共查询到19条相似文献,搜索用时 187 毫秒
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该文建立了一种黑米中亮蓝的提取与测定方法。采用NaHCO 3为辅助提取试剂,样品经体积分数40%甲醇水萃取、离心,固相萃取小柱Strata-X-AW净化后采用高效液相色谱法定量分析。经验证,样品中加入0.52 g辅助提取剂NaHCO 3,40%甲醇水提取液,涡旋12 min后离心,3次重复,能够将黑米中添加的亮蓝完全提取出来。合成着色剂亮蓝线性关系良好(R≥0.9999),方法的检出限为0.02 mg/kg,定量限为0.05 mg/kg。加标回收率为81.70%~91.52%,相对标准偏差为0.39%~1.75%。该方法较GB 5009.35—2016操作方便快捷,简单准确,改进后的提取方法更适用于黑米及遇水易膨胀的谷物粉类制品中亮蓝的快速测定。 相似文献
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目的建立一种适合家庭使用的简便快速鉴别黑色粮油产品的方法。方法取等量各黑色粮油产品放入玻璃杯,倒入一定量的白醋、清水、碱水,静置1~2 min,若3杯分别显红色、紫色、蓝色,则判定为真黑色粮油产品。若静置时间久,因溶液颜色较深不容易辨别,可用筷子蘸取少量溶液滴于白纸上,根据颜色差异判定。结果改进的方法可有效鉴别富含花青素的黑色粮油产品。结论该方法操作简单,无需专业试剂和设备,判定无需专业人员,适合家庭鉴别黑色粮油真伪。 相似文献
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以早籼米、黑米米糠为原料,通过稀碱法提取早籼米中的淀粉,采用有机溶剂酸化甲醇提取黑米米糠中游离酚,并利用高效液相色谱法测定其多酚含量,将黑米米糠游离酚加入到淀粉-碘复合溶液中,通过扫描吸收光谱的变化来考察酚浓度对淀粉-碘结合的影响,进一步加入a-淀粉酶,考察黑米米糠游离酚对a-淀粉酶催化淀粉消化的影响。结果表明,黑米米糠游离酚抑制淀粉和碘的结合,浓度越大抑制效果越明显,且随着酚浓度的增加,最大吸收峰向波长短的方向移动,即发生蓝移,其原因可能是酚与淀粉结合,改变了淀粉性质,从而改变其吸收峰;黑米米糠游离酚能抑制淀粉的消化,其原因可能是酚与淀粉疏水基团结合。 相似文献
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This thesis deals with the development and validation of methods for the quantification of flavonoid derivatives from physiological samples in cases of bioavailability research, as there is always a need for valid and reliable methods suitable for a wide variety of analytes. With the enzymatic proteolysis of plasma samples for flavonoid analysis, a completely new approach to sample preparation of plasma samples was investigated. Various enzymes and procedures were tested as part of the research, and the method was thus continuously optimized. The method validation showed the suitability of the developed method for several analytes of different flavonoid classes. It therefore appears to be promising when it comes to extending the application to further classes of analytes. With regard to the analysis of flavonoids in urine samples, an easy to handle method using evaporation was found and validated for anthocyanidins. In routine analysis, however, this method was not suitable for all anthocyanidins but only for the methoxylated ones. Nevertheless, the possibility of extending it to other analytes, especially the metabolically derivatized flavonoids, appears to be promising in the future. Compared to already established methods, both methods presented here showed at least equivalent results with regard to method validation, apart from for hydroxylated anthocyanidins. But, when considering this it should be noted that due to the different validation guidelines used, there is no absolute comparability between the different analytical methods. It is indisputable, however, that with the methods presented here the costs can be blatantly reduced and the amount of material and the resulting waste can be reduced compared to the established methods using SPE. The application of a single sample preparation procedure for different analyte classes can also be used here, whereas different procedures would often be necessary with the classic SPE. The repertory of available valid methods for bioavailability and metabolism research of flavonoids, and possibly other phytochemicals, could thus be expanded by the research work presented here. 相似文献
