常见干豆类及豆制品中嘌呤含量研究

目的:检测常见干豆类及豆制品中的嘌呤含量,为高尿酸血症与痛风患者健康膳食提供指导。方法:采用高效液相色谱法测定嘌呤含量,色谱柱选用Waters Atlantis T3柱(4.6mm×250mm×5μm),流动相为10.0mmol/L甲酸铵(pH3.6)和甲醇(99%∶1%),流速1.0mL/min,柱温30℃,检测波长254nm。结果:不同种类干豆及豆制品中嘌呤含量具有显著差异,干豆类中嘌呤含量显著高于豆制品;干豆类中,蚕豆最高。豆制品中,豆粉最高。结论:不同种类干豆及豆制品中嘌呤含量有差别;干豆类普遍高于豆类制品。     

高效液相色谱-质谱联用测定婴幼儿配方食品中叶酸的含量

建立了婴幼儿配方食品中叶酸含量的高效液相色谱-质谱联用测定方法。采用C18色谱柱(4.6mm×250mm,5μm)进行分离,以5 mmol/L乙酸铵(含0.1%甲酸)溶液-甲醇为流动相梯度洗脱,柱温25℃,流速1.0 mL/min,进样量20μL,柱后分流比为1∶3,质谱采用多离子反应监测(MRM)方式进行检测,正离子模式,定量离子为m/z442.0→295.2。叶酸在0.001~2.500μg/mL的范围内线性关系良好(r=0.9989),该方法相对标准偏差(RSD)为2.6%~6.0%,回收率为83.9%~104.0%,检出限(S/N=3)和定量限(S/N=10)分别为1.0 ng/mL、3.3 ng/mL。该方法操作简便、灵敏度高、重复性好,可用于婴幼儿配方食品中叶酸的测定。     

UPLC-MS/MS检测柑桔不同组织中的柠檬苦素

目的:检测柑桔果皮、果肉、桔络以及桔籽中柠檬苦素的含量,分析柑桔加工中苦味物质的来源。方法:用UPLC-MS/MS法检测,色谱柱:waters ACQUITY BEH C18(50mm×2.5mm,1.9μm);流动相:A为乙腈,B为纯水,采用梯度洗脱:A:10%(0min)-50%(3min)-10%(4min)-10%(5min);流速:0.3mL/min;柱温:40℃;进样量:5μL;检测时间:5min;正离子模式(ESI+)质谱检测器:柠檬苦素母离子m/z=471.1,子离子m/z=425.3,m/z=161.1。结果:在检测色谱-质谱条件下柠檬苦素检测效果良好,柑桔中柠檬苦素含量依次为:桔籽桔络桔皮桔肉。结论:柑桔加工中尽量选用无籽品种,采用手工剥皮,同时剔除桔络能有效地避免产品的苦味。     

HPLC法同时测定旱芹中木犀草素和旱芹素的含量

建立HPLC法同时测定旱芹中木犀草素和旱芹素含量的方法。采用C1(8 150 mm×4.6 mm,5μm)柱,流动相为乙腈∶0.01 mol/L醋酸铵(pH=4.8)=40∶60,等强度洗脱,检测波长330 nm,柱温25℃,流速1.0 mL/min。木犀草素和旱芹素的质量浓度分别在0.93μg/mL~4.94μg/mL(r=0.999 1)及1.03μg/mL~5.06μg/mL(r=0.999 4)范围内与峰面积呈现良好的线性关系,平均加样回收率依次为99.7%(RSD为2.4%),99.0%(RSD为1.8%)。     

