高效液相色谱法同时检测液体食品中苯甲酸、山梨酸、安赛蜜、糖精钠含量的研究

采用高效液相色谱法同时测定液体食品中的山梨酸、苯甲酸、糖精钠、糖精钠。样品经盐酸酸化,乙醚提取,甲醇和水溶解后过HLB固相萃取小柱净化,以TC-C18(4.6×250mm,5μm)色谱柱分离。结果显示苯甲酸、山梨酸、糖精钠、安赛蜜在1.0μg/mL¹00.0μg/mL范围内呈线性关系,回收率在84.24%100.0μg/mL范围内呈线性关系,回收率在84.24%⁹6.34%之间,相对标准偏差在2.03%96.34%之间,相对标准偏差在2.03%⁴.78%之间,最低检限0.5 mg/kg,适用于同时检测液体食品中的苯甲酸、山梨酸、糖精钠、安赛蜜的含量。     

超高效液相色谱法同时测定饮料中的山梨酸、苯甲酸、脱氢乙酸、糖精钠和安赛蜜

目的建立用超高效液相色谱法(ultra performance liquid chromatography,UPLC)同时测定饮料中的山梨酸、苯甲酸、脱氢乙酸、糖精钠和安赛蜜的分析方法。方法样品中山梨酸、苯甲酸、脱氢乙酸、糖精钠和安赛蜜用水提取,经BEH C_(18)柱(2.1 mm×100 mm,1.7μm)分离,在波长225 nm处检测。结果此方法的线性范围是5~100μg/mL,回收率为95.5%~100.2%,相对标准偏差(relative standard deviation,RSD)为1.0%~3.1%。结论此方法简便快速,准确可靠,灵敏度高,可用于同时检测饮料中的山梨酸、苯甲酸、脱氢乙酸、糖精钠和安赛蜜。     

超高效液相色谱法同时快速测定陈年道菜中安赛蜜、苯甲酸、山梨酸、糖精钠、脱氢乙酸

建立了一种同时快速测定陈年道菜中安赛蜜、苯甲酸、山梨酸、糖精钠、脱氢乙酸的超高效液相色谱法。样品前处理后,经Agilent Ecilpse Plus C18(50mm×2.1mm,1.8μm)色谱柱分离,以甲醇-20mmol/L乙酸铵的乙酸溶液(pH 5.28)为流动相进行梯度洗脱,采用二极管阵列检测器,检测波长为230nm,流速为0.30mL/min,柱温为40℃,以保留时间定性,外标法峰面积定量。结果表明,安赛蜜、苯甲酸、山梨酸、糖精钠、脱氢乙酸在5min内可以完全分开,样品在0.02～0.10g/kg添加三水平范围内的回收率在66.43%～102.87%之间,相对标准偏差小于3.2%。该方法快速准确,分离效果好,适用于陈年道菜中安赛蜜、苯甲酸、山梨酸、糖精钠、脱氢乙酸的快速检测。     

反相高效液相色谱法同时测定黄豆酱中的苯甲酸、山梨酸、安赛蜜

建立一种用反相高效液相色谱法同时测定黄豆酱中苯甲酸,山梨酸和安赛蜜的新方法。样品经酸化后,用无水乙醚萃取,并浓缩吹干,再加入碳酸氢钠溶液溶解,样品调p H后,采用C18柱(250mm×4.6mm,5μm)分离,以甲醇(5%)+0.02mo L/L乙酸铵溶液(95%)为流动相,流速1.0m L/min,检测波长214nm(安赛蜜)及230nm(苯甲酸和山梨酸),出峰时间定性,外标法定量。结果表明:该方法的检出限为1mg/kg,线性范围为1~50μg/m L,相关系数分别为:安赛蜜R=0.99995;苯甲酸R=1.00000;山梨酸R=0.99993。回收率分别为:安赛蜜89.4%~94.1%;苯甲酸97.6%~101%;山梨酸89.6%~93.2%。相关标准偏差(RSD)分别为:安赛蜜0.38%~2.32%;苯甲酸0.26%~1.04%;山梨酸0.44%~1.82%。该方法准确方便,灵敏度高,可实现黄豆酱中苯甲酸、山梨酸、安赛蜜的测定。     

