Objective To establish an analytical method for determining γ-amino butyric acid content in foods of plant origin by high performance liquid chromatography. Method Foods samples were pre-column derivatized with 4-dimethylamino-azobenzene 4-sulfonyl chloride, orthogonal experiments were designed and methodological verification was carried out based on extraction solvent, solid-liquid ratio, extraction method and extraction time. The results of γ-amino butyric acid were analyzed by detecting different plant-derived foods and comparing with instruments. Results The results showed that the optimal conditions were determined as 60% ethanol solution, which was extracted by water bath (40 ℃) or ultrasonic for 30 min at 1:25 (g:mL) solid-liquid ratio. The separation of γ-amino butyric acid was achieved on C₁₈ column (250 mm×4.6 mm, 5 μm) using acetonitrile+sodium acetate solution (20:80, V:V) as the mobile phase at a flow rate of 1.0 mL/min. The absorption wavelength of γ-amino butyric acid was 436 nm and column temperature was set at 30 ℃, respectively. The linear range of γ-amino butyric acid was 1.092-131.064 μg/mL. The relative standard deviation of γ-amino butyric acid was all less than 5.0% in pitaya (white heart), tomato, and malt. The average recovery rate of γ-amino butyric acid was between 95.80%-104.36%, indicating that the method had good precisions and high recoveries. Conclusion The method established in this study has good repeatability and high accuracy, and can accurately quantify the content of γ-amino butyric acid in foods of plant origin.

Objective To screen the crop varieties with low accumulation of heavy metal Cd suitable for cultivation in Qinghai and evaluate of their agricultural product safety. Methods Through field experiments, 9 crops, including barley, oilseed rape and broad bean, were planted in heavy metal-contaminated arable land in a field trial to analyze the Cd content in the roots, plants, seeds and corresponding soils of different crops. Cd content of different crop samples was measured by inductively coupled plasma atomic emission spectrometer (ICP-OES) after digestion in a graphite furnace. The enrichment capacity of each tissue and organ of the crop was analyzed by the enrichment coefficient method, and the non-carcinogenic health risk of Cd in crop seeds was evaluated by the target hazard quotient (THQ) method. Results The soil Cd content of barley and wheat exceeded the standard, but the seed Cd content of all crops met the national standard; the Cd enrichment capacity of wheat roots and plants was lower than that of the other crops, and the lowest soil Cd enrichment capacity of crop seeds was found in oats and wheat; there was no health risk for adults due to the intake of Cd from the edible parts of the 6 kinds of crops, and there was a health risk for children due to the intake of Cd from the edible parts of barley and potatoes. Conclusion Oilseed rape and oats is a kind of Cd low-accumulating crop suitable for local cultivation, which can ensure the safe utilization of local farmland. Therefore, this study can provide a scientific basis for screening crop varieties with low Cd accumulation and applying them on a large scale to polluted croplands in Qinghai.

Extruded rice noodles are made from rice as raw material, ground and blended to a certain moisture content, extruded and matured, and dried. The traditional production process of rice noodles is laborious and time-consuming, which lead to uneven product quality during the multi-step rice noodle production process. By comparison, extrusion technology is a food processing technique that integrates mixing, heating, sterilization, and shaping. Applying extrusion technology to rice noodle processing has the advantages of less loss of nutrients, fewer opportunities for microbial contamination, shorter production time, higher production efficiency, and easier operation. Therefore, in the production of rice noodle processing industry in China, automated mechanical processing is gradually replacing traditional manual workshops. The quality of extruded rice noodles is mainly affected by the raw materials, processing technology, and extrusion parameters during the production process of extruded rice noodles. Therefore, this paper elaborated on the processing technology and forming mechanism of extruded rice noodles, summarized the influence of raw materials and extrusion parameters on the quality of extruded rice noodles, in order to provide theoretical basis for the control of the processing technology and key points of extruded rice noodles.