UPLC-MS/MS分析橘汁发酵液中柠檬苦素的变化趋势

目的:利用超高效液相色谱-质谱检测柑橘果酒发酵工艺中橘汁发酵液的柠檬苦素,分析橘子发酵加工产品中苦味变化趋势。方法:色谱柱Waters ACQUITY BEH C18(50mm×2.5mm,1.9μm);流动相:A为乙腈,B为纯水,A梯度为0～3min(10%～50%),3～4min(50%～10%),4～5min(10%～10%);流速:0.3mL/min;柱温:40℃;进样量:5μL;检测时间:5min;正离子模式质谱检测器:柠檬苦素母离子m/z 471.1,子离子m/z 425.3、161.1。结果:该条件下柠檬苦素检测效果良好,发酵液中柠檬苦素含量随发酵时间变化而变化,保藏时间越长,柠檬苦素含量越低。结论:通过延长橘汁发酵液的贮存时间有利于苦味物质的脱除。     

方便面中丙烯酰胺含量的检测

建立了方便面中丙烯酰胺的液相色谱-串联质谱分析方法.样品用水提取,酶解,净化.以水(0.1%甲酸):乙腈=90:10(V/V)为流动相经反相色谱柱分离后,采用液相色谱串联质谱多反应监测正离子模式检测,丙烯酰胺定性定量离子对为m/z72.10/55.00,同位素内标物定性定量离子对为75.00/58.00.空白样品及其添加实验结果表明,特征离子相对强度比值稳定,无基质干扰,结合保留时间可实现准确的定性定量,方法检出限为25μg/kg(S/N=3),样本添咖水平在5～200μg/kg时,平均回收率为68.1～90.1%,相对偏差(n=6)为4.3%～6.1%.该方法前处理简单、回收率高、精密度好,可满足方便面中丙烯酰胺的确证分析要求.     

HPLC法测定9种金银花凉茶饮料中绿原酸的含量

研究了高效液相色谱法(HPLC法)检测金银花凉茶饮料中绿原酸含量的方法。采用C18柱(4.6 mm×250 mm,5μm),在检测波长327 nm、流动相乙腈-0.4%磷酸溶液(12:88)、流速1 m L/min、进样量20μL、柱温30℃的色谱条件下进行试验研究。结果表明:金银花凉茶饮料中的绿原酸含量在0.4~102μg/m L范围内线性关系良好(r=0.9999),平均回收率为99.87%,RSD=1.44%(n=9),所建立的方法精密度、稳定性、重复性和准确度均良好,可用于金银花凉茶饮料中绿原酸含量的测定。     

HPLC法测定矮地茶中岩白菜素的含量

建立了矮地茶中岩白菜素的含量测定方法。以岩白菜素作为测量指标,采用高效液相色谱法(HPLC法),Venusil XBP-C18色谱柱(φ4.6×250 mm,5μm),以V(甲醇)∶V(水)=70∶30为流动相,流速为1.0 mL/min,检测波长为275 nm,柱温为室温。结果表明:岩白菜素在0.56μg到2.80μg范围内线性关系良好,平均回收率为99.39%(n=5),RSD=1.56%。说明该方法简便、快捷,可用于矮地茶的质量控制。     

反相高效液相色谱法测定保健食品中阿魏酸的含量

目的建立保健食品中阿魏酸的反相高效液相色谱法测定方法。方法采用反相高效液相色谱法,色谱柱:AichromBond-1 C184.6 mm×150 mm,5μm,流动相:乙睛∶0.085%磷酸水溶液=20∶80检测波长320 nm,流速1.0ml/min,柱箱温度30℃。结果阿魏酸在1.0～10.0μg/ml范围内呈好的线性关系(r=0.999 8),平均回收率为90.3%～94.2%,相对标准偏差分别为6.00%～7.51%。结论该方法简便,准确,能够满足保健食品中阿魏酸含量的检测要求。     

SPE-HPLC法测定橄榄油中角鲨烯的含量

该文建立了固相萃取(SPE)——高效液相色谱(HPLC)测定橄榄油中角鲨烯含量的方法。采用硅胶固相萃取小柱提取净化样品。色谱柱:Inertsil ODS–SP–C18(150 mm×4.6 mm,5μm),流动相为乙腈∶四氢呋喃=90∶10,流速1.2 m L/min,检测波长208 nm,柱温35℃。本方法的最低检测浓度为0.02 mg/g。标准曲线在20~500μg/m L范围内线性良好,相关系数R2=0.999 9。角鲨烯的平均回收率为92.2%,相对标准偏差(RSD)为1.47%(N=5),是一种快速、简便、准确、重复性好的检测橄榄油中角鲨烯含量的方法。     

