Objective To establish a detection method for 12 kinds of nicotine pesticides in fruits by ultra performance liquid chromatography-tandem mass spectrometry coupled with cold induced liquid-liquid extraction. Methods Fruit samples were extracted using acetonitrile, and after salting out, shaking, and centrifugation, they were subjected to freeze induced liquid-liquid extraction using acetonitrile water solution for further enrichment and purification. Combined with ultra performance liquid chromatography mass spectrometry, data was collected using a multi reaction monitoring mode, and quantified using isotope internal standard method. Results The linear range of 12 kinds of nicotine compounds was 1-500 ng/mL, and the method showed good linearity (r²>0.999). The limits of detection were 2.15-3.60 μg/kg, and the method limits of quantification were 7.11-13.01 μg/kg. The recovery rates of 12 kinds of nicotine compounds were 73.1%-126.7%, and the relative standard deviations were 3.5%-13.3%. Conclusion This method is easy to operate, has high precision, and good stability, and is suitable for screening and detecting nicotine like compounds in fruit samples.

Objective To develop an ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the determination of pentachlorophenol sodium residues in aquatic products. Methods The sample preparation involved extraction with 80% acetonitrile in water containing 5% triethylamine, followed by purification using Waters Oasis MAX solid-phase extraction cartridges. After elution with a 4% formic acid in methanol solution, the pentachlorophenol sodium was analyzed by UPLC-MS/MS using a Waters XBridge C18 column (100 mm × 2.10 mm, 3.50 µm). The mobile phases consisted of A: 0.1% formic acid in water (containing 5 mmol/L ammonium acetate) and B: acetonitrile. Quantification was carried out using the external standard method. The recovery of pentachlorophenol sodium in the muscle of Ctenopharyngodon idella and the eatable part of Eriocheir sinensis matrices was examined. Results The linear range of the pentachlorophenol sodium residue detection method in Ctenopharyngodon idella and Eriocheir sinensis was 0.2 to 8.0 ng/mL (r²>0.999). The limit of detection was 0.5 μg/kg and limit of quantification was 1.0 μg/kg, respectively. The recoveries at spiking levels of 1.0, 2.0, and 10 μg/kg were within the range of 77.0% to 105%. Intra-assay relative standard deviations ranged from 2.51% to 7.62% (n=6), and inter-assay relative standard deviations ranged from 3.36% to 6.48% (n=3). Conclusion The developed UPLC-MS/MS method for the determination of pentachlorophenol sodium residues in Ctenopharyngodon idella and Eriocheir sinensis matrices is highly sensitive, accurate, and precise, with good repeatability and reproducibility, and is therefore suitable for the detection of pentachlorophenol sodium residues in aquatic products.

Objective To establish a rapid detection method for the simultaneous determination of 24 kinds of veterinary drug residues in pork by QuEChERS technique combined with ultra performance liquid chromatography-tandem triple quadrupole mass spectrometry (UPLC-MS/MS). Methods The samples were extracted with acidified acetonitrile, salted out by 3 g magnesium sulfate anhydrous and 2 g C₁₈ E, separated by Thermo-Fisher Hypersil GOLD aQ chromatographic column (50 mm×2.1 mm, 1.9 μm) via gradient elution of acetonitrile and 0.1% formic acid aqueous solution. The gradient elution of acetonitrile and 0.1% formic acid in aqueous solution was performed in the mode of electrospray positive ion scanning. Results The linear relationship of 24 kinds of veterinary drugs was good, and the correlation coefficients were greater than 0.9910, and the detection limit ranged from 0.2-10.0 μg/kg. The spiked recoveries varied between 70.2%-110.3%, and the relative standard deviations were 1.2%-13.8%. Conclusion The method is simple, rapid, accurate, practical, and suitable for detection of multiple veterinary drug residues in pork.

