Abstract:Objective To investigate the stability of nano-emulsion at different pH levels and its storage stability, and to explore their use in curcumin encapsulation.Methods Nano-emulsion was prepared using the ion complexation method. The amounts of chitosan (CS) and gum Arabic (GA) were optimized based on particle size and Zeta potential. Fourier transform infrared spectroscopy (FTIR) was used to analyze intermolecular interactions, while scanning electron microscopy (SEM) was employed to observe the micro-morphology of CS/GA nano-emulsion. The encapsulation efficiency of curcumin was determined by spectrophotometry.Results When the mass concentrations of CS and GA were 2.5 mg/mL and 1.5 mg/mL, respectively, the prepared nano-emulsion exhibited good stability under acidic conditions, especially when the pH was less than 6.0. When the pH was maintained at 6.0, the polydispersity index (PDI) of the nano-emulsion remained below 0.15 after 28 days, with no precipitation observed. The microstructure of the nano-emulsion exhibited a loose, porous mesh, with the intermolecular forces between the two substances primarily electrostatic. When the mass concentrations of CS and GA were 2.5 mg/mL and 1.5 mg/mL, respectively, the nano-emulsion demonstrated good stability at pH≤6.0, with a curcumin encapsulation efficiency of (93.72±0.04)%.Conclusion CS/GA nano-emulsion can be used as delivery systems for functional ingredients.

Abstract:Objective This paper aims to achieve automatic identification and classification of Chinese spirits, solve the production fluctuation of traditional "alcoholic strength determination based on foam watching" for Chinese spirits, and balance the accuracy, real-time performance, and universality of existing deep learning-based methods for foam classification of Chinese spirits.Methods An automatic foam classification method of Chinese spirit based on image acquisition optimization recognition was proposed. The foam images were collected through a self-built platform, and the data quality was improved by preprocessing via ENet. The foam images were classified by using the Vision Transformer (ViT) and ConvNeXt models.Results This method improved the automation level and accuracy of alcoholic strength determination for Chinese spirits and achieved a classification accuracy of 99.4% while ensuring real-time performance.Conclusion This method effectively optimizes the traditional alcoholic strength determination technology for Chinese spirits, enabling rapid and accurate real-time detection and classification of foams.

Abstract:Objective This study aimed to breed and analyze the aroma characteristics analysis of functional Bacillus subtilis strains derived from high-temperature Daqu to enhance the sauce-flavor and quality stability of sauce-flavor liquor.Methods A combination of solid-state and liquid-state fermentation along with electronic sensory analysis was employed to identify strains with enriched sauce flavor. The solid-state fermentation conditions for aroma production were optimized, and the characteristic aroma compounds were identified using gas chromatography.Results A strain of B. subtilis, Bac14, with sauce-flavor-producing advantages was obtained, and the optimal condition for its sauce-flavor-producing flavor is the temperature gradient of 37 ℃→45 ℃→50 ℃→55 ℃, the vaccination ratio is 10%, and the water content is 50%. Under the control of these conditions, the strain has significant aroma production, and related flavor substances such as 3-hydroxy-2-butanone, 2,3,5-trimethylpyrazine, 2,3,5,6-tetramethylpyrazine, and furfural have significantly increased.Conclusion A high-temperature Daqu-derived B. subtilis strain with excellent sauce-flavor-producing properties was obtained, and its optimal aroma-producing conditions were established. This study provides a foundationfor developing enhanced Daqu and improving the quality and stability of sauce-flavor liquor.

Abstract:Objective Optimization of Xiaoqu varieties in Guangxi for brewing rice-flavored Baijiu.Methods High-throughput sequencing was used to analyze the microbial communities of four Guangxi rice flavored Baijiu Xiaoqu, the physicochemical indexes of Xiaoqu were determined by the conventional methods, then the correlation between physicochemical indexes and the microbial communities was clarified.Results Two dominant fungal phyla and nine dominant bacterial phyla were detected in four Xiaoqu samples. The dominant fungal phyla were Ascomycota and Mucoromycota. As the dominant phyla of bacteria, Firmicutes and Proteobacteria are present in all Xiaoqu. Mould was found in all Xiaoqu samples, namely, Rhizopusa was found in Xiaoqu A, B, and C, and Aspergillus and Monascus were found in Xiaoqu D. The common dominant bacterial genera are Pediococcus and Weissella. In terms of physicochemical indexes, the saccharification power, liquefaction power and fermentation power of Xiaoqu A were all the biggest, while the esterification power of Xiaoqu C was greater than that of the other three Xiaoqu.Conclusion There is a certain correlation between relevant microorganisms and physicochemical indexes.