A method for the determination of acrylamide in a broad variety of processed foods by GC-MS using xanthydrol derivatization

A novel GC-MS method was developed for the determination of acrylamide, which is applicable to a variety of processed foods, including potato snacks, corn snacks, biscuits, instant noodles, coffee, soy sauces and miso (fermented soy bean paste). The method involves the derivatization of acrylamide with xanthydrol instead of a bromine compound. Isotopically labelled acrylamide (d?-acrylamide) was used as the internal standard. The aqueous extract from samples was purified using Sep-Pak? C?? and Sep-Pak? AC-2 columns. For amino acid-rich samples, such as miso or soy sauce, an Extrelut? column was used for purification or extraction. After reaction with xanthydrol, the resultant N-xanthyl acrylamide was determined by GC-MS. The method was validated for various food matrices and showed good linearity, precision and trueness. The limit of detection and limit of quantification ranged 0.5-5 and 5-20?μg?kg?1), respectively. The developed method was applied as an exploratory survey of acrylamide in Japanese foods and the method was shown to be applicable for all samples tested.     

UPLC-MS/MS法快速测定乳酸菌发酵食品中的苯乳酸

建立一种超高效液相色谱-串联质谱(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)快速测定发酵食品中苯乳酸的方法,并利用此方法对45种乳酸菌发酵食品中苯乳酸的含量进行测定。样品经甲醇提取,采用UPLC-MS/MS法,色谱柱为Shim-pack XR-ODS C₁₈(3.0 mm×75.0 mm,2.2μm),流动相为0.3%甲酸-水和0.3%甲酸-乙腈,梯度洗脱,流速为0.4 mL/min。苯乳酸在1~500 ng/mL范围内线性关系良好(R²=0.9999),检出限和定量限分别为0.3和1 ng/mL,回收率为90.5%~105.0%,相对标准偏差为1.2%~4.4%。采用此方法对16种市售乳酸菌饮料、8种发酵乳、11种黄酒样品、发酵豆制品、米酒、奶酪、发酵香肠、馒头、面包等食品中苯乳酸的含量进行测定,结果显示所有样品中均含有苯乳酸。该研究所建立的方法前处理简单、分析时间短、灵敏度高、准确性好,适用于发酵食品中苯乳酸的测定。可以为高产苯乳酸菌株资源的挖掘以及发酵食品品质与营养功能的进一步研究提供科学依据。     

贵州主要发酵豆制品加工中丙烯酰胺形成动态

以水豆豉、黑豆豉、豆瓣酱及腐乳等贵州主要发酵豆制品为试材,采用高效液相色谱-串联质谱（HPLC-MS/MS）方法,测定其各生产阶段的丙烯酰胺含量。结果表明,在发酵前的热处理环节中,均无丙烯酰胺形成;但发酵开始,随着发酵过程的延伸,丙烯酰胺的含量呈上升趋势。到发酵结束时,黑豆豉、水豆豉、豆瓣酱及腐乳样品中丙烯酰胺含量分别达（15 040±191） μg/kg、（16 496±204）μg/kg、（16 821±45） μg/kg及（5 655±24） μg/kg,表明低温发酵的豆制品体系中会形成大量丙烯酰胺,存在一定食用安全风险。     

