in mechanical and thermal properties, suggesting that EAVG is a valuable addition to bioplastics. Therefore, EAVG presents a pathway for advancing bioplastics with enhanced mechanical, thermal, and functional characteristics, with the potential for further advancements in these fields.

Avocado Seed Starch-Based Films Reinforced with Starch Nanocrystals

Biopolymers derived from biomass can provide the advantages of both biodegradability and functional qualities from a circular economy point of view, where waste is transformed into raw material. In particular, avocado seeds can be considered an interesting residue for biobased packaging applications due to their high starch content. In this work, avocado seed starch (ASS)-based films containing different glycerol concentrations were prepared by solvent casting. Films were also reinforced with starch nanocrystals (SNCs) obtained through the acid hydrolysis of ASS. The characterization of the extracted starch and starch nanocrystals by scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis has been reported. Adding 1% of SNCs increased elastic modulus by 112% and decreased water vapor permeability by 30% with respect to neat matrix. Interestingly, the bioactive compounds from the avocado seed provided the films with high antioxidant capacity. Moreover, considering the long time required for traditional plastic packaging to degrade, all of the ASS-based films disintegrated within 48 h under lab-scale composting conditions. The results of this work support the valorization of food waste byproducts and the development of reinforced biodegradable materials for potential use as active food packaging.

Nanofillers in Novel Food Packaging Systems and Their Toxicity Issues

Background: Environmental concerns about petroleum-based plastic packaging materials and the growing demand for food have inspired researchers and the food industry to develop food packaging with better food preservation and biodegradability. Nanocomposites consisting of nanofillers, and synthetic/biopolymers can be applied to improve the physiochemical and antimicrobial properties and sustainability of food packaging. Scope and approach: This review summarized the recent advances in nanofiller and their applications in improved food packaging systems (e.g., nanoclay, carbon nanotubes), active food packaging (e.g., silver nanoparticles (Ag NPs), zinc oxide nanoparticles (ZnO NPs)), intelligent food packaging, and degradable packaging (e.g., titanium dioxide nanoparticles (e.g., TiO2 NPs)). Additionally, the migration processes and related assessment methods for nanofillers were considered, as well as the use of nanofillers to reduce migration. The potential cytotoxicity and ecotoxicity of nanofillers were also reviewed. Key findings: The incorporation of nanofillers may increase Young's modulus (YM) while decreasing the elongation at break (EAB) (y = -1.55x + 1.38, R2 = 0.128, r = -0.358, p = 0.018) and decreasing the water vapor (WVP) and oxygen permeability (OP) (y = 0.30x - 0.57, R2 = 0.039, r = 0.197, p = 0.065). Meanwhile, the addition of metal-based NPs could also extend the shelf-life of food products by lowering lipid oxidation by an average of approx. 350.74% and weight loss by approx. 28.39% during the longest storage period, and significantly increasing antibacterial efficacy against S. aureus compared to the neat polymer films (p = 0.034). Moreover, the migration process of nanofillers may be negligible but still requires further research. Additionally, the ecotoxicity of nanofillers is unclear, as the final distribution of nanocomposites in the environment is unknown. Conclusions: Nanotechnology helps to overcome the challenges associated with traditional packaging materials. Strong regulatory frameworks and safety standards are needed to ensure the appropriate use of nanocomposites. There is also a need to explore how to realize the economic and technical requirements for large-scale implementation of nanocomposite technologies.

The application of starch-based edible film in food preservation: a comprehensive review

Using renewable resources for food packaging not only helps reduce our dependence on fossil fuels but also minimizes the environmental impact associated with traditional plastics. Starch has been a hot topic in the field of current research because of its low cost, wide source and good film forming property. However, a comprehensive review in this field is still lacking. Starch-based films offer a promising alternative for sustainable packaging in the food industry. The present paper covers various aspects such as raw material sources, modification methods, and film formation mechanisms. Understanding the physicochemical properties and potential commercial applications is crucial for bridging the gap between research and practical implementation. Finally, the application of starch-based films in the food industry is discussed in detail. Different modifications of starch can improve the mechanical and barrier properties of the films. The addition of active substances to starch-based films can endow them with more functions. Therefore, these factors should be better investigated and optimized in future studies to improve the physicochemical properties and functionality of starch-based films. In summary, this review provides comprehensive information and the latest research progress of starch-based films in the food industry.

