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It is common to hybridize biopolymers for developing materials with combined properties or functionality. However, biopolymers are usually not fully compatible despite their chemical similarity, posing challenges to create mixed systems. Herein, we investigated how the gelation behavior and rheological properties of hydroxypropyl methylcellulose (HPMC), a thermal gel, and hydroxypropyl starch (HPS), a cooling gel, affect their miscibility and the phase structure of their mixed system. The dependence of the zero-shear viscosity for HPMC/HPS paste on biopolymer concentration in a double-logarithmic coordinate can be divided into two parts with the slopes being 11.9 and 2.8 respectively, indicating different degrees of intermolecular entanglement. A typical "sea-island" morphology was shown in the blends, and the phase structure (continuous or discrete) changed with varying HPMC/HPS blend ratio and temperature. This phase structure change can be well correlated to rheological parameters such as zero-shear viscosity, loss tangent, complex viscosity, and the Arrhenius equation correction coefficient (α). Biopolymer concentration, HPMC/HPS ratio, and temperature together controlled rheological properties and phase distribution for the mixed system. The relationship between rheological behavior and phase structure for HPMC/HPS understood from this work provides an insight into designing mixed biopolymer systems with desirable processability, structure, and properties. Image 1 • Hydroxypropyl methylcellulose (HPMC) and hydroxypropyl starch (HPS) mixture studied. • Strong rheological and gelation effects on the phase structure of HPMC/HPS shown. • HPMC/HPS blend ratio and temperature controls continuous/discrete phase change. • Phase structure correlated to zero-shear viscosity and Arrhenius coefficient α. • A schematic model to describe the temperature-induced conformational change. [ABSTRACT FROM AUTHOR]

This study investigated the impact of non-covalent interactions of pea protein isolate (PPI), quillaja saponin (QS) and tannic acid (TA) on the physiochemical, interfacial, and emulsifying properties of curcumin (Cur)-loaded composite nanoparticles from microscopic to macroscopic scales. Hydrogen bonding was important for all the nanoparticles, while hydrophobic interaction was also the dominate driving force to maintain internal structure of Cur/PPI and Cur/PPI-QS 2:1 nanoparticle. The presence of TA decreased the particle size but increased the encapsulation efficiency of Cur. The encapsulation efficiency of Cur/PPI and TA-Cur/PPI were 49.7% and 74.7%, respectively. The thermal and light stability of Cur were enhanced with the addition of TA. X-ray Diffraction result verified that Cur was successfully captured into composite nanoparticles in an amorphous state. Both of Cur/PPI-QS 2:1 and TA-Cur/PPI-QS 2:1 exhibited relative lower interfacial tension (6.3 and 5.2 mN/m, respectively) and the near-neutral wettability (74.5°and 88.1°, respectively), indicating their stronger interfacial adsorption capability. Quartz crystal microbalance with dissipation (QCM-D) analyses confirmed that TA-Cur/PPI-QS 2:1 showed more viscoelasticity interfacial film with highest K 4 (0.179 × 10−6 Hz). Furthermore, the TA-Cur/PPI-QS 2:1 Pickering emulsion exhibited solid-like behavior and stronger gel network structure. Both of TA-Cur/PPI-QS 2:1- and Cur/PPI-QS 2:1-stabilized Pickering emulsions showed better storage stability than other samples. This study presents a practical strategy for the structural design of protein nanoparticles by tuning non-covalent interactions, and provides theoretical support for multi-scale exploration of structure-properties relationships of nanoparticle. [Display omitted] • Cur-loaded PPI-QS-TA nanoparticle was designed by tuning non-covalent interactions. • Emulsion stability was studied from microscopic to macroscopic scales. • QS and TA improve the encapsulation efficiency and environmental stability of Cur. • TA-Cur/PPI-QS 2:1 showed more viscoelasticity interfacial film measured by QCM-D. • TA-Cur/PPI-QS 2:1-emulsion had strong gel network and excellent storage stability. [ABSTRACT FROM AUTHOR]

