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[Display omitted] • Two safe and eco-friendly dextran based high molecular flocculants were developed. • The flocculation efficiency of both flocculants for kaolin suspension exceeded 96%. • The clarification efficiency of Dex-PL for sugarcane juice reached 91.4%. • The Dex-PL can be biodegraded by dextranase hydrolysis. Polysaccharides have been widely used in many fields. In the field of food water treatment, polysaccharide-based flocculants have attracted extensive attention. Based on the enzymatic preparation of high molecular weight dextran, two safe, sustainable and eco-friendly dextran based high molecular flocculants were developed by introducing flocculating active groups into the molecular chain of dextran through cross-linking (DEPL) and esterification (Dex-PL). The prepared product was characterized by elemental analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis and field emission scanning electron microscopy (FESEM). Because amino group is the main active group of flocculation, more amino groups are retained in esterification reaction. In the flocculation experiment of kaolin suspension, the efficiency of the two flocculants is very excellent, both of which are greater than 96%. The results of the study on the flocculation mechanism showed that charge neutralization, adsorption bridging and sweeping flocculation mechanisms occurred in the flocculation process. Dex-PL was applied to the clarification of sugarcane juice in sugar industry. At the dosage of 118 mg/L, the clarification efficiency reached 91.4%. The results of biodegradation experiment showed that the product can be biodegraded by enzymatic hydrolysis. This study provides experience for the development and application of new polysaccharide based flocculants, and provides safe and effective flocculants for sugar refining. [ABSTRACT FROM AUTHOR]

Abstract: Among natural polymers, starch is one of the most promising biodegradable materials because it is a renewable bioresource that is universally available and of low cost. However, the properties of starch-based materials are not satisfactory. One approach is the use of nano-filler as reinforcement for starch-based materials. In this paper, a nanocomposite is prepared using ZnO nanoparticles stabilized by carboxymethylcellulose sodium (CMC) as the filler in glycerol plasticized-pea starch (GPS) matrix by the casting process. According to the characterization of ZnO–CMC particles with Fourier transform infrared (FTIR), Ultraviolet–visible (UV–vis), X-ray diffraction (XRD), transmission electron microscope (TEM) and thermogravimetric analysis (TG), ZnO (about 60wt%) is encapsulated with CMC (about 40wt%) in ZnO–CMC particles with the size of about 30–40nm. A low loading of ZnO–CMC particles can obviously improve the pasting viscosity, storage modulus, the glass transition temperature and UV absorbance of GPS/ZnO–CMC nanocomposites. When the ZnO–CMC contents vary from 0 to 5wt%, the tensile yield strength increase from 3.94MPa to 9.81MPa, while the elongation at break reduce from 42.2% to 25.8%. The water vapor permeability decrease from 4.76×10−10 to 1.65×10−10 gm−1 s−1 Pa−1. [Copyright &y& Elsevier]

Development of biodegradable food packaging using biomass based materials derived from agricultural wastes has been a trend in recent years. The biopolymer films were prepared using 3% and 5% (w /w) potato peel (PP) powder. Bacterial cellulose (BC) (0, 5, 10 and 15% based on PP powder) was added as a reinforcement agent. The scanning electron microscopy (SEM) revealed that 10% BC had a promising compatibility with the PP matrix. X-ray diffraction (XRD) and thermogravimetric analysis (TGA) showed that the crystallinity and the thermal stability of films did not change with BC addition. Fourier transform infrared spectroscopy (FTIR) indicated the hydrogen bonding interactions between the PP matrix and BC in the films. BC addition significantly improved the tensile strength (TS), but reduced their water vapor permeability (WVP), oxygen permeability (OP) and moisture content (MC) of the PP films. Addition of curcumin further increased the antioxidant properties of the PP films. The PP films with 1–5% curcumin significantly reduced lipid oxidation in the fresh pork during storage with lower malondialdehyde (MDA) content. • BC (10%) addition improved the mechanical properties of the potato peel (PP) films. • BC (10%) addition improved the barrier properties of the PP films. • Hydrogen bonding interactions between the biopolymers of PP and BC were observed. • The active PP films with curcumin had a good ABTS radical scavenging activity. • The active PP films can effectively protect fresh pork form oxidative attacks. [ABSTRACT FROM AUTHOR]

Abstract: A bionanocomposite was cast using ZnO nanoparticles stabilized by soluble starch (nano-ZnO) as filler in a glycerol plasticized-pea starch (GPS) matrix. According to the characterization of nano-ZnO particles by Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TG) and transmission electron microscopy (TEM), ZnO nanoparitlces (70 wt%) were encapsulated by starch (30 wt%) in nano-ZnO particles of about 10nm. In GPS/nano-ZnO nanocomposites, loading a low level of nano-ZnO particles improved the pasting viscosity, storage modulus, glass transition temperature and UV absorbance. When the nano-ZnO content varied from 0 to 4 wt%, the tensile yield strength and Young’s modulus increased from 3.94 to 10.80MPa and from 49.80 to 137.00MPa, respectively. The water vapor permeability decreased from 4.76×10−10 to 2.18×10−10 gm−1 s−1 Pa−1. The improvement in these properties may be attributed to the interaction between the nano-ZnO filler and GPS matrix. [Copyright &y& Elsevier]

• Co-lupulone was successfully separated by acid-base precipitation and recrystallization. • The structure was explored by FTIR, UV–Vis, MS, 1HNMR and single-crystal X-ray diffraction. • The antioxidant and antibacterial abilities of β-acids samples with different contents of Co-lupulone were evaluated. • Co-lupulone has excellent antibacterial activity. β-Acids, important part of hops extract, are consisted by three main homologues (co-lupulone, ad-lupulone and n-lupulone). To study the properties of β-acids homologues, co-lupulone monomer was obtained from hops extract. The structure was explored by Fourier transform infrared spectroscopy (FTIR), UV-Visible Spectrophotometer (UV–Vis), Mass Spectrometer (MS), Nuclear magnetic resonance hydrogen spectrometer(1HNMR) and single-crystal X-ray diffraction. Five β-acids samples with different contents (30%,50%,70%, 90% and 100%) of co-lupulone were prepared by recrystallization method. The antioxidant experiment results showed that there were significant differences of samples with different contents of co-lupulone. The experiment result of antibacterial indicated that all samples against gram-positive bacteria (S. aureus and B. subtilis) was better than gram-negative bacteria (E. coli and S. paratyphi B), especially had no effect on S. paratyphi B. Interestingly, it could be concluded that the sample with higher the content of co-lupulone would have better antibacterial performance; in which the minimum inhibitory concentration (MIC) of pure co-lupulone against the three strains was all 37.5 μg/ml, while the sample containing 30% co-lupulone was only 75.0 μg/ml. These finding suggest that β-acids with high content of co-lupulone could be more value as a high quality natural bacteriostatic agent, as well as contribute to the hop variety breeding. [ABSTRACT FROM AUTHOR]