高效液相色谱法同时检测酸性乳饮料及冰淇淋中安赛蜜、苯甲酸、山梨酸和糖精钠含量

目的建立酸性乳饮料及冰淇淋中安赛蜜、苯甲酸、山梨酸、糖精钠含量的高效液相色谱分析方法。方法样品去除蛋白后,用甲醇提取,提取液用高压液相色谱仪进行检测。结果安赛蜜、苯甲酸、山梨酸、糖精钠在0~100μg/kg范围内,浓度与峰面积有良好的线性关系,相关系数大于0.999,检出限分别为2.87、0.96、0.97和2.69 mg/kg;样品的加标平均回收率分别为95.59%~104.52%、93.21%~108.05%、97.75%~107.98%和97.48%~103.67%,相对标准偏差均小于10%。结论本方法适用于酸性乳饮料及冰淇淋中安赛蜜、苯甲酸、山梨酸、糖精钠含量同时测定的需要。     

HPLC法同时快速测定酱油中的苯甲酸、山梨酸、糖精钠、安赛蜜

建立了一种同时快速测定酱油中苯甲酸、山梨酸、糖精钠、安赛蜜的高效液相色谱法。样品经水提取,取离心后的上清液,过0.22μm滤膜,高效色谱仪(C18柱)分析。色谱条件:色谱柱为C_(18)柱,柱温35℃,流动相为甲醇-0.02mol/L乙酸铵(体积比为5∶95),流速1.0mL/min,二极管阵列检测器检测,以保留时间定性,外标法峰面积定量。结果表明,样品在10～100mg/kg添加水平范围内,苯甲酸、山梨酸、糖精钠、安赛蜜的回收率在90%～104%,相对标准偏差小于3%。该方法简便、准确,适用于酱油中苯甲酸、山梨酸、糖精钠、安赛蜜的快速检测。     

高效液相色谱法同时测定蜜饯中的5种食品添加剂

采用高效液相色谱法同时测定蜜饯中安赛蜜、苯甲酸、山梨酸、糖精钠、脱氢乙酸含量的方法。试验结果表明,制备的样品中安赛蜜、苯甲酸、山梨酸、糖精钠、脱氢乙酸分离良好,安赛蜜、苯甲酸、山梨酸、糖精钠和脱氢乙酸在0.0μg~3.2μg范围内呈良好的线性关系,平均加样回收率均超过94.0%。该方法稳定性和重复性好,可作为测定蜜饯中安赛蜜、苯甲酸、山梨酸、糖精钠、脱氢乙酸的方法。     

UPLC同时测定风味饮料中安赛蜜、糖精钠、苯甲酸、山梨酸方法研究

建立了超高效液相色谱法(UPLC)同时测定风味饮料中安赛蜜、糖精钠、苯甲酸、山梨酸4种食品添加剂检测技术.实验采用Waters ACQUITY BEH C18色谱柱(100mm ×2.1mm,1.7μm),以0.02mol/L的乙酸铵-甲醇(95:5)为流动相,柱温25℃,二极管阵列检测器在波长230nm进行检测.整个分离过程在3min内完成,HPLC检测方法至少需要12min,大大节约了检测时间.安赛蜜、糖精钠、苯甲酸、山梨酸的回收率分别为98.5%～101.3%,相对标准偏差小于0.90%.方法快速准确.     

