In order to optimize the simmering process of bone broth for hotpot soup, a single-factor experiments of bone ratio, material-liquid ratio, simmering time and simmering temperature was conducted using cow, pig and chicken bones as raw materials. The total nitrogen dissolution rate (TNDR) and sensory score of the bone broth were used as evaluation indexes. The Box-Behnken response surface methodology was employed to optimize the bone broth stewing process. Flavor analysis was conducted using an electronic nose and headspace solid-phase microextraction/gas chromatography-mass spectrometry (HS-SPME-GC-MS) detection, with relative odor activity value (ROAV) combined with quantitative descriptive analysis (QDA) for flavor analysis, and orthogonal partial least squares-discriminant analysis (OPLS-DA) to correlate characteristic volatile organic compounds (VOCs) in bone broth from different raw materials with electronic nose data. The results showed that when the bone ratio (cow bone:pig bone:chicken bone) was 3:5:2, the material-liquid ratio was 1:4, the simmering time was 5 h, and the simmering temperature was 96 ℃ at atmospheric pressure, the TNDR of the bone broth under these conditions was the highest of 64.88%, and the organoleptic score was the highest of 86.45 points, and the bone broth was milky in color, with a strong fragrance and a mellow texture. Analyzed by electronic nose and HS-SPME-GC-MS, a total of 49 VOCs were detected in the four samples. The mixed bone broth yielded more benzene and amine flavor substances, and also increased the response values of W1S, W1W, W2S, and W2W, with a more significant flavor. There were 25 key VOCs specifically analyzed for ROAV≥1. A total of three key VOCs for the four samples were octanal, nonanal, and 6-methyl-5-hepten-2-one. A strong correlation was found between the electronic nose signals and the 12 characteristic VOCs that had high flavor contributions (ROAV≥1 and VIP≥1). This study can provide a basis for the industrial flavor optimization of bone broth in hotpot soup and the innovative application of modern cooking technology.

The objective of this study was to investigate the effect of rice wine on the quality of beef jerky. The beef jerky fermentation process was optimized by determining the moisture content, color difference, pH, shear force, texture, and water activity, with sensory evaluation scores serving as the response variables in a response surface methodology experiment. Additionally, changes in myofibrillar proteins during fermentation were thoroughly examined using solubility measurement, surface hydrophobicity assessment, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimal processing conditions were rice wine addition 6%, fermentation time 24 h, and baking time 2.5 h. The beef jerky produced under these conditions exhibited physicochemical properties with moisture content 42.39%, pH 5.61, water activity 0.9298 and shear force 28.97 N. The fermented beef jerky prepared using this process had excellent color, moderate texture, unique flavor, and high overall quality. During the fermentation process, the solubility of myofibrillar proteins in beef gradually decreased with increasing fermentation time, whereas its surface hydrophobicity continuously increased. This phenomenon indicated that the fermentation promoted the gradual unfolding of the highly aggregated structure of myofibrillar proteins, resulting in the exposure of internal hydrophobic groups. The SDS-PAGE results demonstrated that the addition of rice wine was more conducive to the degradation of myofibrillar proteins. The findings of this study provide important theoretical support for the development of new fermented beef jerky products, and offer new insights for research in related fields.

The present study aimed to enhance the quality of purple sweet potato preserves by fermentation with Lactobacillus plantarum. The optimized fermentation process for purple sweet potato preserved fruit (FPSF) was developed using single-factor and orthogonal experiments. Then, this study compared the differences in color, total acid, soluble sugar, texture, water distribution, and tissue structure between the FPSF and the unfermented purple sweet potato preserved fruit (UPSF) directly soaked in sugar under the same conditions. The results revealed the optimal production process of FPSF was as follows: fermentation with 2% L. plantarum for 24 h, solid-liquid ratio of 1:8 (g/g), microwave sugar-soaking at 560 W for 25 min in a 40% (g/g) sugar solution, soaking in sugar at room temperature for 8 h, and drying at 60 ℃ for 140 min. Findings indicated FPSF had a bright color, a sweet and sour taste, and a crisp texture. Compared with UPSF, its total acid content increased by 1.13 times, and texture indexes such as hardness and chewiness nearly doubled. The water mobility of FPSF was lower than that of UPSF. The proportion of the peak area of T₂₂ (immobile water) increased to 91.17%. The degree of surface water aggregation decreased significantly, and the tissue structure became more complete and compact. The overall sensory comprehensive score of FPSF was approximately 16.77% higher than that of UPSF. The findings of this study provide a theoretical basis for the development of diversified preserved fruit products and the modification of the tissue structure of fruits and vegetables.

