This study utilized corn steep liquor (CSL), a byproduct of corn processing, as the raw material. Koji with high protease activity was employed to ferment and degrade CSL proteins, and fermentation conditions were optimized using response surface methodology to investigate the effect of fermentation on its antioxidant activity. The results showed that the optimal process parameters were: Koji addition (based on protease activity) of 28 U/mL, temperature of 53 ℃, fermentation time of 5 h, and pH of 5.7. Under these conditions, the soluble protein content in fermented CSL reached 137.83±2.07 mg/mL, representing an 8.81% increase compared to unfermented CSL. Fermentation promoted the hydrolysis of proteins in CSL and increased the content of small peptides, reduced the average particle size of CSL proteins, and significantly increased the absolute value of Zeta potential (P<0.05). After fermentation, the relative content of α-helix in the secondary structure of CSL proteins decreased by 4.59%, while β-sheet increased by 2.82%, and β-turn increased by 1.77%. Scanning electron microscopy (SEM) revealed that the macromolecular proteins in CSL were degraded into fragments with folded and porous surface structures. At a concentration of 5 mg/mL, the DPPH radical scavenging rate of fermented CSL was 51.35%±2.06%, the ABTS⁺ radical scavenging rate was 92.23%±1.57%, and the FRAP value was 38.54±1.78 µmol/L, representing increases of 11.85%, 7.16%, and 21.77%, respectively, compared to the unfermented group. This study opens a new pathway for the high-value utilization of corn byproducts and the development of novel plant-based protein resources.

To address the low bioavailability of oyster peptide (OP) after gastrointestinal digestion, this study optimized and investigated the preparation process and colloidal properties of chitosan-oyster peptide nanoparticles (CONP). The CONP were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction, with evaluations of their stability, simulated digestion characteristics, and release kinetics. Results indicated that the optimal preparation conditions were: Chitosan (CS) to sodium tripolyphosphate (TPP) mass ratio of 4.8:1, CS concentration of 2.4 mg/mL, CS to OP mass ratio of 1:2, and CS solution pH of 5.5. Under these conditions, the encapsulation efficiency reached 85.44%, with a particle size of 259.67 nm. The CONP formed amorphous nanoparticles primarily through electrostatic and hydrogen bonding interactions, exhibiting irregular elliptical shapes with geometric dimensions around 100 nm and uniform particle size distribution. The peak thermal decomposition temperature of encapsulated OP increased by 37 °C. After treatment with 200 mmol/L NaCl, a 90 °C water bath for 120 min, and pH2 PBS, the particle sizes of CONP were 709, 338, and 431 nm, respectively. After 360 min of continuous simulated gastrointestinal digestion, the cumulative release rate reached 70.80%. After 24 h of separate simulated gastric and intestinal digestion, the release rate in gastric fluid was significantly lower than in intestinal fluid. The formation mechanism and structural characteristics of CONP significantly enhanced its ionic strength stability, thermal stability, and pH responsiveness. It exhibited high stability in simulated gastric fluid following Fickian diffusion, while showing swelling behavior and following Super Case Ⅱ release in simulated intestinal fluid, with rapid release of OP. This study provides a theoretical foundation for the application of OP in functional food development.

The aim of the study was to provide a reference basis for the preparation of high-quality rapeseed protein by salt-extraction. Cold-pressed dehulled rapeseed meal was used. The salt-extraction process was optimized using single-factor experiment and response surface experiments analysis, and the physicochemical properties were investigated and compared with the protein obtained by alkali-extraction and acid-precipitation. The results showed that the optimal conditions were as follows, pretreatment with phytase and hydrated ethanol, 0.75 mol/L CaCl₂ extracting medium, pH6.5, solid-liquid ratio 1:12 g/mL, temperature 53 ℃ and extraction time 90 minutes, and achieving a protein solubility of 27.96% under these conditions. Furthermore, the resulted rapeseed protein achieved a higher protein purity at 77.12%±0.63% and a lower phytic acid content of 0.13%±0.01%, in comparison to the protein obtained by alkali-extraction and acid-precipitation method. What's more, SDS-PAGE analysis revealed that the main components of salt-extracted protein were albumin. Its higher contents of α-helices and β-turns dominated its stable and flexible structure, also leading to better solubility. This experiment provides a basis for using the salt-solution method to prepare high-quality rapeseed protein.