黑曲霉全豆腐乳的制备及其营养特性研究

为解决豆制品企业豆渣囤积易腐败和低值化问题,并提高腐乳产率,该研究以黑曲霉（Aspergillus niger）发酵豆渣为原料,将其回填至豆浆中,制作成黑曲霉全豆腐乳,按照腐乳生产标准进行检测,并与传统腐乳的营养特性进行对比。结果表明：黑曲霉全豆腐乳符合腐乳生产标准,通过扫描电镜观察,黑曲霉全豆腐乳无明显纤维结构,且表现出较好的质构特征;对比传统腐乳,黑曲霉全豆腐乳出品率提高8.43%;持水性降低3.22%;总膳食纤维含量提高25.14%;总皂苷降低48.44%;大豆异黄酮降低45.03%;蛋白体外消化率提高13.02%;黑曲霉全豆腐乳共检出挥发性风味物质39种和17种氨基酸,总氨基酸含量为26.58 g/100 g。该研究对豆渣的综合利用提供了新途径,提高了膳食纤维含量和出品率,降低了成本,具有进一步产业化的潜力。     

高效液相色谱分析蓝莓发酵液中鞣花酸和没食子酸

建立了高效液相色谱法测定蓝莓发酵液中鞣花酸含量和没食子酸含量的两种方法。鞣花酸的测定条件：Waters symmetry C18色谱柱,柱温25℃,流动相为46∶2∶52的甲醇—乙酸乙酯—KH2PO4/H3PO4溶液,流速0.8m L/min,检测波长254nm,检测蓝莓发酵液中鞣花酸平均回收率为92.68%,RSD为0.97%。没食子酸的测定条件：Waters symmetry C18色谱柱（250×4.6mm,5μm）,柱温35℃,流动相为甲醇：水（0.1%磷酸）=10∶90,流速为1.0m L/min,检测波长273nm,该方法检测蓝莓发酵液中没食子酸平均回收率为99.0%,RSD为0.73%。两种方法均操作简单快速,重现性好,准确度高,可分别用于香菇等食用菌发酵蓝莓制品中鞣花酸和没食子酸含量的测定。     

Isotope Internal Standard Method for Determination of Four Acrylamide Compounds in Food Contact Paper Products and Food Simulants by Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometry

A new method was developed for the determination of four acrylamide compounds (acrylamide, methacrylamide, N-methylol acrylamide, N-(Methoxymethyl)methacrylamide) in food contact paper products, three kinds of water-based food simulants, and dry food simulant (modified polyphenylene oxide, MPPO) by using ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Acetonitrile was used as the extraction solvent for different kinds of samples. The extraction solution of paper products was purified with QuEChERS technology. Four analytes were separated by gradient elution in a UPLC HSS T3 column (100 mm?×?2.1 mm, 1.8 μm) with methanol and 0.1 % formic acid water as mobile phases, and then detected in electrospray ionization mode of MS/MS with multiple reaction monitoring (MRM). Under the optimal conditions, the calibration curves for four analytes were linear within the range of 1.0–200 μg/L and the correlation coefficients were higher than 0.998. The quantitation limits of the method (S/N?=?10) of four analytes were in the range of 0.3–20 μg/kg. The mean recoveries for five sample matrixes at three spiked concentration levels of 0.3–200 μg/kg were in the range of 81–108 % with the relative standard deviations (RSDs, n?=?6) values ranging from 2.5 to 7.1 %. The developed method is accurate, simple and rapid, which can be applied to the determination of acrylamide compounds in food contact paper products and food simulants.     

DETERMINATION OF ETHYL CARBAMATE IN COMMERCIAL PROTEIN BASED CONDIMENT SAUCES BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY

Commercially obtained protein based condiments, including soy sauces, were analyzed for the presence of ethyl carbamate (urethane) using combined gas chromatography-mass spectrometry (GC-MS). Samples were spiked with 100 parts-per-billion (ppb) of t -butyl carbamate internal standard, extracted with methylene chloride and concentrated prior to GC-MS analysis. For quantitation, the ratio of the pseudomolecular ions produced during isobutane chemical ionization (CI) at m/z 90 (ethyl carbamate) and m/z 118 ( t -butyl carbamate) were monitored by mass chromatography. Response factors for ethyl carbamate versus the internal standard were determined in both the electron ionization (EI) and chemical ionization modes. The CI mode was used for quantitation as it was more sensitive and interference free. Samples testing positive by CI-MS were subsequently scanned by EI-MS for confirmation of identity as the CI spectra did not contain fragment ions necessary for adequate specificity. This method proved simple and reliable with detection limits less than 1 ppb. Limits of confirmation were 10 ppb. The recovery of internal standard was 86.7%± 5.6%. Only fermented products were found to contain ethyl carbamate.     

