We have developed a series of self-assembled electro-optic dendrimers. Four dendrimers H1, H2, H3 and HLD 1 were synthesized by introducing aromatic dendron (HD), trifluorobenzyl dendron (TFD), pentafluorophenyl dendron (PFD) and anthracene ring (AH) into the donor and bridge parts of chromophores. In addition, threearm trifluorobenzyl dendron containing multichromophore H4 was also synthesis and evaluated. These molecules were supramolecular self-assembled through the n-n interaction of HD-PFD/HD-AH/TFD-TFD to minimize the dipole-dipole interaction of chromophores and maximize the accentric order of chromophores under high load densities. High r33 (328, 317 and 279 p.m./V) have been achieved for neat films containing chromophores 1:1 H1: H3, 1:2 H3: HLD 1 and H4, respectively. Moreover, the long-term orientation stability of chromophores were also improved. After 1000 h at room temperature, the initial electro-optic coefficient of the electrode selfassembled film still remains above 95%.

The effects of near-freezing temperature (NFT) storage on chilling injury and antioxidant metabolism of post-harvest guava were investigated in comparison with 6 degrees C and 10 degrees C storage. NFT storage showed significant inhibition effects on guava chilling injury occurrence, increment in cell membrane permeability and malon-dialdehyde accumulation, and contributed to compact and well-organized cell structure at the end of storage. Besides, remarkable enhancements in radical scavenging activities (DPPH, ABTS), ascorbic acid (ASA) and glutathione (GSH) contents, and activities of catalase (CAT), superoxide dismutases (SOD), peroxidase (POD) and the ASA-GSH cycle-related enzymes were observed in NFT group, leading to the elimination of excessive hydrogen peroxide (H2O2) and superoxide anion (O2.). Further investigation of expression levels of genes related to the ASA-GSH cycle confirmed that NFT induced the transcriptions of PguAPX2, PguMDHAR1, PguMDHAR3, PguGR1 and PguGR2, and activated antioxidant related enzymes, alleviating cell membrane damage and cell disintegration during storage, thus inhibiting chilling injury of guava.

An active bacterial anti-adhesion strategy based on directional transportation of bacterial droplets driven by a triboelectric nanogenerator (TENG) has not been reported to date, although passive defense approaches can prevent bacterial adhesion by regulating superwetting surfaces combined with incorporated antibacterial substances. Here a triboelectric nanogenerator driving droplet system (TNDDS) was built to drive directional transportation of bacterial droplets to be eliminated, which comprises TENG with periodical frictional Kapton film and aluminum foils and a superhydrophobic driving platform (SDP) with paralleled driving electrodes. The current generated by the TENG triboelectricity is transmitted to the paralleled driving electrodes to form an electric field driving the directional transportation of charged droplets. The critical value of the driven droplet volume on SDP is closely related to the distributed electrodes' distance and width, and the driving distance of droplets is related to the number of electrodes. More crucially, TNDDS can actively drive the charged droplets of prepared triangular silver nanoprisms (Ag NPs) forward and back to mix with and remove a tiny bacterial droplet on an open SDP or in a tiny semi-enclosed channel. Bacteria could be killed by releasing Ag+ and effectively removed by TNDDS by regulating the motion direction. Generally, this approach offers a promising application for removing bacteria from material surfaces driven by TENG and opens a new avenue for bacterial anti-adhesion.

A new chitosan/zein-cinnamaldehyde (CHI/zein-CMA) nano composite film was developed, which possessed remarkable features favorable for mango preservation, including retardation of yellowing, respiration rate, weight and vitamin C loss and malondialdehyde (MDA) accumulation during storage of mango at 25 degrees C. The formula of chitosan/zein nano composite film was optimized through single factor experiments and orthogonal experiment with fuzzy comprehensive assessment. The results showed that the optimal formula is chitosan 35.0 g/L, zein 3.0 g/L, nano-cellulose 25.0 g/L, acetic acid 0.26 mol/L. Besides, cinnamaldehyde was incorporated into CHI/zein composite film and 3.0 g/L was chosen as the favorable concentration. The crack-free film surface observed under scanning electron microscopy (SEM) suggested that the incorporation of CMA contributed to a more flexible and dense film structure, and the significant increase in beta-sheets (from 17.06% to 27.00%) accompanied with the decrease in a-helix (from 55.5% to 44.41%) further confirmed the strong cross-linking of CMA with CHI/zein matrix. The results showed that the accumulation of H2O2 to desired level and storage adjusting of antioxidant enzymes activity (SOD) might be related to the excellent storage quality of mango coated with CHI/zein-CMA, suggesting that stress response was beneficial to the preservation of mango.

