Dynamic rheology and microstructure of starch gels affected by triticale genomic composition and developing stage

Abstract

Starches of developing triticale grains, differing in genome composition (complete AABBRR or substituted AABBDR), were evaluated in terms of starch granule distribution, dynamic rheological behaviour and microstructural characteristics on several days after anthesis. The starch granules were of an oblate spheroid shape for A-granules, and of a spherical shape for B-granules. However, those obtained from the complete triticale showed a larger diameter size. An X-ray diffraction analysis revealed the common A-type pattern of cereal starches from early development stages. A dynamic rheological analysis showed that the storage and loss moduli reached maximum levels in the temperature range of 71-86ºC and dropped at around 90ºC. Starches from the complete triticale showed lower phase transition temperatures, compared to those obtained from the substituted genotype (56.1±0.3 and 60.3±0.8°C, respectively). Scanning electron microscopy showed that the gels made with the starch of complete triticales were of a less dense sponge-like structure. K e y w o r d s: triticale developing grains, starch, gels, rheology, microstructure

Triticale Starch-Based pH-Responsive Hydrogel: Synthesis, Characterization, Diffusion & New Perspective of Triticale Crop as Sustainable Source for Stimuli-Response Hydrogels

“…previously reported. 20 but lower than those reported by Seidel et al 44 on starch hydrogels copolymerized with carboxymethylcellulose crosslinked with citrate, succinic acid and tartaric acid, and similar to those crosslinked with glutaric, adipic and malonic acid; however, these crosslinked hydrogels received a retrogradation treatment (140°C) prior to the addition of water, a process that improved their development. In the deformation sweep, prevailed the linear behavior of G' and G'' modulus in both versions of the material, where the XG presented a higher resistance in wide deformation stresses of 29,000-34,000 μN.m (G'max;XG-I 11,209XG-III 11,941XG-II 13,091 Pa) with lower Tan  values compared to gels (G'max;HG-I 672HG-II 423HG-III 390 Pa), where is possible to observe an instability trend due to an inclination that leads to the crossing of the moduli (G''/G'=1) (Figure 4B).…”

“…The SEM micrographs of the granules allow to calculate the approximate distribution frequency of the size of triticale starch granules (micrographs and distribution table in supporting information) where a right-skewed distribution was observed for the largest A-type granules (10≤11-35 μm) with oval-lenticular morphology, followed by a B-type size (6≤10 μm) with spherical morphology; these results were in agreement with previous studies. 4,20 By FT-IR spectroscopy, the absorbance bands of the bonds and functional groups of the native triticale Eronga starch were obtained (Figure 1A), where vibrational spectra of cycloalkane groups (C-C, 900-400 cm -1 ), α-1,4 glycosidic bonds (C-O-C, 930 cm -1 ), vibrational stretching of methylene groups (C-H2, at 1465 cm -1 ) and the hydroxyl bending (O-H, 1640-1630 cm -1 ) by trace moisture in amorphous amylose zones where identified. The hydroxyl functional group (O-H) was observed by an intense vibrational band at 3400-3300 cm -1 , with vibration of the carbonhydrogen bond (C-H) at 2950-2800 cm -1 due to the possible formation of the hydrogen bonds.…”

“…25 Figure 1B shows the starch diffraction pattern by the XRD analysis, where it can be observed that higher intensity peaks appeared at 2θ=12.59°, 16.59°, 17.43°, 18.16°, 19.47°, 23.46° and 34.54°, which represented 29.26% semi-crystallinity, similar to the different spectra varieties of Triticales previously reported. 20 These crystal signals are representative of the A-type pattern, which correspond to a dense structure of parallel amylopectin chains located in a monoclinic plane with less organization, which have been related to greater reactivity with better viscoelastic development in the retrogradation process of gels. 4,28 Finally, the TGA results (Table 1) showed that triticale starch was the most heat-resistant material with an intense endothermic curve in a temperature range of 272-350°C, and degradation of ~50% of mass within the maximum peak at 315°C with activation energy (Ea) of 126.75 kJ/mol; similar to the TGA/Ea results from different starch sources.…”

“…15 Additionally, to the best of our knowledge, there are few reported triticale-based biomaterials, including bioplastics, films and only one previous study of the native hydrogel of triticale starch have been reported. [16][17][18][19][20] Therefore, our effort aims to promote and expand the study of triticale in biomaterials science with sustainable development, introducing this novel application of triticale starch to produce stimuli-response hydrogels.…”

Triticale Starch-Based pH-Responsive Hydrogel: Synthesis, Characterization, Diffusion & New Perspective of Triticale Crop as Sustainable Source for Stimuli-Response Hydrogels

“…The SEM micrographs allowed to calculate the approximate distribution frequency of the size of triticale starch granules (micrographs and distribution table in supporting information), where a right-skewed distribution was observed for the largest A-type granules (10≤11-35 μm) with oval-lenticular morphology, followed by a B-type size (6≤10 μm) with spherical morphology; these results agreed with previous studies. 4,20 By FT-IR spectroscopy, the absorbance bands of the bonds and functional groups of the native triticale Eronga starch were obtained (Figure 1A), where vibrational spectra of cycloalkane groups (C-C, 900-400 cm -1 ), α-1,4 glycosidic bonds (C-O-C, 930 cm -1 ), vibrational stretching of methylene groups (C-H2, at 1465 cm -1 ) and the hydroxyl bending (O-H, 1640-1630 cm -1 ) by trace moisture in amorphous amylose zones where identified. The presence of the hydroxyl group (O-H) was observed by an intense vibrational band at 3400-3300 cm -1 , and the vibration of the carbon-hydrogen bond (C-H) at 2950-2800 cm -1 due to the possible formation of the hydrogen bonds.…”