Oxidative stress is the root cause of chronic diseases.Soybean protein can be hydrolyzed or fermented to obtain antioxidant peptides (SAPs),which can scavenge free radicals and hold great potential in the functional food industry.Research has elucidated their structure-activity relationships and some in vivo and in vitro mechanisms,but large-scale production and safety evaluation still require further exploration.This study aimed to utilize probiotic liquid fermentation of soybean prote in to prepare antioxidant peptides.Two stepwise fermentation methods were adopted:(1)inoculation with Bacillus subtilis natto(37 ℃,24 h),followed by inoculation with Bacillus coagulans (47 ℃,42 h);(2)on the basis of method (1),sequential inoculation with Lactobacillus rhamnosus (37 ℃,36 h).The two fermentation broths were ultrafiltered to obtain fractions with molecular weight <1 kDa (SPAP1,SPAP2),and their in vitro antioxidant activities and in vivo efficacy in Caenorhabditis elegans were evaluated.Results showed that the IC50 values for ABTS radical scavenging activity were (0.509±0.016) and (0.591±0.028) mg/mL,respectively,and the FRAP values were (0.427±0.02) and (0.314±0.019)mmol/L,respectively.The C.elegans assayindicated that SPAP2 was superior to SPAP1 in delaying aging,reducing reactive oxygen species (ROS) levels,improving swallowing ability,and prolonging boths tress resistance and natural lifespan.RP-HPLC-MS/MS analysis identified a total of 175 potential antioxidant peptides in SPAP2.In conclusion,this study explored a probiotic combination and its stepwise fermentation conditions for the preparation of soybean antioxidant peptides,verified their efficacy through in vitro and in vivo experiments,and identified their peptide composition by mass spectrometry,providing technical support for the development and application of soybean bioactive peptides.

Rosa roxburghii pomace is an abundant yet underutilized byproduct of the fruit juice industry,which has attracted extensive research interest due to its rich nutritional composition.In this study,a combined milling and acidic pretreatment was applied to enhance its glucan conversion potential.The effects of pretreatment were systematically investigated using SEM,FTIR,TGA,and XRD.Results demonstrated that the pretreatment significantly improved enzymatic hydrolysis efficiency,increasing cellulose conversion by 30.39%.Compositional analysis revealed an elevated relative cellulose content after pretreatment.SEM and swelling capacity analysis indicated that the pretreatment disrupted the compact structure of the pomace,creating visible pores and a looser,more fragmented morphology,thereby increasing the specific surface area.FTIR,XRD,and TGA analyses confirmed the effective removal of non-cellulosic components,leading to higher cellulose exposure,enrichment,and crystallinity.These structural modifications enhanced cellulose accessibility to enzymes,ultimately improving hydrolysis efficiency.

This study developed a whisky-making process using tartary buckwheat as the raw material and optimized the process.Optimization of tartary buckwheat gelatinization and liquefaction process:Through single-factor and orthogonal experimental designs,the optimal conditions for gelatinization and liquefaction were determined:thermostable amylase 16 U/g,thermostable cellulase 4 U/g,solid-to-water ratio 1∶6(g/mL),temperature 96 ℃,time 30 min.Under these conditions,the dextrose equivalent(ED) value of the liquefied mash reached 18.3%.The optimized saccharification conditions were:α-amylase 75 U/g,pullulanase 60 U/g,protease 50 U/g,tartary buckwheat addition ratio 30%,saccharification time 60 min.The resulting wort contained 11.85% reducing sugars and 203.5 mg/L α-amino nitrogen. Using Headspace Solid-Phase Microextraction Gas Chromatography-Mass Spectrometry(HS-SPME-GC-MS),46 volatile compounds were detected in the heart cut of the tartary buckwheat whisky.Among these,12 compounds had odor activity values(VOA)>1,such as ethyl decanoate(VOA=251),isoamyl octanoate(VOA=36),and ethyl hexanoate(VOA=34).After aging for 2 months in pottery jars with oak chips,the spirit acquired a light caramel hue,retained the aroma of tartary buckwheat ,and its aroma exhibited increased complexity and a more layered profile.