P–CoCO3/CF was developed by a simple hydrothermal–annealing approach, exhibiting ultra-high electrocatalytic performances for the HER, OER and HzOR.

"Calcification" is a deterioration of chestnut quality during storage at room temperature, which draws great concerns due to its unclear mechanism. In this study, the variations in calcification index, moisture content, cell structure, membrane permeability, reactive oxygen metabolism, respiratory metabolism and energy status in postharvest chestnut stored at 50-55% (low relative humidity, LRH) and 85-90% (high relative humidity, HRH) at 25 degrees C were evaluated and the results were analyzed by principal component analysis (PCA). LRH groups showed higher calcification index and moisture loss, and the cell ultrastructure characterized by scanning electron microscopy (SEM) and transmission electron microscope (TEM) indicated that cell integrity in calcified chestnut was destroyed and cell membrane permeability was higher in LRH groups. LRH groups exhibited excessive reactive oxygen species (ROS) accumulation (H2O2 and O-2(-center dot)), weakened activities of superoxide dismutases (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6) and peroxidase (POD, EC 1.11.1.7) in plasma membrane, higher respiration rate, but lower activities of glucose-6-phosphate dehydrogenase (G-6-PDH, EC 1.1.1.49) + 6-phosphogluconate dehydrogenase (6-PGDH, EC 1.1.1.44), succinate dehydmgenase (SDH, EC 1.3.99.1) and cytochmme C oxidase (CCO, EC 1.9.3.1), ATP content and energy charge than HRH groups. These findings together with PCA result indicated that under low relative humidity, changes in respiratory metabolism stimulated excessive ROS accumulation, and limited energy formation in chestnut. Furthermore, excessive ROS severely impaired chestnut cell membrane integrity, while ATP shortage led to inactivation of antioxidant enzymes and dysfunction in membrane repairment, which might contribute to chestnut "calcification" occurrence.

Chestnut calcification is a quality deterioration due to fast water loss, which has been of deep concern for chestnut quality control because its mechanism is unclear. In order to find out the different key metabolites and metabolic pathways related to the occurrence of chestnut calcification, in this study, liquid chromatography-tandem mass spectrometry (LC-MS/MS) based widely targeted metabolomics analysis was performed on chestnuts that were stored at 50%-55% (low relative humidity, LRH) at 25 degrees C and 85%-90% (high relative humidity, HRH) at 25 degrees C. A total of 611 metabolites were detected, and 55 differentially accumulated metabolites were identified as key metabolites involved in chestnut calcification process. The decrease in some monosaccharides accompanied with the increase in some unsaturated fatty acids indicated the degradation of chestnut cell wall and cell membrane during calcification process. As a stress response, amino acid metabolism related to membrane stability was significantly activated. In addition, the enhancement of phenylpropanoid biosynthesis pathway and flavonoid biosynthesis pathway characterized by the accumulation of lignin precursors and antioxidants suggested that lignification process was triggered in calcified chestnut. Therefore, the degradation and hardening of the cell wall and membrane damage were proposed to be associated with the calcification occurrence of chestnut. The metabolic profile of chestnut characterized in this study provided new insights into chestnut calcification process and laid a foundation for further chestnut quality control.