Effects of oregano essential oil Pickering emulsion and ZnO nanoparticles on the properties and antibacterial activity of konjac glucomannan/carboxymethyl chitosan nanocomposite films

Green and environmentally friendly natural bio-based food packaging films are increasingly favored by consumers. This study incorporated carboxylated-cellulose nanocrystal stabilized oregano essential oil (OEO) Pickering emulsion and ZnO nanoparticles (ZNPs) into konjac glucomannan (KGM)/carboxymethyl chitosan (CMCS) complexes to develop active food packaging films. The effects of OEO Pickering emulsion and ZNPs on the physical, structural, and antimicrobial activities of the nanocomposite films were evaluated. The OEO Pickering emulsion had a droplet size of 48.43 ± 3.56 μm and showed excellent dispersion and stability. Fourier transform infrared and X-ray diffraction analyses suggested that the interactions between the Pickering emulsion, ZNPs and KGM/CMCS matrix were mainly through hydrogen bonding. SEM observations confirmed that the Pickering emulsion and ZNPs were well incorporated into the KGM/CMCS matrix, forming tiny pores within the nanocomposite films. The incorporation of the OEO Pickering emulsion and/or ZNPs obviously increased the light and water vapor barrier ability, thermal stability, mechanical strength and antimicrobial properties of the KGM/CMCS nanocomposite film. Notably, KGM/CMCS/ZNPs/OEO Pickering emulsion films exhibited the highest barrier, and mechanical and antimicrobial activities due to the synergistic effect between the OEO Pickering emulsion and ZNPs. These results suggest that KGM/CMCS/ZNPs/OEO Pickering emulsion films can be utilized as novel active food packaging materials to extend the shelf life of packaged foods.

Dual Modification of Cassava Starch Using Physical Treatments for Production of Pickering Stabilizers

Cassava starch nanoparticles (SNP) were produced using the nanoprecipitation method after modification of starch granules using ultrasound (US) or heat-moisture treatment (HMT). To produce SNP, cassava starches were gelatinized (95 °C/30 min) and precipitated after cooling, using absolute ethanol. SNPs were isolated using centrifugation and lyophilized. The nanoparticles produced from native starch and starches modified using US or HMT, named NSNP, USNP and HSNP, respectively, were characterized in terms of their main physical or functional properties. The SNP showed cluster plate formats, which were smooth for particles produced from native starch (NSNP) and rough for particles from starch modified with US (USNP) or HMT (HSNP), with smaller size ranges presented by HSNP (~63-674 nm) than by USNP (~123-1300 nm) or NSNP (~25-1450 nm). SNP had low surface charge values and a V-type crystalline structure. FTIR and thermal analyses confirmed the reduction of crystallinity. The SNP produced after physical pretreatments (US, HMT) showed an improvement in lipophilicity, with their oil absorption capacity in decreasing order being HSNP > USNP > NSNP, which was confirmed by the significant increase in contact angles from ~68.4° (NSNP) to ~76° (USNP; HSNP). A concentration of SNP higher than 4% may be required to produce stability with 20% oil content. The emulsions produced with HSNP showed stability during the storage (7 days at 20 °C), whereas the emulsions prepared with NSNP exhibited phase separation after preparation. The results suggested that dual physical modifications could be used for the production of starch nanoparticles as stabilizers for Pickering emulsions with stable characteristics.

Preparation and characterization of lotus root starch based bioactive edible film containing quercetin-encapsulated nanoparticle and its effect on grape preservation

The present work aimed to develop a novel bioactive edible film prepared by adding quercetin-encapsulated carboxymethyl lotus root starch nanoparticles (QNPs)，gellan gum and lotus root starch. The physicochemical characteristics, preservation effect and mechanism on grapes of the prepared film were investigated. SEM results showed that QNPs (5 %) were dispersed uniformly within lotus root starch matrix, indicating the formation of a stable composite nanoparticle film. In addition, the incorporation of QNPs (5 %) effectively improved the mechanical strength, thermal stability, barrier property and antioxidant activity of QNPs/starch film. Moreover, compared with the control, the QNPs/starch (5 %) film showed effective preservation effect on grapes during 21 days of storage at room temperature, based on the characterization by grape appearance, weight loss, firmness, and titratable acidity. Further studies found that QNPs/starch (5 %) film could exhibit enhanced antioxidant activity and potent anti-fungal ability against Botrytis cinerea, thus extending grape shelf life. In conclusion, the obtained QNPs/starch (5 %) film presented a promising application as an edible packing material for fruit preservation by antioxidant and preventing Botrytis cinerea contamination.

