Objective To investigate the endogeneity and distribution characteristics of vanillin in different growth stages of Oryza sativa. Methods Longjing 46, Yanfeng, and Liaoxing were selected as the experimental materials. Samples were taken at different parts of Oryza sativa during its whole growth period. The vanillin content was determined by high performance liquid chromatography-tandem mass spectrometry method. Results Vanillin was present in Oryza sativa plants as early as the seedling stage. Its content in roots and leaves was 1100-1450 μg/kg and 596-972 μg/kg, respectively. During the growth process of Oryza sativa, the vanillin content in roots reached its peak at heading stage, with a content of 6560-8900 μg/kg. Subsequently, from full-heading stage to maturity stage, the vanillin content in roots gradually decreased, and at maturity stage, the content dropped to 2900-3230 μg/kg. The vanillin content in the leaves reached its peak at maturity stage. The vanillin in Oryza sativa grains started to accumulate continuously from the dough stage and reached its peak at maturity stage. In addition, at the late stage of reproductive growth, the vanillin content in the upper part of the plant (flag leaves and the upper part of the stem) was significantly higher than that in the lower part of the plant (lower leaves and the lower part of the stem), and the vanillin content in Oryza sativa husk was extremely significantly higher than that in the brown Oryza sativa. Conclusion This study confirms that vanillin has a natural background throughout the whole growth period of Oryza sativa, and vanillin is endogenously produced for the first time. Its content shows stage-specific and differential changes at different parts and growth stages. It is speculated that it may be a natural growth regulator of Oryza sativa.

Objective To explore the effects of glnA gene on the production of curdlan by Agrobacterium. Methods A glnA gene knockout strain ΔglnA was constructed in this paper. The growth and metabolism of ΔglnA strain and the changes in yield, gel properties and infrared structure of the obtained gum were analyzed, and the expression of genes related to the synthesis of curdlan was explored by quantitative real-time polymerase chain reaction. Results The amino nitrogen consumption of the ΔglnA strain during fermentation was consistent with that of CGMCC11546. In terms of sucrose consumption, there was no significant difference before 12 h, but there was a significant difference between the ΔglnA strain and CGMCC11546 after 15 h, and sucrose consumption was significantly reduced compared to CGMCC11546. The ΔglnA strain could produce approximately 4 g/L of natural gum, which was 60% lower than CGMCC11546. Conclusion The glnA gene does not affect bacterial growth or the structure of collagen, but it can reduce the synthesis of collagen. This study provides insights into the role of glnA in curdlan production and lays a molecular biological foundation for further efforts to enhance curdlan yield.

Objective To establish an ultra performance liquid chromatography-photodiode array detector method to analysis 3 kinds of furanocoumarins in dried citrus slices. Methods The samples were ultrasonically extracted with 40 mL ethyl acetate for 40 min twice. Vortex-assisted extraction were then repeated twice using 20 mL of ethyl acetate for 10 min. The ethyl acetate extracts were combined, concentrated to dryness in a rotary evaporator at 30 °C. The determination was carried out using an Acquity UPLC HSS C₁₈ SB column (2.1mm×150 mm, 1.8 μm) with a flow rate of 0.3 mL/min, column temperature of 30 ℃, and detector wavelength of 310 nm. A gradient elution was performed with mobile phase A water and acetonitrile as mobile phase B. Results The 6’,7’-dihydroxybergamottin, epoxybergamottin and bergamottin showed good linearity within 3.00~300.00 μg/mL, 4.32-432.00 μg/mL and 4.12-412.00 μg/mL with correlation coefficients greater than 0.999. The limits of detection were 0.09-0.17 μg/g. The limits of quantitation were 0.31-0.57 μg/g. The average recoveries with 3 concentration levels were 94.4%-99.1%. The relative standard deviations were between 2.7% and 4.7% (n=6). This method could separate 3 kinds of furanocoumarins in dried citrus slices well in 25 minutes. The developed method was successfully applied to determine 3 kinds of furanocoumarins in 18 kinds of dried citrus slices and powders. The content of 6’,7’-dihydroxybergamottin was between 1.52 and 159.04 μg/g. The content of epoxybergamottin was between 49.57 and 60.09 μg/g. The content of bergamottin was between 1.49 and 248.71 μg/g. Conclusion The established method has good repeatability and high accuracy, and can be used for the 3 kinds of furanocoumarins determination in dried citrus slices.

