Latest ArticlesTo establish an efficient and accurate method for determining of δ18O values in water of honey, and systematically evaluate the applicability of this method in the geographical traceability and adulteration identification of honey.
A method for the determination of δ18O values in honey water was established based on the OIBW64 oxygen isotope balancing instrument in water of special samples coupled with stable isotope ratio mass spectrometry (OIBW64-IRMS). Integration and automation of sample pretreatment and measurement procedures were realized via ethanol dissolution, CO2-H2O equilibration and an auto-sampling system. The correlation between δ18O values in honey water and adulteration proportion was investigated through simulated adulteration experiments.Furthermore, 31 honey samples covering 9 varieties and collected from 11 provinces across China were analyzed.
This method had good injection stability, high gas tightness of the reaction system, no influence of ethanol and sample moisture content on the determination results, and the determination results were highly consistent with the mainstream analytical techniques [coefficient of determination (r2)>0.999]. In the simulated adulteration experiment, there was a highly linear correlation between the δ18O value in water of honey and the proportion of rice syrup added(Y=0.0956X–8.0719, r2=0.9903). This technique had the potential to identify adulteration and perform quantitative analysis. Sample analysis showed that there were significant geographical differences in the δ18O values in water of honey from different origins, and the transpiration characteristics, honey harvesting period, maturity, and other factors of honey source plants could also affect their δ18O values in water.
The OIBW64-IRMS method established in this study is stable, reliable and highly accurate, and is suitable for the analysis of δ18O values in water of honey. The δ18O value in water of honey not only demonstrates its potential application in identifying adulteration of C3 plant-based syrup, but also serves as a potential indicator for characterizing the characteristics of the production area and plants. This provides a new technical means for studying the authenticity of honey products.
To assist the extraction of polysaccharides from Cistanche deserticola by high-speed shear technology, deeply investigate the optimal combination of process parameters, and evaluate the in vitro antioxidant capacity of the extracted polysaccharides.
Using Cistanche deserticola from Alxa as the raw material, a high-speed shear-assisted extraction technique was employed to extract polysaccharides. The extraction process was optimized using single-factor experiments and response surface methodology. The in vitro antioxidant activity of the polysaccharides was evaluated by measuring their scavenging rates against 1,1-diphenyl-2-picrylhydrazine (DPPH)radicals, hydroxyl radicals and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cationic radicals, as well as their total antioxidant capacity determined by the ferric reducing antioxidant power (FRAP) assay.
The optimal extraction process conditions were as follows: a solid-liquid ratio of 1:30 (g:mL), a shearing speed of 10000 r/min, a shearing time of 30 s and a shearing frequency of 3 times. Under these optimized conditions, the actual average yield of Cistanche deserticola polysaccharides was 2.47%±0.15%, showing essentially no difference from the predicted value(2.32%). The results of in vitro antioxidant experiments indicated that Cistanche deserticola polysaccharides exhibited strong scavenging abilities against different types of free radicals and demonstrated a clear dose-effect relationship within specific concentration ranges.
The high-speed shearing-assist extraction process for Cistanche deserticola polysaccharides, optimize via response surface methodology, demonstrates both stability and feasibility. The extract polysaccharides exhibit notable in vitro antioxidant activity, providing a robust theoretical foundation for their further development and application in functional foods and pharmaceutical industries.
Contamination by foodborne pathogens is a core risk in global food safety, and the resulting food spoilage and foodborne illnesses are widely recognized as a serious threat to public health. Currently, traditional sterilization methods have certain limitations. Thermal sterilization frequently causes the loss of nutritional value and deterioration of sensory quality in heat-sensitive foods, while chemical sterilization methods are associated with potential risks of chemical residue. Consequently, these conventional methods hinder the growing consumer demand for high-quality food and the adaptation to the rapid development of the food industry. As an emerging food processing technology, cold sterilization can effectively inactivate harmful microorganisms while preserving the original nutritional value and flavor of food. Therefore, this review systematically outlined the hazards posed by common foodborne pathogens and elaborated on the inactivation mechanisms and principal advantages of 4 kinds of novel cold sterilization technologies. Furthermore, it reviewed the latest research advances in cold sterilization strategies both domestically and internationally, and compared existing and emerging sterilization technologies from multiple perspectives. Finally, this paper identified issues such as incomplete coverage and insufficient research on synergistic mechanisms in current studies, thereby providing theoretical support for microbial control in the food industry and the industrialization of these technologies.