Abstract:Objective This paper aims to study the effect of ferulic acid (FA) on the aggregation behavior of glutenin subunits and the quality of steamed bread.Methods The interaction behavior between FA and gluten subunits with high relative molecular weight (HMW-GS) and gluten subunits with low relative molecular weight (LMW-GS) was compared to clarify the effect and mechanism of FA addition on the aggregation of gluten subunits.Results Adding FA with a mass fraction of 0.5% can effectively promote the aggregation of HMW-GS and LMW-GS, induce the oxidation of free thiol groups to form more disulfide bonds, increase the average particle size of protein aggregates, and enhance the content of stable α-helices and β-folds. It can also reduce the content of disordered random curls, promote the formation of HMW-GS and LMW-GS aggregates, further lead to the burial of hydrophobic groups, alleviate their surface hydrophobicity, and form a more stable tertiary structure. Adding 0.5% FA can induce more aggregation of HMW-GS than LMW-GS. HMW-GS+0.5% FA can effectively improve the quality of steamed bread. Compared with the original flour, the specific volume increases by 29.62%, and the hardness decreases by 18.59%.Conclusion HMW-GS+0.5% FA can effectively improve the quality of steamed bread.

Abstract:Objective To explore and utilize the abundant lactic acid bacteria resources in nature, promoting the industrial production of traditional Chinese sour soup.Methods Lactic acid bacteria were isolated from naturally fermented foods and raw materials, identified by morphology, Gram staining, and 16S rDNA sequencing, and screened based on their microbial growth characteristics for high acid yield and acid resistance. Sour soup was prepared using these strains as the fermenting agents, and the total acid content and color difference were measured. The fermentation process was optimized using single-factor and response surface methods.Results Lactic acid bacteria such as Limosilactobacillus fermentum, Pediococcus acidilactici, Lactiplantibacillus plantarum, and Lacticaseibacillus paracasei were isolated from samples, including Xiangxi sour soup. Among these, L. paracasei LK10 (LK10) with strong acid-producing ability and L. fermentum T1 (T1) with good acid tolerance were selected. Using LK10 and T1 as the fermenting agents, the optimal process conditions were determined as follows: adjusting the OD_{600 nm} of the seed liquid to 1.00, with a volume ratio of LK10 to T1 at 5∶1, a total inoculation amount of 4.23 mL/100 g, and fermentation at 37 ℃ for 9.75 days. Under these conditions, the total acid content of the sour soup was (19.43±0.12) g/kg.Conclusion The sour soup prepared with L. paracasei LK10 and L. fermentum T1 has a moderate sour and spicy taste, a bright red color, and a rich lactic acid flavor.

Abstract:Objective This study aimed to optimize the preparation process of selenium nanoparticles stabilized by Atrina pectinata polysaccharides (APPS-SeNPs), evaluate their antioxidant activity, and explore their potential as a functional food additive.Methods Selenium nanoparticles were prepared using the sodium selenite reduction method with A. pectinata polysaccharides as stabilizer. The preparation process was optimized using single-factor experiments and response surface methodology (RSM). The particle size, zeta potential and selenium content were measured, and the nanoscale structure was analyzed. Antioxidant activity was evaluated by assessing the scavenging effects on DPPH and hydroxyl (OH) radicals. Four factors influencing particle size-molar ratio of vitamin C to sodium selenite, reaction temperature, reaction time, and polysaccharide concentration-were analyzed.Results The optimal preparation conditions were as follows: molar ratio of vitamin C to sodium selenite was 8.3∶1, reacting at 44 ℃ for 2.3 hours, and polysaccharide concentration of 0.4 mg/mL. Under the control of these conditions, the selenium nanoparticles size was (69.81±1.04) nm, and the Zeta potential was (-35.28±0.41) mV, with the selenium content at (195.73±0.39) μg/g. The structural analysis confirmed successful selenization, with the nanoparticles exhibiting an amorphous form. Antioxidant assays showed that APPS-SeNPs had significant scavenging effect on DPPH and OH radicals, surpassing both A. pectinata polysaccharides and nano-selenium alone.Conclusion The selenium nanoparticles stabilized by A. pectinata polysaccharides demonstrated excellent antioxidant properties and stability, suggesting their potential as a novel functional food additive.

