Effects of pullulanase enzymatic hydrolysis on the textural of acorn vermicelli and its influencing mechanism on the quality.

The effect of pullulanase enzymatic hydrolysis time on the textural properties of acorn vermicelli was investigated by texture analyzer. And the influencing mechanism was revealed by exploring the physicochemical properties of acorn starch under the optimum enzymatic hydrolysis time by texture analyzer, scanning electron microscopy, X-ray diffraction and brabender viscograph. After acorn starch was hydrolyzed by pullulanase for 14 h, acorn vermicelli had excellent textural properties. In addition, the enzymatic hydrolysis transformed the acorn starch from spherical particles with smooth surface to polygonal particles with rough surface, as well as transformed the crystal structure of acorn starch from C-type to B-type. Compared with native acorn starch, enzyme hydrolyzed acorn starch had higher amylose content, better freeze-thaw stability, lower swelling power and, breakdown viscosity, stronger gel strength and, higher light transmittance. These excellent properties contributed to the exceptional textural properties and quality of acorn vermicelli. The results of this study may provide valuable information on the preparation of acorn vermicelli.

Preparation of Pickering emulsion gels based on κ-carrageenan and covalent crosslinking with EDC: Gelation mechanism and bioaccessibility of curcumin.

Pickering emulsions stabilized by zein/carboxymethyl dextrin nanoparticles were added to the κ-carrageenan-based gel matrix to prepare emulsion gels via EDC - induced covalent crosslinking. Texture, WHC and freeze-thaw stability of the emulsion gels increased after crosslinking. The Confocal laser scanning microscope and SEM suggested that droplet clusters could be observed in gel with higher concentration of emulsion. The rheological measurements indicated that the viscosity and gel-like structure were relied on crosslinking agent and emulsion concentration. The photothermal stability of curcumin was significantly enhanced after crosslinking. In addition, in vitro digestion study suggested that the bioaccessibility of curcumin in emulsion gel crosslinked was lower compared to emulsion gel without crosslinking agent. These studies might facilitate the preparation of emulsion gels with excellent stability for bioactive compounds delivery in food and pharmaceutical applications.

Preparation and characterization of zein/carboxymethyl dextrin nanoparticles to encapsulate curcumin: Physicochemical stability, antioxidant activity and controlled release properties.

In this work, zein/carboxymethyl dextrin nanoparticles were successfully fabricated at different zein to carboxymethyl dextrin (CMD) mass ratios. Zein/CMD nanoparticles with the negative charge and the smallest size (212 nm) were formed when the mass ratio of zein to CMD was 2:1, exhibiting improved encapsulation efficiency of curcumin (85.5%). Electrostatic interactions, hydrogen bonding and hydrophobic interactions were main driven forces for nanoparticles formulation and curcumin encapsulation. Fourier transform infrared spectroscopy determined curcumin might be partially embedded in CMD during encapsulation. The spherical structures of zein/CMD nanoparticles and curcumin-loaded zein/CMD nanoparticles were observed by transmission electron microscopy. The photothermal stability and antioxidant activity of curcumin were significantly enhanced after be loaded in zein/CMD nanoparticles. Furthermore, encapsulation of curcumin in zein/CMD nanoparticles significantly delayed the release of curcumin in simulated gastrointestinal fluids. These results indicated that zein/CMD nanoparticles could be effective encapsulating materials for bioactive compounds in food industry.

Preparation, characterization, and encapsulation capability of the hydrogel cross-linked by esterified tapioca starch.

The modified starch-based hydrogels were prepared by crosslinking modified starch with sodium trimetaphosphate. Modified starch was obtained by esterification of tapioca starch with maleic anhydride. The degree of substitution (DS) increased significantly from 0.078 to 0.258 as the content of maleic anhydride increased from 6.67% to 33.33%. Fourier transform infrared spectroscopy demonstrated that starch was successfully esterified. In addition, the thermal properties of modified starch-based hydrogels were investigated by differential scanning calorimeter and thermogravimetry analysis, which proved that hydrogels had better thermal stability. Esterified starch-based hydrogels showed excellent pH sensitivity by measuring of swelling degree. When DS was 0.250, the adsorption capacity and encapsulation efficiency of starch-based hydrogels were 399.23 µg/g and 80%, respectively, which exhibited satisfactory embedding properties for curcumin. Therefore, esterified tapioca starch-based hydrogels could be as the encapsulating materials to protect bioactive substances, which provided a theoretical basis for their application in food field and pharmaceuticals industry.

Chitosan hydrochloride/carboxymethyl starch complex nanogels stabilized Pickering emulsions for oral delivery of ß-carotene: Protection effect and in vitro digestion study.

ß-Carotene was encapsulated in the Pickering emulsions stabilized by chitosan hydrochloride - carboxymethyl starch (CHC-CMS) nanogels. During ultraviolet radiation and storage, the retention of ß-carotene in Pickering emulsions was higher than that of other formulations, such as Tween 80 stabilized emulsions (TEs) and bulk oil. The Pickering emulsions were found to be stable during thermal treatment. Meanwhile, lipid oxidation was delayed in Pickering emulsions compared to TEs and bulk oil. The vitro digestion results suggested that the free fatty acids (FFA) released were below 30% for all Pickering emulsions, which indicated that a physical barrier was formed by CHC-CMS nanogels to restrain the lipid hydrolysis. The bioaccessibility of ß-carotene in Pickering emulsions was higher than that in bulk oil. This research helped establish a connection between the physicochemical properties of CHC-CMS stabilized Pickering emulsions with their applications in the protection effect and oral delivery of bioactive compounds.

Effects of pectin with different molecular weight on gelatinization behavior, textural properties, retrogradation and in vitro digestibility of corn starch.

Effects of pectin with different molecular weight (Mw) on gelatinization behavior, textural properties, retrogradation, and in vitro digestibility of corn starch (CS) were investigated. The pectin addition led to the decrease of peak, setback, and final viscosities of CS, and a further decrease was provided with the pectin of high Mw, whereas the pasting temperature was increased. The syneresis of starch gel during freeze-thaw process was reduced by the addition of pectin. High Mw pectin significantly lowered the hardness of the starch gel from 238.9 and 350.2 N to 222.7 and 318.5 N after 7 and 14 days storage (P < 0.05), respectively. Compared with the retrograded CS alone, the relative crystallinity of starch-pectin mixtures significantly decreased (P < 0.05), but the crystal type of starch remained unchanged. A significant increase was observed in both the proportion of slowly digestible starch and resistant starch for retrograded starch-pectin mixtures.