清涧红枣乳酸菌发酵饮料工艺优化

以清涧红枣为原料,提取红枣枣清汁。通过选择干酪乳杆菌、植物乳杆菌和鼠李糖乳杆菌3种乳酸菌进行单独及复配发酵,探索发酵时间、发酵菌种、接菌量及枣清汁初始可溶性固形物含量对发酵饮料pH及感官评价影响,并通过正交试验优化发酵工艺。结果表明,红枣枣清汁以干酪乳杆菌:植物乳杆菌:鼠李糖乳杆菌=6:1:1 (m/m)复配发酵为宜,接菌量为0.01%,在初始可溶性固形物含量13.5%,37 ℃发酵48 h,pH为3.61,乳酸菌活菌数≥1.5×108 CFU/mL,还原糖含量为10.46 g/100 g,总酸含量为8.99 g/kg,符合QB/T 5356-2018果蔬发酵汁标准;环磷酸腺苷含量为21.4 μg/mL,较好的保留了发酵前枣清汁中含有的环磷酸腺苷。本文制备出一款营养丰富、风味俱佳地清涧红枣乳酸菌发酵饮料。     

基于HACCP的山西老陈醋机械化酿造工艺标准化研究

对经危害分析和关键控制点（HACCP）分析确定的山西老陈醋机械化工艺关键点工艺参数进行标准化研究。确定酒精发酵阶段控制初始淀粉含量14%,入罐温度28 ℃,粮水质量比1∶4,主发酵时间3 d,期间每天进行通气搅拌,之后进行密封发酵,总发酵周期14 d;醋酸发酵阶段控制初始醋醅密度0.53 t/m3,初始酒精度4.50%vol,麸皮∶谷糠∶稻壳质量比1∶1∶0.4,每天通过翻醅机翻醅一次,醋酸发酵至第13天向醋醅中加盐并翻匀;熏醅温度120 ℃,添加量占熏醅罐比例70%,熏醅时间12 h。可得到各项理化指标均优于国标要求且质量安全卫生的山西老陈醋产品。最后拟定了山西老陈醋机械化酿造的工艺参数和企业质量标准。     

中国传统豆制品中异黄酮的超高效液相色谱紫外检测器快速定量法

建立了超高效液相色谱-紫外检测器(UPLC-UV)测定豆制品中大豆苷、黄豆黄苷、染料木苷、大豆苷元、黄豆黄素、染料木素的检测方法。采用酸化提取条件,将豆制品中大豆异黄酮及其修饰物水解成3种葡萄糖苷和3种苷元。采用BEH C18(2.1 mm×50 mm,1.7 μm)色谱柱,以0.1%甲酸和乙腈为流动相进行梯度洗脱,梯度洗脱程序为:0~10 min,10%~45%乙腈;10~12 min,45%~100%乙腈。流速为0.3 mL/min,柱温45℃,在波长260 nm处进行紫外检测。6种大豆异黄酮组分在7.5 min内达到完全分离。建立了外标校正标准曲线(R2 ≥ 0.9998),检出限在0.05~0.1 mg·L-1之间,加标回收率在96.8%~102.0%之间。利用本方法对腐竹、豆干、素百叶、素鸡、嫩豆腐、老豆腐和内酯豆腐等7种传统豆制品中大豆异黄酮进行了定性定量分析,总大豆异黄酮含量在8.67~25.83 g/kg间。不同豆制品间6种大豆异黄酮中以大豆苷和染料木苷为主要成分,占88.0%~93.4%。结果表明,本研究建立的UPLC法可有效降低杂质干扰,色谱基线稳定且峰型良好,在10 min内实现对6种大豆异黄酮的快速定量检测,可良好应用于常见市售豆制品的营养评估与质量控制。