Nanostructural Morphology of Plasticized Wheat Gluten and Modified Potato Starch Composites: Relationship to Mechanical and Barrier Properties

Abstract

In the present study, we were able to produce composites of wheat gluten (WG) protein and a novel genetically modified potato starch (MPS) with attractive mechanical and gas barrier properties using extrusion. Characterization of the MPS revealed an altered chain length distribution of the amylopectin fraction and slightly increased amylose content compared to wild type potato starch. WG and MPS of different ratios plasticized with either glycerol or glycerol and water were extruded at 110 and 130°C. The nano morphology of the composites showed the MPS having semi-crystalline structure of a characteristic lamellar arrangement with an approximately 100 Å period observed by SAXS and a B-type crystal structure observed by WAXS. WG has a structure resembling the hexagonal macromolecular arrangement as reported previously in WG films. A larger amount of β-sheets was observed in the samples 70/30 and 30/70 WG-MPS processed at 130°C with 45% glycerol. Highly polymerized WG protein was found in the samples processed at 130°C vs. 110°C. Also, greater amounts of WG protein in the blend resulted in greater extensibility (110°C), and a decrease in both E-modulus and maximum stress at 110 and 130°C, respectively. Under ambient conditions the WG-MPS composite (70/30) with 45% glycerol showed excellent gas barrier properties to be further explored in multilayer film packaging applications.

Impact of pH Modification on Protein Polymerization and Structure–Function Relationships in Potato Protein and Wheat Gluten Composites

“…As shown in previous studies [5,10,12,31,32,33], the non-modified WG powder showed relatively low amounts of β-sheets, as indicated by a flat shoulder in the amide I region (1620–1625 cm −1 ), while peaks at 1660, 1650 and 1641 cm −1 verified the presence of α-helices, α-helices and random coils, and unordered structures, respectively (Figure 3a). Chemical modification of the WG protein (MWG sample) resulted in a slight decrease in the intensity of peaks in the region 1640–1660 cm −1 , indicating that some of either α-helices, α-helices and random coils, or unordered structures became involved in formation of strong hydrogen bonded β-sheets (Figure 3a).…”

Biodegradability, flammability, dimensional stability, and UV resistance study of green wood starch gluten nanocomposites

“…The peak appeared at 2 θ = 16.86° was found to vanish in the composites (curve 1b–1e) which might be due to crosslinking effect of citric acid with wood, MMA‐ g ‐SG and glycerol. The peak intensity corresponding to cellulose became broad due to high protein concentration in starch gluten blend . The high protein concentration increased the cross‐linking reaction between citric acid and the amine groups of gluten protein and thus decreased the crystallinity .…”

“…Besides this, gluten finds it use in the composite due to its good adhesive properties . The use of higher percentage of gluten in the preparation of the composites has some negative effect like decrease in the mechanical properties .…”

Hydrophobic and Melt Processable Starch‐Laurate Esters: Synthesis, Structure–Property Correlations

“…Starch is among the most promising natural polymers because of its renewability, biodegradability, abundance, low cost, film‐forming properties, and ease of modification . Nevertheless, native starch without modification is not suitable for most polymer applications.…”