Bacillus subtilis is a probiotic with important physiological functions, its activity will decrease during processing, storage and through the digestive tract. To overcome these unfavorable factors and improve the gastrointestinal survival rate and storage stability of Bacillus subtilis, this study combined nanocellulose with sodium alginate and prepared sodium alginate microcapsules (S-MC) and nanocellulose sodium alginate microcapsules (N-MC) using endogenous emulsification method to encapsulate Bacillus subtilis. The preparation process was optimized using single-factor experiments and response surface methodology. The resulting microcapsules were characterized, and their stability as well as performance in simulated gastrointestinal fluids were evaluated. The results showed that when the mass fraction of sodium alginate was 2.0%, the mass fraction of nano cellulose was 1.4%, the stirring speed was 610 r/min, and the volume ratio of water to oil was 1∶2.9, the embedding rate of S-MC and N-MC for Bacillus subtilis was 80.20% and 85.12%, respectively. By analyzing the results of scanning electron microscope, Fourier transform infrared spectroscopy and X-ray diffraction, it was proved that the capsule wall of S-MC had a porous structure, while nanocellulose and sodium alginate in N-MC were crosslinked with calcium ions to form a tighter gel network structure. The number of viable bacteria in N-MC decreased by 1.48 log CFU/g, which was lower than that in S-MC (2.06 log CFU/g) and free group (3.09 log CFU/g). In the simulated intestinal fluid test, S-MC released almost all Bacillus subtilis at 60 min, while N-MC released all Bacillus subtilis at 270 min, N-MC showed better slow-release performance. In addition, the storage stability test showed that N-MC could still release 7.84 log CFU/g Bacillus subtilis after 28 days of storage at 4 ℃. In this study, a new product of Bacillus subtilis microcapsule was prepared, which provided a theoretical basis for the microencapsulation of Bacillus subtilis.

Shrimp shells are currently the primary source of chitin, and demineralization of shrimp shells is a key step in the preparation of chitin. In this study, two acid-producing strains, GXUN-XS3 and GXUN-XS8, were isolated from abandoned shrimp ponds. They were identified through morphological and molecular methods. The optimal fermentation conditions were optimized using single-factor and response surface experiments. SEM analysis was used to characterize the fermentation products. The results showed that the isolated strains GXUN-XS3 and GXUN-XS8 were identified as Enterococcus faecalis and Exiguobacterium aestuarii, respectively. The optimized GXUN-XS3 was fermented in a medium containing 2% shrimp shell powder, 3% glucose, and 1% sodium chloride at a temperature of 30.5 ℃, an initial pH of 5.6, and an inoculum size of 3.3% for 3 days. The demineralization of shrimp shell reached 96.09%, which was an increase of 6.29% compared to before optimization. The optimized GXUN-XS8 fermented in a medium containing 2% shrimp shell powder, 2% maltose, and 1% sodium chloride at a temperature of 30.7 ℃, an initial pH of 5.7, and an inoculum size of 3.9% for 4 days. The demineralization of shrimp shell reached 95.73%, which was an increase of 6.17% compared to before optimization. SEM analysis revealed that the products had a fibrous structure with pores, more intact than industrial chitin produced by acid-alkali methods. This study provides microbial resources and references for the microbial fermentation degradation of shrimp shell waste.

