Objective: The preparation of liquid black garlic by lactic acid bacteria cooperative fermentation and the analysis of aroma components were studied. Methods: Fresh garlic was subjected to high-temperature enzyme inactivation at 180 ℃, then crushed and mixed with water. Different proportions of composite lactic acid bacteria were added for fermentation for a certain period of time. Liquid black garlic was prepared by high-temperature reaction at 80 ℃. The degree of browning, reducing sugar, total phenols, total acids, amino acid nitrogen content and DPPH·, ·OH scavenging rate were measured every two days using liquid black garlic (KB1、KB2) without bacterial fermentation as a reference, and the optimum conditions for preparing liquid black garlic were studied under the fermentation of complex lactic acid bacteria in different proportions, and the aroma components of liquid black garlic under these conditions were analyzed. Results: The best preparation conditions for liquid black garlic were determined as follows: The fermentation time was 9 min, the mass ratio of lactic acid bacteria S (Streptococcus thermophilus):B (Lactobacillus bulgaricus) was 3:1, and the maturation standard of black garlic was reached at 13 d. Under the same conditions, KB1 was used as the standard. At this time, the reducing sugar content was 1.20 times, the total phenol content was 1.82 times, the total acid content was 1.36 times, and the amino acid nitrogen was 1.21 times. DPPH· clearance and ·OH clearance were 1.37 times and 1.34 times, respectively. Compared with single lactic acid bacteria S and B, the thermal reaction was shortened by 2 d and 5 d, respectively. The analysis of aroma components showed that, compared with KB1, the content of thioether in liquid black garlic co-fermented by strains decreased by 54.17%, while the volatile aroma components of aldehydes and furan compounds increased by 47.98% and 6.18% respectively. The liquid black garlic basically had no garlic odor, and the aroma acceptability was better, with a sensory score of 91.38±0.98 points. Conclusion: The fermentation of liquid black garlic by complex lactic acid bacteria has a synergistic effect and can shorten the thermal reaction of black garlic, which has a good application prospect in the development and research of black garlic.

In this study, the effects of corn flour content, sea buckthorn pomace, yeast dosage, and fermentation time on the sensory evaluation of steamed bread were investigated. Based on single-factor experiments sensory scoring, a Box-Behnken experimental design was employed to optimize the formulation of sea buckthorn pomace-corn flour-steamed bread. Analyses were conducted on the quality characteristics, antioxidant activity, in vitro digestibility, and expected glycemic index (eGI) of the optimized product while using steamed bread without sea buckthorn pomace as a control. The results demonstrated that the optimal formulation was 100 g of medium-gluten wheat flour supplemented with 44% corn flour, 4% sea buckthorn pomace, and 1.5% yeast and a fermentation time of 50 min. The sensory score of steamed bread prepared with this formulation was 97.10, closely matching the predicted value of 97.29. Sea buckthorn pomace significantly influenced the specific volume, texture, and flavor of steamed bread. The optimized product contained 0.033 mg/g polyphenols and 0.21 mg/g flavonoids, with DPPH and ABTS⁺ radical scavenging rates of 23.15% and 54.46%, respectively. In vitro digestion tests revealed that incorporating sea buckthorn pomace reduced both the glycemic index value and starch digestion rate, yielding an expected glycemic index (eGI) of 71.87, classifying it as a medium-GI food. This study provides a theoretical reference for applying sea buckthorn pomace to steamed bread products.