高效液相色谱法同时测定饮料中5种添加剂

利用高效液相色谱法同时测定饮料中安赛蜜、苯甲酸、山梨酸、糖精钠和脱氢乙酸。用ZORBAX SB-C18柱(4.6 mm×250 mm,5μm)分离,以甲醇∶乙酸铵(p H=6.5)=5∶95(体积比)为流动性,利用二极管阵列检测器(DAD)检测样品,外标法定量分析。结果浓度在1μg/m L~200μg/m L时,各组分的校准曲线的相关系数分别为:安赛蜜(0.999 6);苯甲酸(0.999 5);山梨酸(0.999 7);糖精钠(0.999 5);脱氢乙酸(0.999 8)。两种样品的回收率范围为:95%~105%。表明该方法快速、准确、简便。     

高效液相色谱法检测果蔬汁中五种添加剂

目的:运用高效液色谱法对果蔬汁中苯甲酸、安赛蜜、脱氢乙酸、糖精钠以及山梨酸添加剂进行检测。方法:色谱柱:Kromasil 100-5 C18(250mm×4.6mm,5μg);流动相:甲醇∶0.02mol/L乙酰胺溶液=5∶95(V∶V);流速:1.0m L/min;进样量:20μL;柱温:30℃;波长:230nm。结果:苯甲酸、安赛蜜、脱氢乙酸、糖精钠以及山梨酸在0.00~0.1mg/m L浓度范围内,均表现为良好的线性关系(r=0.97、r=0.98、r=0.96、r=0.98、r=0.98)。山梨酸、安赛蜜、糖精钠、苯甲酸、脱氢乙酸RSD分别为1.13%、1.01%、1.51%、1.05%、1.18%;平均回收率分别为98%~99%。结论:在液果蔬汁添加剂检测中,高效液相色谱法快速准确,且灵敏度较高,可满足检查需要。     

代可可脂、类可可脂、天然可可脂的组成及性质分析

对代可可脂(月桂酸型和非月桂酸型)、类可可脂、天然可可脂的组成及性质进行比较研究,主要包括Sn-2位和总脂肪酸组成分析、熔化特性、产品成分和氧化稳定性分析。结果表明,天然可可脂和类可可脂脂肪酸组成较相似,但与代可可脂则差异较大;天然可可脂、类可可脂和月桂酸型代可可脂的DSC曲线图上出现一个陡峭而又强烈的吸收峰,表明熔化范围较窄,成分单一,而非月桂酸型代可可脂的DSC曲线图上出现两个吸收峰,表明熔化范围较宽,成分复杂;天然可可脂、类可可脂和代可可脂中甘三酯含量均大于94%;利用Rancimat测定的天然可可脂、代可可脂的氧化稳定性相对类可可脂的较好。     

Oxidation and textural characteristics of butter and ice cream with modified fatty acid profiles

The primary objective of this study was to evaluate oxidation and firmness of butter and ice cream made with modified milkfat containing enhanced amounts of linoleic acid or oleic acid. The influence of the fatty acid profile of the HO milkfat relating to product properties as compared with the influence the fatty acid profile of the HL milkfat was the main focus of the research. Altering the degree of unsaturation in milkfat may affect melting characteristics and oxidation rates, leading to quality issues in dairy products. Three milkfat compositions (high-oleic, high-linoleic, and control) were obtained by modifying the diets of Holstein cows. Ice cream and butter were processed from milkfat obtained from cows in each dietary group. Butter and ice cream samples were analyzed to determine fatty acid profile and firmness. High-oleic milkfat resulted in a softer butter. Solid fat index of high-oleic and high-linoleic milkfat was lower than the control. Control ice cream mix had higher viscosity compared with high-oleic and high-linoleic, but firmness of all ice creams was similar when measured between -17 and -13 degrees C. Nutritional and textural properties of butter and ice cream can be improved by modifying the diets of cows.     