In this work, bioactive peptides with inhibitory effect on dipeptidyl peptidase-IV (DPP-IV) were prepared from corn protein meal. The protease with the best inhibitory effect on DPP-IV was selected by enzymatic preparation technique, and the optimal enzymatic hydrolysis conditions were determined by single factor and response surface optimization experiments. The molecular weight distribution, ultrafiltration classification and amino acid composition of the obtained inhibitory peptides were further analyzed. The results showed that the neutral protease had the best effect on the preparation of DPP-IV inhibitory peptide from corn protein source. The optimal enzymolysis conditions were substrate concentration of 10% (w/v), enzyme dosage of 640 U/g, enzymolysis time of 157 min, enzymolysis temperature of 45 ℃ and enzymolysis pH of 7.0. The half-inhibitory concentration (IC₅₀) value of DPP-IV for the inhibitory peptide obtained under this condition was 0.53±0.06 mg/mL. After ultrafiltration, the molecular weight of components less than 1 kDa accounted for 58.9% of the original inhibitory peptide, and the inhibitory activity against DPP-IV was higher than that of the original inhibitory peptide, which was related to its amino acid composition. The results of enzymatic reaction kinetics showed that the inhibition type of DPP-IV was competitive and reversible. The results of this study provide a theoretical basis for the development and utilization of DPP-IV inhibitory peptide from corn protein source, and suggest a new idea for the high-value utilization of corn protein.

Objective: This study aimed to develop a rapid and visual method for detecting Salmonella detection by integrating strand exchange amplification (SEA) with a smartphone-based application (APP). Methods: A chitosan-modified silica membrane (CMSM) was optimized for nucleic acid enrichment from samples. Primers for the SEA isothermal amplification reaction were designed, and a smartphone application "Salmonella Smart Detection" was developed based on neutral red coloration. The specificity, sensitivity, anti-interference capability, and detection performance for artificially contaminated samples were systematically evaluated. Results: The detection platform exhibited high specificity for Salmonella. The detection limit for genomic DNA was 10 pg/μL, while the sensitivity for bacterial colony detection was 1.5×10² CFU/mL. The method demonstrated strong resistance to interference from natural background bacterial flora in pork, achieving a detection sensitivity of 3.57×10² CFU/mL in artificially contaminated pork samples. Conclusion: The intelligent visual detection system based on SEA developed in this study demonstrates rapid performance, high sensitivity, strong specificity, and advanced intelligent visualization capabilities. This system offers an innovative and practical approach for on-site visual screening of Salmonella in food products.

This study employed a multiplex real-time quantitative polymerase chain reaction (mRT-qPCR) method incorporating SDS (sodium dodecyl sulfate) and PMA (propidium monoazide) pretreatment to enable rapid and accurate detection of three food-borne pathogens Salmonella spp. (SA), Listeria monocytogenes (LM), and Shiga toxin-producing Escherichia coli (STE) in dairy products. Three sets of specific primers and TaqMan probes were designed targeting conserved regions of the invA gene (SA), hly gene (LM), and stx gene (STE), facilitating the development of an optimized mRT-qPCR assay. Furthermore, PMA pretreatment efficacy was evaluated for eliminating false-positive results caused by dead bacterial cells, and the evaluation of the specificity, detection limit, stability, and detection effect in the simulated dairy samples was conducted in this study. The results revealed that pretreatment with PMA combined with SDS prevented the interference of dead bacterial cells, and the optimal effective PMA concentration was 20 μmol/L. The assay showed high specificity and sensitivity and good stability in detecting the three target strains amplified in the presence of 18 non-target strains, with the lowest limits of detection for the three target strains being up to 10² CFU/mL and the variation coefficients of inter-batch and intra-batch being less than 1%. The results obtained for the detection of causal organisms in bacterially contaminated dairy products using the SDS-PMA-mRT-qPCR assay were comparable to those obtained using the national standard method, with a test cycle of 7 h. These findings indicate that the SDS-PMA-mRT-qPCR assay can be used for the rapid and accurate detection of Salmonella spp., L. monocytogenes, and Shiga toxin-producing E. coli in dairy products and represents an appropriate technique for ensuring the safety of dairy products.