Tomato fruit is rich in lycopene,vitamin C,polyphenols and other active ingredients,which have both nutritional and health values.In this paper,the content,physiological function,synergistic effect and lycopene extraction technology of these components were reviewed.Lycopene can resist oxidation through conjugated double bond structure,reducing the risk of cardiovascular and cerebrovascular diseases and cancer;Vitamin C participates in immune regulation and collagen synthesis;Polyphenols regulate inflammatory pathways and induce cancer cell apoptosis.These components can synergistically enhance the physiological functions of tomato,such as antioxidation and anti-inflammation.For the extraction technology of lycopene,the traditional organic solvent extraction method is mature,but the solvent residue is obvious.Enzymatic hydrolysis is suitable for high value-added products,but the cost is high.Modern technologies,such as supercritical CO₂ extraction and membrane separation,are efficient and environmentally friendly.Emerging microbial fermentation and nano-embedding technologies have potential applications,but the problems of safety and scale need to be solved.At present,the optimization of energy consumption and cost of collaborative mechanism analysis and extraction technology still needs to be broken through,and future research can focus on collaborative target mining,industrial adaptation of new technologies and functional product development.This study provides theoretical support for efficient utilization of tomato resources.

To further reveal the influence of grain size and morphology on the mechanical properties of metal additive manufacturing materials,this paper adopts the crystal plasticity finite element method(CPFEM) and takes the AlSi10Mg alloy formed by selective laser melting(SLM) as the research object to establish representative volume element(RVE) models with different average grain sizes.It explores the impact of grain size on its mesoscopic tensile mechanical behavior.The results show that as the grain size decreases,the distribution of stress and strain becomes more uniform,and the yield strength and tensile strength of the AlSi10Mg alloy increase.When the average grain size decreases from 20 μm to 6 μm,the yield strength and tensile strength of the material increase by approximately 37.89% and 17.91% respectively,which is consistent with the Hall-Petch relationship.In addition,stress and strain are concentrated at the grain boundaries,indicating that grain boundaries can hinder the movement of dislocations.The distribution of strain bands is affected by crystal orientation and forms a 45° angle with the loading direction,which is in line with Schmid's slip law.

Ceramic coatings were synthesized on the surface of 2195 Al-Li alloy by micro arc oxidation(MAO),and the structure and high temperature friction wear performance of the coatings were studied.The phase and elemental composition were investigated by XRD and SEM.The surface,cross-section and abrasion morphology and elemental composition of the coatings were observed by SEM and EDS.The 3D morphology of abrasion tracks were observed by laser confocal microscopy(CLSM).The frictional wear performance of the coating was investigated at 200 ℃using an HT-1000 high-temperature friction and wear tester.The results show that the coatings consist of α-Al2O3 phase.The surfaces of the coatings are rough and porous,showing a "lotus leaf" like pile-up shape,with a surface roughness of about 14.3 μm.The thickness of the coating is about 7.1 μm.The average friction coefficient of the coating is about 0.68.The volume wear rate and mass loss of the coating are much lower than that of the Al-Li alloy substrate,with the mass loss being about one-ninth of that of the substrate and the wear rate being about one-tenth of that of the substrate.This indicates that the micro arc oxide coating has desirable wear resistance under high temperature conditions.Analysis of the wear track morphology and composition reveals that the wear mechanism of the Al-Li alloy substrate at 200 ℃ is abrasive wear,fatigue wear and oxidation wear,and the abrasive wear is the main one,while the MAO coating is mainly adhesive wear and also accompanied by oxidation wear.The researches have shown that micro-arc oxidation coatings exhibit good wear resistance under high-temperature conditions.

In practical engineering applications,factors such as modeling errors and parameter perturbations can lead to model uncertainties,while external disturbances may significantly degrade the tracking accuracy and dynamic performance of the controlled system,even causing instability.To address these critical challenges,this paper proposes a control strategy based on disturbance estimation for linear systems subject to both model uncertainties and external disturbances,achieving system stabilization.First,a stabilizing controller is designed for model uncertainties using Lyapunov stability theory.Subsequently,for external disturbances,a disturbance observer with asymptotic estimation capability is constructed by selecting an appropriate filter,enabling asymptotic rejection of the disturbances.Theoretical analysis demonstrates that the proposed control method not only effectively mitigates the impact of parameter uncertainties but also achieves complete cancellation of external disturbances,ensuring global asymptotic stability of the closed-loop system.Numerical simulations further validate the superior performance of the control scheme in terms of dynamic response and robustness.

This study utilizes data from Chinese A-share listed companies from 2007 to 2019 to empirically analyze the impact of urban agglomeration population concentration on firms’ new quality productivity and its heterogeneous characteristics.It also examines the mediating roles of knowledge exchange and industrial structure optimization.The findings are as follows:(1) Urban agglomeration population concentration has a significant impact on the level of firms’ new quality productivity;(2) Knowledge exchange and industrial structure optimization play mediating roles in the relationship between urban agglomeration population concentration and firms’ new quality productivity;(3) Population concentration in cross-regional urban agglomerations has a positive impact on firms’ new quality productivity,with this promoting effect being more remarkable in central and western regions and areas with lower marketization levels.