Impact of ultrasound treatment on the physicochemical and rheological properties of acid hydrolyzed sorghum starch

Improving paste stabilities of cassava starch through molecular density after maltogenic amylase and transglucosidase

To improve paste stability of cassava starch, including acid resistance, high-temperature shear resistance and freeze-thaw stability, cassava starch was modified by sequential maltogenic amylase and transglucosidase to form an optimally denser structure, or branched density (12.76 %), molecular density (15.17 g/mol/nm3), and the proportions of short-branched chains (41.41 % of A chains and 44.01 % of B1 chains). Viscosity stability (88.52 %) of modified starch was higher than that (64.92 %) of native starch. After acidic treatment for 1 h, the viscosity of modified starch and native starch decreased by 56.53 % and 65.70 %, respectively. Compared to native starch, modified starch had lower water loss in freeze-thaw cycles and less viscosity reduction during high-temperature and high-shear processing. So, the appropriate molecular density and denser molecule structure enhanced paste stabilities of modified starch. The outcome expands the food and non-food applications of cassava starch.

Effects of synchronous intermissive multi-ultrasound and esterification dual modification on functionalities of starch and its emulsion stabilization ability

Dodecenylsuccinic anhydride (DDSA) has been widely used to obtain amphiphilic starches. In this study, we investigated the functionalities of synchronous intermissive multi-ultrasound-assisted esterified starch. Compared to native starch (NS), it was deduced that multi-ultrasound-modified starch (US), esterified starch (ES), and multi-ultrasound-assisted esterified starch (UES) exhibited increased viscosities but reduced gelatinization temperatures and thermal stabilities. The viscoelastic moduli, retrogradation behaviors and hydrophobicity of the ES and UES species significantly altered. Moreover, the results of structural characterization suggested that esterification reduced the molecular weight and structural order of starch, whereas the intermissive ultrasonication treatment did not aggravate the structural disruption of ES. Additionally, compared with NS and US, the emulsification abilities of the ES and UES specimens were improved, leading to the desirable effect of stabilizing astaxanthin. Overall, this study provides a method for preparing amphiphilic starch, which can be exploited as a potential emulsifier and emulsion stabilizer for bioactive compounds.

Effect of ultrasound geometry on the production efficiency of damaged starch: Determining rheology parameters, and non-isothermal reaction kinetics

Present study investigates the effects of probe size geometry on thermodynamic kinetics, rheology, and microstructure of wheat and tapioca starch. Ultrasound treatment using different probe diameters (20 mm and 100 mm) significantly influenced the gelatinization process. Results showed reduced enthalpy (ΔH) and Gibbs energy (ΔG), indicating enhanced gelatinization efficiency. According to the results, using a 20 mm and 100 mm probe leads to a reduction of 52.7 % and 68.6 % in reaction enthalpy for wheat starch compared to native starch, respectively. Microstructure analysis revealed structural changes, with ultrasound treatment leading to granular fractures and a sheet-like structure with air bubbles. The rheological behavior of the starches is found to exhibit shear thinning behavior, with the Casson model providing the best fit for the experimental data. Moreover, rheology modeling using Herschel-Bulkley and power law models showed increased viscosity and shear stress in larger probes. Numerical simulation data demonstrated that probe size influenced ultrasonic pressure, sound pressure level, and thermal power dissipation density, affecting fluid motion and velocity field components. Moreover, the maximum dissipated power decreases from 8.43 to 0.655 mW/m3 with an increase in probe diameter from 20 to 100 mm. The average yield shear stress values are calculated as 3.36 and 3.14 for wheat and tapioca starches, respectively. The larger probe diameter leads to greater entropy increases, with tapioca starch showing a 4.72 % increase and wheat starch a 4.97 % increase, compared to 2.56 % and 3.11 %, respectively, with the smaller probe. Additionally, the Keller-Miksis model provided insights into bubble dynamics, revealing increased pressure and temperature with higher pressure amplitudes.

