Objective To develop a highly sensitive detection method suitable for accurate qualitative and quantitative analysis of monosaccharide composition in edible fungi polysaccharides. Methods Four kinds of edible fungus polysaccharides samples: Lentinus edodes, Pleurotus eryngii, Hypsizygus marmoreus and Auricularia auricula were selected, after hydrolyzing with trifluoroacetic acid, and deriving with acetic anhydride, the sample was analyzed by gas chromatography-mass spectrometry (GC-MS/SIM). The specificity, precision, linear range, limits of detection (LOD) and limits of quantification (LOQ) of this method were investigated with mixed standards of 7 kinds of monosaccharides. At different m/z, the best linear relationship was used as the standard to select the most suitable quantitative ion for each monosaccharide. The stabilities and recoveries of the method under selected ion monitoring (SIM) mode were investigated using edible fungus polysaccharide samples. Results The results showed that m/z 115, m/z 103, m/z 115, m/z 115, m/z 115, m/z 115 and m/z 103 were selected as the characteristic quantitative ions of the corresponding derivatives of ribose, rhamnose, arabinose, xylose, mannose, glucose and galactose, respectively. The separation of each monosaccharide was greater than 1.2, and the linear relationship between each monosaccharide in SIM mode was good between 10.00-50.00 μg/mL, and the correlation coefficient (r²) was greater than 0.998. The LOD and LOQ were 5.75-22.23 ng/mL and 17.26-66.67 ng/mL, respectively. Using monosaccharide mixed standard and lentinan as sample matrix, it was proved that this method had good precision and stability, and the average recovery of each monosaccharide was between 94.4% and 101.3% under different standard adding levels. And the rationality of selecting the above characteristic ions was discussed by mass spectrometry analysis. Conclusion This method has good separation, precision and stability, and its sensitivity is higher than most similar detection methods reported so far. It is suitable for the detection of monosaccharide composition in various edible fungi polysaccharides.

Objective To establish an analytical mehod for the determination of nicotinamide mononucleotide (NMN) and nicotinamide adenine dinucleotide (NAD⁺) in health food by high performance liquid chromatography. Methods Determination was performed on Waters BEH-Amide column with mobile phase consisting of 0.1% phosphoric acid solution-acetonitrile (gradient elution). The flow rate was 1.0 mL/min, and the sample size was 2 μL. The column temperature was 35 ℃, and the detection wavelength was set at 263 nm. Health food was extracted with 60% methanol solution in ultrasonic water bath for 10 min. The extract was filtered through micoron filter, and analyzed by high performance liquid chromatography. Results The results showed that NMN and NAD⁺ exhibited excellent linear relationships, the correlation coefficient (r) was over 0.999 in the range of 10-1000 μg/mL. The method limit of quantitation was 0.50 g/kg. Recoveries were ranged from 95.9% to 98.8%, and relative standard deviations were ranged from 1.19% to 3.05%. Conclusion This method is accurate and suitable to determine NMN and NAD⁺ in health food.

Objective To optimization of enzymatic hydrolysis of yak butter based on response surface design. Methods Employed lipase to enzymatically treat yak butter. The 3 factors of enzyme addition, enzymatic hydrolysis time and enzymatic hydrolysis temperature were determined as independent variables by single factor test. The sensory score of ghee and ghee milk tea was taken as the response index, and the enzymolysis process of yak milk ghee was optimized by response surface methodology. Results When the addition amount of lipase was 0.48%, the enzymatic hydrolysis time was 3.75 h, and the enzymatic hydrolysis temperature was 46 ℃, the optimal enzymatic hydrolysis effect could be obtained. Under these conditions, the enzymatic hydrolysis yak milk ghee had bright color, pure frankincense flavor, and the odor of ghee was significantly improved. The ghee milk tea prepared with enzymatic hydrolysis yak milk ghee had moderate smell, unique taste, and better sensory evaluation. Conclusion The method of enzymatic hydrolysis of yak milk ghee by lipase can effectively improve the taste and odor of yak milk ghee, optimize the smell of ghee, and improve the sensory quality of its additional products, which provides new ideas and technical support for the further development of Tibetan characteristic products.