Abstract:Objective To establish a new method for simultaneous detection of quinolones (QNs) and sulfonamides (SAs) in aquatic products and livestock products.Methods In pretreatment, this work compares the effect of extraction solvents on the recoveries and investigates the reduction or elimination effect of purification methods such as liquid-liquid extraction (n-hexane), dispersive adsorption of the matrix (C₁₈ and ethylenediamine-N-propyl silylated silica), and general solid phase extraction (PRiME HLB) on the matrix effect. The sample is pretreated by acetonitrile with 1.0% formic acid, purified by EMR-Lipid, and separated by ACQUITY UPLC^?HSST₃ column (3.5 μm, 2.1 mm×100 mm) in 10 min. MS detection is performed by multi-reaction monitoring (MRM) in positive ion mode. QNs and SAs are quantified by the external standard method.Results The calibration curves of QNs and SAs exhibit a good linear relationship with the correlation coefficients (R²) exceeding 0.99, in the range of 1.0~100.0 ng/mL. The limits of detection (LODs) and quantification (LOQs) are 1.0 and 2.0 μg/kg, respectively. The average recoveries of QNs and SAs are between 61.9% and 115.3% under low, middle, and high spiked levels and the relative standard deviations (RSDs) are less than 15% (n=6).Conclusion Compared with literature and standard methods, the established method increases the scope of application and reduces the pre-treatment process and cost.

Abstract:Objective To establish an analysis method for the simultaneous determination of 10 neonicotinoid pesticide residues in raw milk by dispersive solid-phase extraction combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS).Methods The samples are extracted with acetonitrile, salted out with a QuECHER salt pocket, and purified by the dispersive solid-phase extraction (d-SPE) method. The analytes are detected by UPLC-MS/MS and quantified by the external standard method.Results 10 targeted compounds show a good linear relationship in a certain concentration range with the coefficient of determination (R²) over 0.999. The limits of detection (LODs) are 0.2~0.5 μg/kg, while the limits of quantification (LOQs) are 1.0 μg/kg. At the supplemental levels of 1.0, 2.5, and 5.0 μg/kg, the average recovery rates of standard addition of analytes in raw milk are between 75.9%~108.9%, with the intra-day precision (RSD_r) of 1.8%~7.6% and the inter-day precision (RSD_R) less than 11.7%.Conclusion The established method is simple for pretreatment and has good repeatability and high sensitivity. It is suitable for the detection of neonicotinoid pesticide residues in raw milk.

Abstract:Objective To establish a rapid detecting method for the determination of dimethyl fumarate in beverages by ultrasound-assisted dispersive liquid-liquid micro-extraction coupled with high performance liquid chromatography.Methods The beverage samples were spiked with extractant and dispersant, extracted by ultrasonic extraction, centrifuged and determined by high performance liquid chromatography.Results The optimal microextraction conditions were 100 μL of chloroform as extractant, 300 μL of acetone as dispersant, and a sonication time of 4 min. Under the optimal extraction conditions, dimethyl fumarate had a linear range of 0.1~100.0 μg/mL with a detection limit of 0.02 μg/L. The relative standard deviation (RSD) of the method was less than 3.7%, and the spike recovery rate was between 75.0% and 85.0%.Conclusion The method is simple, rapid, reproducible, sensitive and environmentally friendly, and is suitable for the qualitative and quantitative analysis of dimethyl fumarate in beverages.

Abstract:Objective To establish a method for rapid detection of 59 kinds of drugs illegally added in alcoholic products by high performance liquid chromatography-triple quadrupole mass spectrometry.Methods After ultrasonic extraction of methanol-water (volume ratio 5∶5), the samples are determined by high performance liquid chromatography-triple quadrupole mass spectrometry and quantified by external standard method.Results The 59 tested drugs show a good linear relationship in the corresponding mass concentration range, with a correlation coefficient greater than 0.992. The limits of quantitation are 0.1 and 0.2 mg/kg respectively. Under three addition levels, the average recoveries of 59 drugs range from 86.7% to 119.9%, and the relative standard deviation of precision and repeatability for the method is below 13.7% (n=6).Conclusion The method, boasting simplicity, good repeatability, high efficiency, and accuracy, is suitable for the detection of illegal additives including aphrodisiac, anti-fatigue, antipyretic, analgesic, sedative, and diuretic drugs in alcoholic products.

Abstract:Objective To understand the microwave heating characteristics and moisture content changes of fresh Camellia oleifera seeds.Methods Numerical simulations coupling electromagnetic loss with solid/fluid heat transfer are conducted to analyze the temperature rise characteristics of a single C. oleifera seed, thereby determining the appropriate sample placement and microwave power ranges. Microwave drying experiments of individual and small batches of C. oleifera seeds are performed to validate the numerical results against the actual internal and surface temperatures. Two-term, Henderson and Pabis, and Midilli and Kucuk models are employed to fit the dry basis moisture content changes to analyze the microwave drying kinetics of C. oleifera seeds.Results The actual temperatures of C. oleifera seeds are in general consistence with the simulated results, which validates the reliability of the numerical simulations. The microwave drying process of C. oleifera seeds can be divided into three stages: acceleration, stabilization, and deceleration, and the Midilli and Kucuk model can accurately describe this drying kinetics behavior. Under the preferred drying conditions (microwave power of 200~350 W, single heating duration of 5 min, and interval duration of 2 min), a single batch of C. oleifera seeds (200 g) can achieve the desired dry basis moisture content (9%) in 42~126 min. This drying method has a 70%~90% higher efficiency than conventional hot-air drying or infrared drying and avoids carbonization and cracking due to overheating.Conclusion Microwave heating technology can realize efficient and controllable drying of fresh C. oleifera seeds.

