Actin Determination as a Means of Calculating the Meat Content of Meat Products

Double radioisotope labelling and peptide isolation can be used to determine the amount of actin in protein mixtures. Muscle samples from a variety of animals have similar actin contents as measured by this method and two common meat extenders, soy and milk protein, contain no material measured as actin. The potential usefulness of actin determination as a measure of the meat protein content of meat products was examined. Curing processes lead to a reduced apparent actin content in meats as determined by double labelling. However, it was found that there was a significant correlation between the ground beef derived protein content of extended ground beef samples and the actin content per unit protein when double labelling was used to determine the actin content of ground beef preparations containing various amounts of soy protein.     

肉与肉制品中磷酸盐含量测定方法的改进

目的:对GB/T5009.87-2003中样品处理过程进行改进,建立一套微波消解处理法.方法:使用微波消解仪,在肉与肉制品中加入硝酸密闭消解,消解液用磷钼蓝分光光度法在660nm波长处测定样品中磷的含量.结果:微波消解技术可将样品消解完全,采用磷钼蓝分光光度法测定体系中磷酸盐(以磷酸根计)的含量在0～150 μ g(25ml比色管)时,磷酸盐的含量与吸光度呈线性关系,相关系数0.9999;对实际样品的加标平均回收率在97.0%-105.5%之间.结论:该法操作简单,试剂用量少、重现性好,用微波消解技术大大缩短了样品前处理时间,适于肉与肉制品中磷酸盐含量的测定.     

HPCE法同时检测果蔬及肉制品中硝酸盐和亚硝酸盐含量

为了能够同时、快速检测果蔬及肉制品中的硝酸盐和亚硝酸盐,利用高效毛细管电泳对其进行检测,重点研究检测条件的筛选和干扰离子的排除。使用内径50?μm、总长40?cm、有效长度30?cm的毛细管柱,在214?nm条件下,采用毛细管区带电泳-直接紫外法,研究分离缓冲液的pH值、浓度、电渗流改性剂十六烷基三甲基溴化铵的添加量、排除Cl－干扰方式以及分离电压对分离效果的影响,同时进行方法学检验,以确定其回收率、线性、检出限和精密度。结果表明：对于含盐量500?mmol/L以下的样品在6?min内NO3－和NO2－能够达到很好分离,该方法的加标回收率在81.82%～100.91%之间,线性范围较宽,相关系数均在0.99以上,检出限分别为0.69?μg/mL和0.50?μg/mL,精密度均不高于3.2%,具有简便、快速、准确、环保等优点,也为生产中快速监控硝酸盐和亚硝酸盐残留量提供了科学依据。     

Determination of the Collagen, Elastin and Bone Content in Meat Products using Television Image Analysis

Television image analysis offers a method for the automatic determination of surface areas. The method was tested for its suitability for use in the quantitative estimation of raw and gelatinized collagen, elastin and bone particles of histological sections of meat and meat products. Five different experiments show that television image analysis correlates closely to the results obtained using the point count technique (correlation coefficient r > 0.981), the bone content determined by chemical means (r > 0.97) as well as the experiments using added collagen (r = 0.988) and elastin (r = 0.854). It can be concluded that the automatic image analysis is an adequate alternative to chemical analysis.     

高效毛细管电泳法测定奶制品中三聚氰胺含量

目的：建立奶制品中三聚氰胺的含量测定方法。方法：采用高效毛细管电泳法测定,以30mmol/L 磷酸盐缓冲液(pH5.0)为电泳介质,未涂层石英毛细管(75μm× 78cm,有效长度70cm)为分离通道,紫外检测波长240nm,分离电压10kV。结果：三聚氰胺在10.0～50.0μg/mL 范围内线性关系良好,r=0.9992。平均加标回收率为97.04%,平均RSD 为1.24%(n=3)。结论：该方法快速简便、灵敏度高、重现性好,可用于奶制品中三聚氰胺含量的测定。     

