Effect of amylose content and nanoclay incorporation order in physicochemical properties of starch/montmorillonite composites

Impact of Nanoclays Addition on Chickpea (Cicer arietinum L.) Flour Film Properties

Chickpea flour is an affordable natural blend of starch, proteins, and lipids, which can create films with suitable properties as an eco-friendly packaging material. Nanoclays' incorporation into natural biopolymers enhances the barrier properties of the resulting nanocomposites, so they could improve the properties of flour films. The objective of this work was to assess the influence of three types of nanoclays (halloysite, bentonite, and Cloisite 20A) at two concentrations on the characteristics of chickpea flour films. In general terms, when the lowest dose (5%) was added, no or very slight significant differences with the control were observed in most parameters, except for thermal stability and opacity, which increased, and solubility, which decreased. At the highest concentration (10%), films containing any of the nanoclays demonstrated greater thermal stability, opacity, and rigidity while being less soluble than those without nanofillers. Bentonite exhibited superior film structure distribution compared to other nanoclays. At the highest concentration, it had the most significant impact on modifying the properties of chickpea flour films, increasing their tensile and puncture strengths while decreasing elasticity and water vapor permeability. The incorporation of nanoclays into chickpea flour films could be a useful technique to enhance their properties.

The Effect of Montmorillonites on the Physicochemical Properties of Potato Starch Films Plasticized with Deep Eutectic Solvent

In the paper, the method of obtaining the potato starch nanocomposites plasticized with a deep eutectic solvent is described. The deep eutectic solvent based on choline chloride and malic acid (CM, molar ratio 1:1) was used as the plasticizer. The effect of the sodium and calcium montmorillonite (MMTNa, MMTCa respectively) addition on the properties of potato starch films was investigated. The thermal, mechanical, and barrier properties were determined. Moreover, a moisture absorption test was performed. The starch gelatinization temperature increased in the presence of montmorillonite. The values of glass transition determined by DMTA depended on the nanofiller type. For the systems containing MMTCa, they generally decreased with its content (although still lower than reference samples). The obtained nanocomposites showed improved mechanical and barrier properties. The highest values of tensile strength and Young's modulus were noted for the system containing 1% MMTNa. The XRD revealed that only the films with MMTNa exhibited intercalation. The homogeneity of the samples decreased with increasing nanofiller concentration. This was probably due to the occurrence of choline chloride-montmorillonite interactions, which were more favored than clay-starch interactions.

Maltol-Incorporated Acetylated Cassava Starch Films for Shelf-Life-Extension Packaging of Bakery Products

Maltol is widely used as a flavor enhancer in baked goods and has an antimicrobial function. Maltol can also be incorporated into biopolymer films to produce active biodegradable packaging for bakery products. This research investigated the incorporation of 1-10% maltol into acetylated cassava starch films as functional packaging for shelf-life extension of butter cake. Films were determined for morphology, chemical interaction and packaging properties. Infrared absorption indicated H-bonding between starch and maltol, while plasticization effects decreased mechanical relaxation temperature. Microstructures showed enhanced smoothness at up to 3% maltol, while maltol crystallization occurred at higher concentrations, giving non-homogeneous matrices. Tensile strength and elongation at break reduced by 37% and 34%, respectively, with the addition of maltol up to 10%. Maltol concentration modified the hydrophilicity and molecular mobility of the matrices, impacting water vapor and oxygen permeability. Films incorporated with maltol were used as packaging for preservative-free butter cake and delayed visible mold growth at room temperature. Starch films with maltol at 1-5% delayed fungal growth by up to 2.7-times, while films containing 10% maltol inhibited mold growth by 6-times (up to 19 days of storage). Incorporating maltol into starch films produced bioactive materials, extending shelf-life while maintaining the aroma of bakery products.

Intelligent labels manufactured by thermo-compression using starch and natural biohybrid based

This work aims to develop intelligent labels based on cassava starch and biohybrid pigments by thermo-compression. The biohybrid pigment (BH) was developed by the adsorption of anthocyanins (ACNs) extracted from the jambolan fruit (Syzygium cumini L.) into montmorillonite (Mt) in order to improve its stability. The effect of the addition of biohybrid on the physicochemical properties of the thermo-pressed starch labels was evaluated. ACNs from jambolan extract show a visible pH-dependent color-changing ability at pH 1 - 12, and the adsorption did not modify the color property. The intelligent labels presented a homogeneous surface, and the BH was well dispersed in the starch matrix. The presence of BH increased the solubility in the water of starch labels. Chemical structure characterization revealed that the BH interacted with starch matrices through hydrogen bonds. Furthermore, the thermal stability of starch labels increased with the presence of BH. Hence, the purple color of intelligent labels was preserved at high temperatures. Finally, labels containing BH show visible changes from purple to a blue color when exposed to ammonia vapor, which simulates the degradation of meat products. Thus, the label content jambolan pigments will be used to control meat deterioration.