Abstract:Objective A green walnut peeling machine integrating peeling, cleaning, and grading was designed, and the strength, stiffness, and vibration characteristics of the roller shaft and link plate, the key components in the machine, were analyzed to determine its working condition parameters.Methods Mechanical analysis was conducted to determine the force of the green walnut peeling process, determine the rotational speeds of the roller and link plate, and calculate the roller power. Solidworks was used to model the whole machine and key parts, and the roller shaft and link plate entities were imported into Ansys Workbench for static analysis and modal analysis.Results At the roller shaft rotational speed of 300 r/min, the intact machine showed the maximum deformation of 0.003 mm and the maximum stress of 60.62 MPa. At the link plate rotational speed of 120 r/min, the intact machine showed the maximum deformation of 0.352 mm and the maximum stress of 168.97 MPa, which were in line with the design requirements. The working frequency of the roller shaft and link plate was much smaller than its first six-order inherent frequency, and thus resonance damage would not occur in the working process.Conclusion The strength and stiffness of the roller shaft and link plate meet the requirements of actual production, and no resonance damage will occur under normal working conditions.

Abstract:Objective To improve the mechanization and automation of tender coconut processing.Methods This paper designs a new tender coconut processing machine consisting of a compression rotating mechanism, a side-top integrated trimming mechanism, a clamping manipulator, and a bottom trimming mechanism. Mechanical analysis and calculation, 3D modeling, and finite element analysis are carried out on the most critical side-top integrated trimming mechanism to optimize the design scheme.Results The main factors influencing the trimming effect are ranked as the tool feed rate>tender coconut's rotation speed>tool trimming angle. The optimal parameter combination of the tender coconut processing machine is the tender coconut's rotation speed of 450 r/min, the tool feed rate of 1 mm/s, and the tool trimming angle of 16.7°.Conclusion The success rate of coconut green processing of the developed machine reaches 100%, with the efficiency reaching 100 pieces/h. Thus, the machine has high engineering application significance.

Abstract:Objective In response to the limitations of traditional temperature control methods (such as PID control), including slow response, significant overshoot, and the inability to fully utilize predictive information in dynamic, multi-variable complex scenarios, an intelligent food temperature control method combining fuzzy control and the Transformer prediction model is proposed. This method aims to improve temperature control accuracy, response speed, and energy consumption efficiency.Methods The Transformer model is used to predict the trend of future multi-time-step ambient temperature and target temperature, and real-time temperature deviation control is implemented based on fuzzy logic. The proposed method is experimentally validated using pizza billet temperature control as an example.Results The experimental results show that the proposed intelligent temperature control method outperforms traditional methods in both prediction and control performance. Compared with other prediction models, the mean absolute error (MAE) of the Transformer model is reduced by 21.30% (from 0.19 ℃ to 0.15 ℃), and the root mean square error (RMSE) is reduced by 16.67% to 25.00% across three time-series predictions. In the cold storage temperature control scenario, compared with the other four methods, the temperature overshoot is reduced by 15.73%~39.27%, the response time is shortened by 14.24%~33.52%, and the steady-state error is reduced by 33.30%~62.50%. In the oven temperature control scenario, compared with the other four methods, the temperature overshoot is reduced by 11.24%~33.05%, the response time is shortened by 11.54%~33.03%, and the steady-state error is reduced by 40.00%~71.43%.Conclusion The intelligent temperature control method combining fuzzy control and Transformer shows excellent prediction accuracy and control performance in complex food storage and processing scenarios, with significant performance advantages over other methods.

Abstract:Objective This study aimed to improve the on the storage quality of bubble green semidry noodles.Methods By adjusting the treatment pulse energy, pulse distance, and storage time of bubble green semidry noodles, the effects of these factors on the storage quality of bubble green semidry noodles were comprehensively analyzed. By comparing indicators such as microbial content, color difference, chlorophyll content, texture characteristics, moisture distribution, and protein secondary structure, the optimal parameters for pulsed light treatment of bubble green semidry noodles were determined.Results The optimal parameters for pulsed light treatment of bubble green semidry noodles were as followed: pulse energy of 900 J, pulse frequency of 20 times, and pulse distance of 5 cm. Under these conditions, effectively extending the shelf life of bubble green semidry noodles. Compared with the untreated group, pulsed light sterilization technology can improve the hygiene quality of semidry noodles and maintain better hardness, chewiness of texture qualities during the same storage time.Conclusion Intense pulsed light treatment is one of the effective methods to extend the shelf life of semi-dried Paopaoqing noodles. The semi-dried Paopaoqing noodles after treatment maintained a relatively low total number of colonies and better texture characteristics within a certain storage period.