In this work, a typical electrospinning technology and subsequent calcination is developed for fabrication of Co2P/Co2N core-shell nanostructure embedded in N-doped carbon nanofiber (Co2P/Co2N@CNF-DNA(C)) for oxygen evolution reaction, where DNA is used as template and P-source. In such unique nanostructure, (1) the synergistic interaction between Co2P and Co2N in the core-shell nanostructure optimizes the electron interaction, thus reducing the energy barrier; (2) the binding effect of DNA reduces the charge transfer resistance and improve the stability of the obtained materials, the base sequence of DNA also has significantly effect on the electric catalytic performance; (3) the porous conductive carbon nanofiber matrix provides more exposures of reaction sites, thus enhancing electrolyte penetration and facilitates the release of O-2 bubbles. In view of these advantages, the Co2P/Co2N@CNF-DNA(C) nanofiber shows a remarkable OER catalytic performance and prominent electrochemical stability, outperforming those of the Co2N@CNF as well as its many counterparts. Therefore, the typical electrospinning followed by calcination strategy in which DNA used as template and P-source pave a way to synthesize other transition metal phosphides electrocatalysts in the future. (C) 2020 Published by Elsevier Ltd.

Chitosan (CHI) and whey protein are usually used to prepare edible films for food preservation. However, the composite film composed of the two components does not yield satisfactory properties for chestnut preservation. In this study, nano-cellulose and cinnamaldehyde (CMA) were added to CHI and whey protein, creating a new composite film with strong water retention, bacteriostatic, and mechanical properties. The water vapor permeability (WVP) of the film decreased by 21.61% with the addition of 0.5% (w/v) nano-cellulose, and 23.02% with the addition of 0.3% (w/v) CMA. Furthermore, water solubility (WS) decreased 22.05%, and the density of the film was significantly improved with the addition of 0.3% (w/v) CMA. The optimized formula of the film was CHI 2.5% (w/v), whey protein 3.0% (w/v), nano-cellulose 0.5% (w/v), CMA 0.3% (w/v), and pH 3.8, as determined by orthogonal testing L9(3(4)), with fuzzy comprehensive assessment, of WVP, WS, tensile strength, and elongation at break. The film clearly inhibited the growth of E. coli, S. aureus, and Chinese chestnut fungus, destroying the mycelial structure of the fungus. In addition, coating effectively reduced the weight loss, mildew rate, and calcification index during 16 days of storage of chestnuts at 25 degrees C.

以桑葚为原料,感官评分和总花色苷含量为指标,通过正交试验对桑葚果糕配方及加工工艺进行优化,同时进一步对桑葚果糕成品的微生物及理化指标进行检测.结果 表明,桑葚果糕胶凝剂选用二元复配胶凝剂,其中黄原胶和琼脂复配成型性和韧劲最好,最优配方为:采用黄原胶-琼脂复配(质量比1.5∶1),以浓度40％的桑葚果浆为基质,胶凝剂、蔗糖、麦芽糊精、柠檬酸添加量分别为基质质量的3％、35％、35％、1.5％.最佳加工工艺配方为:注模厚度1.3 cm、烘烤温度60℃、翻面时间17 h、烘烤时间23 h.所得桑果糕呈紫红色,风味独特,酸甜适中,总花色苷含量(1.52±0.003) mg/g.经检测,桑葚果糕各项微生物指标均符合GB/T 10782-2006果糕类国家标准要求.

A modified quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction method was developed for the simultaneous determination of 42 steroid hormones in milk and milk powder by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Sample pretreatment was studied and the detection conditions were optimized to obtain a rapid and accurate method. The steroid hormones from samples were extracted with 0.1% formic acid in acetonitrile followed by a salting-out step with anhydrous MgSO4and NaCl. After centrifugation, the supernatant was cleaned up with 50 mg of octadecylsilane (C18), 100 mg of primary secondary amine (PSA), and 300 mg of aluminum oxide (Al2O3-N) and re-dissolved with 40% formic acid acetonitrile. The separation was performed on a Waters ACQUITY UPLC? BEH C18column (2.1 mm × 100 mm, 1.7 μm) with gradient elution using acetonitrile and water containing 0.1% formic acid as the mobile phase. The electrospray ionization mass spectrometry was operated in the positive mode using multiple reaction monitoring (MRM). The target compounds were quantified by the matrix-matched external standard method. Under the optimal conditions, the calibration curves of all the analytes were linear in the concentration range of 0.5-500 μg/L with correlation coefficients larger than 0.99. The limits of quantitation (LOQs) ranged from 0.06-1.5 μg/kg. The average recoveries for milk and milk powder at three spiked levels ranged from 70.3%-118.1% with relative standard deviations (RSDs) of 0.6%-14.7%. The method due to its simplicity, rapidity, high accuracy and high precision was suitable for the simultaneous detection of 42 steroid hormones in milk and milk powder.