Physicochemical properties and in vitro digestibility of ginseng starches under citric acid-autoclaving treatment

In this study, the effects of citric acid-autoclaving (CA-A) treatment on physicochemical and digestive properties of the native ginseng starches were investigated. The results showed that ginseng starch exhibited a B-type crystal structure with a low onset pasting temperature of 44.23 ± 0.80 °C, but high peak viscosity and setback viscosity of 5897.34 ± 53.72 cP and 692.00 ± 32.36 cP, respectively. The granular morphology, crystal and short-range ordered structure of ginseng starches were destroyed after CA-A treatment. The more short-chain starches were produced, resulting in the ginseng starches solubility increased. In addition, autoclaving, citric acid (CA) and CA-A treatment promoted polymerization and recrystallization of starch molecules, increased the proportion of amylopectin B1, and B3 chains, and improved molecular weight and resistant starch (RS) content of ginseng starches. The most significant multi-scale structural change was induced by CA-A treatment, which reduced the relative crystallinity of ginseng starch from 28.26 ± 0.24 % to 2.75 ± 0.08 %, and increased the content of RS to 54.30 ± 0.14 %. These findings provided a better understanding of the structure and properties of Chinese ginseng starches and offered new ideas for the deep processing of ginseng foods.

Differences in the structural properties of three OSA starches and their effects on the performance of high internal phase Pickering emulsions

The emulsifying properties of emulsions are significantly influenced by the structural properties of octenyl succinic anhydride (OSA) starch. The purpose of this work was to elucidate the effect of the structure of OSA starch on its performance as an emulsifier to stabilize Pickering high-internal-phase emulsions (HIPEs). The degrees of substitution (DS) of the three OSA starches were 0.0137, 0.0177 and 0.0236, and their degrees of branching (DB) were 13.96 %, 14.20 % and 14.32 % measured by 1H NMR, which were sequentially labeled as OSA1, OSA2, and OSA3. The OSA3 starch with higher DS and DB had a lower critical micelle concentration (CMC) (0.11 mg/mL). Its emulsification activity (EAI) and emulsion stability (ES) were 61.8 m2/g and 72.5 min, respectively, which were higher than OSA1 and OSA2 starches. The contact angle of the three OSA starches increased from 45.35° to 80.03° with increasing DS and DB. Therefore, it is hypothesized that OSA3 starches have better emulsification properties. The results of physical stability of HIPEs confirmed the above results. These results indicated that DS and DB have a synergistic effect on emulsion properties, and OSA starch with higher DS and DB values were more conducive to the construction of stable HIPEs systems.

Physicochemical Characteristics of Porous Starch Obtained by Combined Physical and Enzymatic Methods, Part 1: Structure, Adsorption, and Functional Properties

Porous starch can be applied as an adsorbent and encapsulant for bioactive substances in the food and pharmaceutical industries. By using appropriate modification methods (chemical, physical, enzymatic, or mixed), it is possible to create pores on the surface of the starch granules without disturbing their integrity. This paper aimed to analyze the possibility of obtaining a porous structure for native corn, potato, and pea starches using a combination of ultrasound, enzymatic digestion, and freeze-drying methods. The starch suspensions (30%, w/w) were treated with ultrasound (20 kHz, 30 min, 20 °C), then dried and hydrolyzed with amyloglucosidase (1000 U/g starch, 50 °C, 24 h, 2% starch suspension). After enzyme digestion, the granules were freeze-dried for 72 h. The structure of the native and modified starches were examined using VIS spectroscopy, SEM, ATR-FTIR, and LTNA (low-temperature nitrogen adsorption). Based on the electrophoretic mobility measurements of the starch granules using a laser Doppler velocimeter, zeta potentials were calculated to determine the surface charge level. Additionally, the selected properties such as the water and oil holding capacities, least gelling concentration (LGC), and paste clarity were determined. The results showed that the corn starch was the most susceptible to the combined modification methods and was therefore best suited for the production of porous starch.