超高效液相色谱法检测保健品中的大豆异黄酮各组分含量

目的建立超高效液相色谱法检测保健品中大豆异黄酮各组分含量的方法。方法利用超高效液相色谱仪,将供试品用80%甲醇溶解提取,用Waters XSELECT HSS T3色谱柱分离,以乙腈和1%磷酸溶液进行梯度洗脱,流速为0.5 mL/min,用紫外检测器在波长260 nm对大豆异黄酮组分进行检测。结果大豆异黄酮各组分的在各自范围内线性关系良好。大豆苷、大豆黄苷、染料木苷、大豆素、大豆黄素、染料木素的相关系数均大于0.9999,平均回收率为97.2%~103.3%,相对标准偏差为0.4%~4.8%。结论该方法运行时间短、结果的重复性好。超高效液相色谱法更为快捷简单,溶剂使用量更少,能够提高检验准确性,降低检验成本。     

Effect of processing,fermentation, and aging treatment to content and profile of phenolic compounds in soybean seed,soy curd and soy paste

This study reports the effect of processing, fermentation, and aging treatment on the content and profile of 43 phenolic compounds in soybean seeds, soy curd (tofu), and soy paste (ChungGukJang, CGJ). Mean content of phenolic compounds was ranked as soybean seed = CGJ aged for 3 days (CGJ-3D) = CGJ aged for 6 days (CGJ-6D) > tofu (P < 0.0001). Low percent recovery (47.1%) of phenolic compounds in tofu was due to heating (boiling), leaching in water, filtering, coagulation, and whey exclusion during tofu making. Aging period did not affect the mean contents of 43 phenolic compounds in the CGJ, whereas it affected the phenolic acids contents in the CGJ (P < 0.01). Benzoic, ferulic, chlorogenic, gentisic, protocatechuic, or β-Resorculic acid was major phenolic compounds in soybean seeds, tofu, CGJ-3D, or CGJ-6D. Especially, the CGJ-3D contained large amounts of isoflavone aglucons and phenolic acids compared to soybean seeds or tofu.     

Determination of soybean proteins in soybean–wheat and soybean–rice commercial products by perfusion reversed-phase high-performance liquid chromatography

The determination of additions of soybean proteins in commercial bakery products containing soybean–wheat and soybean–rice binary mixtures has been achieved in this work by high-performance liquid chromatography using a perfusive column. Soybean proteins were solubilized in a 25:75 acetonitrile–water mixture containing 0.3% (v/v) acetic acid by ultrasonication for 10 min and centrifugation for 5 min. Soybean proteins were separated from rice and wheat proteins in less than 4 min using a linear binary gradient of acetonitrile–water containing 0.3% (v/v) acetic acid as ion-pairing agent. The proposed method was proved to be specific and sensitive making possible the detection and the quantitation of additions of about 0.10% (w/w) and 0.33% (w/w), respectively, of soybean proteins in soybean–wheat and soybean–rice products (related to 1 g of initial product). Precision and recoveries observed were also acceptable. The method was applied to the determination of soybean proteins in different commercial bakery products.     

Isoflavone content of Italian soy food products and daily intakes of some specific classes of consumers

In Western countries food products containing soybean proteins are primarily directed to some specific classes of consumers, in particular vegetarians, milk-intolerant or gluten-intolerant subjects, and hypercholesterolemic patients. The consumption of these products is associated with the presence of isoflavones, which recently have become a very controversial issue because their beneficial properties are counterbalanced by some undesirable effects. Taking into account that information on the average isoflavone daily intake in European countries and especially in Italy is very scarce, we decided to quantify the isoflavones in some products for different classes of consumers, with the objective of evaluating their possible exposition. The total isoflavone contents were in the range 21–803 g/g_d.w. and were particularly high in imitation dairy and meat products. Infant formulas contained 121–427 g/g_d.w., whereas the isoflavone contents in gluten-free products were in the range 77–220 g/g_d.w.. Only in the case of infants and children, the daily intake may overcome the recommended limit introduced by the Italian Health Authority for isoflavone supplements.     

