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This review focuses on describing and discussing recent findings regarding the effects of high hydrostatic pressure (HHP) on the supramolecular structure and technofunctional properties of starch, as well as on analyzing the hypothesis to explain these changes. The non-thermal modification of starch through HHP involves complex supramolecular structural changes that depend on the botanical source, amylose content, and treatment intensity. Overall, the granular morphology, lamellar and crystalline structures, and double helices undergo different degrees of modification/disorganization during HHP, but these changes are distinguished from thermal modification by an improvement at the same gelatinization degree. The HHP-induced supramolecular modifications determine the properties of starch, including water solubility, swelling power, pasting, water and oil holding capacity, thermal properties, and in vitro digestibility., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Normal and high amylose corn starches were modified using HMDSO plasma at different time treatments. Changes in functional properties of starch granule, film-forming solutions (FFS) and films were investigated. SEM analysis revealed HMDSO coating deposition on the granule surface, which limited the amylopectin leach out from the granules to the continuous matrix, affecting the rheological properties of the FFS. The amylopectin restriction resulted in a low reinforcement of the network decreasing the viscosity as indicated by n and k values. Also, a gel-like behavior (G' > G″) was observed when the amylose and time treatment increased, suggesting that the matrix becomes less elastic with softer entanglement. This behavior was confirmed by creep test and Burger model parameters. The plasma treatments allowed obtaining FFS with low viscosity, suitable for developing soft and hydrophobic films with low flexibility, as indicated by the decrease of the maximum stress, Hencky strain and permeance values., (Copyright © 2020. Published by Elsevier Ltd.)

In this study, the chemical, mechanical and barrier properties of films made from plasma-modified corn starch (MSF) were evaluated as a function of the amylose content (30, 50 and 70 %). SEM analysis revealed the presence of remnant starch granules (RSG) in all films, which promoted the ordering of helices as suggested by the FTIR results. Moreover, XPS analysis was used to identify the oxidation mechanism in all MSF as the atomic proportion of hydroxyl, carbonyl and carboxyl groups changed. Also, the increase of C-C proportions suggested crosslinking in MSF70. TGA analysis indicated low interaction between starch and the plasticizer as the tensile strength and elongation at break diminished in MSF50 and MSF70 due to the low plasticizing effect of glycerol, the oxidation phenomena and the depolymerization of starch chains. However, the crosslinking of MSF70 showed characteristics of rigid films with good hydrophobic performance., Competing Interests: Declaration of Competing Interest The authors have declared no conflicts of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Nanoparticles (montmorillonite, MMT) can enhance biopolymer-based film properties. The structure-property relationship between polymers and nanoparticles may be explained by the rheological tests of nanocomposite forming solutions (NFS). The aim of this work was to study the effect of MMT concentration and amylose content on the rheological properties of NFS based on corn starch and glycerol following two preparation methods, through steady shear and dynamic tests. The organization level of NFS was influenced by the addition order of the components. Decreasing in flow index behavior when increasing amylose content was attributed to interactions between the starch components. In all NFS, G' was higher than G″ indicating a gel-like behavior and suggesting that the MMT reinforced the starch matrix as observed by the increase in the storage modulus of films with MMT. Films obtained from method 2 have better mechanical properties probably due to the starch-MMT interactions., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The effect of iodine concentration on the acetylation of starches with low and moderate degree of substitution (DS<0.5) and its impact on the physicochemical feature and structural features was evaluated. The acetylated starches were prepared with 0.03 mol anhydroglucose unit, 0.12 mol of anhydride acetic, and 0.6, 0.9 or 1.4 mM of molecular iodine as catalyst in a sealed Teflon vessel using microwave heating (600 W/2 min). Pasting profile and rheological properties were obtained under steady flow; dynamic oscillatory test was used. Structural features were obtained by HPSEC-RI. In acetylated starches, DS and acetyl groups increased when the iodine concentration increased, corn starch showed higher values than banana starch. The viscosity of acetylated starches decreased relative to unmodified starches while, acetylated corn starch had lower value than acetylated banana starch. In the flow curves, a non-Newtonian pattern (shear-thinning) was shown in the pastes of native and modified starches. Storage modulus (G') and loss modulus (G") showed low dependence on frequency (G'αω(0.1); G"αω(0.2)) on frequency sweep test, which is characteristic of a viscoelastic gel. Debranched native banana and corn starches presented trimodal chain-length distribution. The pattern was maintained in the acetylated starches, but with different level of short and long chains. The structural differences in native and acetylated samples explain the rheological characteristics in both starches., (Copyright © 2012 Elsevier Ltd. All rights reserved.)