Determination of levulinic acid in soy sauce by liquid chromatography with mass spectrometric detection

A novel method using liquid chromatography coupled with mass spectrometry (LC–MS) was developed for the determination of levulinic acid (LV) in soy sauces to identify the addition of acid hydrolyzed vegetable protein (acid-HVP). One hundred percentage naturally brewed soy sauce (NBS) and enzymatic hydrolyzed vegetable protein (enzymatic HVP) did not contain LV (<0.01 mg/mL). There was apparent detection of LV in acid-HVP and blended soy sauce with acid-HVP (2.98–21.66 mg/mL). Gas chromatography (GC) and high performance liquid chromatography (HPLC) at 430 nm methods were also investigated. The results by GC gave similar data to those by LC–MS. In enzymatic HVP, LV was detected by HPLC at 430 nm, but it was confirmed that the detected component was not in fact LV by mass spectrometric identification of the isolated peak compound. We found that LV is under the detection limit in enzymatic HVP. This study showed that LV is below the detection limit in NBS and enzymatic HVP and is apparently detected in acid-HVP and blended soy sauces with acid-HVP. These results indicate that LV is a practical index of blend with acid-HVP and also corresponds with the JAS (Japanese Agricultural Standard) or CNS (Chinese National Standard) criteria in which the presence of LV in soy sauces indicates adulteration with acid-HVP. The LC–MS method is analytically optimal for the precise determination of LV, because peak misidentification may be practically eliminated.     

酿造酱油与配制酱油远红外光谱鉴别研究

采用傅里叶变换远红外光谱结合最小偏二乘法(PLS),对酿造酱油、酸水解植物蛋白液(HVP)以及添加不同比例(10%-50%)HVP而得的配制酱油进行类别分析。结果发现,酿造酱油、酸水解植物蛋白液及配制酱油在以PLS主成分为坐标的二维线性投影图中分布差异明显;通过模型相关系数(R2)和交互验证标准差(RMSECV)比较,筛选出建模光谱波段为4000-500cm-1;通过残余方差(RVV)分析,确定了最适主成分数为10。利用模型成功对21份盲样进行鉴定,证明利用PLS建立的模型能有效地检测配制酱油中HVP的添加量,且最大偏差小于3.5%。     

3-Monochloro-1,2-propandiol (3-MCPD) in soy sauce from the Bulgarian market

The 3-monochloro-1,2-propandiol (3-MCPD) levels in soy sauces which contained hydrolysed vegetable protein were evaluated for the Bulgarian market. For analysis of 3-MCPD, a gas chromatography–mass spectrometry (GC-MS) method was applied with a linear range of 0.03–2.00 μg mL^?1 and a limit of detection (LOD) of 2.3 μg kg^?1 and a limit of quantification (LOQ) of 3.4 μg kg^?1. At these levels, the standard deviation was 5.1%, with recoveries between 81% and 102%. The method was applied to the analysis of 21 samples of soy sauce from the Bulgarian market. Results ranged from 3.7 to 185.6 μg kg^?1. Soy sauces produced from hydrolysed soy protein contained higher levels of 3-MCPD than naturally fermented sauces. In 38.4% of samples of Bulgarian origin, the 3-MCPD content was above the EU limit of 20 μg kg^?1. In all analysed samples, 33.3% had a 3-MCPD content above the EU limit.     

酿造酱油与配制酱油鉴别方法研究进展

以氯丙醇、铵盐、乙酰丙酸、氨基酸作为鉴别酿造酱油与配制酱油的指标,采用同位素稀释气相色谱-质谱联用法、顶空衍生化固相微萃取法等检测酸水解植物蛋白液(HVP)的氯丙醇,采用凯氏定氮法、近红外光谱法检测酱油中的铵盐与氨基酸,采用液相色谱-质谱法、气相色谱法等检测HVP中的乙酰丙酸,采用高效液相色谱法、氨基酸自动分析仪检测酱油中的氨基酸。     

Evaluation of non-volatile taste components in commercial soy sauces

The dominating non-volatile taste compounds in commercial brewed soy sauces were determined by HPLC and evaluated on the contributions to overall taste. Aspartic acid and glutamic acid accounted for 8.77 to 147.98 mg/mL in ten commercial soy sauces samples. Lactic acid (ranging from 0.83 to 13.19 mg/mL) and pyroglutamic acid (ranging from 0 to 12.80 mg/mL) were the dominant organic acids, contributing to the acidity and ensuring a balance in taste of soy sauces. 5?-Inosine monophosphate was the most abundant nucleotide, followed by 5?-guanosine monophosphate, and they accounted for 0.30 to 3.54 mg/mL in ten soy sauces. According to the determination of non-volatile taste compounds in soy sauce samples, taste activity value (TAV) and equivalent umami concentration (EUC) of different soy sauces were calculated and compared. An exclusive cluster analysis based on TAV was proposed to classify the commercial soy sauces. The EUC value of new class A is much higher than other classes.     

