石墨炉原子吸收法测定豆豉中铅和镉

豆豉样品经微波消解后,采用石墨炉原子吸收光谱法快速测定铅、镉。实验优化了石墨炉原子吸收光谱法的测定条件。以磷酸为基体改进剂可提高灰化温度,消除样品中的氯化钠等复杂基体的干扰。该法铅、镉的回收率分别为95.0％、94.6％,精密度（RSD）分别为8.7％和5.1％。结果表明豆豉中铅、镉含量较低。本方法简便、快速、准确,适合于实际的分析工作。     

直接电导检测-离子排斥色谱法测定芳香族羧酸

研究了直接电导检测-离子排斥色谱法分离测定芳香族羧酸(邻苯二甲酸、水杨酸、苯乙酸、对羟基苯甲酸、苯甲酸和邻甲苯甲酸)。以Shim-packSCR-102H色谱柱为分离柱,H2SO4为流动相,考察了流动相浓度、色谱柱温度、流速对分离和测定芳香族羧酸的影响,确定最佳色谱条件为:0.08mmol/LH2SO4作为流动相,柱温45℃,流速1.2mL/min。所测芳香族羧酸的检出限为0.07～0.98mg/L;相对标准偏差在2.6%以下(n=5);回收率为95.8%～100.1%。本方法用于酱油样品的分析,得到满意结果。     

酿造酱油、配制酱油及酿造食醋、配制食醋的鉴别

乙酰丙酸是配制酱油的特有成分，在硫酸溶液中，乙酰丙酸可与香草醛反应而呈现蓝绿色。掺有尿素的酱油在与丁二酮肟、磷酸混合后，加热煮沸会呈现红色。用酱色、食盐等配制的劣质酱油可用测定氨基酸态氮和酱色含量的方法进行鉴别。酿造食醋和配制食醋的常用鉴别方法是碘液法和高锰酸钾法。     

Effective extraction and simultaneous determination of Sudan dyes from tomato sauce and chili‐containing foods using magnetite/reduced graphene oxide nanoparticles coupled with high‐performance liquid chromatography

A simple, effective, and robust magnetic solid‐phase extraction method was developed using magnetite/reduced graphene oxide nanoparticles as the adsorbent for the simultaneous determination of Sudan dyes (I, II, III, and IV) in foodstuffs. The magnetite/reduced graphene oxide nanoparticles were characterized by X‐ray diffraction, scanning electron microscopy, and vibrating sample magnetometry. The extraction parameters including extraction time, elution solution, and elution time and volume were investigated in detail. Such magnetite/reduced graphene oxide nanoparticles based magnetic solid‐phase extraction in combination with high‐performance liquid chromatography and variable wavelength detection gave the detection limits of 3–6 μg/kg for Sudan I–IV in chili sauce, tomato sauce, chili powder, and chili flake samples. The recoveries were 79.6–108% at three spiked levels with the intra‐ and inter‐day relative standard deviations of 1.2–8.6 and 4.5–9.6%, respectively. The feasibility was further performed by a comparison with commercial alumina‐N. This method is suitable for the routine analysis of Sudan dyes due to its sensitivity, simplicity, and low cost.     

石墨炉原子吸收光谱法测定新疆出口番茄酱中的铅和镉

报道了微波消解石墨炉原子吸收光谱法测定番茄酱中的铅、镉。研究了石墨炉原子吸收测定的最佳条件。该方法测定铅和镉的线性范围分别为0.00~25 ng/mL、0.00~8 ng/mL;相对标准偏差分别为2.15%、3.10%;回收率分别为98.6%、104.5%。利用国家标准物质番茄叶(ESP-1)验证了方法的准确度,测定值与标准值基本吻合。研究表明,该方法具有很好的准确度和精密度。     

Compositions for health products obtained by treatment of tomato with beta-cyclodextrin

The aim of this work was to produce lycopene-containing powders from tomato products by a solvent-free method making use of β-cyclodextrin (βCD). Powders were prepared by spray-drying a tomato concentrate (TC), one of the most bioavailable form of lycopene, after mechanical treatment with βCD in different weight ratios. The obtained product was centrifuged to eliminate partly food matrix and characterized for the amount of lycopene hydrodispersed/hydrosolubilized in the aqueous fraction. The chemical antioxidant activity of sera was evaluated too. Powders obtained by spray-drying sera exhibited good flow properties, a lycopene content between 0.4 and 1.09 mg/g and excellent water dispersability. The process developed, which makes use of βCD for the treatment of tomato products, turns to be of great interest to obtain a bulk material for nutraceuticals displaying superior biovailability of lycopene.     