Objective To establish the detection of 172 kinds of pesticide residues in brown sugar by QuEChERS-gas chromatography-tandem mass spectrometry (GC-MS/MS). Methods The samples were fully dissolved in ultrapure water and extracted by high-speed homogenization of n-hexane, nitrogen blowing and concentration, and purified by QuEChERS method, and the data was collected in selective reaction monitoring mode by GC-MS/MS detection technology, and quantitatively detected by matrix curve and solvent curve. Results The 172 kinds of pesticides had a good linear relationship in the linear range of 10-200 ng/mL, and the linear correlation coefficient was between 0.9962 and 0.9999, the limit of quantification of the method was 0.01 mg/kg, performed 6 repeated spiked experiments at concentrations 1, 2, and 10 times the limit of quantification each, the recovery rate of spikes was between 71.0%-113.0%, and the relative standard deviation (n=6) was 0.49%-17.00%. Conclusion This method can detect hundreds of pesticides in one injection, which is fast, simple, high-throughput and economical, and is suitable for the detection of a variety of pesticide residues in brown sugar.

Objective To explore the effect of stir-frying and ultramicro grinding on the quality of Crataegus pinnatifida kernel. Methods The Crataegus pinnatifida kernels produced and processed by the enterprise were used as the test materials, and the Crataegus pinnatifida kernels were treated by ordinary grinding, frying-ordinary grinding and frying-ultrafine grinding combined treatment technology, and the physical properties of surface color, surface structure, water-holding capacity, oil-holding capacity, and the changes of oxidation resistance and flavonoid release were determined. Results The Crataegus pinnatifida kernel powder treated by frying and ultrafine grinding had an increased binding capacity to water, a solubility of 35.63%, an expansion force of 3.71 mL/g, and an oil-holding capacity of 2.61 g/g. The angle of repose and slip angle were reduced to 37.12° and 43.63°, respectively. The flavonoid release rate of Crataegus pinnatifida kernel powder increased from 60.47% to 71.48%, and the oxidant resistance increased by nearly 20%, which was manifested by a increase in the scavenging rates of 2,2-diazine-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) cationic radical, 1,1-diphenyl-2- picrylhydrazyl (DPPH) radicals and hydroxyl radicals. Conclusion Therefore, the combined treatment technology of frying and ultrafine grinding is a feasible processing method for Crataegus pinnatifida kernel powder. This technology can effectively improve the physicochemical properties of Crataegus pinnatifida kernel powder and increase the total flavonoid release rate. The results of this study are helpful to enhance the market value of Crataegus pinnatifida nuclear powder and promote the sustainable development of Crataegus pinnatifida industry.

Objective To explore the effects of harvesting periods on nutritional quality, processing properties and antioxidant activities of different parts of Fagopyrum tataricum. Methods The harvesting period was determined based on the first flowering time, and the flavonoid content, protein content, dietary fiber content, water holding capacity, oil holding capacity and antioxidant activity of seeds, stems, flowers and leaves of Fagopyrum tataricum at different harvest periods were determined measured and analyzed. Results The seeds, stems, leaves, and flowers of Fagopyrum tataricum all include the rich nutrients and the biological activity ingredient, with excellent processing properties. The flavonoid content, protein content, dietary fiber content, water and oil holding capacity of Fagopyrum tataricum seeds showed a downward trend, while the dietary fiber content of Fagopyrum tataricum stems and flowers generally showed an upward trend. The flavonoid and protein content of Fagopyrum tataricum stems and leaves decreased. The dietary fiber content of Fagopyrum tataricum leaves, flavonoid content and total antioxidant activity of Fagopyrum tataricum flowers increased first and then decreased. The total antioxidant capacity and flavonoid content of Fagopyrum tataricum flowers were significantly higher than other parts of tartary buckwheat. The highest total antioxidant capacity and flavonoid content were found 14 days after flowering, at 369.42 μmol/g and 7.83%, respectively, which were 6.2 and 8.8 times that of Fagopyrum tataricum seeds. Conclusion As food processing raw materials, different parts of Fagopyrum tataricum have the potential and value for food development and processing, and can be fully utilized. The nutrition and functional components of different parts of Fagopyrum tataricum are directly affected by harvest period, and the reasonable harvest period shall be determined based on the purpose in production.