Quantification of ethyl carbamate in soy sauce consumed in Korea and estimated daily intakes by age

To estimate the daily intake of ethyl carbamate (EC, a possible human carcinogen) from soy sauce consumed in Korea, 136 soy sauce samples were collected from various regions and analysed by gas chromatography/selected ion mode mass spectrometry (GC/SIM‐MS). The distribution of EC varied significantly among samples, ranging from not detected to 128.9 µg kg^?1, with the highest level in Japanese‐style soy sauce. Based on individual intakes in the Complementary Report on 1998 National Health and Nutrition Survey and EC contents analysed in the present study, the contribution of soy sauce to EC intake was estimated by multiplying the mean concentration of EC by individual soy sauce intake data. Daily intakes of EC kg^?1 body weight by high consumers were particularly high in age groups 1–2 years (78.59 ng), 3–6 years (86.37 ng), 50–64 years (86.24 ng) and ≥ 65 years (76.86 ng). Based on a benchmark dose confidence limit (BMDL) of 0.3 mg EC kg^?1 body weight day^?1, the margin of exposure (MOE) calculated from the daily intake of EC in soy sauce for high consumers ranged from 3488 to 7317, which is of concern. Daily EC intakes are likely to be exceeded in groups who consume other fermented foods as well as alcoholic beverages. Copyright © 2006 Society of Chemical Industry     

A study of chemical characteristics of soy sauce and mixed soy sauce: chemical characteristics of soy sauce

Mixed soy sauce is one among the Korean traditional fermented soy sauces consumed as condiment for cooking in Korea, especially mixed soy sauce is made of the fresh seafood and the meat different from the soy sauce. Therefore, mixed soy sauce provides the strong and complicated umami taste, which is stronger than that of soy sauce. The objective of this study was to investigate for the chemical characteristics changes of mixed soy sauce in comparison with soy sauce during fermentation process (0, 120, 240 and 360 days) at different fermentation temperatures (4 and 20 °C), change in moisture, total nitrogen, crude fat, ash, pH, titratable acidity, total acidity, salt content and reducing sugar of mixed soy sauce in comparison with soy sauce. Especially, histidine, arginine, threonine, methionine, phenylalanine, and lysine, essential amino acid and among adenosine triphosphate (ATP)-related compounds, inosine (HxR) and hypoxantine (Hx) were prominent in mixed soy sauce at 20 °C. Otherwise, 2,4-dinitrophenylhydrazine (DNPH) derivative and 3DG content were prominent in soy sauce at 20 °C. The content of 2,4-DNPH derivative and 3DG in soy sauce is correlated with its browning intensity.     

An Improved HPLC-FLD for Fast and Simple Detection of Ethyl Carbamate in Soy Sauce and Prediction of Precursors

A high-performance liquid chromatography with fluorescence detection (HPLC-FLD) method for ethyl carbamate (EC) determination in Chinese soy sauce was developed and used to predict EC precursors, and extraction, derivatization, and chromatographic conditions were optimized systematically. Under optimal conditions, the limit of detection, linear range, and recoveries were 3.91 μg/L, 12.87–274.87 μg/L, and 81.5–95.4%, respectively. The method precision was less than 8.9% (RSD) and no significant difference was found between EC determinations measured by HPLC-FLD and GC/MS. Using the proposed HPLC-FLD method, the EC contents in Chinese soy sauces ranged from not detected to 64.88 μg/L (n = 19). Except for one soy sauce brand, the EC contents in low-salt solid-state fermented (LSF) soy sauces were lower than those in high-salt liquid fermented (HLF) soy sauces and were mainly affected by alcohol content. Moreover, the free ornithine and total arginine contents were significantly correlated with EC content in the soy sauce products. The results of this work provide a foundation for further study of EC formation and inhibition in Chinese soy sauces.     

活性干酵母在酱油中的应用

酵母菌在酱油及酱类生产中能产生特殊的香味,是酱香的重要来源;在酱油生产中添加酱油活性干酵母,能使酱油中的乙醇和总酯的含量等指标明显提高,酱油品质显著改善;酱油活性干酵母作为一种活性干菌体使用、存储也非常方便.     

