Starch behaviors and mechanical properties of starch blend films with different plasticizers

Effects of Organic Modification of Montmorillonite on the Properties of Hydroxypropyl Di-Starch Phosphate Films Prepared by Extrusion Blowing

The knowledge gained from starch-nanocomposite-film research has not been fully applied commercially because of the lack of appropriate industrial processing techniques for nanofillers and starch films. Three organically modified montmorillonites (OMMTs) were prepared using a semidry kneading method. The effects of the OMMTs on the structures and properties of starch nanocomposite films, prepared by extrusion blowing, were investigated. The X-ray diffraction (XRD) analysis results revealed that the OMMTs with various quaternary ammonium salts possessed differing layer structures and d-space values. The results of the XRD and Fourier-transform infrared spectroscopy (FT-IR) showed that the starch⁻OMMT interaction resulted in a structural change, namely the starch⁻OMMT films possessed a balanced exfoliated and intercalated nanostructure, while the starch⁻MMT film possessed an exfoliated nanostructure with non-intercalated montmorillonite (MMT). The results of the solid-state nuclear magnetic resonance (NMR) analysis suggested that the starch-OMMT nanocomposite possessed comparatively large quantities of single-helix structures and micro-ordered amorphous regions. The starch⁻OMMT films exhibited good tensile strength (TS) (maximum of 6.09 MPa) and water barrier properties (minimum of 3.48 × 10−10 g·m·m−2·s−1·Pa−1). This study indicates that the addition of OMMTs is a promising strategy to improve the properties of starch films.

How Glycerol and Water Contents Affect the Structural and Functional Properties of Starch-Based Edible Films

As starch is an inexpensive, filmogenic, easily processable and a widely available material, it is a material that can be utilized in the creation of biodegradable films and containers, presenting as a viable alternative to polymers derived from petrol. Moreover, starch could also be used to create edible coatings for fresh foods in order to extend shelf life. As such, wheat starch films with two glycerol contents were formulated to mimic the effects of compounds currently used to coat fruit. Their structural and functional properties were characterized. This study found that the transfer properties of starch films containing 33% of plasticizer was less effective than film comprised of 50% glycerol. Water diffusivity, oxygen permeability, and water vapor permeability at two different humidity gradients, surface tension, works of surface adhesion and cohesion, and moisture sorption were tested. Glycerol content does not play a significant role on the color or mechanical properties. This work shows that glycerol can strongly affect the functional properties of starch-based coatings and films.

Development and characterization of cassava starch films incorporated with blueberry pomace

This work is focused on the development of renewable and biodegradable films by the valorisation of wastes from food processing industries, with the aim of contributing to the development of more sustainable films. In this context, different contents of blueberry pomace (BP) were incorporated into cassava starch (CS) film forming solutions and the functional properties of the films prepared by solution casting were investigated, specifically, thermal, optical and physicochemical properties. BP-incorporated films showed good barrier properties against light, indicating their beneficial effect to prevent food deterioration caused by UV radiation when these films are used for food packaging applications. These results were related to the presence of aromatic compounds in BP, which can absorb light at wavelengths below 300nm. Furthermore, all films maintained their structural integrity after immersion in water (24h) and the maximum swelling displayed was lower than 300%. Additionally, the release of active compounds from BP into food simulants (after 10days) showed higher migration into the acetic acid medium in comparison with the ethanol medium. Therefore, the incorporation of BP into CS film forming solution resulted in the improvement of film performance, suggesting the potential application of these films as active packaging.

Effect of blueberry agro-industrial waste addition to corn starch-based films for the production of a pH-indicator film

Intelligent packaging is an emerging area of food technology that can provide better preservation and be of further convenience for consumers. It is recommended that biodegradable materials be used to develop low-impact designs for better packaging, which could benefit the environment by simply expanding their use to new areas. In this work, corn starch, glycerol and blueberry powder (with and without prior fruit bleaching) were used to produce films by casting. Blueberry powder, a co-product from juice processing, which is rich in anthocyanins, was added in the films to evaluate its potential as a colorimetric indicator, due to the ability of anthocyanin to change color when placed in an acidic or basic environment. After the films were immersed in different buffer solutions, visual color changes were observed, where the films became reddish at acidic pH and bluish at basic pH. The ΔE* values were greater than 3, suggesting a visually perceptible change to the human eye. The samples with fruit bleaching (CB) were visually darker (lower luminance values), while the samples without bleaching (SB) had a lighter color and higher brightness, represented by larger L* values. These results indicate the potential of blueberry powder as a pH indicator for intelligent food packaging or even for sensing food deterioration.

Design, synthesis of novel starch derivative bearing 1,2,3-triazolium and pyridinium and evaluation of its antifungal activity

Based on cuprous-catalyzed azide-alkyne cycloaddition (CuAAC), starch derivative bearing 1,2,3-triazole and pyridine (II) was prepared and subsequently followed by alkylation with iodomethane to synthesize starch derivative bearing 1,2,3-triazolium and pyridinium (III). The antifungal activities of starch derivatives against Colletotrichum lagenarium, Watermelon fusarium, and Phomopsis asparagi, were then assayed by hypha measurement in vitro. Apparently, starch derivatives showed enhanced antifungal activity against three fungi at the tested concentrations compared with starch. Especially, the best inhibitory index of starch derivative (III) against Colletotrichum lagenarium attained 97% above at 1.0mg/mL. Meanwhile, starch derivative (III) had stronger antifungal activity than starch derivative (II), which was reasonable to propose that the alkylation of 1,2,3-triazole and pyridine was significant for enhanced antifungal activity. As this novel starch derivative bearing 1,2,3-triazolium and pyridinium could be prepared efficiently and exhibited superduper antifungal activity, this material might provide an effective way and notion to prepare novel antifungal agents.