To evaluate the pesticide residue levels and their distribution characteristics in commercial tea products.
In this study, 73 kinds of pesticide residues were detected and analyzed in 132 randomly collected commercial tea samples, in accordance with the GB 2763—2021 National food safety standard-Maximum residue limits for pesticides in food and the GB 2763.1—2022 National food safety standard-Maximum residue limits for 112 pesticides including sodium 2, 4-dichlorophenoxyacetate. Quality control measures such as spiked recovery experiments were adopted to ensure data accuracy.
The overall qualified rate of the samples was 99.24%, with only one oolong tea sample exceeding the maximum residue limits for fenvalerate and S-fenvalerate. The total pesticide detection rate was 50.00%, and 18 kinds of pesticides were detected in total. Among them, carbendazim (35.61%), acetamiprid (28.79%) and bifenthrin (16.67%) constituted the main risk combination, showing obvious tea-type preference. Further analysis revealed significant differences in pesticide residues among different tea categories. Oolong tea (68.42%) and reprocessed tea (68.18%) exhibited significantly higher pesticide detection rates and more detected pesticide species (11 kinds and 13 kinds, respectively) than other tea types, representing relatively high-risk categories.
The quality and safety of commercially available tea are generally controllable at present, but pesticide application is relatively common. It is still necessary to focus on the pesticide residue risks of oolong tea and reprocessed tea, strengthen the supervision of pesticides with high detection rates such as carbendazim, as well as restricted and banned pesticides like fenvalerate and S-fenvalerate, so as to promote the sustainable development of the tea industry.
To explore and optimize a novel preparation process of black rice vermicelli and to systematically analyze the changes in cooking quality, texture characteristics and in vitro starch digestion characteristics of the vermicelli before and after process optimization.
Preparation parameters were optimized via single-factor experiments, using anthocyanin leaching value and breakage rate as evaluation indicators. The breakage rate, cooking loss rate, anthocyanin leaching value, in vitro starch digestion characteristics, texture properties and microstructure of black rice vermicelli were measured to evaluate the impact of the optimized process on product quality.
The optimal preparation conditions were determined as follows: grinding using a combination of a pulverizer and a colloid mill, moisture content of 40%, extrusion temperature of 95 ℃, screw speed of 8 r/s, aging time of 12 h and drying temperature of 25 ℃. Under these conditions, the cooking loss rate, breakage rate and anthocyanin leaching value decreased by 39.36%, 95.17% and 52.94%, respectively, and the cooking quality was significantly improved. Moreover, the optimized vermicelli exhibited increased peak viscosity (965.67 mPa•s), trough viscosity(830.33 mPa•s) and final viscosity (1468.67 mPa•s), while breakdown (135.67 mPa•s) and setback (631.67 mPa•s) were reduced. Furthermore, the content of damaged starch in the optimized black rice vermicelli increased, but there were no significant changes in the content of rapidly digestible starch, slowly digestible starch and resistant starch (P>0.05). The estimated glycemic index (eGI) was 79.09. Microstructural analysis revealed a significant reduction in surface pores of the optimized vermicelli.
Based on the novel preparation process established in this study, the cooking quality of black rice vermicelli has been improved, the anthocyanin dissolution rate has decreased, and the texture properties have been regulated, but there is no significant change in its in vitro starch digestion characteristics. The research results provide technical guidance for the actual production of black rice vermicelli.