Dry rice noodles are associated with difficulties in rehydration and high cooking losses. The aim of this research was to improve the rehydration and edible quality of dried rice noodles by adding erythritol, a natural sweetener. Results from water contact angle (WCA), X-ray diffraction (XRD), small angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and other indicators indicated that erythritol significantly decreased the water contact angle, crystallization degree, crystalline layer thickness, and enthalpy of gelatinization of dried rice noodles while loosening their network structure. The addition of 20% (w/w) erythritol greatly enhanced the rehydration and edible quality of dried rice noodles. Compared with the unmodified control group, the rehydration time, cooking losses, and cooking breakage rate were reduced by 43.61%, 22.45%, and 91.78%, respectively. Besides, the tensile strain, chewing hardness and toughness increased by 44.34%, 102.90%, and 66.89%, respectively. All the results confirmed that the addition of erythritol is an effective method for producing high-quality dried rice noodles. [Display omitted] • Erythritol infiltrated the amorphous region and decreased the lamellar thickness. • Erythritol significantly decreased the contact angle of dried rice noodles. • The rehydration time was reduced by 43.61% with 20% (w/w) erythritol. • The cooking breakage rate was reduced by 91.78% with 20% (w/w) erythritol. [ABSTRACT FROM AUTHOR]

Debranched starch (DBS) has attracted immense interest from the food, pharmaceutical, and cosmetic industries as a versatile ingredient. Herein, we firstly developed a simple fractionation method using an edible alcohol solution to separate DBS of different degrees of polymerization (DP). These DBSs were separated from debranched waxy corn starch on the basis of their differential solubility in aqueous/ethanol solutions of different volumetric ratios (1:1.5 and 1:3). Four DBS products were obtained with DP values of 23.53, 20.04, 9.14, and 6.75. The DBS (DP 23.53) exhibited higher iodine staining index values compared to DBSs of lower DPs. The thermograms of DBSs (DP 9.14 and DP 6.75) displayed no apparent peak, indicating their amorphous nature. Compared to freeze-drying, oven-dried DBS (DP 23.53) exhibited a higher relative crystallinity (72.0%). Therefore, the ethanol precipitation method developed here serves as a simple, scalable, and green approach for preparing DBS fractions of different molecular weights. [ABSTRACT FROM AUTHOR]

Effect of pressure with shear stress on the gelatinization of cornstarch with different amylose/amylopectin ratios (waxy 0/100; maze 23/77; G50 50/50; G80 80/20) was systematically investigated using a high-pressure rheometer. Onset and peak temperature of starch gelatinization as well as the peak viscosity were used to discuss the influence of pressure together with shear stress on the gelatinization of starch granules. The results showed that without shear stress, pressure could resist the gelatinization process due to weak swelling of starch granules and lower quantity of amylose released. However, the shear stress can simply counteract the influence of the pressure since its impact is much high on gelatinization. Under certain pressure and shear stress, both onset and peak temperatures of gelatinization were increased with increasing amylose content, which is in correspondence with the results from differential scanning calorimeter measurement, while the overall viscosity was lower when starches with a higher amylose content was used because part of its granular was not fully dissolved during the measurement. SAXS measurements were used to study the gel structure and stability of starch suspensions. It was found that the scattering intensity of starches in the measured range (0.1–1.0 nm −1 ) is G80 > waxy, indicating the amount of ordered semi-crystalline structures in amylose is higher. Peak values, q = 0.4 nm −1 and q = 0.2 nm −1 , detected for waxy starch under different shear rates, indicates that higher shear stress which plays a dominant role compared with pressure, resulted in more degradation in amylopectin, inhibiting the formation of aggregate structure. [ABSTRACT FROM AUTHOR]

