The temperature induced disruption process of amylopectin under ultrasonic treatments

Physicochemical properties of ultrasound-pretreated pea starch and its inclusion complexes with lauric acid

Ultrasound is a promising green technology for modifying starch. The influence of ultrasound pretreatment (UPT) at diverse temperatures on the morphology and molecular structure of pea starch and its ability to form inclusion complexes with lipids were investigated. After UPT at each temperature, the starch granules retained an unchanged crystalline structure but exhibited notable changes in short-range molecular order and molecular structure. In comparison with the samples treated at 0 and 20 °C, pea starch subjected to UPT at 40 °C had a significantly (P ≤ 0.05) higher complexing index with lauric acid (LA) and the starch-LA inclusion complex exhibited a higher enthalpy change, relative crystallinity, and resistant starch content. These differences were attributed to the higher temperature causing changes in the disruption points of starch chains and an enlargement in the molecular weight of linear chains. These results may promote the utilization of ultrasound for effective starch modification.

The alterations in granule, shell, blocklets, and molecular structure of pea starch induced by ultrasound

Understanding the alterations to starch multi-scale structure induced by ultrasound treatment can help in determining the effective application of ultrasound in functional-starch preparation. This study aimed to comprehensively characterize and understand the morphological, shell, lamellae, and molecular structures of pea starch granules treated by ultrasound under different temperatures. Scanning electron microscopy and X-ray diffraction analyses showed that UT (ultrasound treatment) did not change C-type of crystalline, but caused a pitted surface and endowed a looser structure and higher enzyme susceptibility as the temperature increased above 35 °C for pea starch granules. Fourier transform infrared spectroscopy and small-angle X-ray scattering analyses revealed that UT reduced the short-range ordering and increased the thickness of semi-crystalline and amorphous lamellae by inducing starch chain depolymerization, which was manifested by molecule weight and chain length distribution analysis. The sample ultrasound-treated at 45 °C had the higher proportion of B2 chains compared with the other ultrasound-treated samples because the higher ultrasonic temperature altered the disruption sites of starch chains.

Effect of dual modification with citric acid combined with ultrasonication on hydrolysis kinetics, morphology and structure of corn starch dispersions

Corn starch dispersions (CSD) were hydrolyzed with citric acid and compared with CSD co-treated with citric acid combined with ultrasonication for 1 to 18 days, which are designated as single modification (CSD-SM) and dual modification (CSD-DM), respectively. The logistic functions monitor the dynamics of the hydrolysis advance (%) of the CSD-SM and CSD-DM as a function of time, where the zones most vulnerable to the single-treatment and/or co-treatment of the corn starch granules (CSG) are the amorphous or disordered regions. The characterization results of CSD-DM suggest that the structural changes caused by dual modification affected the morphology, sequence, and microstructure of the CSG. The heterogeneous changes caused by the dual modification changed the configuration of the CSG, generating a kind of destemming of the amorphous lamellae (depolymerization), an increase in the percentage of relative crystallinity of the CSD-DM and an active rearrangement of the intralamellar chains that promoted the relative amount of double helix for 18 days of double modification. The synergistic effect of the dual modification for CSD by the sequential combination of a chemical treatment followed by a physical one improved the hydrolyzed advance by 12 %, the relative crystallinity by 10 %, and the promotion of double helices by 25 % during 18 days of co-treatment.

Optimization of the Sustainable Production of Resistant Starch in Rice Bran and Evaluation of Its Physicochemical and Technological Properties

In this study, the optimization of ultrasound (US) (850 kHz, 120 W) processing parameters (temperature, time, and power) for the enhanced production of resistant starch (RS) in rice bran (RB) matrixes was performed. The effect of US cavitation at different temperatures on the morphology, physicochemical properties, and mechanical performance of RS was evaluated. Ultrasonication at 40−70 °C temperatures affected the chemical structure, reduced the crystallinity of RS from 23.85% to between 18.37 and 4.43%, and increased the mechanical and thermal stability of RS pastes, indicating a higher tendency to retrograde. US treatment significantly (p < 0.05) improved the oil (OAC) and water (WAC) absorption capacities, swelling power (SP), solubility (WS), and reduced the least-gelation concentration (LGC). The mathematical evaluation of the data indicated a significant effect (p < 0.05) of the US parameters on the production of RS. The largest increment of RS (13.46 g/100 g dw) was achieved with US cavitation at 1.8 W/cm2 power, 40.2 °C temperature, and 18 min of processing time. The developed method and technology bring low-temperature US processing of rice milling waste to create a new sustainable food system based on modified rice bran biopolymers.