Rice oligopeptides were prepared from rice protein powder by two-step enzymatic hydrolysis.Based on the analysis of their basic physical and chemical components，the structure of rice oligopeptides was characterized by amino acid composition，relative molecular weight distribution，scanning electron microscopy，ultraviolet spectrum  and circular dichroism.The in vitro antioxidant activity of rice oligopeptides was investigated by four index of in vitro antioxidant evaluation system including hydroxyl radical scavenging ability，ferric ion reducing antioxidant power （FRAP），oxygen radical absorbance capacity （ORAC） and reduction capacity.The results show that： the protein and peptide contents in rice oligopeptides are 95.75%±0.53% and 89.11%±0.94%；rice oligopeptides are rich in antioxidant amino acids such as leucine，alanine and valine，and the components with relative molecular weight less than 1000 accounted for 91.84%；rice oligopeptides are obvious spherical granules，and have irregular folds and pores on the surface；the maximum absorption peak appears at 270 nm wavelength；the contents of α-helix，parallel β-fold，antiparallel β-fold，β-turn and random coil are 6.0%±0.3%，3.3%±0.2%，40.2%±1.9%，19.5%±1.0%，and 32.1%±2.5%，respectively.The IC50 value of rice oligopeptides to hydroxyl free radical is about 11.1g/L，and ORAC value is （498.88±18.29） μmol/g （with Trolox as the standard）；the FRAP value of rice oligopeptides at 15.0g/L is equivalent to that of 0.04g/L positive control Vc，and the redu-cing ability of rice oligopeptides at 15.0g/L is equivalent to that of 0.05g/L Vc. 

Eicosapentaenoic acid （EPA） is a kind of n3-polyunsaturated fatty acid with important physiological functions.It has broad commercial prospects in health food，medicine，feed and other industries.However，the deep-sea fish oil as the traditional source of EPA cannot meet the increasing market demand.In this paper，Schizochytrium was taken as the original strain，and a two-stage temperature and low-dissolved-oxygen（TST-LDO） strategy is proposed.The effect of fermentation temperature was optimized by single factor experiment at the shaking flask level，and the effects of two-stage temperature change time and dissolved oxygen on the fermentation performance of EPA production in Schizochytrium were studied in a 5L fermenter.The change of fatty acid components in the process of fermentation was studied.The results show that the highest EPA content （8.35%） is obtained at two-stage-temperature strategy （28℃（0~24h）→34℃（24~120h））.The optimal temperature change time is 24h，which is determined in a 5 L fermenter.The results of different dissolved oxygen studies show that the medium and high dissolved oxygen （10%DO and 25%DO） are more conducive to the growth and lipid accumulation of Schizochytrium，but the low dissolved oxygen （2%DO） is more conducive to the accumulation of EPA，and the content of EPA is 2.05 times and 4.98 times of the medium and high dissolved oxygen level，respectively.When fermentation reached 96 h under TST-LDO strategy，the biomass，lipid yield，EPA content in total fatty acid and EPA yield reached 56.60g/L，9.62g/L，12.50% and 1.14g/L，respectively.Compared with the pretreatment，EPA content and EPA yield increased by 14.5 times and 6.1 times，respectively.