Objective To establish a method for determining the volatile components of lubricating oil mixed in edible oil by headspace-gas chromatography-mass spectrometry. Methods The 1.0 g oil sample was directly taken into a 10 mL headspace bottle, then capped and sealed. Headspace-gas chromatography-mass spectrometry analysis was carried out at 90 ℃ equilibration for 20 min. Qualitative analysis was performed on 5 kinds of compounds: 4-methyl-2-pentanol, isooctanol, nonane, undecane and dodecane, while quantitative analysis was performed on isooctanol, nonane, undecane, and dodecane. Results The 4 kinds of quantitative compounds showed good linear relationships within the range of 0.5-8.0 mg/kg, and the correlation coefficients were all above 0.9980. Soybean oil was used as the sample for the spike recovery experiment. The recoveries of nonane, isooctanol, undecane, dodecane were 91.5%-98.2%, 81.9%-92.7%, 92.8%-94.6%, 89.3%-93.7% respectively and the relative standard deviations were all less than 10%. In the 5 kinds of edible oils: Soybean oil, peanut oil, rapeseed oil, corn oil and sunflower seed oil, the limits of detection of nonane, isooctanol, undecane, dodecane were 0.006-0.013 mg/kg, 0.016-0.045 mg/kg, 0.011-0.020 mg/kg, 0.020-0.036 mg/kg respectively. Conclusion This method has the advantages of simple operation and rapid detection, and does not have high requirements for the instrument, which can be carried out in general laboratories, and is suitable for the screening of trace lubricating oil contamination in edible oil.

Cichorium intybus L. is a plant with high medicinal value and wide range of uses. The roots, stems, leaves and seeds of Cichorium intybus L. are highly nutritious and have a wide range of health benefits, such as regulating blood sugar, weight loss, combating malaria and preventing cardiovascular disease. Cichorium intybus L. root is rich in inulin, a polysaccharide composed mainly of fructose units, but also contains a small amount of monosaccharides, as well as chlorogenic acid and sesquiterpene lactones and other biologically active compounds, which have the function of regulating and improving gastrointestinal function, balancing blood glucose metabolism, improving lipid metabolism, lowering blood pressure, strengthening the immune system, antioxidant, anti-fatigue effects and other functions. Cichorium intybus L. can be processed into a variety of products, such as root tea, bread, functional foods, sugar substitutes and so on. This paper summarized the nutritional composition, functional characteristics, and research progress of Cichorium intybus L. in the food industry, and proposed solutions based on the problems existing in the application of Cichorium intybus L. in the food industry, which can provide reference for the development of the Cichorium intybus L. industry.

Animal derived foods are one of the important sources of nutrients for humans. During the breeding process, the rational use of steroid hormones can achieve the goals of promoting growth, weight gain and anti-inflammatory effects, but excessive abuse can lead to serious threats to food safety and consumer health. At present, the detection methods for steroid hormones mainly rely on liquid chromatography, gas chromatography and their combined techniques with mass spectrometry. They also heavily rely on large precision instruments and complex preprocessing, requiring professional laboratories and technical personnel. In recent years, with the rapid development of analytical science and technology, rapid detection technologies for various steroid hormone residues have emerged, providing solid technical support for food safety. This paper presented a comprehensive review of current rapid detection methods for steroid hormones, including electrochemistry, colorimetric methods, fluorescence/phosphorescence methods, Raman spectroscopy and lateral flow immunoassay. It analyzed the advantages and disadvantages of these methods, discussed the challenges they face, and explored their future development directions. This review served as a reference for the design of rapid detection methods for steroid hormone residues in food and provided insights and inspiration for relevant researchers.

Objective To evaluate the residual levels of tolfenpyrad and diafenthiuron in Brassica oleracea and assess the chronic dietary intake risk. Methods Brassica oleracea samples sprayed with 30% diafenthiuron·tolfenpyrad suspension concentrate were collected. The pesticide residues were detected using dispersive solid phase extraction coupled with ultra performance liquid chromatography-triple quadrupole tandem mass spectrometry. Based on the detection results, the chronic dietary intake risk was calculated using a risk probability formula, and a safety assessment was conducted. Results When 30% diafenthiuron·tolfenpyrad suspension concentrate was applied once at the maximum recommended dose of 180 g a.i./hm² with a 7-day pre-harvest interval, the residual concentrations of tolfenpyrad and diafenthiuron in Brassica oleracea were <0.01-0.39 mg/kg and 0.03-0.12 mg/kg, respectively. Both pesticide residues were below China’s maximum residue limits (MRLs) (0.5 mg/kg for tolfenpyrad and 2.0 mg/kg for diafenthiuron). Based on China’s pesticide registration and usage data, the national estimated daily intake of tolfenpyrad and diafenthiuron for the general population was 0.2215 mg and 0.0967 mg, respectively, with risk quotient of 58.6% and 51.2%, both below 100%. This indicated that the dietary intake risk was within an acceptable range. Conclusion When 30% diafenthiuron·tolfenpyrad suspension concentrate is applied at the recommended dose with a 7-day pre-harvest interval for controlling Plutella xylostella in Brassica oleracea, the pesticide residues in harvested Brassica oleracea comply with food safety standards. The long-term dietary intake risk for the general population is controllable, ensuring safe consumption.