气象因子与大豆异黄酮含量的通径分析

以异黄酮含量显著不同的栽培大豆和野生（半野生）大豆为试验材料,采用分期播种的方法研究大豆不同生长发育阶段气象因子对大豆异黄酮总含量的影响。通径分析结果表明：在大豆生长发育的不同阶段各气象要素对大豆异黄酮的影响不同,在大豆生长发育中日照时数对大豆异黄酮含量的直接正效应排在第一位（野生大豆出苗一开花阶段除外）;各生长发育阶段均存在0．5左右的剩余通径,表明还存在未分析的气象因子影响大豆异黄酮含量。     

QuEChERS-高效液相色谱-串联质谱法测定毛豆中常用21种农药残留

目的建立液相色谱-串联质谱法同时检测毛豆中21种常用农药残留的分析方法。方法样品以乙腈-甲酸(99:1,V:V)作为提取剂,经Qu ECh ERS方法前处理,采用Phenomenex的Kinetex C_(18)色谱柱(50 mm×2.1mm,2.6μm,100?)分离,以乙腈-0.1%甲酸水溶液为流动相梯度洗脱,以电喷雾电离(ESI)、正离子模式和负离子模式2种多反应监测(MRM)模式检测,外标法定量。结果 21种农药在5~200 ng/m L范围内,线性相关系数均大于0.99,线性良好。分析目标物添加水平为0.01~0.10 mg/kg时,回收率范围为73%~113%,RSD范围为1.3%~10.9%,符合残留分析的要求。21种农药的定量下限为0.01 mg/kg。结论该方法的提取简便,基质分散效果好,灵敏度满足国内外限量标准的要求,适合毛豆中常用农药残留的同时测定。     

超高效液相色谱法同时测定保健品中4种大豆异黄酮

目的 建立超高效液相色谱法(ultra performance liquid chromatography,UPLC)同时测定保健品中大豆苷(daidzin)、染料木苷(genistin)、染料木素(daidzein)和大豆素(genistein)4种大豆异黄酮的分析方法.方法 样品用80％甲醇超声提取后,以甲醇-0....     

大豆发芽过程中异黄酮含量和抗氧化活性变化研究

该文通过光度分析法对大豆发芽过程中异黄酮总含量的变化、大豆中的异黄酮在子叶和芽茎中的分布进行了研究,结果表明,大豆发芽后,大豆中异黄酮总含量有所增高,且在芽长为3cm时达到最高。豆芽芽茎中异黄酮的总含量显著高于大豆原料和豆芽子叶,随着豆芽的增长,子叶中异黄酮的含量有所升高,但芽茎中异黄酮的含量有所降低。进而通过DPPH和ORAC两种方法对大豆发芽过程中的抗氧化活性的变化进行了研究,研究表明,随着豆芽的增长,子叶和芽茎的抗氧化活性均和其中的异黄酮含量呈现显著正相关的统计关系。     

Determination of isoflavones in commercial soy products by HPLC and coulometric electrode array detection

The concentrations of the isoflavones daidzein, genistein and glycitein were determined in a large number of commercially-available soy products by high-performance liquid chromatography with coulometric electrode array detection using estriol as internal standard.During extraction, the naturally occurring glycosides were converted into their respective aglycones by acid hydrolysis. The analytes were separated on a C-18 reversed phase column, eluted with methanol/acetonitrile/50 mM sodium acetate pH 4.8 (40/5/55, v/v/v), and detected by a coulometric electrode array detector using twelve electrodes set to potentials between +250 and +800 mV (in increments of 50 mV) against palladium reference electrodes.The isoflavones could be determined over a wide concentration range (0.8–1135.0 mg/kg for daidzein, 1.9–1442.5 mg/kg for genistein and 0.5–154.6 mg/kg for glycitein). The recovery of the isoflavones in the different matrices was determined by the standard addition method and varied between 40.9–94.4%. The detection limits (S/N=3) depend on the matrix of the soy product and were found for daidzein between 0.3–1.6 mg/kg, for genistein between 0.3–1.7 mg/kg and for glycitein between 0.5–2.3 mg/kg.     

高效液相色谱法测定乳与乳制品中 L-羟脯氨酸的含量

目的建立高效液相色谱法测定乳与乳制品中L-羟脯氨酸的含量。方法样品水解衍生后采用C18色谱柱,以乙腈和10 mmol/L乙酸钠(p H=5.0)为流动相,梯度洗脱,流速为1.0 m L/min,柱温35℃,荧光检测器进行检测。结果 L-羟脯氨酸检出限为0.5 mg/kg,线性范围为1.0~100.0μg/m L,加标回收率在95.3%~102.7%之间,相对标准偏差在1.46%~7.56%之间。结论该方法操作简便、准确、快速,提高了样品检出灵敏度,适用于测定乳与乳制品中L-羟脯氨酸的含量。     

Determination of soybean proteins in commercial heat-processed meat products prepared with chicken,beef or complex mixtures of meats from different species