In order to achieve a high-value utilization of pigeon blood, a by-product during the processing of meat pigeon, this study focused on the preparation of antioxidant and anti-aging peptides from pigeon blood through enzymatic hydrolysis. First, pretreatments of pigeon blood were adopted to help the hemoglobin in blood erythrocytes dissolve out. Then, different proteases were employed to enzymatically hydrolyze the hemoglobin in pigeon blood, and the DPPH and ABTS⁺ radical scavenging activity of the resultant hydrolysate, as well as the tyrosinase inhibitory activity were selected as screening indexes to optimize the enzymolysis conditions. The enzymatic hydrolysis process of active peptides in pigeon blood was optimized by using single-factor and orthogonal experiments. Result showed that ultrasonic treatment for 5 min at 100 W owned the highest dissolving hemoglobin content for 192.65 mg/mL, which indicating the best hemolysis effect. The DPPH and ABTS⁺ radical scavenging activity and tyrosinase inhibitory activity of hydrolysate obtained from pepsin treatment were all basically higher than those from other proteases, and the protein recovery was also relative higher, revealing pepsin as the most effective protease for the enzymatic hydrolysis. The optimum conditions for the preparation of antioxidant and anti-aging peptides from pigeon blood established: blood-to-water ratio at 1:1.2, protease addition at 12000 U/g, hydrolysis time at 4 h, hydrolysis temperature at 37 ℃, and pH at 2.0. Under this process, the tyrosinase inhibition rate of the obtained pigeon blood hydrolysate reached the highest, at 45.93%, and the ABTS⁺ scavenging rate was 83.84%. The hydrolysate was mainly consisted of peptides with molecular weight smaller than 5000 Da, accounting for 78.98% of the total. And the essential amino acids, hydrophobic amino acids, and antioxidant amino acids accounted for 42.01%, 38.62%, and 27.22% of the total amino acids, respectively, which indicated excellent nutritional value and antioxidant and anti-aging effects of the hydrolysate obtained from pigeon blood. All these provided a fundamental basis for the development of bioactive peptides from pigeon blood and the reutilization of meat pigeon processing by-products.

To explore the effect of mycosporine-like amino acids (MAAs) extracted from Sargassum sp. on the activity of tyrosinase, this study first employed single-factor and response surface optimization experiments to analyze the effects of several factors such as methanol concentration, liquid-to-solid ratio, extraction temperature and extraction time on the extraction of MAAs from Sargassum sp. An optimal extraction process for MAAs from Sargassum sp. was then established using the yield of MAA extracts and their inhibitory rate against tyrosinase activity as indicators. Further, thin-layer chromatography, ultraviolet spectroscopy, high-performance liquid chromatography, and spectrophotometry were used to conduct qualitative and quantitative analysis, in vitro antioxidant analysis, and anti-tyrosinase activity analysis of MAA extracts. And then, the inhibition mechanism of MAAs from Sargassum sp. on the activity of tyrosinase was determined through enzyme reaction kinetics analysis, copper ion chelation experiments, and tyrosinase fluorescence quenching experiments. The results showed that the appropriate extraction parameters for MAAs from Sargassum sp. were a temperature of 41 ℃, a liquid-solid ratio of 26 mL/g, a time of 2.6 h, and a methanol concentration of 31%. The yield of MAA extracts was 89.87±0.73 mg/g, and the IC₅₀ (half maximal inhibitory concentration) value of its inhibitory rate on the activity of tyrosinase was 2.23±0.32 mg/mL. MAA extracts from Sargassum sp. exhibited the capacity to scavenge DPPH (IC₅₀ of 0.17±0.06 mg/mL) and ABTS⁺ (IC₅₀ of 1.03±0.21 mg/mL) free radicals, and could chelate copper ions (with a half-chelation concentration of 0.70±0.21 mg/mL). The inhibitory effect of MAAs from Sargassum sp. on the activity of tyrosinase was a reversible and mixed-type inhibition. MAAs from Sargassum sp. possess the inhibitory activity against tyrosinase and can effectively block the melanin synthesis pathway. They have potential application prospects in preventing the enzymatic browning of fresh fruits, vegetables and beverages, as well as in preventing melanosis in shrimps.