Abstract:Objective To investigate the antibacterial effect of ε-polysine hydrochloride on Shewanella baltica and Pseudomonas fluorescens derived from large yellow croaker.Methods The antibacterial effects of ε-polylysine hydrochloride on the growth of Shewanella baltica and Pseudomonas fluorescens was analyzed by the minimum inhibitory concentration and the growth curve. By measuring the bacterial fluid conductivity, alkaline phosphatase activity, ultraviolet absorbent substances and biofilm formation inhibition rate, the cell integrity and permeability were evaluated. The aerobic plate count and total volatile basic nitrogen of the flesh of large yellow croaker inoculated with spoilage bacteria were determined the effect of ε-polylysine hydrochloride on the spoilage ability of Shewanella baltica and Pseudomonas fluorescens.Results The minimum inhibitory concentrations of ε-polylysine hydrochloride against Shewanella baltica was 0.250 mg/mL, while Pseudomonas fluorescein was 0.125 mg/mL. With the treatment of ε-polylysine hydrochloride, the growth of Shewanella baltica and Pseudomonas fluorescein was significantly inhibited, and the conductivity, AKP enzyme activity and UV absorbent leakage were significantly increased in a mass concentration dependent manner. Fish inoculated with Shewanella baltica and Pseudomonas fluorescein showed a significant decrease in total bacterial count and TVB-N values.Conclusion ε-polylysine hydrochloride can destroy the cell integrity of Shewanella baltica and Pseudomonas fluorescein, inhibit the growth and affect the spoilage ability.

Abstract:Objective To study the application of Bacillus velezensis D44 in the biological control of postharvest diseases in peaches.Methods Hu nectarine 018 (hard-soluble), Jinxiu yellow peach (hard-soluble), and Hujing Milu honey peach (soft-soluble) were used as test materials. The antagonistic effects of B. subtilis A9, B. velezensis D44, and B. licheniformis W10 against seven postharvest pathogens-Polyporus pink, Penicillium, Fusarium, brown rot fungus, Botrytis cinerea, Alternaria alternata, and Rhizopus-were examined. Additionally, the impact of these bacteria on the diameter of disease lesions, volatile substances, and preservation effects in peach fruits after inoculation with these pathogens was evaluated.Results B. velezensis D44 exhibited strong inhibitory effects on brown rot fungus, Rhizopus, B. cinerea, Penicillium, and Fusarium in peaches. At room temperature, the onset of brown rot in Hu nectarine 018 and Hujing Milu peaches inoculated with brown rot fungus was delayed by 2 days compared with the control, with an inhibition rate of 85% to 99%. The onset of soft rot in Hu nectarine 018 and Hujing Milu peaches inoculated with Rhizopus was delayed by 3 days compared with the control, with a disease inhibition rate of 87.61% to 99.82%. B. velezensis D44 also significantly inhibited the changes in volatile substances caused by decay. The safe storage period of Hu nectarine 018 treated with D44 at room temperature was 6~8 days, which was 4~6 days longer than the control, with a decay rate of less than 5%, a weight loss rate below 4.5%, and a decline in soluble solids controlled within 8%. The safe storage period of Hujing Milu peaches at room temperature was 4~6 days, which was 2~4 days longer than the control, with a decay rate below 8%, a weight loss rate below 8%, and a decline in soluble solids controlled within 4%. The treated fruits exhibited high commercial and edible value.Conclusion B. velezensis D44 significantly delays the onset of brown rot and Rhizopus and effectively preserves the storage quality, thereby extending the shelf life.

Abstract:Objective To optimize the fabrication process of chitosan (CS) and soy protein isolate (SPI) composite films, enhance their comprehensive performance, and evaluate their impact on the preservation of mangoes.Methods CS and SPI were used as the film-forming substrates. The tensile strength, elongation at break, water vapor transmission rate, oxygen permeability, carbon dioxide permeability, and light transmittance of the composite film were used as evaluation indexes. The K-value of the composite film's comprehensive performance was calculated using fuzzy comprehensive evaluation. Response surface analysis was applied to optimize the formulation of the CS-SPI composite film, with the K-value as the response variable.Results The optimal preparation conditions for the CS-SPI composite film were as follows: 1.9 g/100 mL of CS, 22.7 mg/mL of SPI, and 2.2 g/100 mL of glycerol at pH 2.9. Under these conditions, the K-value of the CS-SPI composite film reached 0.904. The internal network structure of the composite film was denser, effectively preventing the migration of water and gases. When applied to mango preservation at room temperature, the CS-SPI composite film extended the shelf life of the mangoes to 15 days.Conclusion The CS-SPI composite film prepared with the optimized process exhibited significantly improved comprehensive performance and demonstrated excellent preservation capabilities for mangoes.