双孢菇酱油双酿工艺研究

以双孢菇及豆粕、小麦、麸皮等为原料,通过米曲霉和鲁氏酵母的混合种曲在28℃～30℃发酵40d,将原料中蛋白质降解,从而酿制出双孢菇酱油。该产品具有红褐色、酱香浓郁、菇香味突出、口感鲜美、咸淡适口等特征,其理化指标均达到酿造酱油一级的标准,为双孢菇的利用提供了新的思路。     

甜油和酱油中氨基酸和还原糖含量的比较研究

探讨甜油和酱油中两种关键营养成分氨基酸和还原糖的含量差异,分析原料不同、工艺相近的两种调味品特征指标存在差异的原因,并提出甜油和酱油存在的优势和缺点。结果表明,甜油中氨基酸总量和鲜味氨基酸谷氨酸低于酱油,甜油和酱油中氨基酸总量分别为15.86～23.21 mmol/L和31.69～46.04 mmol/L,其中谷氨酸含量分别为2.94～7.54 mmol/L和20.62～35.34 mmol/L;但每类氨基酸含量差距不大,比较协调;甜油中甜味氨基酸比例较大,为49.41%,酱油中的鲜味氨基酸比例较大,为71.19%;甜油中还原糖含量（14.24～27.53 g/L）高于酱油（4.80～8.26 g/L）。因此,酱油因高氨基酸和谷氨酸含量鲜味明显、口感厚重,适合烧制菜肴,而甜油口感协调、丰满,适合炒菜和凉拌菜;另外,甜油中高含量的还原糖含量能够改善菜肴质量、色泽和口感。     

典型广式酱油与日式酱油的风味物质差异研究

广式酱油和日式酱油在原料、微生物和工艺均有极大的差异。通过比较研究,广式酱油酱香、豉香浓郁,而日式酱油醇香、酯香和甜味更加突出。在氨基酸分析中,广式酱油的总游离氨基酸为5.220 g/100 mL,而日式酱油则为5.903 g/100 mL,但两者氨基酸种类的相对百分含量没有显著的差异（P＞0.05）。气相色谱-质谱法（GC-MS）鉴定出挥发性化合物134种,其中广式酱油的主要挥发性化合物为酯类（25.39%）、醇类（25.23%）、酸类（13.51%）、酮类（4.24%）、醛类（2.57%）、酚类（0.31%）和烷烃类（28.75%）,而日式酱油主要为酯类（56.02%）、醇类（21.11%）、酸类（5.92%）、酮类（3.42%）、醛类（0.69%）、酚类（0.15%）和烷烃类（12.69%）,酱油挥发性化合物的种类、含量及比例构成是引起两种酱油风味独特差异的重要原因。     

HNSS01的分离鉴定以及用于酱油酿造的初步研究

摘要：HNSS01是从阳江豆豉中分离得到的1株枯草芽孢杆菌,用其作为发酵菌种,以大豆为原料,结合高盐稀态发酵工艺的某些特点进行酿制酱油的实验研究。结果表明：加入2倍体积的水进行发酵得到的头油氨基态氮含量为0．991g／100mL的酱油,头油总酸含量为1．425g／100mL,还原糖含量为2．283mg／mL,可溶性固形物为39．394．g／100mL,全氮含量为1．045g／100mL。色泽呈棕黄色,具有酱油的浓郁香气．     

氢化物原子荧光光谱法测定酱油中微量铅的方法研究

建立了一种快速、高效的QuEChERS-高效液相色谱-质谱联用法（QuEChERS-HPLC-MS/MS）测定谷类杂粮制品中脱氧雪腐镰刀菌烯醇（DON）、3-乙酰脱氧雪腐镰刀菌烯醇（3-ADON）、15-乙酰脱氧雪腐镰刀菌烯醇（15-ADON）和玉米赤霉烯酮（ZON）共4种真菌毒素。样品前处理采用乙腈-水溶剂提取，经Florisil+C18+无水硫酸镁净化后检测。以0.10%甲酸-乙腈作为流动相，在质谱检测器的多反应监测模式下进行分析。结果表明，4种真菌毒素在各自的线性范围内线性关系良好，相关系数R2均大于0.999，回收率在85.1%～102.0%，相对标准偏差（RSD）为2.11%～6.22%。该方法具有前处理简单、净化效果好、灵敏度高和检测速度快的优点，适用于谷类杂粮制品中DON、3-ADON、15-ADON 和ZON的分析和定量检测。     

光照对酱油发酵影响初步研究

研究了不同光质对发酵酱油的影响,结果显示不同光质发酵酱油在其色泽(A530)、氨氮含量、固形物含量、还原糖含量、总酸含量、红指、黄指等指标之间的变化率没有明显差异(p>0.05),经感官评价,其色泽、香气、滋味方面也均没有显著差异(p>0.05)。对无光控温发酵酱油与传统晒露发酵酱油进行比较,中性和酸性蛋白酶活力在无光控温发酵酱油中均下降得较快,但氨氮含量却增加较快。它们的总游离氨基酸含量分别为5.246g/100mL和4.480g/100mL;通过GC-MS对酱油的挥发性成分进行分析,无光控温发酵酱油中的挥发性成分较丰富,而且其大部分醇类、酸类、酯类、醛类、酚类和其他挥发性物质的含量均比传统晒露发酵酱油高。     