As a new type of food-grade Pickering particles，solid lipid particles （SLPs） draw wide attention due to their good bioavailability，safety，wide sources and high industrialization prospects.Controlling the size and morphology of SLPs is of great significance for the preparation of stable SLPs Pickering emulsion.This paper took high-melting-point solid fat-fully hydrogenated soybean oil （FHSO）as the research object and Tween 40 （T40） as emulsifier.SLPs with different particle size，crystal forms and morphologies were prepared with different ultrasonic power （300，350，400 and 450 W） and time （1，2，4，and 6 min）.The influence of SLPs on emulsion droplet size was studied.The results show that SLPs without T40 is wide stip-like with the average particle size（Z-average） of 1.6~2.9μm，and the crystal form is α-form；SLPs containing T40 is rod-like and with spherical shape，its Z-average is 259~480 nm，and the α-form and β-form crystals coexist.When the ultrasonic time is 4 min，Z-average of SLPs without T40 increase with the increase of ultrasonic power，with no obvious change in the crystal form and morphology，whereas Z-average of SLPs containing T40 increase gradually，and β-form and spherical crystals increased.When the ultrasonic power is 350 W，Z-average of SLPs without T40 decrease with the increase of ultrasonic time，with no obvious change in the crystal form and morphology，whereas Z-average of SLPs without T40 decrease significantly （from 480 nm to 261nm），but the morphology and crystal form does not change significantly.It can be concluded that the addition of T40 reduces the particle size of SLPs，changes the crystal form of SLPs，and promotes the transformation of the crystal morphology from plate-like to rod-like and spherical.For the emulsions prepared with the above SLPs，it is found that the emulsions containing SLPs without T40 are unstable and massive flocs appears on the upper layer；while stable white emulsions were obtained with the SLPs containing T40，and the emulsion particle size changes with the SLPs particle sizes，polymorphs and morphologies.

Klebsiella pneumoniae is a opportunistic pathogen associated with acquired infections and is listed by the World Health Organization （WHO） as a drug-resistant pathogen that urgently needs to develop new antibiotics.Siderophores is an important virulence factor for K.pneumoniae to proliferate in host cells，mainly including enterobactin，yersiniabactin，aerobactin，and salmochelin.A multi-drug resistant K.pneumoniae ST37 KP200 was isolated from the liver of sick pigs.This study analyzed the evolutionary relationship and genetic diversity of si-derophores of KP200 and 160 K.pneumoniae ST37 strains from NCBI with bioinformatics software.The single-copy core genes analysis results show that KP200 and a Chinese K.pneumoniae of human origin locate in the same clade with similarity of 99.8%.Siderophores analysis shows that all ST37 strains carry enterobactin entABCEF and fepABC.KP200 and other 15 K.pneumoniae strains carry aerobactin transporter gene iutA.The nucleotide homo-logy of 16 iutA gene sequences is 73.49%～100%.Compared with the iutA nucleotide sequence carried by the hypervirulent K.pneumoniae NTUH-K2044，it finds that the iutA nucleotide carried by KP200 results in two amino acid substitutions due to two base mutations： Leu is replaced by Phe and Val is replaced by Leu.This study provides basis for studying the evolution and virulence of K.pneumoniae ST37.

This paper mainly introduced the preparation and anticoagulant activity of sulfated Schizophyllan polysaccharides （S-SPG）.The single-factor and response surface method were used to optimize the preparation of polysaccharides-SPG with the sulfur trioxide-pyridine method.The anticoagulant activity was evaluated through APTT，TT，and PT assays.The results show that when the mass ratio of sulfur trioxide-pyridine complex to Schizophyllan polysaccharides （SPG） is 4，the reaction temperature is 70℃，and the reaction time is 3h，the degree of substitution of S-SPG was the highest （1.85）.The FT-IR and 13C NMR spectroscopy data proved that the sulfated group was successfully inserted into schizophyllan.Anticoagulant assays show that sulfated Schizophyllan polysaccharides exhibits strong anticoagulant activity and prolongs APTT and TT，but has no effect on PT.The anticoagulant acti-vity is positively correlated with the concentration and degree of substitution.S-SPG3 with the highest degree of substitution shows the strongest anticoagulant activity.When the mass concentration is 0.2g/L，the APTT values of S-SPG3 is 184.35s，which is 1.86 times of S-SPG2 and 2.49 times of S-SPG1 under the same concentration.Besides，the TT values of S-SPG3 was over 90 s at the mass concentration of 0.2g/L.