Objective To study the beef quality characteristics of Pingliang red cattle. Methods The 12-13 thoracic intercostal eye muscles of A3 grade Pingliang red cattle were taken. The nutritional characteristics, tenderness and water retention of Pingliang red cattle were analyzed by measuring the protein, fat, moisture content, amino acid and fat composition, as well as the shear force and cooking loss. The sensory evaluation of raw and fried steak and rinsed meat slices were carried out respectively. The meat quality of A3 grade imported snowflake beef was compared, and the meat quality of Pingliang red cattle was comprehensively analyzed. Results There was no significant difference in crude protein, moisture and total fat content between Pingliang red cattle and imported snowflake beef (P>0.05); Pingliang red beef was rich in amino acids, and the ratio of essential amino acids to total amino acids was 0.45±0.05, which was higher than that of A3 grade imported snowflake beef (0.42±0.00); Pingliang red cattle had the advantages of low saturated fatty acid and high unsaturated fatty acid content. The fatty acid content of Pingliang red cattle was lower than that of imported snowflake beef, but the difference was not significant (P>0.05); the shear force of Pingliang red beef was (4219.10±225.29) g, which was significantly higher than that of imported snowflake beef (P<0.05). Sensory evaluation results showed that fresh Pingliang red beef was slightly lower than imported snowflake beef, but cooked Pingliang red beef scored higher, especially chewing elasticity, juiciness and aftertaste were significantly higher than imported snowflake beef (P<0.05). Conclution Pingliang red cattle A3 grade snowflakes beef can completely reach the quality level of imported snowflake beef, but the content and distribution of functional fatty acid needs to be regulated.

Objective To explore of odor differences and volatile differences between rape honey-adulterated and syrup-adulterated samples and real honey. Methods Different proportions of 5%, 10%, 20% and 30% syrup-adulterated and rape honey-adulterated samples were constructed, and the electronic nose technique and headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) were used to analyze the odors and volatiles of the adulterated and authentic honey samples. Results The electronic nose (E-nose) combined with the principal component analysis (PCA) and sparse partial least squares discriminant analysis (sPLS-DA) could distinguish different botanical honey of linden honey, jujube honey acacia honey, and could distinguish syrup-adulterated samples from real honey, but could not distinguish rape honey-adulterated samples from acacia honey. The GC-MS results showed that 62 kinds of volatile compounds were identified in acacia honey, linden honey and jujube honey, with the highest content of alcohols in acacia honey, aldehydes in jujube honey, terpenes in linden honey. The content of volatile compounds in combination with sPLS-DA could distinguish 100% acacia honey, 100% linden honey from 5%-30% syrup-adulterated samples and 5%-30% rape honey-adulterated samples. Conclusion The odor analysis and volatiles analysis based on E-nose and GC-MS combined with chemometrics analysis can be used to identify syrup-adulterated and rape honey-adulterated samples. The results of the study provide a reference for honey traceability and adulteration identification studies.