The addition of foreign proteins (mainly soybean proteins and milk proteins) to heat-processed meat products is a common practice. This work approaches the determination of additions of soybean proteins in heat-processed meat products prepared with chicken meat, beef meat, and complex mixtures of meats from different species (chicken, pork, beef, and turkey) by perfusion reversed-phase high-performance liquid chromatography. The applied method was previously developed for the determination of soybean proteins in pork and turkey meat products but it has never been tested for the determination of soybean proteins in other heat-processed meat products containing other kinds of meats. This paper demonstrates the validity of this method for the detection of soybean proteins in heat-processed meat products containing different varieties of meats and even in the presence of other foreign proteins such as milk proteins. The specificity and existence of matrix interferences have been checked for these samples and accuracy has been evaluated by the comparison of the soybean protein contents determined by the proposed method and the official ELISA method.     

Effect of soybean varieties on the content and composition of isoflavone in rice-koji miso

To clarify the effect of soybean varieties on isoflavone, a useful component for human health, in soybean products, we investigated changes in the isoflavone content and composition in rice-koji miso, after fermentation/aging for 6 or 12 months using varieties of soybeans (Tohoku-126, Tohoku-135, Tohoku-139, Suzuyutaka and Chinese soybeans), by high performance liquid chromatography. In soybeans, the total isoflavone content in Tohoku-126 was 444 mg/100 g, which was 1.2–2.0 times the content in the other soybean varieties. The malonyl glycosides and aglycones in soybeans accounted for more than 60% and only a few percent, respectively. As for rice-koji miso, the total isoflavone and aglycone contents were the highest in miso prepared from Tohoku-126. The ratios of glycosides to aglycones (80.1–92.6%) in miso were higher than those in the original soybeans. The time course of the isoflavone composition during the fermentation/aging process of rice-koji miso indicated that glycosides decreased from 86.4% to 44.9% after 6 months but aglycones increased from 9.6% to 53.3%.     

高效液相色谱-紫外检测法测定水产品中组胺含量

目的对高效液相色谱法测定水产品(鲭鱼)中组胺含量的试验方法进行改进,建立一种提取方法简单、衍生物稳定、操作方便的检测方法。方法用0.4 mol/L高氯酸溶液提取水产品中的组胺,采用10 mg/m L丹磺酰氯溶液作为衍生剂进行衍生,用甲醇、水的流动相梯度洗脱,高效液相色谱-紫外检测法测定水产品中的组胺含量。结果该方法提取完全、操作简单、峰型理想、组胺出峰干扰少,回收率大于90%,方法检出限为50 mg/kg。结论该方法能够满足水产品中组胺含量的测定要求,是一种理想的组胺检测方法。     

Enhancements of isoflavone aglycones, total phenolic content, and antioxidant activity of black soybean by solid-state fermentation with Rhizopus spp.

In the present study, a solid-state fermentation process of black soybean was developed. Three filamentous fungi including Rhizopus oligosporus (BCRC 31996), R. oligosporus (NTU-5), and Rhizopus oryzae (BCRC 30894) were cultivated with steam-cooked intact and dehulled black soybeans. It was found that fermentation enhanced the total phenolic and isoflavone aglycone content as well as antioxidant activity of the black soybean methanol [80 % (v/v)] extracts. Among the three candidates, R. oligosporus BCRC 31996 was chosen as the working strain, and dehulled Tainan NO.3 black soybeans were used as the substrate based on the relatively high total phenolic content, isoflavone aglycone accumulation, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging effect of the fermented extracts. In a 6-day fermentation, extracts of the fermented dehulled black soybeans yielded higher total phenolic content (2,876.2 μg/g) which was 1.16 times of the result from the intact soybean extracts. The DPPH scavenging effect of the fermented dehulled black soybean extract reached its maximum on the third day. The activity of β-glucosidase of dehulled black soybean samples increased with time and resulted in accumulation of isoflavone aglycones. The product of solid-state black soybean fermentation serves as a functional ingredient in the products of nutritional supplements and health foods.     

Concentration of phytoestrogens in soybeans and soybean products in Korea

Concentrations of total isoflavones in soybean varieties of different origins and soybean products were determined by high performance liquid chromatography. Wild soybeans showed the trend to have more isoflavone content than cultivars or landraces, showing mean value of 1528, 1265 and 1249 mg kg⁻¹, respectively. There were no meaningful differences in the ratio of genistein and daidzein among the modern variety groups. Korean varieties including South Korea and North Korea seemed to have total isoflavone content more than Chinese varieties, although samples of Chinese varieties were limited. In a dried basis of soyfoods, total isoflavone contents were in order of soybean sprout, chungkukjang, soymilk, soybean curd, denjang, kochujang, respectively. Five soybean foods contributed 96% of total genistein and daidzein intake in Korea: soybean sprout, soybean curd, denjang, chungkukjang and soybean seed itself. According to a Korean National Survey Report and our data, the average Korean daily intake of isoflavone from soybean foods can be estimated as 21 mg day⁻¹. © 2000 Society of Chemical Industry     