Objective To investigate the key factors that may influence plasmin activity during the production of ultra high temperature (UHT) milk. Methods An enzyme-linked immunosorbent assay (ELISA) was employed to assess and analyze the effects of various factors on plasmin activity throughout the UHT milk production process. The specific factors examined included the degree of mastitis in cows, somatic cell count in milk, vaccination status, changes in feeding conditions, centrifugation processes, pasteurization preheating conditions, microfiltration techniques, and UHT preheating conditions. Results At the raw milk stage, a significant positive correlation was observed between plasmin activity levels in bovine milk and both the severity of bovine mastitis and somatic cell counts. However, no significant correlation was found regarding vaccination status or changes in feed type. During UHT milk production, centrifugal sterilization resulted in a slight increase in plasmin activity; pasteurization preheating at 55 ℃ proved most effective at inhibiting this increase. Microfiltration reduced plasmin activity by approximately 10%. Additionally, varying UHT preheating conditions led to an overall increase in enzyme activity; however, under treatment at 90 ℃ for 5 seconds, a condition yielding only a minimal increase of 1.52%, the rise remained relatively low. Conclusion For pasture, it is essential to focus on managing cows with mastitis and monitoring those milk with abnormal somatic cell counts. At the processing stage, implementing appropriate preheating conditions for pasteurization and UHT can effectively inhibit increases in plasmin activity within milk. Furthermore, incorporating microfiltration can serve as an additional strategy to reduce such enzymatic activities. This study provides a scientific foundation for further research aimed at controlling elevations of plasmin activity in UHT milk.

The safety and quality of dairy products have long been a focal point of consumer concern. Alarmingly, the prevalence of dairy product adulteration not only poses a potential threat to consumer health but also severely infringes upon their legitimate rights and interests. In recent years, spectral technologies have emerged as a critical tool for detecting dairy adulteration, garnering widespread attention and application due to their efficiency, rapidity, and non-destructive nature. This comprehensive reviewed delves into the application of spectral technologies in the detection of dairy adulteration, encompassing advanced techniques such as near-infrared spectroscopy, Raman spectroscopy, and atomic fluorescence spectroscopy. It thoroughly examined the fundamental principles, advantages, and limitations of each spectral technique, along with their practical effectiveness in adulteration detection. For example, ultraviolet-visible spectroscopy for detecting melamine and formaldehyde; near-infrared spectroscopy for detecting vanillin and urea; Raman spectroscopy for identifying dicyandiamide and maltodextrin; atomic fluorescence spectroscopy for detecting trace elements and protein types; X-ray fluorescence spectroscopy for analyzing whey and salicylic acid; and hyperspectral imaging for detecting thiourea and starch. By systematically analyzing relevant literature, this paper aims to provide a thorough and valuable reference for quality control and safety inspection in the dairy industry. It is designed to assist professionals in better understanding and utilizing these cutting-edge detection technologies, thereby ensuring that consumers can enjoy safe and high-quality dairy products, ultimately safeguarding their health and rights.

Objective To investigate the effects of different processes on nutritional compositions and minerals in the processing of tender Laminaria japonica. Methods In this paper, the effects of blanching and salting processes on the main nutritional compositions and minerals of tender Laminaria japonica during processing were studied. Results The content of water, crude protein, dietary fiber, crude fat, alginate, mannitol, iodine, amino acids, manganese, phosphorus, iron, and potassium in fresh tender Laminaria japonica were the highest, followed by blanched tender Laminaria japonica, and the lowest was salted tender Laminaria japonica, which might be due to the high temperature of blanching and the dehydration process of salting, resulting in varying degrees of loss of nutrients in tender Laminaria japonica. Amino acid composition analysis showed that fresh tender Laminaria japonica was more in line with the ideal protein pattern recommended by Food and Agricultural Organization of the United Nations/World Health Organization (FAO/WHO). Heavy metal content analysis showed that the content of heavy metal elements in tender Laminaria japonica met the food safety standards at home and abroad. The results of principal component analysis showed that the comprehensive scores of fresh tender Laminaria japonica was the highest and the quality was the best. After blanching and salting, the comprehensive nutritional quality of fresh tender Laminaria japonica decreased. Conclusion During the processing of tender Laminaria japonica, nutritional compositions and minerals are lost to varying degrees after blanching and salting. This study can provide a scientific basis for the high-value development, utilization, and sustainable development of tender Laminaria japonica in the future.

Objective To study the difference of nutritional quality of different varieties of Prunus avium . Methods Taking 12 varieties of Prunus avium from Yantai of Shandong Province as the research object, the quality differences of different varieties of Prunus avium were analyzed by measuring the appearance indexes such as cross diameter and color difference, as well as the flavor and nutritional indexes such as soluble solids, organic acids, vitamin C, phenolic acids, flavonoids and anthocyanins. The one-way analysis of variance was used to clarify the differences in the content of each indicator among different varieties. The core quality indicators of Prunus avium were screened by correlation analysis, principal component analysis and cluster analysis. Results The soluble solids were found to be more than 15%, the titratable acid content was more than 0.5 g/100 g, and the purple-red fleshy cherry was rich in anthocyanins, and the determination of 26 quality indicators was simplified, 4 core indicators were determined to be chlorogenic acid, vitamin C, cyanidin-3-O-rutinoside, proanthocyanidins B₂. Based on the core indicators, Prunus avium could be completely separated by color, indicating that the core indicators were feasible. Finally, principal component analysis was used to comprehensively evaluate the quality of Prunus avium. According to the comprehensive score, it was found that the purple-red fleshy Russian cultivar had the best quality. The results of the measured quality index showed that it had the highest content of cyanidin-3-O-glucoside and rutin. Conclusion There are significant differences in the nutritional quality indexes of different varieties of Prunus avium. This paper provides data support for the construction of cherry quality indicator database, which is of great significance for standardizing the cherry quality evaluation system and promoting the high-quality development of the Prunus avium industry.

