Objective To explore the effects of different drying methods on the physicochemical characteristics and volatile aroma components of Amomum tsaoko. Methods The fresh fruit of Amomum tsaoko in Nujiang Prefecture was used as the raw material, and 6 kinds of drying methods commonly used in Nujiang Prefecture were used to dry it. The physical and chemical indexes such as color and volatile oil content of Amomum tsaoko were detected, and the volatile aroma components were analyzed by gas chromatography-mass spectrometry (GC-MS). Results The color difference and volatile oil content of Amomum tsaoko dried by different drying methods were significantly different. The L^*, a^* and b^* of Amomum tsaoko dried by air energy heat pump drying and high efficiency electric energy drying were higher, suggesting that the color of Amomum tsaoko was bright brown red and the quality was high. The volatile oil content was (1.04±0.07)-(1.29±0.07) mL/100 g. The volatile oil content of natural sun drying, air energy heat pump drying and high efficiency electric energy drying was relatively high. The composition of volatile aroma substances in Amomum tsaoko dried by different drying methods had both similarities and differences. There were 19 kinds of common substances, and the relative content of most common substances was significantly different. There were 13 kinds of main volatile aroma components (relative content≥3%), and the common components were eucalyptol, trans-nerolidol, P-propylbenzaldehyde and (Z) -citral, and their relative contents had great difference. The relative content of aldehydes and alcohols in the volatile aroma components of Amomum tsaoko was 82.75%-95.69%. The relative content of aldehydes in Amomum tsaoko obtained by biomass hot air drying was the highest, and the alcohols in other drying methods were the highest. Conclusion Therefore, different drying methods have great influence on the physical and chemical characteristics and aroma of Amomum tsaoko. The color of Amomum tsaoko is different, and the aroma and flavor of Amomum tsaoko are significantly different.

Objective To optimize the new product formulations of zero-fat oil vinegar liquid seasoning based on the quantitative descriptive analysis and consumer preference testing. Methods Quantitative descriptive analysis was used to confirm the main attributes of four zero-fat oil vinegar liquid seasonings. The consumer preferences of the overall flavor were evaluated through 9-point hedonic tests. The intensity perception of the attributes of the zero-fat oil vinegar liquid seasoning were evaluated by 5-point just-about-right (5-JAR) method. Results The Luoshenhua flavor performed best for consumer overall likings, followed by the Sichuan style spicy flavor zero-fat oil vinegar liquid seasoning. The fruity flavor and the Japanese style original flavor got the lowest acceptance scores among the four zero-fat oil vinegar liquid seasoning. According to the JAR analysis, the attributes needed to be adjusted such as the strength of the color, aroma, acidity, saltiness, and aftertaste of the Japanese original flavor and fruity flavor zero-fat oil vinegar liquid seasoning samples, and the flavor of Luoshenhua and Sichuan style spicy samples needed to be fine-tuned for individual attributes. Conclusion By utilizing quantitative descriptive analysis and consumer sensory testing, the sensory attributes of products can be combined with consumer preferences, which could effectively reflect the consumer acceptance of each attributes of the product. This provided guidance and reference for new product development and formula adjustment.

