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Active edible films based on okara soluble dietary fiber (SDF), pectin, sodium carboxymethyl cellulose (CMC Na) and thyme essential oil (TEO) were successfully prepared. We aimed to exploit biodegradable edible films and realize the full utilization of waste resources. The effects of different amounts of pectin on the properties and structural characterization of the composite film with or without TEO were studied using a solution casting evaporation method. In general, the addition of TEO can improve the properties of the composite membrane. Pectin was homogeneously distributed within the films and exhibited good interaction with the polymer matrix. The addition of pectin led to significantly higher mechanical and optical properties of the composite film, compared with SDF/CMC-Na composite film. The tensile strength reached 21.419 ± 2.22 MPa, and the minimum transparency reduced to 88.9% ± 0.42%, with increasing pectin. Notably, the water resistance and oil resistance were enhanced. The composite films also possessed satisfactory antioxidant activity, with a DPPH-free radical scavenging rate of 46.33% ± 0.72%, while antibacterial activity against E. coli and S. aureus bacteria was not obvious. Antioxidant and antibacterial SDF/pectin/CMC-Na composite films with enhanced mechanical, optical and barrier properties are excellent candidates for active edible packaging. [ABSTRACT FROM AUTHOR]

Abstract The physicochemical and digestive properties of acetylated corn starch with different degrees of substitution were studied, which were prepared by microwave pretreatment and acetate esterification. Native corn starch-wheat noodles, acetylated corn starch-wheat flour noodles and native wheat noodles were prepared and their properties were compared. The results showed that the transparency, condensation volume ratio, hydrophilicity and lipophilicity of modified corn starch increased with increasing of substitution degree, which were 4.0% to 12.1%, 21.11% to 31.78%, 0.73 g/g to 0.91 g/g and 0.66 g/g to 0.88 g/g, respectively and the rate of water evolution decreased from 44.9% to 33.3%. Fourier transform infrared spectroscopy showed that acetyl group was successfully introduced. Scanning electron microscopy showed that microwave pretreatment and group introduction made the surface of starch granules locally porous and rough. Differential scanning calorimetry showed lower onset temperature, peak temperature, conclusion temperature and enthalpy than native corn starch, which proved that acetylated corn starch reduced the content of rapidly digestion starch and increased the content of slow digestible starch and resistant starch. At the same time, the results showed that the color, texture and tensile properties of noodles with acetylated corn starch were improved. It showed that acetylated corn starch prepared by microwave pretreatment and acetate esterification had certain application prospects. Highlights • Starch was prepared by microwave pretreatment and esterification with acetate. • Physicochemical and digestive properties of acetylated starch were studied. • Three kinds of noodles were prepared by adding NCS-WN, ACS-WN and NWN. • The color, texture and tensile properties of three kinds of noodles were studied and compared. [ABSTRACT FROM AUTHOR]

Abstract Compared with the traditional method, the microwave assisted method can greatly shorten the reaction time of hydroxypropyl starch and improve product quality. The microwave assisted conditions and physicochemical properties of natural corn starch were studied. Response surface methodology was used to optimize the reaction conditions of three-level-three-factorial center composite design. The optimum parameters were as follows: the additive amount of propylene oxide was 8%, the radiation time was 6.08 min, and the microwave power was 303.43 W. The optimal degree of substitution (DS) of hydroxypropyl starch was determined by the optimal conditions predicted by RSM, which was 0.0729 mg/g. The analysis of physicochemical properties showed that with the increase of the DS of starch derivatives, the transparency (4% to 8.81%), the volume ratio of the condensing volume (21.11% to 33.11%), the hydrophilic (0.73 g/g to 2.46 g/g), and the hydrophobicity (0.67 g/g to 1.01 g/g), and the water evolution rate (46.91% to 36.16%) decreased. Fourier transform infrared spectroscopy showed that the enhancement of peak intensity at 1149 cm−1 indicated the successful introduction of hydroxypropyl group. Scanning electron microscopy showed that the surface morphology of corn starch was affected to some extent. The modification did not change the crystalline type of starch, which was still A type. Highlights • Hydroxypropyl starch with different DS was prepared by microwave-assisted preparation. • The optimum preparation conditions of hydroxypropyl starch were determined by single factor method and RSM method. • The properties of hydroxypropyl starch with different DS were studied. • The DS of hydroxypropyl starch was compared and analyzed by FTIR, SEM and XRD. [ABSTRACT FROM AUTHOR]

The formation and characterization of conjugates of soybean protein isolate (SPI) and dextran with varying molecular weights (4, 10, and 70 kDa) and their effects on quality of glucono-δ-lactone (GDL)-induced tofu were investigated. The extent of glycosylation was negatively related to the molecular weight of dextran. Thus, the SPI-dextran4 conjugate exhibited a darker color and a biggest decrease in whiteness from 70.49 to 45.51. SPI-dextran70 conjugate exhibited an increased surface hydrophobicity and free sulfhydryl content. Volume-average diameter of SPI-dextran70 conjugate-added soymilk and gel strength of the corresponding tofu ranged from 10.34 to 11.24 μm and 0.068 to 0.083 N, respectively, which were lesser than those of the control (11.12 μm and 0.133 N). However, SPI-dextran10 conjugate incubated for 6 days and SPI-dextran4 conjugate incubated for 2 days increased the gel strength of tofu to 0.146 and 0.143 N, respectively. Conjugates-added tofu exhibited an increased water holding capacity and a discontinuous and loose microstructure, but a lowered whiteness and a color change to yellow. Results demonstrated that the selection of dextran with an appropriate molecular weight and controlling the glycosylation degree were capable of improving the quality of SPI-dextran conjugate-added GDL-induced tofu. • Soybean protein isolate (SPI)-dextran (4, 10, 70 kDa) conjugates were prepared. • Molecular weight of dextran affected the physicochemical properties of conjugates. • SPI-dextran70 conjugates reduced particle size of soymilk and gel strength of tofu. • Impact of SPI-dextran4/10 conjugates on gel strength of tofu depended on reaction time. • The addition of conjugates enhanced the water holding capacity of tofu. [ABSTRACT FROM AUTHOR]