Micro foaming performance of scCO2-aid glutaraldehyde/hexametaphosphate/thermoplastic starch foams modified by alkali treatment and montmorillonite nano-platelets

The micro foaming performance, moisture resistance and dynamic viscosity of scCO2-aid glutaraldehyde/hexametaphosphate/thermoplastic tapioca starch (GA/SHMP/TOS) foams were considerably improved by proper NaOH treatment. The expansion ratio, resilience rate, dynamic viscosity values of these NaOH modified foams improved to a maximum, as the time for NaOH treatment approached a proper value. The dynamic viscosity, expansion ratio and resilience rate of the scCO2-aid GA/SHMP/TOS foams modified using 110 atm scCO2-pressure, the proper alkali treatment time, SHMP loading and varying montmorillonite (MMT) loadings improved further, as their MMT loadings approached a proper value of 2.5 part per hundred parts of tapioca starch (PHTOS). Relatively large dynamic viscosity (7.1x104 Pa·s), extremely large expansion ratio (∼75), cell density (1.1x109 cells/cm3) and/or resilience rate (∼80%) were acquired for the scCO2-aid GA/SHMP/TOS/MMT foam modified using the proper alkali treatment time and MMT loading. Thermal analyses results showed that crystallization onset temperatures and crystallization rates of scCO2-aid GA/SHMP/TOS/MMT foams modified using the proper alkali treatment time and varying MMT loadings improved to a highest value by adding 2.5 PHTOS of MMT nano-platelets. Possible reasons accounting for the considerably improved micro foaming performance of scCO2-aid GA/SHMP/TOS/MMT foams modified using the proper alkali treatment time and MMT loading are proposed in this study.

Biobased sustainable materials made from starch and plasma/ultrasound modified Agave fibers: Structural and water barrier performance

This study aims to investigate the effect of green modification methods (ultrasound and plasma treatment) on a by-product of the tequila industry (Agave fibers), which can be useful as raw material to elaborate biodegradable and hydrophobic starch films. FTIR analysis indicated a decrease of hydrophilic lignocellulosic components, since the cavitation and etching effect of ultrasound/plasma treatment reduced the large number of hydroxyl groups of the fibers. The inclusion of ultrasound/plasma modified fibers in the starch matrix limited the starch-glycerol interactions, reducing the free volume of the starch and the binding sites for water. Therefore, the solubility (%S), swelling (%W) and water vapor permeance (WVPe) of the films decreased from 27 to 16%, 57 to 50% and 0.37 to 0.21 g/day m²Pa, respectively. Furthermore, the water contact angle (WCA) and relative crystallinity values increased. The results indicated that the treatments are suitable green technologies to obtain hydrophobic fillers useful to develop sustainable materials.

Study of interactions between cassava starch and peanut skin on biodegradable foams

The present work reports the effects of adding an agro-industrial residue (peanut skin) to cassava starch-based foams developed by thermopressing process. For this purpose, foams composed of cassava starch (CS foams) and cassava starch added of 24% (w/w) of peanut skin (CS/PS foams) were compared regarding their chemical structures, thermal, morphological and mechanical properties, moisture sorption isotherms, contact angle, and biodegradation. Results of dynamic mechanical analysis (DMA) showed the addition of peanut skin reduced the stiffness due to the increase of mobility of the starch chains. CS/PS foams exhibited a decrease in the storage modulus and glass transition temperatures as observed DMA. The addition of peanut skin did not influence on tensile stress and Young's modulus but reduced the tensile strain of the foams. The water contact angle of CS/PS foam was higher than CS foam, and as a result, CS/PS foams were found less hydrophilic than CS foams, which broaden the application of these materials. The reduction of hydrophilicity was related to the composition of the additive, mainly regarding lipids and proteins fractions, as well as to the interactions between cassava starch and peanut skin, reducing the availability of OH groups to bond with water.

A novel method to produce sustainable biocomposites based on thermoplastic corn-starch reinforced by polyvinyl alcohol fibers

Adding reinforced fiber or cross-linking agent into thermoplastic starch (TPS) is an effective method to improve its performance. Herein, biodegradable polyvinyl alcohol fiber (PVAF) and sodium hexametaphosphate (SHMP) were not added into TPS directly; the PVAFs were preliminary treated (pre-soaking) by an SHMP solution, and then mixed with starch and glycerol to prepare 2 wt% PVAF/TPS composites through extrusion and injection molding. This process promoted crosslinking action between PVAFs and starch, and as a consequence enhanced the mechanic and dynamic mechanic behavior. The PVAFs with different immersion times were characterized by SEM, FTIR, and WAXD. The results confirmed that the SHMP coating was formed by a chemical bond connection on the surface of the PVAFs, particularly for the PVAFs soaked for 1.5 h, which produced a corresponding PVAF/TPS composite with a maximum tensile strength of 9.18 MPa and an impact strength of 21.29 kJ m⁻². The corresponding tensile fractured cross-section images were shown by SEM. The DMA curves indicated that the pre-soaked PVAFs effectively improved the energy storage modulus and transition temperature of composites, and the activation energy of the starch macromolecules reached a maximum of 349.9 kJ mol⁻¹ during the dynamic mechanic process. The contact angle attained a maximum of 66.25°. Compared with TPS, the pre-soaked PVAF-reinforced PVAF/TPS composites had better mechanical properties, good processability through traditional extrusion and injection molding, reduced water wettability, and potential applications for packaging and catering.

Adding reinforced polyvinyl alcohol fiber (PVAF) pre-soaked in an SHMP solution into thermoplastic starch (TPS) is an effective method to improve its performance.