Objective To explore the differences in volatile aromatic substances of Marselan wine from the eastern foot of Helan Mountain production area during the aging periods of 0, 3 and 6 months. Methods Comprehensive two-dimensional gas chromatography-time of flight mass spectrometer (GC×GC-TOF MS) was used to detect the volatile aromatic substances in the wine. Key differential volatile substances were screened according to the variable importance in projection (VIP) value and orthogonal partial least squares-discriminant analysis (OPLS-DA). Results The types of volatile aromatic substances during the wine aging period mainly included alcohols, esters, acids, phenols, etc. A total of 1286 kinds of substances were detected in the 3 aging periods. The relatively high contents of volatile aromatic substances were alcohols, esters and hydrocarbons. With the increase of the aging period, the content of esters increased from 16.9% to 27.9%, and the content of hydrocarbons increased from 13.6% to 21.5%, both showing a significant upward trend. However, the content of alcohols decreased from 53.8% to 30.3%, showing a downward trend. Taking VIP≥1.22 and P<0.01 as the indicators, a total of 21 kinds of volatile aromatic substances with important contributions to the wine in different aging periods were determined, which were 2,6,6-trimethylcyclohexadiene-1-methanol, 2-propyl-1-heptanol, heptanal, 4-tert-butylbenzyl alcohol, (S)-1-phenylethanol, diethyl methylsuccinate, isoamyl propionate, acetal, methoxyacetaldehyde, 3-chloro-1-butene, 1,8-cyclopentadeca- 1,3-diyne, β-ionone, linalool, linalyl formate, 2-furanmethanol, rose oxide, hexahydro-1,3,5-trinitro-1,3,5-triazine, 4-ethyl-5- hydroxy-3,5-dimethylfuran-2(5H)-one, 2(5H)-furanone,4,5,5-trimethyl-3-(3-methyl-2-methylidenebutyl), N-methylhexylamine, and dimethyl disulfide. Conclusion This study, by analyzing the volatile aromatic substances in Marselan wine during different aging periods, provides a theoretical basis for the control of the flavor quality during the wineaging period.

Objective To establish a method for the simultaneous detection of multiple amino acids in each part of pork by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Methods The samples were extracted by acidizing high-temperature hydrolysis, acidizing microwave hydrolysis and alkalization high-temperature hydrolysis, determined by HPLC-MS/MS, electrospray ionization in positive ion mode, multiple reaction monitoring (MRM), used formic acid solution-methanol acetonitrile (1:4, V:V) solution of formic acid as mobile phase with gradient elution. Results It was extracted by acidizing microwave hydrolysis with short time and high efficiency. The detection method had a good relationship in the linear range, r² was between 0.9905 and 0.9956, the limits of detection were 0.012-0.133 ng/mL, the limits of quantitation were 0.038-0.444 ng/mL, the average recoveries were in the range 85.58% and 98.84%, the relative standard deviations (RSDs) were 0.68%-6.71%. Conclusion The method has simple process, good repeatability and stability, and can not only be used for simultaneous detection of multiple amino acids in each part of pork to achieve the purpose of high-throughput and rapid detection, but also can effectively monitor the adulteration behavior of pork products.

Objective To use summer Baojing Huangjincha 1 straight black tea, jasmine flowers, and fresh Finger citron peel as raw materials, and the flower and fruit black tea with sweetness, fruitiness and tea flavor is made through processing. Methods In this study, the sensory evaluation of flower tea, high performance liquid chromatography and visible spectrophotometer were used to study the effects of kilning, drying, jacquard and other processes on the formation of the main taste substances and quality of black tea made from flowers and fruits. Results The taste intensity of floral-fruit-scented black tea showed significant differences (P<0.05) across various processing stages. During the scenting→drying→flower removal sequence, the taste characteristics exhibited dynamic evolution: Sourness and bitterness significantly intensified during scenting (P<0.05), while sweetness began transforming during drying and peaked at the flower removal stage. Key findings included: Tea polyphenols showed a “V”-shaped change pattern during processing, while free amino acids and soluble sugars accumulated continuously, enhancing umami and sweetness. Water extracts and flavonoids initially decreased before rebounding. Non-esterified catechins, gallic acid and caffeine decreased significantly in the final product, synergistically reducing astringency and bitterness. Total esterified catechin content decreased by 16.89% during scenting but partially recovered after drying and flower removal. Notably, gallocatechin gallate content increased remarkably by 55%, while epicatechin gallate showed an initial decrease followed by recovery. Sweetness-contributing amino acids (serine, threonine, alanine, proline and glycine) collectively increased by 9.40%, significantly enhancing tea sweetness. Total theaflavin content decreased significantly, with theaflavin-3-gallate, theaflavin-3’-gallate and theaflavin-3,3’-digallate decreasing by 25.69%, 27.28% and 6.02% respectively. Taste activity value analysis revealed decreasing trends for bitterness/astringency-related compounds including caffeine, gallic acid, ECG and catechins Conclusion In this study, the mixture of jasmine flowers and fresh fruit peel of Finger citron and the processing of Baojing Huangjincha 1 straight strip black tea in summer show that the taste of black tea made from flowers and fruits mainly showed the quality characteristics of “sweet and fruity”, and effectively improved the bitterness, astringency and sourness of summer black tea, which provided a theoretical basis for the brewing process of flower and fruit tea.