Objective To study the tissue distribution and metabolic regulation of diazepam (DZP) in Carassius auratus after feeding with positive bait containing DZP. Methods Carassius auratus was selected as the study object and exposed to DZP-enriched bait through gavage, and tissue samples including scales, skin, muscle, plasma, gills, intestines, liver, gallbladder, gonads, and brain were collected at specific intervals ranging from 1 h to 456 h post-exposure. High performance liquid chromatography coupled with tandem high-resolution mass spectrometry was employed to detect DZP and its metabolites—nordazepam (NZP), temazepam (TZP), and oxazepam (OZP)—in these tissues, analyze their distribution and metabolic patterns. Results Following exposure to DZP-enriched bait, DZP rapidly accumulated in Carassius auratus tissues, with substantial residues persisting for up to 456 h. The highest concentrations were primarily found in the gonads, liver and gallbladder, with the gonads consistently showing elevated levels. NZP and TZP emerged as the primary metabolites. Conclusion DZP predominantly exists in its prototype form in Carassius auratus and tends to accumulate in the gonads. The prolonged metabolic cycle of DZP and its metabolites in Carassius auratus indicates potential food safety and health risks for consumers of aquatic products caught with DZP-containing bait.

Objective To study the growth heterogeneity of different serotypes of Vibrio parahaemolyticus (VP) under different culture conditions, and to establish growth prediction models for epidemic strains (O3:K6, O10:K4). Methods Seventeen VP strains of different serotypes were selected as the research objects, and different culture conditions were set, including salinity (0.5%-10.0%), pH (3.0-11.0) and temperature (16-50 ℃). The modified Gompertz model was used to establish the primary growth model. The optimal growth range was determined by comparing the maximum OD value (Y_max), the Lag time (λ) and maximum specific growth rate (μ_max). The second-order response surface growth model was established by Design-Expert 13 software. Results There was growth heterogeneity among VP strains. The coefficient of variation for differences in growth parameters μ_max and Y_max between VP strains at salinity levels of 1.0%-3.0%, pH of 7.0-9.0, and temperatures of 20-40 ℃ was lower than that under other culture conditions. The growth ability of the epidemic strains (serotype O3:K6, O10:K4) was significantly greater than that of other serotypes when the salinity was 7.0%, the pH was 10.0, and the temperature was 16 ℃, with a statistically significant difference (P<0.05). The determination coefficients of the first-order growth models fitted under different salinity and temperature were greater than 0.98, and the correlation coefficients under different pH were greater than 0.9. The second-order response surface growth model was significant (P<0.05), and the determination coefficient was greater than 0.94. Conclusion There is growth heterogeneity among VP strains, but in certain extreme conditions, there are more obvious growth differences between different serotypes. The modified Gompertz model and the second-order response surface growth model can be used to analyze and predict the growth of VP under different experimental conditions, which can provide reliable and safe prediction for the growth trend of VP.

Objective To establish subsequently the real-time quantitative polymerase chain reaction (PCR) method that could quickly and accurately identify Cronobacter sakazakii, and design specific primer probes based on the DNA gyrB subunit gene. Methods The target gene sequences were searched and downloaded from National Center for Biotechnology Information (NCBI), sequence comparison was performed using DNAMAN, and primer probes were designed by Primer Express software. This established real-time quantitative PCR method was validated through specificity tests, absolute sensitivity tests, relative sensitivity tests and anti-interference tests. The 40 common pathogenic bacteria standard strains were selected for specificity validation. Results The results of multi-dimensional specificity validation showed that the method was able to specifically detect Cronobacter sakazakii, and there was no non-specific amplification for other closely related Cronobacter and common pathogenic bacteria in food. DNA detection sensitivity was 0.0100 ng/μL, while relative sensitivity was 10³ CFU/mL. The anti-interference experiment results showed that mixing interfering bacteria and their DNA with Cronobacter sakazakii DNA and Cronobacter sakazakii did not significantly affect the detection results, indicating that this method had good anti-interference ability. Conclusion The primer probes designed in this study are specific, rapid, sensitive and anti-interference for the detection of Cronobacter sakazakii in food samples under real-time fluorescence PCR method. It can provide technical support for detection of Cronobacter sakazakii in the future.