In view of the serious threat of organophosphorus pesticide (OPs) residues to the environment and human health, it is important to develop a rapid, sensitive and enzyme-free detection method to solve the problems of existing technologies that rely on biological enzymes, high cost and complex operation. In this study, gold nanostars (AuNS) were synthesized by seed-mediated growth method, and platinum nanoparticles were loaded on their surface to prepare AuNS/Pt nanocomposites (AuNS@Pt). The synthesized AuNS@Pt exhibited oxidase-like activity, whose catalytic mechanism was elucidated through kinetic analyses. Capitalizing on the inhibitory effect of OPs on the active sites of AuNS@Pt, a novel colorimetric detection platform was developed. AuNS@Pt could efficiently catalyze the oxidation of TMB to generate blue products (characteristic absorption peak 652 nm). The adsorption of OPs (dimethoate, omethoate, malathion) inhibited its catalytic activity. The absorbance value was linearly related to the concentration of OPs within a certain range, and the limit of detection were 0.015, 0.022 and 0.050 μg/mL, respectively. The recoveries of spiked cabbage samples ranged from 85.6% to 103.2%, with relative standard deviation below 5.18%, which was consistent with the results of gas chromatography-mass spectrometry. The proposed method provides a new strategy for the rapid detection of OPs and is suitable for practical application in complex matrix samples.

This study aimed to construct a highly sensitive, reliable, and low-cost electrochemical sensor based on graphitic carbon nitride (g-C₃N₄) modified materials for efficient and convenient detection of purine content in edible mushrooms. The g-C₃N₄ material was fabricated through a high-temperature calcination method, and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), cyclic voltammetry (CV), and differential pulse voltammetry (DPV). The results indicated that the g-C₃N₄ material exhibited a two-dimensional sheet-like nanostructure, characterized by a high degree of graphitization, abundant N-functional group content, and a specific surface area of 61.35 m²/g. An electrochemical sensor (g-C₃N₄/GCE) was fabricated by modifying a glassy carbon electrode (GCE) with the composite material. Under optimal conditions (pH5.5, enrichment potential of 0.3 V, and enrichment time of 5 min), the peak current of the sensor demonstrated a favorable linear relationship with the concentration of xanthine. Within the low concentration range of 0.5~5 μmol/L, a linear relationship was established as Ipa=0.310C_XA+2.859 (where Ipa represented the peak current and C_XA denoted the xanthine concentration), with a coefficient of determination R²=0.990. In the high concentration range of 5~200 μmol/L, the linear relationship was determined to be Ipa=0.051C_XA+4.034, with R²=0.997. The minimum detection limit (LOD) was calculated to be 0.28 μmol/L. According to this sensor, the xanthine content in shiitake mushrooms, tea tree mushrooms, and wood ears were 307.50, 229.22, and 47.27 mg/100 g, respectively. Compared with the commonly used high-performance liquid chromatography method, the g-C₃N₄ electrochemical sensor exhibited good stability, with a relative standard deviation (RSD) of 1.45%~3.69%, and the operation was simple, which could be used for the detection of xanthine in edible mushrooms.

This study conducted a systematic analysis of the quality characteristics of different rapeseed varieties from the Hulunbuir region and established a comprehensive evaluation system. Ten rapeseed varieties were selected, and the differences among various quality indicators were examined. Comprehensive evaluation was performed using correlation analysis, principal component analysis, and cluster analysis, leading to the development of a quality assessment model. The results showed significant differences (P<0.05) in key quality indicators among the varieties, with coefficients of variation ranging from 3.07% to 91.67%. Substantial variation was observed in indicators such as sterols, vitamin E, and mineral elements, reflecting clear differences in nutritional composition among varieties. Correlation analysis revealed strong correlations between certain components. PCA extracted six principal components, explaining 85.330% of the total variance, effectively representing the majority of the original information. Among the tested varieties, Longyou 10 had the highest comprehensive score, followed by Qingza 7 and Qingza 15, which exhibited superior performance in oil content, mineral elements, and sterol composition. Cluster analysis divided the ten varieties into six groups, among which group I, consisting of Qingza 15, Qingza 7, and Longyou 10, demonstrated the best overall quality. Collectively, this study provides a reference for evaluating the quality of different rapeseed varieties in Hulunbuir and offers a scientific basis for the selection of superior varieties and the regional industrial development of rapeseed resources.