Effect of fermentation by pure and mixed cultures of Streptococcus thermophilus and Lactobacillus helveticus on isoflavone and B-vitamin content of a fermented soy beverage

Enhancement of nutritional or vitamin content of foods is commonly touted as a major benefit of probiotics. In this paper, we examined the ability of three probiotic bacteria either alone or in combination to enhance nutritional content. Pure and mixed cultures of Streptococcus thermophilus ST5 and Lactobacillus helveticus R0052 or Bifidobacterium longum R0175 were used to prepare fermented soy beverages. The effects of strain, acidification and mixed cultures on the deconjugation of soy isoflavones were examined. Acidification to pH 4.7 alone resulted in a 7% drop in isoflavone levels. Deconjugation levels varied between the different glucosides. Fermentation by L. helveticus R0052 resulted in the 50% reduction in total glucosides with O-malonyl glucosides being reduced 64%. Fermentation by S. thermophilus ST5 or B. longum R0175 had no significant effect on isoflavone levels. Combining a S. thermophilus strain with a L. helveticus culture reduced the effectiveness of the latter. Fermentation did not significantly modify vitamin B1 or B6 levels.     

高效液相色谱法测定乳制品中的叶黄素

建立了一种简单、快速、可靠的测定乳制品中叶黄素的新方法。乳制品中的叶黄素经正己烷提取,氮气吹至近干,残余物用正己烷-乙酸乙酯(70+30)溶解后,高效液相色谱法测定,标准曲线法定量。该方法具有良好的准确度和精密度,在不同乳制品中添加回收率范围为91.0%～102.6%,相对标准偏差(RSD)为0.64～2.92。该方法的检出限和最低定量限分别为20μg/kg和50μg/kg。     

高效液相色谱法检测水产品中双酚A及其蓄积特征研究

目的 建立一种利用高效液相色谱(high performance liquid chromatography, HPLC)联用紫外(ultraviolet absorption detector, UV)检测器检测水产品中双酚A (bisphenol A, BPA)蓄积量的分析方法并探究BPA的蓄积特征研究。方法 根据线性、极限检测、精密度和回收率等标准对该分析方法进行了验证。采用不同浓度BPA胁迫常见海洋底栖动物-单环刺螠(Urechis unicinctus),以二氯甲烷作为萃取剂,对单环刺螠肌肉进行前处理,用上述HPLC方法检测。结果 在所建立的检测条件下,采用内标外标法定量 ,BPA在质量浓度0~10 mg/L范围,浓度与峰面积呈显著正相关(r＝0.9998,P<0.01),检出限(the limit of detection,LOD)为0.247 mg/L,定量限(the limit of quantification,LOQ)为0.464 mg/L,加标回收率为99.68%,日间精密度(relative standard deviation,RSD)为2.2121.28%。单环刺螠肌肉内BPA蓄积量随着暴露浓度的增加而上升,各浓度处理组BPA蓄积量随胁迫时间的延长呈现先降后升趋势。结论 该HPLC检测方法可以检测出水产品中μg/g级BPA含量,操作简便,可用于水产品质量安全检测。BPA在单环刺螠肌肉内蓄积量随暴露时间延长,先降低后上升,具有潜在的水产品安全风险。     

Evaluation of isoflavone content and antioxidant activity of soy-wheat pasta

The purposes of this work were to determine isoflavones profile and antioxidant activity of two soy flours and spaghetti produced from semolina blended with increasing amount of these flours. Defatted and toasted soy flour (DSF and TSF, respectively) showed different isoflavone profiles though glucosides were the most abundant isoflavone forms in both the meals. The pasta-making procedure determined an increase of the aglycone forms that was at least 37 and 21% in TSF and DSF pasta, respectively. Cooking operations induced severe decreases of the isoflavone content (the losses ranged from 60.44 to104.91 mg kg⁻¹ for TSF pasta and from 85.41 to 469.33 mg kg⁻¹ for DSF pasta). The results of the antioxidant activity were quite different as a function of the methods applied but they resulted generally well correlated with the isoflavone contents of the samples. Cooking induced significant decreases of the antioxidant activity in almost all samples. This result appears well correlated with the decrease of the total isoflavone content and the presence of antioxidant activity in the cooking water.