As one of the famous teas in China, Pu’er tea has a high reputation at home and abroad. As one of the main active components in tea, tea polyphenols have the effects of lipid-lowering, anti-inflammatory, regulating intestinal microflora, anti-oxidation, anti-cancer, inhibiting viral infection, and anti-bacteria. It has broad application prospects in many fields such as food and medical treatment. With the in-depth development of research and the continuous discovery of new functions of tea polyphenols, it has firmly occupied an important position in contemporary human life in the 21 st century and has attracted the attention of many researchers. In this paper, systematically reviewed the content determination method of tea polyphenols in Pu’er tea and the related research on biological activity in disease prevention and improvement by consulting the relevant literatures published at home and abroad in recent years. The purpose of this review is to provide a scientific basis for the targeted research of tea polyphenols in Pu’er tea, which is conducive to the better use of tea polyphenols in Pu’er tea, so as to provide a positive reference for the innovation and development of Pu’er tea related industries in China.

Objective To gain a more intuitive understanding of the academic context and evolutionary trends of the ion mobility spectrometry applied in the field of food science. Methods This study took the literature from the Web of Science core database over the past 15 years as the research object, and used bibliometric analysis methods to reveal the current status, hotspots and development trends of research in this field. Results Our study had shown that the number of publications on the application of ion mobility spectrometry in food science research is constantly increasing, which involves the interdisciplinary fields such as chemistry, nutrition, biochemistry, agriculture, spectroscopy, environment and pharmacy beyond food science and technology. The number of the China’s publication was far ahead, and its institutions had great international discourse power, but the personal academic influence of Chinese authors still needs to be improved. At present, the main hotspots included the studies on different food qualities and flavors, metabolomics, volatile (organic) compounds and enrichment, optimization of instrument parameters and conditions, statistical methods, sample identification and classification, and multiple instrument combination analysis based on the application of ion mobility spectrometry. The co-occurrence, clustering and emergence analysis of the keywords further reveal the evolution process and mutation situation of research hotspots. Conclusion This study can provide theoretical basis for experts and scholars in the fields of food science and analytical chemistry to grasp the international application status and future development trends of ion mobility spectrometry.

Objective To investigate the effects of varying heat treatment conditions on the texture profile and volatile/non-volatile flavor compound dynamics in fermented milk produced by Lacticaseibacillus paracasei K56. Methods Fermented milk produced by Lacticaseibacillus paracasei K56 was subjected to heat treatment at temperatures ranging from 80 to 121 ℃. The texture, volatile flavor compounds and non-volatile flavor compounds were analyzed using a texture analyzer, headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results Under heat treatment conditions ranging from 80 to 110 ℃, the hardness of fermented milk produced by Lacticaseibacillus paracasei K56 decreased, while cohesiveness, and springiness increased. The optimal textural properties, particularly in terms of cohesiveness and gumminess, were achieved at 110 ℃ for 4 s, exhibiting a hardness of 6.2 g, cohesiveness of 0.18, springiness of 0.708 mm, and gumminess of 4.8 g. The 59 kinds of volatile flavor compounds were detected following heat treatment, with the 90-121 ℃ range significantly enhancing the levels of ketones and alcohols. Odor activity value (OAV) analysis identified esters, ketones and organic acids as the dominant flavor contributors in the fermented milk, with δ-decalactone and isoamyl acetate serving as the key odorants. Among the 652 kinds of non-volatile metabolites analyzed, the heat treatment groups 90 ℃, 15 min and 110 ℃, 4 s, 100 ℃, 15 min and 115 ℃, 4 s exhibited overlapping metabolites. Comparative analysis revealed 12 significantly differentiated indole compounds among the control group and 6 heat-treated samples. Conclusion The textural properties and flavor compounds of fermented milk produced by Lacticaseibacillus paracasei K56 vary significantly under different heat treatments. The treatment at 110 ℃ for 4 s achieves optimal results, enhancing texture and increasing flavor diversity. These findings provide a critical scientific basis for quality enhancement in fermented dairy products.