To compare the differences in volatile components between white pepper essential oil extracted by ultrasound-assisted steam distillation and traditional steam distillation, the two methods were used to prepare the essential oil in this study. Subsequently, combined with LLE, the sample was comprehensively analyzed using GC×GC-O-TOF-MS. Additionally, aroma extraction dilution analysis (AEDA) was conducted to screen for aroma-active compounds with a dilution factor (FD) of ≥32 for precise quantification, and their odor activity values (OAVs) were subsequently calculated. The results indicated that a total of 109 volatile odor compounds, including 49 terpenoids, 27 alcohols, 12 ketones, 7 aldehydes, 5 esters, and 9 other compounds, were identified in the two white pepper essential oils. By comparing the types and concentrations of volatile compounds in these oils, it was observed that ultrasound-assisted hydrodistillation exhibited effective extraction of terpenoids. Olfactory analysis detected odors from 41 aroma-active compounds in the two white pepper essential oils. The OAVs of aroma-active compounds, including 3-carene, myrcene, α-terpinene, (+)-limonene, p-cymene, caryophyllene, linalool, and terpinine-4-ol, in white pepper essential oils obtained through ultrasound-assisted hydrodistillation were all increased. These findings suggested that ultrasound-assisted hydrodistillation not only improves the extraction rate of white pepper essential oil but also effectively promotes the generation or release of aroma-active compounds. This study provides a methodology and insights for enhancing the flavor quality of plant essential oils extracted by traditional hydrodistillation.

This study aimed to develop a quick and accurate discrimination method to realize the identification of Chinese Huzhu Qingke Liquor (CHQL), and to provide reliable technical support for the quality control and authenticity identification of Qingke liquor. First, ultraviolet spectrum (UV) and near-infrared spectroscopy (NIR) were used to examine the spectral properties of CHQL, Other Brand Qingke Liquor (OBQL), and Non-Qingke Based Liquor (NQBL). Then, partial least square-discriminant analysis (PLS-DA), support vector machine (SVM), and random forest (RF) were established using UV, NIR single spectrum and UV-NIR fusion spectrum. Additionally, interval partial least squares (iPLS), variable importance of projection (VIP), and competitive adaptive reweighted sampling (CARS) were used respectively for extracting feature variables from spectra. The results showed that the fusion spectra could complement each other and improve the performance of the classification model. The feature variable screening method further improved the model performance and reduced the model complexity. The RF model constructed using the 78 optimal wavelengths filtered by the VIP technique had the best classification and prediction results, with 100% accuracy on both the training and test sets. In summary, the combination of data fusion strategy and chemometrics method can effectively enhance the model performance and realize the rapid discriminant analysis of Huzhu Qingke liquor.

In order to fill consumers' growing demands for healthy dried noodles and promote the high-quality development of the wheat flour industry, 16 types of wheat flours nationwide were selected as research subjects, 40 quality indicators were evaluated from three dimensions, including nutrition, processing and edible quality. The dried noodles produced with these wheat flour samples were further digested using an in vitro dynamic simulation digestion system, and then the key indicators and their value ranges of wheat flour that suitable for producing digestion-resistant noodles were identified through correlation analysis, principal component analysis, and cluster analysis. Results showed that the variation coefficients of quality indicators of these wheat flour samples ranged from 1.13% to 227.90%, indicating their more representative. According to correlation analysis and principal component analysis, the key indicators of wheat flour for dried noodles with resistant starch digestion were identified as B-starch content, ash content, flour particle size (10xx/11xx), dough development time, peak viscosity, and gelatinization enthalpy. Meanwhile the reference ranges for these key indicators were provided by cluster analysis, which were B-starch content of 10.15%~16.91%, ash content of 0.42%~0.73%, the mass ratio of flour with particle size (10xx/11xx) that was 6.06%~26.20%, dough development time of 4.20~15.00 minutes, peak viscosity of 1492.00~2697.00 cP, and gelatinization enthalpy of 1.34~2.85 J/g. This study can provide a theoretical reference for predicting the resistant-digestion quality of wheat flour for dried noodles and for developing nutritious and functional noodle products.