In this study, highly oil-absorbing deacetylated konjac glucomannan octenyl succinate gel (DK-OS) was prepared using deacetylated konjac glucomannan gel (DK-G) as the raw material and octenyl succinic anhydride (OSA) as the esterifying agent. The Box-Behnken experimental design was employed to investigate the effects of four factors (reaction temperature, pH, DK-G concentration, and OSA and DK-G mass ratios [m_OSA/m_DK-G]) on the degree of substitution (DS) and oil absorption capacity (OAC) of DK-OS. To optimize the process conditions, DK-OS with high OAC and DS was prepared under optimal conditions. The DK-OS was further characterized via infrared spectroscopy, crystalline structure analysis, hydrophobicity assessment, and microscopic morphology. The influence of the four factors on the OAC of DK-OS followed the order of m_OSA/m_DK-G>pH>reaction temperature>DK-G concentration, whereas the order of influence on DS was m_OSA/m_DK-G>DK-G concentration>pH>reaction temperature. The optimal conditions for the esterification process were 39 °C, pH8.5, 2% DK-G concentration, m_OSA/m_DK-G=1.9, and 4 h reaction time. Under these conditions, the resulting DK-OS exhibited a DS of 0.0623±0.0002 and an OAC of 53.88±0.02 g/g. Infrared spectroscopy revealed that the peak intensity of DK-OS at 1727 cm⁻¹ (associated with the ester group) was enhanced after esterification. Additionally, methylene stretching vibration peaks and carboxylate asymmetric stretching vibration peaks were observed at 2926, 2857, and 1566 cm⁻¹, respectively. Notably, the pores that developed on the microstructural surface of DK-OS exhibited increased roughness, whereas the crystal form of the esterified product remained unchanged. The hydrophobic angle increased significantly from 61.5° to 105.3°, thereby reflecting a marked enhancement in surface hydrophobicity. This study provides a technical reference for the development of high-oil-absorption dietary fibers.

This study aimed to analyze the variation patterns of volatile metabolites in ginseng after lactic acid bacteria fermentation combined with traditional processing and their influence on flavor. Ginseng was fermented with Lactobacillus pentosus and further processed. Non-targeted GC-MS metabolomics and electronic nose technology were used to conduct systematic analysis of the samples before and after treatment. The results showed that fermentation and fermentation-processing treatment significantly reduced the total sugar content from 556 mg/g to 335 mg/g and 221 mg/g, while the total saponin content first decreased from 194 mg/g to 140 mg/g and then rebounded to 221 mg/g. Fermentation and processing significantly changed the composition of volatile components in ginseng. A total of 77 significantly differentiated metabolites were identified, mainly including 11 major categories such as alcohols, terpenoids, hydrocarbons, ketones, heterocyclic compounds and esters. The changes in OAV of key aroma active components such as linalool and α-pinene indicated that the overall flavor of ginseng after treatment had transformed from grassy and pungent to a soft and harmonious fruity and caramel aroma. The analysis results of electronic nose were consistent with those of GC-MS and OAV. Fermentation enhanced the sour and fruity aroma characteristics of ginseng, and the processing process generated caramel aroma and sweet aroma substances. This study reveals the synergistic mechanism of fermentation and processing, providing an important theoretical basis and technical reference for the deep processing of ginseng and the regulation of its flavor and quality.