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从黑豆种子中分离纯化1 种黑豆脂氧合酶--bsLOX,对其酶学活性及降解花色苷等性质进行初步研究。采用缓冲液抽提、硫酸铵沉淀、透析、阳离子交换层析及凝胶层析等方法纯化出具有β-葡萄糖苷酶活性的bsLOX;分别以亚油酸钠和对硝基苯基-β-D-吡喃葡萄糖苷(p-nitrophenyl β-D-glucopyranoside,pNPG)为反应底物鉴定bsLOX的脂氧合酶活性和β-葡萄糖苷酶活性。从黑豆种子中纯化获得的bsLOX在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electropheresis,SDS-PAGE)图谱显示单一条带,分子质量约为95 kD。酶活性分析表明,纯化的bsLOX以亚油酸钠为底物时,酶活力为13 U/mL;当以pNPG为底物在405 nm波长处检测到了对硝基苯酚的生成,从而推测bsLOX具有β-葡萄糖苷酶活性。高效液相色谱实验结果表明bsLOX可以降解花色苷(矢车菊素-3-O-葡萄糖苷、矮牵牛素-3-O-葡萄糖苷)为花色素(矢车菊素、矮牵牛素)。由于降解作用不完全,继而发现花色素能抑制bsLOX的酶活性。bsLOX是黑豆中的一种兼具β-葡萄糖苷酶功能的蛋白质,而花色素可能是天然的bsLOX抑制剂。 相似文献
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目的建立掺假咖啡的形态鉴别方法。方法通过电子显微镜镜检对巴西莓果粉、炒大麦粉末、黑玉米粉末掺假咖啡进行鉴别。结果咖啡颗粒显微镜镜检大多呈棕色不规则砂粒、砂晶状,镜下串联成直链和支链,10%咖啡水溶液镜下大多呈棕色不规则砂晶状,表面密布卷曲纹;巴西莓果粉及其水溶液镜下常见深浅不一紫红色、紫色表面平滑晶块晶片,还有极少表面呈紫红色、棕红色蜂窝状纹路碎块;炒大麦粉末镜下大多呈灰色、灰黑色、棕黑色无定型不规则碎粒状、块状,其水溶液镜下呈边缘较柔和或散碎无定型银灰色、银黑色、灰黑色碎块或糊化团;黑玉米粉末及其水溶液镜下大多呈银灰色、银黑色不规则块状物,边缘或柔和或散碎。咖啡粉末显微透光性强于大麦、黑玉米等禾谷类淀粉颗粒。结论通过本形态鉴别方法,可分辨出巴西莓果粉、大麦、玉米等掺假的咖啡。 相似文献
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利用超高效液相色谱(ultra-high performance liquid chromatography,UPLC)技术,建立一种以牛β-乳球蛋白为掺假标识物的检测方法,用于定性定量检测骆驼乳中掺假的牛乳,并且探讨不同热处理方式对掺假标识物的影响,以期满足不同商品化驼乳制品的检测需求。结果表明:该方法能有效地检测鲜驼乳、巴氏杀菌驼乳以及驼乳粉中掺假的牛乳,3 种类型掺假乳样本的定量检测回归方程线性良好,线性相关系数(R2)分别为0.997 9、0.996 9和0.997 8;鲜驼乳、巴氏杀菌驼乳和驼乳粉中掺假牛乳的检出限分别为2%、3%和5%,可满足检测需求;利用该方法在10 种不同品牌市售纯驼乳粉中检测出4 种掺假驼乳粉产品。UPLC法可以有效地检测骆驼乳及其制品中掺假的牛乳,为骆驼乳行业的掺假检测提供一定的技术方法支持。 相似文献
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Li Wu Meijing Zhai Yang Yao Chuan Dong Shaomin Shuang Guixing Ren 《Food science and biotechnology》2013,22(4):917-923
The present study was undertaken to assess the changes in nutritional composition, anthocyanins, and volatile compounds during 3 successive processes (soaking, steaming, and roasting) for black rice tea production. Significant (p<0.05) decreases of cyanidin-3-glucoside and peonidin-3-glucosidetotal content were presented in black rice grains during soaking, steaming, and roasting. However, only steaming and roasting caused significant (p<0.05) decreases in the contents of total starch and crude fat, whereas accompanied with a stable level of total starch during all the processes. Furthermore, 94 of volatile compounds were identified in the raw and processed black rice. Nonanal, butylated hydroxytoluene, 1-hexanol, naphthalene, and 1-octen-3-ol were the main volatile compounds. These volative compounds extracted from raw black rice grain varied widely compared to the processed materials. The study indicated that processing could significantly affect the profiles of nutritional compositions, anthocyanins, and volatile compounds during the production of black rice tea. 相似文献
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核磁共振波谱技术在食品掺假鉴别中的应用研究 总被引:1,自引:1,他引:0
核磁共振波谱技术具有快速无损、操作简单及重复性好等优点,近年来被广泛应用于食品掺假鉴别领域。利用核磁共振技术中的低场核磁、定量核磁以及杂核核磁等技术能够对掺假不同成分的牛乳(掺水、食盐、尿素、豆浆及复原乳等)、掺假低价值油(大豆油、玉米油等)的橄榄油、掺假的高价值米、蜂蜜、红酒等进行检测,结合统计学分析方法,包括主成分分析法、偏最小二乘判别法和相似分类法等可以实现对这些食品掺假成分的有效鉴别。本文就近年来核磁共振技术在国内外食品掺假鉴别中的应用研究进行综述,以推动核磁共振技术在食品质量安全检测领域的进一步应用,并为其它领域的掺假鉴别提供新的思路和方法。 相似文献
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采用核磁共振(NMR)技术对山西省内生产的亚麻籽油进行脂肪酸组成检测及品质鉴别。首先运用气相色谱-质谱联用(GC-MS)法确认纯亚麻籽油和掺杂亚麻籽油脂肪酸组成的差异;然后通过核磁共振谱仪确认差异核磁共振氢谱(1H NMR)和碳谱(13C NMR)的特征峰,以快速判别亚麻籽油是否掺杂;最后,采用1H NMR法计算亚麻籽油中的脂肪酸含量,并与国标GC法进行对比。结果表明:与纯亚麻籽油相比,掺杂亚麻籽油中含有花生一烯酸和芥酸;通过花生一烯酸和芥酸1H NMR和13C NMR特征峰可以定性鉴别亚麻籽油是否掺杂;采用1H NMR法计算的亚麻籽油中亚麻酸含量与GC法一致。说明基于NMR技术对亚麻籽油脂肪酸组成进行检测,可以快速鉴别亚麻籽油品质。 相似文献