酱油澄清及浊度的测定

酱油是一种发酵食品，生产中会出现浑浊现象，需要进行澄清。对酱油的澄清程度仅有感官要求，缺少量化方法。本文采用一种15度前散射光的浊度计，使用卤素灯作为光源，内置了独特的光学系统及散射透过比率式的计算程序，以15度前置散射光直接检出方式，因此不受酱油颜色的影响，线形关系强，还可以直接显示数据，样液中颗粒直径对测定值的影响较小，十分适合酱油浊度测定。     

连续流动分析-盐酸萘乙二胺分光光度法测定酱油中的亚硝酸盐和硝酸盐

建立了一种同时测定酱油中亚硝酸盐和硝酸盐的连续流动分析-盐酸萘乙二胺分光光度法。酱油样品经25 ℃超声15 min预处理,乙酸锌-亚铁氰化钾体系沉淀蛋白质后,自动进样且采用气泡隔断样品,并经透析膜透析,采用双通道同时测量亚硝酸盐和硝酸盐。结果表明,亚硝酸盐在0.025～1.0 mg/L质量浓度范围内线性良好,加标回收率在83.54%～98.56%之间,精密度试验结果相对标准偏差（RSD）＜3%;硝酸盐在0.25～5.0 mg/L质量浓度范围内线性良好,加标回收率在92.95%～102.32%之间,精密度试验结果RSD＜2%。该方法准确、高效、灵敏,可以用于测定酱油中亚硝酸盐和硝酸盐。     

酱油的罐式与池式发酵过程中关键呈味物质对比分析

从发酵罐和发酵池中选取发酵过程中的酱油进行中性蛋白酶活力、氨基酸态氮含量、游离氨基酸含量、pH值、总酸含量、有机酸含量、还原糖含量、淀粉酶活力和食盐含量的检测与分析。结果表明：池式发酵酱油的中性蛋白酶活力、氨基酸态氮含量、氨基酸总量、有机酸总量、淀粉酶活力、还原糖含量、总酸含量和pH值都高于罐式发酵酱油;食盐含量则是罐式酱油更多;其中鲜味氨基酸在发酵12 d后池式酱油的含量就高于罐式酱油的含量,尤其是池式酱油的谷氨酸在发酵45 d时已达到10.42 g/kg,而罐式酱油的谷氨酸含量仅7.91 g/kg;两种方式发酵的酱油都能检测出7种有机酸,且含量较高的两种有机酸分别是乳酸和乙酸;在发酵结束时池式酱油的还原糖含量比罐式酱油的还原糖含量高1.01 g/100 g;池式酱油的食盐含量比罐式酱油的食盐含量低0.90 g/100 g,说明在关键呈味物质上池式发酵酱油优于罐式发酵酱油。     

高效液相色谱法测定酱油中组胺的含量

目的建立丹磺酰氯柱前衍生-高效液相色谱法测定酱油中组胺含量的方法。方法样品酱油以1,7-二氨基庚烷作为内标,用正丁醇:三氯甲烷(1:1,V:V)萃取净化,经丹磺酰氯衍生,乙醚萃取后氮气吹干,用乙腈定容,高效液相色谱仪测定,内标法定量。结果组胺含量在1~100 mg/L线性关系良好,线性相关系数r=0.9999,检出限为0.5 mg/kg。在精密度实验中,其相对标准偏差为2.59%~6.48%,在1.0、10.0、50.0 mg/kg的添加水平下,加标回收率为88.0%~104.2%。结论该方法线性关系好、检出限低、稳定性好、回收率高、测定结果准确,适合酱油中组胺的测定。     

挥发性成分聚类分析在酱油鉴别中的应用

应用同时蒸馏萃取法和气质联用技术对对酿造酱油、配制酱油和酸世界植物蛋白调味液共17个样品的挥发性成分进行分析,筛选其特征挥发性组分进行比较。发现酿造酱油特征组分以醇类、醛类、酸类为主,酸水解植物蛋白调味液特征组分以醛类、酚类、杂环化合物为主,而配制酱油挥发性成分则兼有前两者的特征组分。以17个样品的挥发性成分及其含量进行聚类分析,建立了区分酿造酱油、配制酱油和酸水解植物蛋白调味液的识别模型,为建立酿造酱油和配制酱油鉴别技术打下较好的基础。