The study aims to optimize the starter culture of Chinese traditional fermented rice cake.Lactobacillus plantarum DMDL9010 and L. delbrueckii subsp.bulgaricus DMDL-H1 at the ratio of 1：1 were deployed in the batter fermentation and co-fermented with Anqi yeast to ascertain the optimal addition of compound lactic acid bacteria.It turned out that the rice cake got high sensory score and the best texture when the optimal addition of compound lactic acid bacteria was 6%.Twenty two aroma compounds were detected in the co-fermented rice cake by headspace-solid-phase microextraction gas chromatography mass spectrometry （HP-SPME-GCMS）.Compared with the traditional one，compound lactic acid bacteria fermented rice cake was rich in esters.The investigation of sto-rage property of co-fermented rice cake in different storage temperature （4，28，37℃） and package methods （vacuum package，modified atmosphere packaging （50% of CO₂ + 50% of N₂），sealed package） showed that modified atmosphere packaging with 28℃ storage temperature can effectively maintain the sensory quality of co-fermented rice cake and significantly decrease the hardness and chewiness of it.

PPO （Polyphenol Oxidase）-induced enzymatic browning affects the quality of fruits and vegetables.To elucidate the mechanism of cold plasma on PPO and avoid browning，this study investigated the effect of cold plasma on PPO activity and conformation.The results showed that the enzyme activity of PPO could hardly be detected when the treatment time reached 120s and 180s.The active species of cold plasma destroyed the PPO secondary structures with the decrease of α-helix （from 39.92% to 9.47%），and the increase of β-sheet （from 15.32% to 44.30%） （180s）.Fluorescence emission spectrum showed that after cold plasma treatment，the PPO fluorescence intensity decreased from 512.9 to 330.6，and the position of the maximum absorption peak showed a red shift of 1.75nm.The 3D fluorescence spectra showed that the DBD plasma destroyed the polypeptide chain skeleton of the PPO molecule.Atomic force microscopy （AFM） showed that DBD plasma induced PPO molecule aggregation and then depolymerization，thus affecting the enzyme activity.In conclusion，cold plasma treatment changed the secondary and tertiary structures of PPO，and promoted the degeneration of protein oxidation and reduction of enzyme activity，providing theoretical support for the application of cold plasma in the inhibition of enzymatic browning and the maintenance of quality for fruits and vegetables.

Unspecific peroxygenase （UPO） has broad application prospects due to its unique stereoselectivity and enantioselectivity in catalyzing organic substrate.In this study，a putative unspecific peroxygenase gene （GmaUPO） was found from the genome of Galerina marginata，and the corresponding gene sequence was obtained by means of the whole gene synthesis technology.Moreover，Pichia pastoris X-33 gene engineering bacteria of GmaUPO inducible expression was constructed.Under the optimal fermentation condition，the enzyme activity of the fermentation broth can reach 6U/L，the relative molecular mass of GmaUPO is about 40ku，the optimal reaction temperature is 35℃and the optimal pH is 9.0.The recombinant GmaUPO can synthesize aromatic oxygen-containing compounds by using H2O2 to catalyze the hydroxylation of the inert C—H bond in aromatic substances under mild condition，which means that it possesses great application potential in the fields of flavors and fragrances.

In this study，the acute toxicological safety，prebiotic in vitro and functional characteristics in vivo of Bacillus coagulans 13002 were evaluated.The results show that Bacillus coagulans 13002 is non-toxic，which acutely oral for female and male KM mice，and that it possesses good tolerance to simulated gastrointestinal digestion fluid.Moreover，it is resistant to Staphylococcus aureus ATCC 12598 （G+） and Escherichia coli ATCC 25922 （G-），which can obviously destroy the microstructure.These results indicate that the combination of Bacillus coagulans 13002 with fructooligosaccharide has a certain recovery effect on cyclophosphamide-induced tissue damage in mice，which can increase blood cells，improve protein synthesis rate and glucose utilization，and remove excess cholesterol to maintain the health of mice.