Objective To establish a rapid identification model for 5 different types of vegetable oils (Camellia oil, soybean oil, corn oil, sunflower seed oil and peanut oil) and adulterated Camellia oil, using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and chemometrics methods such as cluster discriminant analysis. Methods The 99 samples of 5 different types of vegetable oils, including Camellia oil, soybean oil, corn oil, sunflower seed oil, and peanut oil were collected. According to the mass percentage of 5%-95%, soybean oil, sunflower seed oil, corn oil, 1:1 corn soybean oil, and palm oil was mixed into the Camellia oil, and 196 samples of the adulterated Camellia oil were obtained. Their infrared spectrum were collected in 600‒4000 cm^‒1 region. The models for partial least squares discriminant analysis (PLS-DA), principal component analysis discriminant analysis (PCA-LDA), K-nearest neighbor (KNN), and data driven soft independent modeling of class analogy (DD-SIMCA) were established and compared to determine the optimal recognition model. Results The infrared spectra of each sample group had similar characteristic peaks, peak positions, and peak shapeswere with slight differences. The discriminant model established by DD-SIMCA could completely separate Camellia oil samples from those of other types of vegetable oil. By comparison of PLS-DA, PCA-LDA, and KNN models, it was found that the predicted values of each sample in the training and testing sets of the classification of 5 types of edible vegetable oils samples using PLS-DA and PCA-LDA models were accurate and reliable. Except for peanut oil, the recognition and prediction accuracy of the training and testing sets of other edible vegetable oils were both 100.0%. The quantitative analysis of Camellia oil adulteration using ATR-FTIR combined with PLS could be accurately carried out, which could be used for qualitative and quantitative analysis of adulterated soybean oil, corn oil, sunflower seed oil, etc. The results were reliable, and the lowest limit of detection could reach 5%. Conclusion Adulterated Camellia oil can be determined accurately and efficiently based on ATR-FTIR combined with chemometric methods.

Objective To assess the dietary exposure risk of fenthion in Vigna unguiculata among Shanghai residents from 2021 to 2023. Methods The primary method employed was the chronic risk quotient assessment. The measured exposure concentrations of fenthion in Vigna unguiculata were used to characterize the risk, with the chronic risk evaluated based on the risk quotient values. Results From 2021 to 2023, a total of 2301 Vigna unguiculata samples from Shanghai markets were tested, with an overall detection rate of fenthion at 3.00% and a non-compliance rate of 2.3%. The average fenthion concentration was 1.23×10^-2 mg/kg, with a maximum value of 4.45 mg/kg. Analysis by different months showed that in February each year, the non-compliance rate and average detection value of fenthion in Vigna unguiculata were the highest, at 18.9% and 0.12 mg/kg, respectively. Analysis by different sampling locations indicated that Vigna unguiculata sold online had the highest detection and non-compliance rates. The average daily dietary exposure of Shanghai residents was 5.88×10^-6 mg/(kg·bw) with a P₉₅ exposure of 3.05×10^-5 mg/(kg·bw). The average risk quotient was 8.40×10^-4, with a P₉₅ of 4.36×10^-3. Conclusion The risk quotient for different population groups in Shanghai from 2021 to 2023 is far below 1, indicating that the health risk from fenthion exposure through Vigna unguiculata consumption is low for Shanghai residents.

Objective To establish a solution for fungal culturomics in food by comparing the performance of 3 fungal culture media and optimising fungal culturomics techniques. Methods The 24 food samples and 2 proficiency test samples were tested using commonly used fungal culture media for food testing, including potato dextrose agar (PDA), rose Bengal agar, and a novel Pan Fungi medium (PF). The cultured fungi were isolated and identified using matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Results Yeast phase fungi could grow well on all 3 kinds of media, and the colony growth rate, colony morphology size and colony numbers had no significant difference. Filamentous fungi were able to grow well on the 3 kinds of medias, but growth rate and colony morphology were significantly different. There were 12 kinds of fungal species identified in the 24 samples, including 2 kinds of yeast phase fungi and 10 kinds of filamentous fungi. Conclusion With excellent accuracy and stability and self-limited growth of cultured colonies, PF fungal medium is favourable for isolation and identification of single colonies, and can be used as a supplement to the commonly used fungal medium for fungal culturomics studies in food.