Changes of antioxidative enzymes and cell membrane osmosis in tomato colonized by arbuscular Mycorrhizae under NaCl stress

Salinity toxicity is a worldwide agricultural and eco-environmental problem. Many literatures show that arbuscular mycorrhizal fungi (AMF) can enhance salt tolerance of many plants and some physiological changes occurred in AM symbiosis under salt stress. However, the role of ROS-scavenging enzymes in AM tomato is still unknown in continuous salt stress. This study investigated the effect of Glomus mosseae on tomato growth, cell membrane osmosis and examined the antioxidants (superoxide-dismutase, SOD; catalase, CAT; ascorbate peroxidase, APX; peroxidase, POD) responses in roots of mycorrhizal tomato and control under different NaCl stress for 40 days in potted culture. NaCl solution (0, 0.5 and 1%) was added to organic soil in the irrigation water after 45 days inoculated by AMF (Glomus mosseae). (1) AMF inoculation improved tomato growth under salt or saltless condition and reduced cell membrane osmosis, MDA (malonaldehyde) content in salinity. So the salt tolerance of tomato was enhanced by AMF; (2) SOD, APX and POD activity in roots of AM symbiosis were significantly higher than corresponding non-AM plants in salinity or saltless condition. However, CAT activity was transiently induced by AMF and then suppressed to a level similar with non-AM seedlings; (3) higher salinity (1% level) and long stress time suppressed the effect of AMF on SOD, APX, POD and CAT activity; (4) this research suggested that the enhanced salt tolerance in AM symbiosis was mainly related with the elevated SOD, POD and APX activity by AMF which degraded more reactive oxygen species and so alleviated the cell membrane damages under salt stress. Whereas, the elevated SOD, POD and APX activity due to AMF depended on salinity environment.     

微波消解凯氏定氮法快速测定酱油中全氮

研究了凯氏定氮法测定酱油中全氮时样品的微波消解方法,进行了微波消解条件的选择及消解结果精密度试验,并与国家标准方法对比,验证了方法的准确度。试验结果表明,消解完全仪需20min,相对标准偏差均小于2%（n=7）,回收率范围为96%～103%,经t检验,微波溶样法与国家标准凯氏定氮法的测定结果无显著性差异。     

Effect of plasma-activated water and buffer solution combined with ultrasound on fungicide degradation and quality of cherry tomato during storage

The purpose of this study was to examine plasma-activated buffer solution (PABS) and plasma-activated water (PAW) combined with ultrasonication (U) treatment on the reduction of chlorothalonil fungicide and the quality of tomato fruits during storage. To obtain PAW and PABS, an atmospheric air plasma jet was used to treat buffer solution and deionized water at different treatment times (5 and 10 min). For combined treatments, fruits were submerged in PAW and PABS, then sonicated for 15 min, and individual treatment without sonication. As per the results, the maximum chlorothalonil reduction of 89.29% was detected in PAW-U₁₀, followed by 85.43% in PABS. At the end of the storage period, the maximum reduction of 97.25% was recorded in PAW-U₁₀, followed by 93.14% in PABS-U₁₀. PAW, PABS, and both combined with ultrasound did not significantly affect the overall tomato fruit quality in the storage period. Our results revealed that PAW combined with sonication had a significant impact on post-harvest agrochemical degradation and retention of tomato quality than PABS. Conclusively, the integrated hurdle technologies effectively reduce agrochemical residues, which helps to lower health hazards and foodborne illnesses.     

Discoloration Investigations of Yellow Lantern Pepper Sauce (Capsicum chinense Jacq.) Fermented by Lactobacillus plantarum: Effect of Carotenoids and Physiochemical Indices

Color is one of the important indicators affecting the quality of fermented pepper sauces, and it is closely related to carotenoid composition. This study systematically analyzed the changes in carotenoids and related physiochemical indices during the fermentation of yellow lantern pepper sauce. The CIELab color values indicated that L* and C* displayed a significant decreasing trend during fermentation. After 35 days of fermentation, the total carotenoid content significantly reduced from 3446.36 to 1556.50 μg/g DW (p < 0.05), and the degradation rate was 54.84%. Among them, the total content of carotene decreased by 56.03% during fermentation, whereas the degradation rate of xanthophylls and their esters was 44.47%. According to correlation analysis, violaxanthin myristate and lutein played a pivotal role in L*, a *, b *, chroma (C*), and yellowness index (YI). Moreover, PCA analysis indicated that lactic acid and acetic acid were the important qualities affecting the stability of pigment in fermented yellow lantern pepper sauce, which might also be the inducement of the color change. This work gives additional information concerning the discoloration of yellow lantern pepper sauce during fermentation and provides theory evidence regulating and improving the sensory qualities of yellow lantern pepper sauce.