Resveratrol (RES) is a kind of stilbene compound with bioactivities, and its structure would be destroyed under ultraviolet or heating treatment, thus weakening its bioactivities. Pectin was able to form non-covalent bonds with RES, which was in favor of protecting antioxidant activity of RES. In this study, the structure of pectin was modified by the method of enzymolysis combined with ultrasound treatment. The molecular and microscopic structure of modified pectin was first characterized, and then the interaction mechanism between pectin and RES was discussed by isothermal titration method. At last, the antioxidant activity of RES-pectin complex under ultraviolet or heating treatment was tested. The resulted showed enzymolysis combined with ultrasound modification method remarkably reduced molecular weight and degree of methyl esterification (DM) of pectin. The molecular weight of 4 -min enzymolysis pectin (PE45U) was only 2% of that of unmodified pectin. SEM images showed more irregular fragments of pectin structure after modification. The combined enzymolysis with ultrasound method exposed a great number of –OH of pectin, which considerably increased the interaction sites and affinity between RES and pectin. The interaction sites number between PE45U and RES was 24 times of that between unmodified pectin and RES. The antioxidant activity of RES was significantly enhanced after interacting with pectin under ultraviolet or heating treatment (p<0.05). This study provided new insights to solve the problem of poor ultraviolet and thermal stability of RES and other stilbene when applied in food industry.

Traditional brown sugar production uses lime to clean cane juice，and the product contains a large amount of calcium and residual flocculants． Sodium alginate ( SA) contains a large number of carboxyl which has a strong chelation on calcium ions． This article explored SA's application to decalcification of brown sugar solution， and examined the effects of SA dosage，brown sugar solution's content，reaction temperature，and pH value on the calcium removal rate and reaction efficiency of SA． The results show that: the SA flocculent precipitate ( main body) of the brown sugar solution is calcium alginate; the unit mole ratio of Ca∶SA is the most important influencing factor of the calcium removal rate and the reaction efficiency of SA． The larger the dosage of SA is，the higher the removal rate and the lower the reaction efficiency of SA are． When the unit molar ratio of Ca∶SA is about 2. 5， the suitable mass fraction of brown sugar solution is 50% ～ 60% ，and the reaction efficiency of SA is about 90% ． Temperature also has a certain effect on the calcium removal rate and reaction efficiency of SA． The calcium removal rate is the highest when temperature is 50 ～ 60 ℃，and this temperature range is also good for dissolving operation． The removal effect is similar in the pH range of 5. 1 ～ 9. 0，so sugar solution can be obtained by directly using water-soluble commercial brown sugar without adjusting the pH value． It is safe and feasible to remove some calcium ions from the brown sugar solution by SA and to use the product as a flocculant．

The aim of this paper is to investigate the effect of microbiological method extraction of fermented Polygonatum sibiricum polysaccharides on the improvement of blood lipid levels and intestinal flora in mice with high-fat diet． Firstly，the cholesterol and cholate sorption experiments were carried out to evaluate the in vitro lipid-lowering capacity of Polygonatum sibiricum extracted by hot water extraction and microbiological method，and fermented Polygonatum sibiricum polysaccharides ( FPSP) extracted with the microbiological method which has better in vitro lipid-lowering capacity was used for animal experiments． The results of in vivo studies show that FPSP can significantly reduce the body weight，fat index，liver index，serum TC，TG，LDL-C levels，increase HDL-C levels，and significantly inhibit TNF-α and IL-6 release ( P ＜ 0. 05) ． High-throughput sequencing technology analysis finds that，after the intervention of FPSP，the total relative abundance of Firmicutes and Bacteroidetes in mouse feces increased in the phylum level; at the genus level，the relative abundance of probiotics such as Lactobacillus and Barnesiella relatively increased，and the relative abundance of pathogenic bacteria such as Clostridium XIVa，Helicobacter，Streptococcus，and Alistipes decreased． The above results show that Polygonatum sibiricum polysaccharides can improve the blood lipid level of high-fat diet mice and regulate the intestinal flora disorders．