Abstract:Objective To achieve fine classification of eggs and improve the accuracy of egg appearance detection.Methods An egg appearance detection scheme based on improved convolutional neural network (CNN) and hierarchical support vector machine (SVM) was proposed. ① Egg images with different orientations and appearances were captured using an egg machine vision image acquisition device, and image enhancement techniques were applied to expand the egg image database. ② An improved Coati optimization algorithm (COA) and fuzzy C-means (FCM) clustering algorithm were designed, based on which the structure and hyperparameters of the CNN model were optimized to enhance its generalization ability. The optimized CNN was then used for deep learning on the egg image database to effectively extract features from egg appearance images. ③ A hierarchical SVM was established for fine classification of egg appearance, ultimately achieving accurate detection and classification of egg appearance.Results The detection accuracy of the proposed egg appearance detection scheme improved by 1.74%~4.31%, and the detection time was reduced by 21.68%~53.51%.Conclusion The proposed method effectively enables online real-time fine classification of eggs.

Abstract:Objective This paper aims to characterize the composition and structure of two polysaccharides extracted from Noni fruit and compare their in vitro hypoglycaemic and hypolipidemic activities.Methods Two polysaccharides, NFP-30 and NFP-80, were extracted and isolated from Noni fruit by water extraction and ethanol precipitation method. They were then characterized by means of physicochemical analyses, spectral analyses, and scanning electron microscopy observations, and their in vitro hypoglycaemic and hypolipidemic activities were evaluated by the determination of the inhibition rates of α-glucosidase and pancreatic lipase.Results The neutral sugar contents of NFP-30 and NFP-80 were (50.73±1.32)% and (42.30±1.11)%, respectively, and the glucuronic acid contents were (61.48±0.40)% and (27.05±0.28)%, respectively, which indicated that both of them were acidic polysaccharides. When passing through the DEAE-52 chromatographic column, both polysaccharides had a main peak at the NaCl concentration of 0.9 mol/L, indicating that the components of both polysaccharides were relatively concentrated. In terms of the maximum inhibition rate of α-glucosidase, NFP-30 reached 58.45%, while NFP-80 only had 0.21%. In terms of the maximum inhibition rate of pancreatic lipase, NFP-30 reached 34.63%, while NFP-80 only had 9.77%, and the inhibition rate of NFP-80 on the activities of the two enzymes was significantly lower than that of NFP-30.Conclusion The neutral sugar content and glucuronic acid content of NFP-30 are higher than those of NFP-80, and its in vitro hypoglycaemic and hypolipidemic activities are better than those of NFP-80.

Abstract:Objective To improve the biological activity and application range of Porphyridium aerugineum exopolysaccharide (EPS).Methods EPS was modified using the concentrated sulfuric acid method, with the degree of sulfation as the indicator. The preparation process of sulfated P. aerugineum exopolysaccharide (S-EPS) was optimized using response surface methodology. The physicochemical properties of S-EPS were also determined.Results The optimal conditions were a reaction time of 6 h, a reaction temperature of 26 ℃, and a mass ratio of ammonium sulfate to EPS of 4∶5. Under these conditions, the degree of substitution was 0.807 5±0.008 7. Infrared analysis confirmed that EPS was successfully sulfated. Thermogravimetric analysis showed that the thermal stability of S-EPS was superior to that of EPS. Particle size and Zeta potential analysis indicated that samples with a higher degree of substitution were more stable, with higher —SO₃H group content, larger absolute potential, and less aggregation. The results of the antioxidant activity experiment showed that the DPPH· clearance rate of S-EPS was 92.17%, significantly higher than EPS.Conclusion Sulfation modification improved the antioxidant capacity of EPS, indicating that sulfation is a feasible method for enhancing polysaccharides.