Texture of butter from cows with different milk fatty acid compositions

Milk fatty acid composition and textural properties of butter are known to be affected by the cows' diets. We examined the phenotypic variation in milk fatty acid composition among cows fed the same diet to see if the variation was sufficient to produce butter with different textural properties. Ten cows were selected that tested higher (n = 5) or lower (n = 5) in their proportion of milk unsaturated fatty acids. Milk samples were collected a week after testing, and butter was prepared from the individual samples. Milk and butter samples were again analyzed for fatty acid composition. Butter at 5 degrees C was evaluated by a sensory panel for spreadability and by a texture analyzer at both 5 and 23 degrees C for hardness and adhesiveness. Milk and butter samples from cows with a more unsaturated milk fatty acid composition had a lower atherogenic index, and the butter samples were more spreadable, softer, and less adhesive. Thus, phenotypic variation in milk fatty acid composition among cows fed the same diet is sufficient to produce butter with different textural properties.     

固相分散萃取-离子对液相色谱法测定花生酱中苯甲酸和山梨酸

采用固相分散萃取技术处理样品,无水硫酸钠为分散剂,反相离子对色谱法测定花生酱中苯甲酸和山梨酸.色谱条件:C18柱,甲醇-5 mmol/L四丁基溴化铵水溶液(40:60,V/V)为流动相,检测波长230 nm.在0.5～100 μg/mL范围内线性良好,相关系数均为0.9997.两组分平均回收率91.7％和77.4％,相对标准偏差2.02％和2.99％,检出限分别为0.90 μg/g和1.35 μg/g.     

The linear relationship between the proportion of fresh grass in the cow diet, milk fatty acid composition, and butter properties

Fresh grass in the cow diet improves the rheological and nutritional properties of butter. However, the relationship between the proportion of fresh grass in the diet and these properties is still unknown. The objective of the study was to determine the relationship between the proportion of fresh grass in the diet and the properties of milk and butter. Four groups of 2 cows were fed 4 isoenergetic diets characterized by increasing amounts of fresh grass (0, 30, 60, and 100% dry matter of forage) according to a Youden square design. Energy levels were similar among all diets. Thus, no effect of mobilization was observed and the results were only due to the proportion of fresh grass in the diet. Milk yield linearly increased with the proportion of fresh grass in the diet (+0.21 kg/d per 10% of grass). Fat yield remained unchanged. Thus, by effect of dilution, increasing the proportion of fresh grass in the diet induced a linear decrease in fat content. Milk fat globule size decreased by 0.29 μm when the proportion of grass reached 30% in the diet. Increasing the proportion of fresh grass in the diet induced a linear increase in unsaturated fatty acids percentages at the expense of saturated fatty acids. Relationships were +0.38, +0.12, +0.05 and −0.69 points/10% of fresh grass in the diet for C18:1 trans-11, C18:2 cis-9,trans-11, C18:3n-3, and C16:0, respectively. These modifications in fatty acid composition, and in particular in the spreadability index, C16:0/C18:1, were responsible for linear decreases in final melting temperature and solid fat content in butter fat, perceived in sensory analysis by a linear decrease in firmness in mouth. The nutritional value of butter was also linearly improved by the proportion of fresh grass in the diet by halving the atherogenicity index.     

Effects of feeding camelina (seeds or meal) on milk fatty acid composition and butter spreadability

The nutritional and rheological properties of butter depend on the fatty acid composition of milk. Therefore, feeding oilseeds rich in unsaturated fatty acids is likely to affect butter properties. The aim of this trial was to examine to what extent feeding the linolenic acid-rich cruciferous plant camelina can affect the fatty acid composition of dairy products and the properties of butter. A control diet composed of 60% corn silage-based ration and completed with high-energy and nitrogenous concentrates was compared with 2 experimental diets designed to provide the same amount of polyunsaturated fatty acids via either camelina seed (630 g/d, CS diet) or camelina meal (2 kg/d, CM diet). The diets were isoenergetic and isonitrogenous. The trial followed a double 3 × 3 Latin-square design with 4-wk periods on 6 Holstein dairy cows. The camelina diets tended to decrease dry matter intake but did not have a significant effect on milk production. They generated a slight decrease in milk protein and a strong decrease in milk fat yield and content. The CM diet led to a stronger decrease in fat content. Camelina generated a greater proportion of monounsaturated fatty acids, notably C18:1 trans isomers, including trans-10 and trans-11 C18:1, which increased by 11.0- and 2.6-fold, respectively, with the CM diet. Camelina also led to an increase in conjugated linoleic acids, particularly rumenic acid, cis-9, trans-11 C18:2. Camelina did not affect parameters of buttermaking except churning time with milk from CM fed cows, which was longer. The butters of camelina diets were softer at all temperatures tested, especially with the CM diet. In conclusion, feeding camelina can modify milk fatty acid profile and butter spreadability.     