Calcification, a kind of quality deterioration, occurs in chestnut due to fast water loss when stored at low relative humidity (RH) and room temperature. In this study, the relationship between water loss rate and plasma membrane lipid oxidation in chestnut stored at low (50-55%) RH and high (85-90%) RH at 25 degrees C has been investigated to understand the mechanism of calcification. Water loss rate per day in chestnut at low RH was 6% and 1.5 times that at high RH, while the calcification index at low RH was 0.4 and 3.5 times that at high RH. At low RH, the activities of plasma membrane lipase and lipoxygenase (LOX), the content of malonaldehyde (MDA) and saturated fatty acid (SFA) in chestnut were higher than those at high RH. Meanwhile, unsaturated fatty acid (UFA) index decreased in low RH, but increased in high RH. The correlation coefficient (r) between MDA content and calcification index in chestnut stored at low RH and high RH was 0.928** and 0.937** respectively, which implied that the plasma membrane lipid oxidation induced by fast water loss might be related closely to occurrence of calcification in chestnut. In contrast, at high RH, the moisture content in chestnut decreased slowly and the hydrolysis and oxidation of membrane lipid were a low, and was associated with better maintenance of quality. (C) 2016 Elsevier B.V. All rights reserved.

Theoretically,electrical conductivity can be used to evaluate the quality of edible oils.Given its convenience,it has the brilliant application in normal kitchens.However,since the correlation between electrical conductivity and polar component of edible oils was poor,some researchers have contemplated its accuracy.In order to clarify the relationship between electrical conductivity and other indexes of edible oils,this paper detected the peroxide values,acid values,and the electrical conductivity of seven edible oils when they were stored at 60 ℃.The results showed that there was little correlation between electrical conductivity and acid value,,while there was a linear correlation between electrical conductivity and the double variables (peroxide values plus acid values).Among the oils tested,maize germ oil and peanut oil had correlation coefficients higher than 0.98.Therefore,electrical conductivity can be used for the rapid detection of edible oils.

The activity against bacteria of flavonoids-propionic acid mixtures,different purity and different polar flavonoid from banana peel was studied by filter paper with Escherichia coli and Staphylococcus aureus.The re-sults showed that the higher the purity of flavonoid was and the stronger the polarity was,the more powerful the antibacterial activity of flavonoid was.Antibacterial activity against gram positive bacteria Staphylococcus aureus was significantly greater than that against gram negative bacteria Escherichia coli.The minimal inhibitory con-centration(MIC)of purified flavonoids on Staphylococcus aureus and Escherichia coli were 1 3.00 mg·mL -1 and 3.25 mg·mL -1 .Flavonoids-propionic acid compound could increase antibacterial activity against Escherichia coli,both had synergistic effect.

Crude flavonoid extract was obtained from banana peel by microwave extraction and purified using H103 macroporous resin and combined with propionic acid to produce flavonoid-propionic acid mixtures. Toxicology testing was conducted using these mixtures as per the Procedures for Toxicological Assessment of Food published by Ministry of Health of The Peopleu0027s Republic of China. Toxicology testing included using the acute toxicity test for minimum lethal dose for 50% mice(LD50), bone marrow cell micronucleus test, mice sperm morphology test, and Ames test. The results showed that the LD50 values for female and male mice were 10.8 and 12.6 g/kg body weight(BW), respectively; while the fiducial limits for female and male mice were 7.41~15.7 and 7.75~20.5 g/kg BW, respectively. The results from the acute toxicity test, bone marrow cell micronucleus test, and sperm morphology test were all negative, which implied that flavonoid-propionic acid mixtures from banana peel showed no mutagenic effects on somatic and germ cells and that they did not show indirect or direct mutagenicity. Therefore the mixtures are non-toxic and can be used as preservatives.