Hydroxycinnamic acid is a type of natural phenolic acid with cinnamic acid as the basic chemical structure and extensively distributed in plants. It has a variety of biological activities, including antioxidant, anti-inflammatory, anti-cancer, regulation of blood sugar and lipid levels, while also having the functions of adjusting food flavor, food preservation, inhibiting bacteria, anti-corrosion, and preventing the degradation of other bioactive compounds in food. Therefore, it is used in the food industry as a flavoring agent, preservative, antimicrobial agent, and nutrient supplement, etc. This article reviewed the recent years research achievements of hydroxycinnamic acid compounds including extraction methods, biological functions, and applications, with the aim of providing reference and basis for further developing relevant products and expanding the application scope of hydroxycinnamic acid compounds.

Bamboo shoot shells, which constitute approximately 60% of the total mass of the bamboo shoot, represent a significant byproduct of bamboo shoot processing. Currently, issues such as low utilization rates and resource wastage persist. To enhance the comprehensive utilization of bamboo shoot shells, this study summarized the key nutrients (including cellulose, hemicellulose, lignin) and active compounds (including flavonoids, polyphenols, sterols, and polysaccharides) found in bamboo shoot shells, based on a review of both domestic and international literature. Additionally, it outlined the extraction and processing technologies for these active substances, highlighting their respective advantages and disadvantages. It also discussed the development and utilization prospects of bamboo shoot shells in various fields such as food, textiles, edible fungus cultivation, animal feed, and liquid fuel. Furthermore, it provided insights into future development directions of the processing and utilization of bamboo shoot shells, aiming to serve as a reference for enhancing the added value and effective utilization of bamboo shoot shells.

Objective To achieve rapid and non-destructive detection of lactic acid and total acidity during the fermentation process of sour meat. Methods Utilizing hyperspectral imaging technology, spectral reflectance images in the range of 408 to 1049 nm were collected to obtain spectral information of sour meat at different fermentation stages. After extracting the reflectance spectra from the regions of interest in the images, the kennard-stone algorithm (KS) was employed to divide the data into training and testing sets. The raw data underwent preprocessing through standard normal variate transformation (SNV) and multivariate scatter correction (MSC), followed by model establishment using partial least squares regression (PLSR). Feature wavelengths were extracted using the successive projection algorithm (SPA), competitive adaptive reweighted sampling (CARS), and uninformative variable elimination (UVE). Models were developed based on PLSR and compared with full-wavelength prediction models. Results The optimal prediction model for lactic acid in sour meat was SNV-CARS-PLSR, with a coefficient of determination (R²) of 0.9113 and a root mean square error of cross-validation (RMSECV) of 0.7236 for the training set, while the testing set yielded an R² of 0.9104 and RMSECV of 0.7342. The MSC-CARS-PLSR model for total acidity demonstrated the best predictive performance, with training set R² and RMSECV values of 0.9307 and 0.6782, respectively, and prediction set R² and RMSECV values of 0.8682 and 0.6907. Conclusion The models constructed using hyperspectral imaging technology have the potential to enable rapid and non-destructive detection of lactic acid and total acidity in sour meat, indicating significant application value.

Objective To optimize the production process of casein peptone with yak milk casein as raw material. Methods The combination of alkaline protease and trypsin was used to hydrolyze yak milk casein. On the basis of single factor experiment, according to the principle of Box-Behnken central combination test design, the response surface analysis method of four factors and three levels was adopted, and the degree of hydrolysis was used as the response value. The response surface and contour line were used to obtain the optimal process conditions for the hydrolysis of yak milk casein by the combined enzyme, and then the yak milk casein peptone product was obtained by acid precipitation, neutralization and finally spray drying. Results The results of single factor showed that the degree of hydrolysis of casein increased with the increase of enzyme concentration. When the amount of enzyme added was higher than 2.5%, the degree of hydrolysis increased slowly. With the increase of temperature and pH, the degree of hydrolysis increased first and then decreased. The degree of hydrolysis of yak milk casein reached the maximum when the substrate concentration was 5%, and the substrate concentration would hinder the effect of the enzyme on the cutting site, resulting in a decrease in protein conversion. The results of response surface showed that the degree of hydrolysis was the best when the amount of combined enzyme was 2.6% (alkaline protease:trypsin=4:1), the hydrolysis time was 160 min, the hydrolysis pH was 7.0, the substrate concentration was 5%, and the hydrolysis temperature was 55 °C, which was 23.63%. Conclusion This study optimize the production process of peptone from yak milk casein, and provided support for the further development and utilization of yak milk casein.