The aim of this study was to develop a rapid quality assessment method for Antarctic krill (Euphausia superba) by integrating near-infrared spectroscopy (NIRS) with partial least squares (PLS) regression. Quantitative models were established to predict two critical quality indicators: non-protein nitrogen (NPN) and total volatile base nitrogen (TVB-N) contents. Following spectral acquisition, the key model parameters, including the preprocessing methods, characteristic spectral ranges, and principal factor numbers, were systematically optimized. Model performance was evaluated using the coefficient of determination (R²), root mean square error of calibration (RMSEC), and root mean square error of prediction (RMSEP). For the NPN model, multiplicative scatter correction (MSC) was selected as the optimal preprocessing method, with a characteristic spectral range of 8887.1 to 7774.2 cm⁻¹. The TVB-N model utilized a combination of MSC and Savitzky-Golay smoothing (SG), with the full spectral band employed for modeling. Both models adopted five principal factors. After optimization and external validation, the optimized NPN model demonstrated a robust performance, with R²=0.9384, RMSEC=0.279, and RMSEP=0.443, whereas the TVB-N model achieved R²=0.8685, RMSEC=3.800, and RMSEP=4.070. These results indicated that both models exhibit high predictive accuracy (R²>0.85) and stability, with the NPN model outperforming the TVB-N model in terms of predictive capability. In conclusion, quantitative analysis models constructed by combining NIRS and PLS can predict the NPN and TVB-N content in Antarctic krill. This approach provides a rapid solution for Antarctic krill quality assessment, addressing the growing demand for the efficient monitoring of Antarctic krill resource utilization.

This study aims to investigate the potential of dietary supplementation with wolfberry honey in improving inflammatory bowel disease. Wolfberry honey was collected from different apiaries in the widely cultivated wolfberry area of Golmud, Qinghai Province. Ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)-based widely targeted metabolomics was used to identify the metabolites in wolfberry honey. The main physicochemical indicators (proline content, glucose oxidase, hydrogen peroxide, total phenolic acids, total flavonoids) and antioxidant activity were measured. The effect of wolfberry honey supplementation (5 g/kg) on the gut microbiota in dextran sulfate sodium (DSS)-induced ulcerative colitis mice was assessed using 16S rRNA sequencing. The results showed that the glucose oxidase activity in wolfberry honey was 54.49 μg/g·0.5 h, proline content was 390.00 μg/g, and hydrogen peroxide content was 42.68 μmol/L. The total phenolic acid content was 108.00 mg GAE/kg, and the total flavonoid content was 42.47 mg/100 g. The iron ion reducing capacity (FRAP) was 0.58 mmol/L Fe²⁺/kg. The ability of wolfberry honey to scavenge DPPH, ABTS cation, and hydroxyl radicals increased with concentration, with the highest activity observed in scavenging ABTS cation radicals, showing an EC₅₀ of 62.94 mg/mL. A total of 1201 metabolites were identified in wolfberry honey by UPLC-MS/MS, with lipids (16.94%) being the largest group, followed by carbohydrates and their derivatives (15.29%), flavonoids (13.64%), amino acids and derivatives (13.22%), alkaloids (10.74%), and phenolic acids (7.44%). For the first time, wolfberry spermidine-like compounds were identified in wolfberry honey, which could serve as biomarkers for authenticity. Wolfberry honey significantly increased the relative abundance of beneficial bacteria in the gut of DSS-induced colitis mice, such as norank_f__Muribaculaceae, Lactobacillus, Candidatus_Saccharimonas, and Faecalibaculum, and reduced the relative abundance of harmful bacteria like Escherichia-Shigella, thus maintaining gut ecological balance. This study provides a comprehensive analysis of the chemical composition of wolfberry honey and offers a theoretical basis for its application in the prevention and treatment of ulcerative colitis.