Abstract:Objective To investigate the anti-fatigue effect of compound aqueous extracts of Ginseng Radix et Rhizoma, Polygonati Rhizoma, Polygonati Odorati Rhizoma, and Citri Reticulatae Pericarpium in mice.Methods The experiment included a blank control group, a positive control group (Rhodiola rosea capsules, 0.70 g/kg), and low, medium, and high dose groups of compound ginseng aqueous extracts (1.56, 3.30, and 6.60 g/kg, respectively), which were administered by gavage for 30 days. The anti-fatigue effect was evaluated using the weight-bearing exhaustion swimming test and by measuring biochemical markers, including hepatic glycogen, blood lactate, and blood urea nitrogen.Results Compared with the blank control group, the compound ginseng aqueous extracts had no significant effect on the normal weight gain or mental state of the mice (P>0.05). The medium and high dose groups significantly prolonged the swimming time during weight-bearing exhaustion (P<0.05). The high dose group significantly increased hepatic glycogen levels (P<0.05) and reduced blood lactate, blood urea nitrogen, and malondialdehyde levels (P<0.05).Conclusion The compound ginseng aqueous extracts help alleviate exercise-induced fatigue in mice and demonstrate strong anti-fatigue effect.

Abstract:Objective To realize the high-value utilization of tuna by-products and prepare antioxidant peptides from them.Methods Antioxidant protein peptides were prepared from the dark meat of yellowfin tuna by stepwise enzymatic hydrolysis using protease. The degree of hydrolysis and DPPH radical scavenging rate were used as evaluation indexes. The preparation process was optimized through one-way and response surface experiments, and the antioxidant activities, amino acid composition, and relative molecular mass distributions of the peptides were analyzed.Results The optimal preparation process for the antioxidant peptides was enzymatic hydrolysis with flavor protease at 50 ℃, pH 7.00, enzyme concentration of 6 000 U/g, and digestion time of 4.00 h. In the two-step enzymatic digestion, pepsin was used at 55.69 ℃, pH 1.41, enzyme concentration of 3 200 U/g, and digestion time of 5.16 h. Under these conditions, the degree of hydrolysis of the protein peptide and the DPPH radical scavenging rate were the highest, reaching 21.55% and 85.89%, respectively. The semi-inhibition concentration (IC₅₀) for DPPH radical scavenging by the tuna dark meat flavor protease-pepsin protein peptide was 1.613 mg/mL. Additionally, the peptide contained eight essential amino acids, accounting for approximately 39.60%, and hydrophobic amino acids, accounting for about 35.13%. Its relative molecular mass was mainly concentrated below 3 000, comprising approximately 63.86%.Conclusion Protein peptides obtained from tuna by-products through stepwise enzymatic digestion possess excellent antioxidant activity and high nutritional value.

Abstract:Objective Using the oyster (Crassostrea hongkongensis) as raw material, this study explores the improvement effect of combined treatment of composite deodorization and spray drying on the characteristic flavor of oyster proteolytic products, aiming to efficiently obtain a better-flavored base material of oyster protein enzymatic hydrolysates.Methods The oyster protein enzymatic hydrolysates were treated with a combination of three deodorants of lime juice, stevia powder, and black tea powder combined with spray drying, The sensory score and the powder yield were used as indicators to investigate the optimal process conditions for the preparation ratio of the composite deodorant, the solid-liquid ratio of the composite deodorant to enzymatic hydrolysates, and spray drying. The flavor analysis was carried out by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), assisted by electronic nose and electronic tongue sensory testing.Results The optimal process conditions are m_{stevia powder}∶V_{lime juice}∶m_{black tea powder} in 1∶3∶2, the solid-liquid ratio m_{composite deodorant}∶V_{oyster enzymatic hydrolysate} in 1∶20, the inlet air temperature at 180 ℃, the peristaltic pump speed at 10 r/min, and the maltodextrin addition amount of 1.5 times. Under these conditions, the obtained base material of oyster protein enzymatic hydrolysates has a better overall taste and flavor.Conclusion Spray drying alone can make the enzymatic hydrolysates rich in oyster meat aroma and salty and delicious. However, the combined treatment of composite deodorization and spray drying produces a sweet and sour taste on a whole, effectively reduces the saltiness, reduces the content of aldehydes that cause fishy and rancid odors, increases the relative content of olefins that have pleasant floral and fruity aromas and produces a better flavor.

Abstract:Objective This study aims to develop liquors with excellent deodorizing and aroma-enhancing abilities.Methods The characteristic fishy substances of chicken gizzards were identified by gas chromatography-ion mobility spectrometry (GC-IMS) combined with relative odor activity value (ROAV). The deodorizing and aroma-enhancing effects of three cooking Baijiu products (A, B, and C) on chicken gizzards were investigated.Results A total of 73 volatile components were detected by GC-IMS, and 13 differential flavor substances were screened as biomarkers based on the VIP values to distinguish between different treatment groups. Additionally, nine fishy and off-flavor components were identified based on ROAV, including butyraldehyde, hexanol-M, 2-octanone, and 2-butanone-M. The fingerprint and quantitative analyses of flavor substances demonstrated that the three cooking Baijiu products showed better deodorizing effects than cooking wine.Conclusion Cooking Baijiu A exhibited a strong deodorizing effect and imparted significant amounts of characteristic aroma components such as ethyl esters and terpenes to the chicken gizzards, showing a strong aroma-enhancing effect.