The development of active packing materials has been focused on the incorporation of additives into the materials to afford more attractive and functional properties. In this paper, maize starch‐based functional films were prepared by adding prebiotics into the starch matrix. It was shown that with the addition of prebiotics and a decrease in their molecular weight, the starch‐based films became more soluble and more flexible. Specifically, the time for the waxy maize starch‐based films to be dissolved in water was reduced from 150 to 10 s. This could be ascribed to the disruption of starch film integration by the water‐soluble prebiotic, which enhanced the penetration of water to the films. Besides, the elongation at break of the films was increased from 15 to 46%, apparently due to the plasticization effect of the prebiotics. Moreover, the in vitro microorganism results indicated that the prebiotic activity of the functional films would not be affected by the film preparation (solution casting) process. These results demonstrated that starch‐based functional films can be prepared with prebiotic activity and instant water‐dissolution property. These films could be used as the packaging materials for water soaking foods, such as freeze‐drying vegetables.

Preparation technology of tilapia protein hydrolysates by built single factor test and response surface methodology(RSM)were defined with the index degree of dydrolysis(DH), TCA-soluble nitrogen index (TCA-NSI) and yield of acid-solubility peptide (YASP). The effect of hydrolysis temperature, pH, the quantity of Alcalase, the ratio of Liquid-to-solid on DH, TCA-NSI, YASP were studied by RSM, and Regression model was obtained by response surface analysis. Regression model indicated that the optimal condition hydrolyzed Animal Protein of Tilapia Meat by Proteinase was described in the following:hydrolysis temperature 54.30℃, pH 8.77, the quantity of Alcalase 2.4 L was 3 702 U/g, the ratio of Liquid-to-solid was 3.06∶1, hydrolysis time 1hour. under such condition, the DH (%), TCA-NSI (%) and YASP (%) reached 33.63%, 22.10%, 64.55%respectively. Experiment result showed that the DH(%), TCA-NSI(%) and YASP(%) were 33.57%, 22.09%, 64.52%, the predictive value and experimental value have small deviation , indicated that Regression model was reasonable and reliable.

The best macroporous resin for purification of banana peel flavonoid(BPF) was selected from X-5,AB-8,H103 and D-101 by static adsorption and desorption capacities.H103 was identified as the best resin for BPF purification.The adsorption equilibrium was reached in about 3 h and the maximum adsorption quantity for BPF was 3.66 mg/g,while the time required to reach desorption equilibrium was about 2.5 h,yielding a desorption percentage of 89.11%.The optimal conditions for purifying BPF by dynamic adsorption and desorption on H103 were determined as 7.0,2.0 mL/min,3.0 mL/min and 75% ethanol for pH sample loading flow rate,desorption flow rate and desorbent,respectively.Under these conditions,the recovery and purity of BPF were 72.50% and 73%,respectively.BPF could inhibit the growth of Candidaalbicans,Escherichiacoli,Bacillussubtilis,and purified BPF had better antimicrobial activity.

The optimal formula and processing parameters of the epidermis and filling materials of a new kind of cake made of Chinese yam,tuckahoe,lotus seed and red jujube were studied by one factor and orthogonal test.The results showed that the optimal formula of epidermis was: Chinese yam powder 8.00%,tuckahoe powder 7.33%,sugar 14.67% and salad oil 6.67%.The best formula of filling materials was: sugar 20.00%,red jujube powder 20.00%,lotus seed powder 24.00% and citric acid 0.20%.The cake contained coarse polysaccharide 13.92% with good shap,uniformity colour,good texture and flavour.In addition,microbiology detection of the product showed bacteria count 10 and mildew colony 20,lower than the detection limits of the national standard.