There are also cases of returned shipments due to quality issues in China’s aquatic product import and export trade. The U.S. Food and Drug Administration (FDA) regularly publishes the cases of rejecting imports of certain fish and shrimp products from our country, with the General Administration of Customs reporting unapproved food entries, the unpassed reasons includes spoilaged food, violations of veterinary drug/pesticide residue limits, Salmonella contamination. The current situation reveals that some aquatic product producers are unfamiliar with relevant regulations, leading to non-compliant production practices or unauthorized drug use, which results in substandard product quality and customs clearance failures. To facilitate the import-export trade of key aquatic products like fish and shrimp, it is necessary to clarify the quality and safety control standards between China and the United States, this paper found 3 key points: (1) Regarding veterinary drugs, both China and the United States prohibited the use of chloramphenicol, nitrofurans and malachite green in fish and shrimp. (2) Regarding pesticides, China had established maximum residue limits for hexachlorocyclohexane, DDT and cypermethrin in aquatic products. Pendimethalin was prohibited from being used in domestic aquatic products; the United States stipulated that the residue limit of pendimethalin in lobsters was 50 μg/kg. (3) Regarding microorganisms, both countries mandated that no Salmonella detection was allowed in any aquatic products. Based on customs data and import-export perspectives, this paper concluded the key impacts effected import-export trade were non-compliance of veterinary drugs, pesticides and Salmonella and proposed solutions to existing issues and suggests that the development direction for fish and shrimp should focus on compliance, avoidance of prohibited substances and quality improvement.
To analyse cooking degree of salted Apostichopus japonicus during cooking process by mechanical property characteristics.
Taking salted raw Apostichopus japonicus from Dalian as research objects, they were classified into 6 cooking degree grades via sensory evaluation, namely control group (uncooked), 30% cooked, 50% cooked, 70% cooked, fully cooked and overcooked. Tensile and compression tests were conducted to determine mechanical parameters such as elastic modulus, stiffness and deformation energy. A 3-dimensional finite element model was established based on the measured parameters to simulate the manual pressing process.
With the increase of cooking degrees, the elastic modulus of Apostichopus japonicus body wall decreased significantly from (1.024±0.110)×105 Pa in the control group to (0.210±0.020)×105 Pa in the fully cooked group, and further dropped to (0.136±0.020)×105 Pa in the overcooked group, with a reduction of 79.49% and 86.72%, respectively. Stiffness and deformation energy decreased most significantly during the early cooking stage (from the control to 30% doneness), with reductions of 75.12% and 44.08%, respectively. The finite element simulation results indicated that under the same compression displacement, the maximum equivalent stress of Apostichopus japonicus body wall decreased with the rise of cooking degree, which was consistent with the variation trend of elastic modulus. Moreover, the simulated force-displacement curves were in good agreement with the experimental ones, with the maximum relative error less than 6.09%. Correlation analysis revealed that cooking degree was extremely significantly negatively correlated with elastic modulus and maximum compressive reaction force (P<0.01).
This study verifies that elastic modulus can serve as a core quantitative index to characterize the cooking degrees of Apostichopus japonicuss, which provides theoretical basis and data support for the development of rapid, non-destructive and intelligent detection technology for Apostichopus japonicus cooking degree based on mechanical response.
To screen lyophilization protectants for Lactiplantibacillus plantarum DPA1C and develop an efficient composite lyoprotectant formulation.
A basal lyoprotectant was first established to ensure a certain survival rate of the freeze-dried bacterial powder. On this basis, single-factor experiments were conducted to identify lyoprotectant components with significant effects on the freeze-drying survival rate of the strain. Subsequently, orthogonal experimental design was employed to optimize the ratio of the selected single-factor protectants.
The final formulation contained 12% skim milk, 9% trehalose, 3% exopolysaccharide produced by Lactiplantibacillus plantarum DPA1C and 2% sodium glutamate. Under these conditions, the survival rate of Lactiplantibacillus plantarum DPA1C reached 95.26%±2.01%, markedly higher than those with single protectants or control groups. This demonstrated a notable synergistic protective effect against lyophilization damage.
The exopolysaccharide produced by Lactiplantibacillus plantarum DPA1C is incorporated as one of the components of its own lyoprotectant, and an optimized composite protectant that significantly enhances the strain’s resistance to freeze-drying stress is obtained. This work provides a data reference for the industrial production of highly active bacterial preparations, and also offers a reference for the application of exopolysaccharides produced by other lactic acid bacteria.
To establish a method for the system assessment of quality differences of Codonopsis pilosula introduced and cultivated in Xinjiang from the main production areas such as Inner Mongolia, Gansu and Shanxi by high performance liquid chromatography (HPLC) fingerprint combined with chemometrics.