Recent preparation, modification and application progress of starch nanocrystals: A review

Due to the advantages of wide sources, high biocompatibility and favorable biodegradability, starch nanocrystals (SNCs) have gradually attracted attention and have bright development prospects in food, agriculture, materials, medicine and other fields. However, the traditional preparation method of SNCs is time-consuming and inefficient, and the physicochemical properties cannot fully meet the needs of multiple applications. Fortunately, the unique onion-like structure of starch granules and the large number of hydroxyl groups present on the surface entitle SNCs to efficient preparation and modification. This paper comprehensively reviewed the improvement methods of SNCs preparation process in recent years, and the advantages and disadvantages of the two improvement strategies were compared. Besides, the importance of introducing different pretreatment methods into the SNCs preparation process was emphasized. It also focused on the different modification treatment and application progress of SNCs, especially in the starch-based surface coating of fruits and vegetables. The information will contribute to further improve the preparation efficiency and physicochemical properties of SNCs, and ultimately expand the application field.

Thermoplastic Starch Biocomposite Films Reinforced with Nanocellulose from Agave tequilana Weber var. Azul Bagasse

In this work, cellulose nanocrystals (CNCs), bleached cellulose nanofibers (bCNFs), and unbleached cellulose nanofibers (ubCNFs) isolated by acid hydrolysis from Agave tequilana Weber var. Azul bagasse, an agro-waste from the tequila industry, were used as reinforcements in a thermoplastic starch matrix to obtain environmentally friendly materials that can substitute contaminant polymers. A robust characterization of starting materials and biocomposites was carried out. Biocomposite mechanical, thermal, and antibacterial properties were evaluated, as well as color, crystallinity, morphology, rugosity, lateral texture, electrical conductivity, chemical identity, solubility, and water vapor permeability. Pulp fibers and nanocelluloses were analyzed via SEM, TEM, and AFM. The water vapor permeability (WVP) decreased by up to 20.69% with the presence of CNCs. The solubility decreases with the presence of CNFs and CNCs. The addition of CNCs and CNFs increased the tensile strength and Young's modulus and decreased the elongation at break. Biocomposites prepared with ubCNF showed the best tensile mechanical properties due to a better adhesion with the matrix. Images of bCNF-based biocomposites demonstrated that bCNFs are good reinforcing agents as the fibers were dispersed within the starch film and embedded within the matrix. Roughness increased with CNF content and decreased with CNC content. Films with CNCs did not show bacterial growth for Staphylococcus aureus and Escherichia coli. This study offers a new theoretical basis since it demonstrates that different proportions of bleached or unbleached nanofibers and nanocrystals can improve the properties of starch films.

A Comparative Investigation of the Surface Properties of Corn-Starch-Microfibrillated Cellulose Composite Films

Starch-based materials seem to be an excellent alternative for conventional plastics used in various applications. Microfibralted cellulose can be used to improve the surface properties of starch-based materials. This study aims to analyze the surface properties of starch-microfibrillated cellulose materials. The surface properties of films were evaluated by ATR-FTIR, surface roughness, water wettability, and surface free energy. The surface homogeneity between corn starch and microfibrillated cellulose (MFC) fibers was confirmed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Microscopic analyses of the film surfaces confirm good compatibility of starch and MFC. The addition of MFC increased the surface roughness and polarity of developed starch/MFC materials. The surface roughness parameter has increased from 1.44 ± 0.59 to 2.32 ± 1.13 for pure starch-based materials and starch/MFC material with the highest MFC content. The WCA contact angle has decreased from 70.3 ± 2.4 to 39.1 ± 1.0°, while the surface free energy is 46.2 ± 3.4 to 66.2 ± 1.5 mJ·m^-2, respectively. The findings of this study present that surface structure starch/MFC films exhibit homogeneity, which would be helpful in the application of MFC/starch materials for biodegradable packaging purposes.