Anti-obesity effects of conjugated linoleic acid, docosahexaenoic acid, and eicosapentaenoic acid

Obesity has become a prevailing epidemic throughout the globe. Effective therapies for obesity become attracting. Food components with beneficial effects on "weight loss" have caught increasing attentions. Conjugated linoleic acid (CLA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) belong to different families of polyunsaturated fatty acids (PUFA). However, they have similar effects on alleviating obesity and/or preventing from obesity. They influence the balance between energy intake and expenditure; and reduce body weight and/or fat deposition in animal models, but show little effect in healthy human subjects. They inhibit key enzymes responsible for lipid synthesis, such as fatty acid synthase and stearoyl-CoA desaturase-1, enhance lipid oxidation and thermogenesis, and prevent free fatty acids from entering adipocytes for lipogenesis. PUFA also exert suppressive effects on several key factors involved in adipocyte differentiation and fat storage. Despite their similar effects and shared mechanisms, they display differences in the regulation of lipid metabolism. Moreover, DHA and EPA exhibit "anti-obesity" effect as well as improving insulin sensitivity, while CLA induces insulin resistance and fatty liver in most cases. A deeper and more detailed investigation into the complex network of anti-obesity regulatory pathways by different PUFA will improve our understanding of the mechanisms of body weight control and reduce the prevalence of obesity.     

高油酸花生油酶促酯交换合成类可可脂工艺优化

为促进高油酸花生油的高值化利用,在无溶剂体系中以高油酸花生油为原料,棕榈酸乙酯、硬脂酸乙酯为酰基供体,酶促酯交换合成类可可脂。以目标甘三酯1,3-二棕榈酸-2-油酸(POP)、1-棕榈酸-2-油酸-3-硬脂酸(POS)、1,3-二硬脂酸-2-油酸(SOS)含量,硬脂酸指数和酰基位移率为评价指标,在单因素实验的基础上采用响应面法对酶促酯交换合成类可可脂的工艺条件进行优化。结果表明：酶促酯交换合成类可可脂的最佳工艺条件为硬脂酸乙酯与棕榈酸乙酯物质的量比1.3∶1、酰基供体与高油酸花生油物质的量比12∶1、加酶量2.7%(以底物质量计)、反应温度60℃、反应时间7 h,在该条件下产物甘三酯中POP、POS、SOS的含量分别为14.55%、48.87%、25.17%,硬脂酸指数为0.56,酰基位移率为7.35%。产物的目标甘三酯组成和脂肪酸组成与可可脂相近,可作为可可脂替代品应用。     

气相色谱法同时快速测定食品中丙酸、山梨酸、苯甲酸及脱氢乙酸

通过液液萃取净化样品研究,建立了食品中丙酸、山梨酸、苯甲酸、脱氢乙酸及其盐含量气相色谱同时快速测定方法,适用于固体非酯(脂)类食品的检测。结果表明:丙酸的回收率在85.1%~91.3%之间,其余3种防腐剂的回收率均在95.2%~99.4%之间;实验室内变异系数(CV,n=6)最大值≤4.7%,4种防腐剂检出限均在0.002 g/kg以下。4种目标物在有杂质干扰时,可用不同的极性毛细管柱做进一步的确认。本方法具有适用范围广、检测效率高、重现性好、准确度高、检出限低的特点,推广应用对我国食品安全的监督检验具有重要的意义。