Since hydroxypropyl methylcellulose (HPMC) is a thermal gel while hydroxypropyl starch (HPS) is a cool gel, their blends show some unique and interesting behaviors of phase transitions and microstructures, which control their performances. This work focused on the effect of processing conditions on the microstructure and mechanical properties of these blends with various ratios of HPMC/HPS, in particular for incubation and drying conditions. To clearly identify the changes of starch phase in such blending system, the technique of dyeing HPS with iodine was developed and used. Rheometer, small angel X-ray scattering (SAXS), X-ray diffraction (XRD), dynamic mechanical analysis (DMA) and mechanical testing apparatus were used to study the changes of microstructure and the relative properties of the blending gels and dried films incubated at different temperatures. It was found that the higher incubation temperature resulted in higher storage modulus, more solid-like behavior and more compact self-similar structure of the blending gel. Moreover, the films prepared from the gels dried at high temperature showed higher crystalline degree and more compact amorphous structure, and therefore result in increasing tensile strength and modulus but decreasing elongation. [ABSTRACT FROM AUTHOR]

Oil-in-water Pickering emulsions prepared by food-grade particles have gained increasing interest on account of their potential application in the delivery system for lipophilic active compounds. In this project, hydrolyzed rice glutelin (HRG) nanoparticles were successfully fabricated inducing by different concentrations of ethanol. The structure, interfacial properties of HRG nanoparticles, Pickering emulsion stability and in vitro gastrointestinal digestion characteristics were investigated. With ethanol concentration increasing from 25% to 100%, the Z-average diameter and surface activity of HRG nanoparticles increased firstly and then decreased, whereas the magnitudes of the ζ-potential and surface hydrophobicity increased. Quartz crystal microbalance with dissipation (QCM-D) indicated that HRG nanoparticles induced by ethanol with the concentration of 50% (HRG50) and 75% (HRG75) showed a more viscous interfacial film. HRG50- and HRG70-stabilized emulsions had better storage stability compared with other samples. Furthermore, the curcumin was loaded into Pickering emulsions using the pH-shift method. The light stability and gastrointestinal fate were assessed. Compared with curcumin-loaded HRG75-Pickering emulsion, HRG50-Pickering emulsion exhibited higher photochemical stability, whereas the lower FFAs release, bioaccessibility and transformation. This behavior was attributed to the thicker interfacial layer for HRG50 Pickering emulsion. This knowledge indicated that emulsion stabilized by HRG nanoparticles could be used as a delivery system to protect hydrophobic bioactive compounds. This research provided theoretical support to develop the utilization of HRG nanoparticles. [Display omitted] • Structure, interfacial and emulsifying properties of HRG nanoparticles were studied. • HRG50 and HRG75 showed more viscous interfacial film measured by QCM-D. • Droplet flocculation could be found for HRG25-and HRG100-emulsion. • HRG50 emulsion had higher curcumin retention rate when exposure to UV radiation. • HRG75-emulsion performed higher FFA release and bioaccessibility of curcumin. [ABSTRACT FROM AUTHOR]

This study aimed to develop a rapid ethanol annealing method by incubating pea starch and potato starch in 60% and 75% ethanol solutions at 95 °C for 0.5–3 h (to improve their heat, shear, and acid stability). The peak viscosities of the annealed starches decreased, the breakdown values declined to 0 cP, and the trough and final viscosities decreased remarkably. Furthermore, the pea starch transformed from a C-type to an A-type crystalline form, while the potato starch remained a B-type. Ethanol annealing also increased the pasting temperatures and decreased the enthalpy change values of the starches. When annealed in the 60% ethanol solution for 3 h, the pea starch showed the highest peak gelatinization temperature at 80.97 °C, which was 15.55 °C higher than the native starch. Moreover, the annealed starches showed remarkable decreases in swelling and solubility. Compared to traditional water annealing, this method could reduce the incubation period and lead to a higher gelatinization temperature of starch, which would have applications for thickening and stabilizing in the food system, for example, in the production of soups, puddings, and deep-fried foods. [Display omitted] • A new strategy for annealing starch in ethanol solution was studied. • The progress of ethanol annealing starch was shorter than that of water annealing. • Ethanol solution annealing treatment formed a complex between ethanol and amylose. • The thermal stability of starch was enhanced by ethanol annealing treatment. [ABSTRACT FROM AUTHOR]