Objective To understand the overall situation of biogenic amine content in various types of seafoods in Hainan Province, and conduct dietary risk assessment on the detected histamine. Methods A total of 387 batches of seafoods from supermarkets and farmers’ markets in 19 cities and counties of Hainan Province in 2022 were detected for 14 kinds of biogenic amines by ultra performance liquid chromatography-tandem mass spectrometry. Based on the detection results, the dietary exposure risk of the detected histamine was assessed by the hazard quotient (HQ). Results The average content of biogenic amine detected in 387 batches of seafoods were 0.101-55.248 mg/kg, and the maximum value were 2.248-10819.835 mg/kg. The higher levels of several biogenic amines were spermine, spermidine, histamine, putrescine, cadaverine and so on. And two samples detected histamine levels over 200 mg/kg. The dietary risk assessment showed that the estimated daily of histamine in different populations in Hainan Province were 0.00000-0.06690 mg·kg^-1·bw^-1·d^-1, with HQ of 0.00000-0.00134 (HQ<1). Conclusion Biogenic amines are detected in all kinds of seafoods in Hainan Province to varying degrees, but the risk of histamine exposure is low, posing a small threat to human health.

Objective To evaluate the degradation dynamics of the combined use of bifenazate and etoxazole on Vigna unguiculata and assess the dietary exposure risks for different population groups. Methods Bifenazate (sum of bifenazate and bifenazate-diazene) in samples of Vigna unguiculata collected from eight regions of China were detected by liquid chromatography-tandem mass spectrometry. Dietary exposure risk assessment was conducted based on the test results, dietary consumption data and body weight data of different population groups in China. Results The dissipation behaviors of bifenazate in Vigna unguiculata from Shandong, Anhui, Hunan and Guangxi all did not follow first-order kinetics. The dissipation behaviors of etoxazole in Vigna unguiculata from Shandong, Anhui, Hunan, and Guangxi followed first-order kinetics, and their half-lives were 1.93-2.54 d. Using a suspension concentrate containing 45% bifenazate and etoxazole with 8 mL formulation per mu (Chinese acre) to control red mites on Vigna unguiculata, spraying once, at the harvest interval of 10 d, terminal concentrations of bifenazate and etoxazole in Vigna unguiculata were <0.0100 mg/kg and <0.0020-0.0042 mg/kg, respectively. The contribution rate of the long-term dietary exposure risk of these 2 kinds of pesticides were all lower than 100% for different population groups, indicating that there was no unacceptable risk. Conclusion 45% bifenazate·etoxazole suspension concentrate is applied at a dosage of 8 mL per mu for controlling spider mites on Vigna unguiculata, with one spray application and a recommended pre-harvest interval of 10 days.