To enable rapid and convenient detection of zearalenone (ZEN) and aflatoxins (AFB1) in coarse cereals, this work developed an aptamer-based sensor integrated with image analysis software. The sensor utilized specific aptamers targeting ZEN and AFB1 as recognition elements, gold nanoparticles (AuNPs) as the colorimetric indicator, and NaCl as the chromogenic agent. Images of samples captured by a smartphone were analyzed using ImageJ software through measuring the integrated pixel density, allowing for specific and rapid detection of ZEN and AFB1 in ten different types of coarse cereals. Under optimal conditions, the aptasensor based on microplate reader absorbance measurement showed linear detection ranges of 0.05~3 ng/g for ZEN and 0.2~8 ng/g for AFB1, with calibration equations y=0.021x+0.3353 (R²=0.9983) and y=0.0207x+0.3075 (R²=0.9986), and detection limits of 0.035 ng/g and 0.1 ng/g, respectively. When using smartphone image acquisition combined with ImageJ analysis as an alternative method, secondary calibration equations were derived: y=−16.141x+189.88 (R²=0.991) for ZEN and y=−12.928x+247.08 (R²=0.9901) for AFB1, with LODs of 0.037 ng/g and 0.106 ng/g. Method validation confirmed good accuracy and precision, with spike recoveries ranging from 85.88%~101.13% (RSD 1.56%~5.34%) for ZEN and 87.76%~109.30% (RSD 0.9%~5.07%) for AFB1. The aptasensor successfully detected ZEN and AFB1 in all ten tested coarse cereal samples. By integrating smartphone image analysis, this approach achieves highly sensitive, rapid (15 min) and accurate detection of both mycotoxins in coarse cereals, making it an effective tool for on-site screening applications.

In order to study the effects of two enzyme-producing yeasts, Kluyveromyces marxianus (M19) and Pichia fermentans (M26) on the flavor of cheese, SPME-GC-MS and electronic nose detection were used to identify the volatile compounds in Cheddar cheese produced without (control) and with Kluyveromyces marxianus (M19) and Pichia fermentans (M26). The results showed that a total of 64 volatile compounds were detected across the three groups of cheese samples, including 10 acids, 16 alcohols, 19 esters, 6 aldehydes, 8 ketones, 2 lactones and 3 others. Principal component analysis (PCA) and cluster analysis of the detected volatile compound content and types revealed that the main volatile substances in the cheese group with M26 addition were acids, alcohols, esters, and ketones. The main volatile substances in the cheese group with M19 addition were alcohols, while the main volatile substances in the control group were alcohols. Comparative analysis of key flavor substances based on relative odor activity value (ROAV) during cheese ripening showed that the M19 group exhibited the highest number of volatile flavor compounds at 20 days of ripening, including acetic acid, isoamyl alcohol, n-amyl alcohol, ethanol, ethyl hexanoate, ethyl acetate, phenethyl acetate, ethyl decanoate, ethyl butyrate, and benzaldehyde. In contrast, the M26 group at 30 days of ripening primarily contained acetic acid, isoamyl alcohol, n-amyl alcohol, and ethyl hexanoate. Among these, ethyl hexanoate showed the highest ROAV in both treatment groups, indicating it as the most critical flavor compound in cheeses fermented with enzyme-producing yeasts, imparting distinct fruity and wine-like aromas. The odor of the M19 fermented cheese experimental group was strongest when the maturity period was 20 days, indicating that M19 fermented cheese could more efficiently promote cheese flavor formation, shorten the maturation period to 20 days, and help reduce production costs and improve efficiency. However, the flavor development ability of M26 fermented cheese was relatively weak, which might lead to a single flavor and a long maturation cycle of the product. These findings provide a valuable reference for the application of yeast in cheese production.