An InertSustain C18 chromatographic column (250 mm×4.6 mm, 5 μm) was adopted. Gradient elution was performed using acetonitrile (A)-0.1% phosphoric acid solution (B) as the mobile phase at a flow rate of 1.0 mL/min. The detection wavelengths were set at 220 nm for tangshenoside I and atractylenolide III and 210 nm for lobetyolinning and lobetyolin.The column temperature was 25 ℃ and the injection volume was 10 μL. Methodological validation was carried out.Fingerprints were established for similarity evaluation. Hierarchical cluster analysis (HCA), principal component analysis (PCA) and orthogonal partial least-squares discriminant analysis (OPLS-DA) were applied to investigate the quality differences among samples from different producing areas and with different cultivation modes.
The 4 kinds of components exhibited favorable linear relationships within their respective concentration ranges ( r2≥ 0.999).The average spike recoveries ranged from 94.74% to 97.60%, with all relative standard deviation (RSD) values below 3.5%. Significant differences were observed in the content of the 4 kinds of components among 18 batches of Codonopsis pilosula samples. Obvious discrepancies in chemical composition existed between samples from traditional major producing areas and Xinjiang-introduced cultivated Codonopsis pilosula. The fingerprint similarity values ranged from 0.910 to 0.996, and a total of 16 common peaks were calibrated. HCA and PCA could completely distinguish Xinjiang-introduced cultivated samples from those of traditional major producing areas. Tangshenoside I and lobetyolin were screened as core quality differential markers via OPLS-DA. The maximum tangshenoside I content in Xinjiang-introduced samples reached 0.940 mg/g, which was 3.0 times the average value of samples from traditional major producing areas.
The established HPLC method is accurate and reliable. Combined with chemometrics, it can quickly distinguish Codonopsis pilosula from different origins, which is suitable for its quality safety detection and origin identification, and provides a scientific basis for the development and quality control of Xinjiang introduced Codonopsis pilosula.
To investigate the flavor quality of ‘Yangta Dabaicha’ white tea made from different raw material grade (Yuemeiren, Yuanguangbai and Yuanguangshou) across various seasons.
The sensory quality, main biochemical indicators and volatile components were analyzed by sensory evaluation, ultra performance liquid chromatography (UPLC) and headspace solid-phase microextraction-gas chromatography-mass spectrometry(HS-SPME-GC-MS).
Significant differences in the quality of ‘Yangta Dabaicha’ white tea made from different raw material grade across various seasons. Among them, the Yuemeiren obtained the highest total sensory score, and the sensory quality of ‘Yangta Dabaitea’ produced in different seasons was relatively stable. Analysis of biochemical components revealed that ‘Yangta Dabaicha’ white tea harvested in Spring had a higher content of water-soluble extracts. Specifically, the Yuemeiren contained higher tea polyphenol content than other varieties; the Yueguangbai variety had the highest total amino acid content; within the same season, the Yuemeiren showed the highest phenol-to-amino acid ratio and caffeine content. The 71 kinds of volatile substances and 14 kinds of common volatile components were detected in the ‘Yangta Dabaicha’ white tea. Using relative odor activity value (rOAV) and variable importance in projection (VIP) greater than 1 as screening criteria, 7 kinds of differential aroma-active compounds were identified, including linalool, linalool oxide II, linalool oxide III, β-ionone, linalool oxide I, dihydrochalcone and phenylacetaldehyde.
‘Yangta Dabaicha’ white tea exhibits distinct varietal characteristics, featuring exceptionally high water-soluble extracts and abundant monoterpene alcohol aromas. The Yuemeiren, with its stable combination of linalool, phenylacetaldehyde and β-ionone, demonstrates outstanding downy and sweet fragrance profiles across different seasons, making it the preferred raw material grade for standardized production of this variety.These findings provide a theoretical references for understanding the flavor quality characteristics of ‘Yangta Dabaicha’white tea. The results of this study can provide theoretical references for the research on the material basis of the flavor and quality of ‘Yangta Dabaicha’ white tea.
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