Objective To screen lactic acid bacteria from Viili fermented milk and explore the proportion of bacteria in the compound starter cultures. Methods Lactic acid bacteria were isolated using streak plating, and their taxonomic classification was determined through phylogenetic analysis based on 16S rRNA sequences. The composition of strain ratios in mixed cultures was designed with reference to the bacterial abundance observed in Viili fermented milk. Comprehensive analyses were performed to evaluate the acidity, exopolysaccharide production, textural properties and volatile flavor compounds of the mixed fermentation groups. Results Diversity analysis identified 4 bacterial genera, among which Lactococcus, Streptococcus and Leuconostoc were the dominant genera, comprising 49.12%, 40.67% and 10.21% of the total bacterial composition, respectively. Lactococcus lactis H2, Streptococcus thermophilus H17, Leuconostoc mesenteroides H30 and Lactobacillus paracasei H33 were isolated and screened. A total of 20 fermentation trials with different strain compositions were designed to conduct a comprehensive assessment of key parameters, including pH, coagulation time, textural properties, exopolysaccharide content and flavor profile. The results indicated that formulations S13 (H2:H17:H30:H33=11:4:4:1) and S17 (H2:H17:H30:H33=30:35:16:19) demonstrated the highest similarity to Viili fermented milk in terms of physicochemical and sensory properties. Conclusion The blended formulations S13 (H2:H17:H30:H33=11:4:4:1) and S17 (H2:H17:H30:H33=30:35:16:19) exhibit promising potential as compound starter cultures. This study provides a theoretical basis for developing compound starter cultures in Viili fermented milk production.

Objective To establish a rapid analysis method based on solid phase extraction-high performance liquid chromatography-evaporative light scattering detection (SPE-HPLC-ELSD) for determining the γ-aminobutyric acid (GABA) content in edible enzymes from medicinal and edible homologous sources. Methods Fermented panacis quinquefolii radix liquid was selected as a representative sample. After centrifugation (8000 r/min, 10 min) and ultrasonic extraction (10 min, 25 ℃), 3 kinds of different sample pretreatment methods—non-purification, dispersive solid phase extraction purification, and hydrophilic-lipophilic balance (HLB)-based solid phase extraction purification were compared and optimized. An optimized HPLC-ELSD instrumental method was developed to achieve accurate content determination. The method was then applied to determine the GABA content in other medicinal and edible homologous enzyme products. Results GABA was determined by optimized SPE-HPLC-ELSD. GABA showed a good linear relationship (r=0.999) in the mass concentration range of 50-2000 μg/mL. The recovery rate ranged from 85.93% to 96.30%, with a repeatability relative standard deviation of 0.87% (n=6). Conclusion This method is efficient and accurate, suitable for the quantitative analysis of GABA in various medicinal and edible homologous enzymes. It also provides a new approach and reference for GABA determination in complex matrices and for detecting small molecules with strong polarity and low ultraviolet absorption.

Objective To analyze the status of foodborne pathogenic bacteria contamination in meat and meat products in Yantai City, Shandong Province from 2020 to 2023, and understand the safety of related food in the city. Methods According to national food safety standard Food microbiological examination GB 4789 series standards and the requirements of Shandong food pollutants and harmful factors risk monitoring manual, 6 kinds of foodborne pathogens were detected from meat and meat products, including Salmonella, Listeria monocytogenes, Yersinia enterocolitica, Campylobacter, Diarrheagenic Escherichia coli and Staphylococcus aureus. Results The 5 kinds of foodborne pathogens and 46 positive strains were detected in 363 samples, with the total detection rate of 12.67%. The highest detection rate was Salmonella (10.48%), followed by Campylobacter (1.97%) and Staphylococcus aureus (1.33%), and no Diarrheagenic Escherichia coli was detected. Among the 4 types of samples, the highest detection rate was in raw poultry meat (26.67%) and the lowest was in cooked meat products (2.35%). The detection rate of Salmonella in prepared meat products reached 20.00%. The detection rates of pathogenic bacteria in the samples collected by farmers’ markets and online stores were relatively high (19.53%, 22.22%). Salmonella had the highest probability of causing illness in the third quarter. Conclusion Meat and meat products in Yantai City are contaminated by foodborne pathogens to various degrees, so it is necessary to focus on raw poultry meat and bulk prepared meat products, especially those originating from farmers’ markets and online stores, and it is important to strengthen the relevant circulation supervision, enhance food safety awareness and take measures to reduce the risk of cross-contamination during the sale of bulk meat products, so as to ensure food safety for consumers.