The variety of mustard greens is a key factor influencing the formation of fermented pickle quality. By comparing microbial counts, physicochemical indicators, organic acids, glucosinolates and volatile metabolites during the fermentation of mustard (Brassica juncea) varieties, this study assessed differences in fermentation characteristics among distinct mustard cultivars. The results indicated that differences existed in microbial counts, total acidity, and organic acid content during the fermentation of the two mustard (Brassica juncea) varieties. At the end of fermentation, the yeast count in the fermentation broth of Chuanjie No.1 was approximately 1 lg CFU/mL higher than that of Chuanjie No.2. The total acid content of Chuanjie No.2 was 0.156 g/100 g higher than that of Chuanjie No.1, and the increase in lactic acid was 2.3 mg/mL higher. In terms of glucosinolates and their primary volatile metabolites, the total glucosinolate content in fresh Chuanjie No.2 was 50.09% higher than that in Chuanjie No.1, Allyl isothiocyanate, 3-butenyl isothiocyanate, phenethyl isothiocyanate, 3-butenonitrile, and acetonitrile were key differential glucosinolate metabolites that distinguished the flavor profiles of Chuanjie No.1 and Chuanjie No.2 during different fermentation stages. Correlation analysis indicated that total glucosinolates showed a negative correlation with bacteria and lactic acid bacteria during fermentation. Volatile glucosinolate metabolites of the isothiocyanate class showed a negative correlation with bacteria and lactic acid bacteria, while exhibiting a positive correlation with total glucosinolate content. The glucosinolate content in different mustard varieties might influence the growth and metabolism of fermenting microorganisms as well as fermentation quality, leading to significant variations in the final product's flavor. The experimental results provided a theoretical basis for the targeted selection of high-quality fermented mustard.

Xinhui dried tangerine peel fruit pulp was used as a raw material to establish a rapid and quantitative analytical method for monitoring the total soluble sugar (TSS) and nitrogen (TN) contents during carotenoid fermentation by Rhodotorula mucilaginosa (R. mucilaginosa). Near-infrared spectroscopy (NIR) was integrated with partial least squares regression (PLSR) to construct models for quantifying the TSS and TN in fermentation broth. The coefficient of determination for the prediction set (R²p), root mean square error of prediction (RMSEP), and relative percent deviation (RPD) were used as evaluation metrics, and the effects of different spectral preprocessing methods and feature wavenumbers on model performance were systematically compared. The results were externally validated using independent samples. The optimal models for quantifying the TSS and TN contents were obtained using multiplicative scatter correction (MSC) for preprocessing the spectrum and competitive adaptive reweighting sampling (CARS) for selecting the feature wavenumber. The model for quantifying TSS achieved a R²p of 0.9670, a RMSEP of 2.6587, and an external validation RPD of 4.8386, indicating high-precision quantitative analysis. The model for quantifying TN yielded R²p and RMSEP values of 0.9502 and 0.0624, respectively, with an external validation RPD of 2.7423, which indicated suitability for routine quantitative analyses. The t-test results for the TSS and TN models indicated that the predicted and measured values did not significantly differ (P>0.05), indicating high accuracy and stability. These models can be used for rapidly monitoring the TSS and TN contents in R. mucilaginosa carotenoid fermentation broth samples.

Goat meat is favored by consumers for its high protein and low-fat content. The Yimeng black goat and Huanghuai white goat, as local goat breeds in Shandong Province, had received less systematic research in terms of meat quality. This study focused on the longissimus dorsi muscle and semimembranosus muscle of these two breeds, measuring pH, water retention capacity, color, texture parameters, electronic nose data, and volatile flavor substances. Principal component analysis (PCA) was used to analyze the correlation of multiple indicators, and a backpropagation artificial neural network (BP-ANN) classification model was constructed. The Shapley Additive Explanations (SHAP) method was employed to identify key features, and partial least squares discriminant analysis was used to screen key flavor substances. The Mantel correlation analysis was combined to preliminarily reveal the correlation between meat quality and key flavor substances. The results demonstrated that, in comparison with Huanghuai white goats, Yimeng black goats exhibited lower cooking loss, higher a^* values, and greater concentrations of volatile flavor compounds. The BP-ANN model developed using 27 quality indicators achieved a classification accuracy of 97.5% for breed and meat cut in the test dataset, indicating strong discriminative performance. SHAP analysis identified seven key predictors influencing model output, including h value and S14 sensor response. Mantel correlation analysis revealed significant associations between these critical quality indicators and specific flavor compounds, namely n-butyl aldehyde, n-octanol, and ethyl acetate, suggesting that lipid oxidation derivatives might serve as pivotal mediators linking mutton eating quality and flavor profile. These findings indicate that Yimeng black goats possess superior eating quality characteristics, and the established BP-ANN model offers a reliable methodological framework for future rapid, objective, and intelligent grading and discrimination of mutton.