Abstract:Objective To improve the efficiency and quality of salted egg pickling.Methods Vacuum pulsation technology is applied to the pickling of eggs and compared with atmospheric pressure pickling (control group). Vacuum-holding time, atmospheric pressure holding time, and pickling time are selected as the influencing factors, and the egg weight gain rate, egg white salt content, egg yolk salt content, egg yolk index, and egg yolk color of salted eggs during pickling are used as indicators for single factor experiments.Results Under the conditions of a vacuum degree of -90 kPa and immersion in saturated salt water, with the pulsation ratio of vacuum-holding time to atmospheric pressure holding time of 4∶5 (Vacuum-holding time is 12 min and atmospheric pressure holding time is 15 min) and the pickling time of 48 h, the salted eggs are of good quality. Under these conditions, the egg weight gain rate, egg white salt content, egg yolk salt content, and egg yolk index were 3.73%, 5.85%, 3.98%, and 91.00%, respectively, and the pickling rate is 9~15 times faster than that of atmospheric pressure pickling. After 36 h of ripening (post-pickling storage at low temperatures), egg white salt content, egg yolk salt content, egg yolk index, and color h^* of salted eggs are 5.12%, 4.13%, 91.00%, and 82.32, respectively.Conclusion Compared with atmospheric pressure pickling, vacuum pulsation pickling can not only greatly shorten the pickling time, but also significantly improve the curing quality.

Abstract:Objective To address the browning issue during chestnut processing.Methods Taishan chestnuts were used as the raw materials. The color protection process conditions were determined through a single-factor experiment. Three factors-melatonin concentration, malic acid mass fraction, and citric acid mass fraction-were selected for a response surface optimization experiment to determine the optimal concentrations of the color protection agents. The effects of different treatments on the physicochemical properties of the chestnuts were assessed by measuring the total phenol content, reducing sugar content, ascorbic acid content, malondialdehyde content, DPPH and ABTS free radical scavenging rates, and water content.Results The optimal color protection process conditions were determined as follows: soaking in the color protection agent at 40 ℃ for 60 min, followed by boiling in the color protection agent at 100 ℃ for 10 min. The optimal concentrations of the color protection agents were: melatonin at 0.5 mmol/L, malic acid at 0.87%, and citric acid at 1.08%. The determined color protection process effectively reduced the browning index of the chestnuts, increased the L^* value, and demonstrated good browning inhibition. Additionally, the total phenol content, reducing sugar content, ascorbic acid content, and DPPH and ABTS free radical scavenging rates increased, while malondialdehyde content decreased. There was no significant difference in water content.Conclusion The adopted color protection process can effectively inhibit browning during chestnut processing.

Abstract:Food safety has become a hot topic of widespread concern across society, and efficient, sensitive detection technologies are essential tools for ensuring food safety. Immunoassay is the gold standard for high-sensitivity detection of biochemical targets, providing an excellent platform for the detection of food contaminants. In recent years, it has gradually been applied to various food safety detection methods. Nanoenzymes, as synthetic analogs of natural enzymes, offer advantages such as good stability and high sensitivity, meeting the demands of rapid detection methods under increasingly stringent detection limits. This article reviews the detection principles and advantages of immunoassay technology based on nanoenzyme labeling, discussing its applications in different areas of food safety detection, including agricultural and veterinary drug residues, heavy metal residues, mycotoxins, foodborne pathogenic bacteria, and other harmful substances. It also addresses the future development trends of nanoenzymes.

Abstract:Ice cream, a complex whipped and aerated colloidal system, requires an appropriate degree of fat globule destabilization during its production to form a specific structure. Small-molecule emulsifiers can regulate the degree of fat destabilization by adsorbing onto the fat globule surface, reducing surface tension, and competing with proteins for positions at the oil-water interface. At the same time, they can promote the dispersion of fat particles or form a protective film at the oil-water interface, thereby influencing fat crystallization. Moreover, small-molecule emulsifiers can act as template molecules, guiding the assembly of fats into various specific shapes, such as spherical, rod-like, and lamellar forms, and adjusting the size and morphology of fat crystals. This process affects the degree of fat globule destabilization, which in turn alters the texture and stability of ice cream. The structure and types of small-molecule emulsifiers were mainly explored, and their interactions with fats and proteins were explored, as well as their mechanism of action in ice cream. In addition, the impact of small-molecule emulsifiers on ice cream texture was analyzed.