Objective To investigate the effects of 1-methylcyclopropene (1-MCP) and ZSM-5 nano molecular sieve blended polyethylene (PE) film on the quality and oxidative stress of Prunus persica during cold storage. Methods The 4 kinds of treatments were set up: PE packaging (P), PE packaging combined with 1-MCP (PM), PE film blended with ZSM-5 Nano molecular sieve blended polyethylene film (PN), and the combination of ZSM-5 and 1-MCP (PMN). Samples were stored at 0-2 °C for 35 days with sampling every 7 days. Texture, chromatic indexes, soluble solids content, titratable acidity, electrical conductivity, and the activities or content of polyphenol oxidase (PPO), peroxidase (POD), superoxide dismutase (SOD) and malondialdehyde (MDA) were measured. Results 1-MCP and the nano molecular sieve blended polyethylene film effectively inhibited fruit softening, color change and fibrosis. On day 21, the fruit hardness in the PM and PMN groups was significantly higher than in other groups (P<0.01), while the cohesiveness of the PMN group was significantly lower than the P group on day 27 (P<0.01). Color analysis showed that the redness and yellowness changes in other treated groups were significantly reduced compared to the P group (P<0.05). Although the PMN group's fruit appeared more yellow by day 35, the over-ripening process was suppressed. In terms of physicochemical indicators, the PM and PMN groups exhibited significantly lower electrical conductivity ratio and titratable acidity lose than the P group (P<0.01), indicating that 1-MCP and the nano molecular sieve blended polyethylene film effectively slowed down the increase in cell membrane permeability and the decrease in flavor and nutrients. Physiological measurements showed that by day 35, the MDA level in the PMN group was significantly lower than in the P group (P<0.01), with delayed peak POD and PPO activities. The PMN group's PPO activity was significantly lower than the P group (P<0.01). Conclusion The combination of 1-MCP and ZSM-5 nano molecular sieve blended polyethylene film significantly alleviates color change, over-ripening, and oxidative stress in Prunus persica during cold storage, demonstrating promising application potential.

Objective To establish the qualitative and quantitative methods for water soluble sugars in Cyperus esculentus meal, and to analyze the effects of producing areas and climatic conditions on the kinds and content of sugars in Cyperus esculentus meal. Methods High performance liquid chromatography equipped with a refractive index detector was performed to analyze maltose, raffinose, sucrose, D-glucose, D-galactose, and D-fructose in Cyperus esculentus meal. Aminex^® HPX-87C (300 mm×7.8 mm) sugar-analyzing column was used with a column temperature of 85 °C and a mobile phase of pure water at a flow rate of 0.3 mL/min. The D-galactouronic acid in Cyperus esculentus meal was analyzed with high performance liquid chromatography equipped with an evaporative light scattering detector. XBridge^® Amide 3.5 μm amino column was used with the column temperature of 40 °C. The mobile phase of 0.2% triethylamine water-acetonitrile (20:80, V:V) was used with the flow rate of 0.6 mL/min, and the gas pressure was 40 psi, drift tube temperature was 82 ℃ and the gain of 800. Results An analytical method for 7 kinds of water-soluble sugars in soybean oil was established, which had good accuracy and precision. The limits of detection of the 7 kinds of water soluble sugars were 0.02-0.05 μg and the limits of quantification were 0.06-0.10 μg. The content of 7 kinds of water-soluble sugars, including maltose, raffinose, sucrose, D-glucose, D-galactose, D-fructose, and D-galactouronic acid in 186 samples from 11 Provinces and regions were analyzed based on the method. The total sugar content in the Cyperus esculentus meal samples ranged from 11.10% to 25.51%, with significant differences among different regions. Samples from Northeast, North, and Northwest of China were higher than those from Southern China. The water soluble sugars in Cyperus esculentus meal were mainly sucrose, accounting for 65.48% to 75.85% of total sugar. In addition, maltose, raffinose, and D-galactouronic acid had high content, ranging from 1.01%-2.93%, 0.37%-1.09%, and 1.94%-2.53%, respectively, accounting for 9.11%-12.73%, 1.62%-6.37%, and 7.95%-17.75% of the total sugar content. The content of D-glucose and D-fructose was 0.01%-1.07% and 0.02%-0.78%, respectively, accounting for 0.07%-4.21% and 0.17%-3.28% of the total sugar content, respectively. Except for the samples from Heilongjiang Province, a few amount of D-galactose was also detected in most of other samples. Conclusion This study establish an analysis method for sugar content in Cyperus esculentus meal and investigated the content of water soluble sugars in samples from different producing areas. This provides a basis for breeding and planting research of Cyperus esculentus, and also can offer the guideline to the deep processing of Cyperus esculentus and the preparation and application of carbohydrates.