The antioxidant capacities of Lactobacillus rhamnosus ZB1107-01 ( LR ZB1107-01) and Lactobacillus rhamnosus GG ( LGG) in vitro were compared． Taking free radical scavenging activity of DPPH clearance，hydroxyl clearance and superoxide anion as the indexes and establishing the oxidative damage model of Caco-2 cells，this study investigated the effects of LR ZB1107-01 on oxidative stress of Caco-2 cells by measuring the activities of SOD and GSH-Px． The results show that the higher the concentration of bacteria，the stronger the ability of scavenging the three free radicals． The scavenging capacity of LR ZB1107-01 fermentation liquor on DPPH is significantly higher than that of LGG，the scavenging capacity of supernatant on hydroxyl radical is slightly higher than that of LGG，and the scavenging capacity of cell lysate on superoxide anion free radical is significantly higher than that of LGG． In the model of oxidative damage of Caco-2 cells，the measurement of the enzymatic activity of SOD and GSH-Px shows that LR ZB1107-01 can reduce the oxidative stress damage of Caco-2 cells and increase its antioxidant function under oxidative stress．

COMSOL multiphysics software was used to simulate the electric field，flow field and temperature field of the plate type continuous treatment chamber． The experimental results show that the distribution of the electric field is not uniform，and the structure of the treatment chamber has little effect on the sterilization effect when the inlet velocity is 5 cm /s． The sterilization experiment was performed on acetic acid bacteria using this processing chamber． By controlling the input energy，the effects of applied voltage，pulse width，and frequency on the sterilization effect were explored． The experimental results show that the effect of voltage on the sterilization effect is more significant than that of pulse width and frequency．

A strain of Lactobacillus was isolated from the homemade yogurt in Inner Mongolia． Through physiological，biochemical and morphological identifications and 16S rDNA homology analysis，the strain was known to be Lactobacillus delbrueckii DMLD-H1． The biological characteristics of the strain were studied to clarify its gastrointestinal tolerance，antibacterial effect and probiotic characteristics． The safety of the strain was evaluated through hemolytic experiment and acute toxicity test． The fermentation medium of the strain was optimized by response surface methodology． The results show that Lactobacillus delbrueckii DMLD-H1 grow rapidly at the optimum temperature of 37 ℃ and pH value ranging from 3. 0 ～ 7. 0． The blood agar plate study shows that the strain has no hemolytic activity． The acute toxicity test indicates that Lactobacillus delbrueckii DMLD-H1 has no acute oral toxicity to mice． Thus the strain has the characteristics of edible bacteria． After incubation for 3 h in artificial gastric and intestinal juice whose pH value is 3. 0 ～ 4. 0，the survival rate of the strain is above 85% ，with good tolerance． Its fermentation products have inhibitory effects on both Escherichia coli and Staphylococcus aureus，indicating that Lactobacillus delbrueckii DMLD-H1 has potential probiotic properties． When the best components of the fermentation medium are optimized as follows: oligo-fructose content 20. 2g /L，bacteriological peptone content 19. 7g /L and magnesium sulfate content 0. 596 g /L，the concentration of viable bacteria of Lactobacillus delbrueckii DMLD-H1 is 1. 32 ×109 CFU/mL． Under this condition，the fitting rate between the above-mentioned concentration and the measured value is 98. 48% ，indicating that after the optimization of the medium，the model can well predict the bacteria's growth characteristics．

3D printing is a new food processing technology with important application prospects，and is also a research hotspot in the field of food science． Based on the acquisition of starch gelatinization materials with different gelatinization degrees，this paper investigated the evolution behavior of multi-scale structure of rice，wheat and potato starch materials in the gelatinization control system and the influence of structural evolution on the molding properties of 3D printing through modern structural analysis technology． The results show that with the increase of gelatinization degree from 30% to 70% ，the layered structure of starch granules is destroyed gradually and the compactness of nano aggregates decreases significantly; relative crystallinity decreases continuously; the content of double helix and single helix decreases significantly and the proportion of amorphous structure increases significantly． Meanwhile，with the increase of starch gelatinization degree，the thread width of 3D printing decreases first and then increases，while the number of printing layers increases first and then decreases． The ideal printing molding properties can be achieved when the gelatinization degree of rice，wheat and potato starch materials is 50% ，40% and 30% ，respectively． The research results provide a certain data basis for the precise design and quality control of starch gelatinous materials and starch food．