肉制品中亚硝酸盐国标检测法的改进研究

针对GB/T5009.33 - 2003 食品中硝酸盐与亚硝酸盐检测方法的样品预处理过程复杂、耗时长等问题,改用天然高分子絮凝剂W-3 取代原有蛋白质沉淀剂--亚铁氰化钾和乙酸锌,不但节省试剂,且显著缩短处理时间。用改进后的方法测定肉制品中亚硝酸盐含量,检出限较低,回收率高,与国标法对比,相对误差低于3%。     

银量法测定肉制品中氯化物的方法研究

肉制品企业常常会同时检测肉制品中亚硝酸盐含量和氯化物含量,依据目前有效的检测方法标准,这两个检测项目的样品前处理方法基本相同,如果合并两个检测项目的样品前处理,能够有效提高检测效率,降低检测成本。实验证明:合并样品前处理对检测结果无影响,精密度小于2%,符合要求。     

烟熏肉制品中甲醛含量的测定

为测定烟熏肉制品中的甲醛含量,比较室温浸泡法和水蒸气蒸馏法预处理方法,并对不同产地和种类烟熏腊肉中的甲醛含量进行测定。结果表明,综合考虑加标回收率、相对标准偏差以及方法检出限,采用水蒸气蒸馏预处理方法要优于采用室温浸泡法。而对烟熏肉制品甲醛含量的测定结果表明,传统烟熏肉制品中甲醛含量较高,其中表层的甲醛含量21～124mg/kg,内部的甲醛含量8～22mg/kg。     

毛细管气相色谱法测定肉制品中脱氢乙酸含量

建立肉制品中脱氢乙酸含量的毛细管气相色谱测定方法。该法采用WBI进样口,毛细管色谱柱（弱极性）DB-5（30m×0.53mm,0.5μm）,FID检测器进行检测。进样口温度：250℃;载气流速：10mL/min;程序升温：初始80℃,以10℃/min升至200℃,保持5min;检测器温度：250℃,样品用硫酸溶液酸化无水乙醇定容后直接进样测定。方法简单、快速、重现性好,平均回收率为97.5%,RSD为1.16%,线性范围为10～200μg/mL。     

一种基于实时荧光聚合酶链式反应的肉及肉制品中猪源性成分含量测定

为了建立一种基于实时荧光聚合酶链式反应的肉及肉制品猪源性成分含量测定方法,分别以猪线粒体DNA的NADH4基因和16S rRNA基因为靶位点设计猪特异性引物、探针和通用引物、探针,建立猪源性成分含量测定方法,通过特异性、灵敏性、线性、准确度及市售肉制品检测,对该方法体系进行检验和评价.结果表明:建立的猪源性成分含量实时荧光聚合酶链式反应测定方法体系具有良好的特异性及灵敏性,最低可检测到0.4pg/μL纯猪肉DNA;无论是猪特异性体系还是通用体系都呈现良好的线性关系(R2均达到0.999以上)和较宽的线性范围;通过含猪源性成分的模拟混合肉样检测,样品猪源性成分含量的回收率平均值为122.27％,说明该方法具有较高的准确度;通过市售肉制品检测表明该方法可以用来检测实际样品(包括生鲜样品和熟肉样品)中猪源性成分含量.     

毛细管电泳法对乳及乳制品中乳源蛋白的测定

采用毛细管电泳方法对乳及乳制品中乳源蛋白成分进行检测.选择聚乙烯醇涂层毛细管,采用柠檬酸缓冲体系,在紫外检测214 nm、分离电压20 kV条件下对乳及乳制品中的α-乳白蛋白(α-La)、β-乳球蛋白(β3-Lg)、α-酪蛋白(α-CN)、β-酪蛋白(β-N)和k-酪蛋白(k-N)进行分离测定.五种蛋白线性良好,线性相关系数均大于0.997 8,各蛋白峰面积的相对标准偏差为1.76％～3.28％,加标回收率范围为88.1％～110.8％.应用该方法对液态奶、酸奶及奶粉中的乳源蛋白进行测定.本法准确、简便、易行,适于测定液态奶、酸奶、奶粉中蛋白质的检测.     

毛细管电泳法对乳及乳制品中真蛋白的测定

利用毛细管电泳法对市售乳清蛋白粉、采自当地奶牛场的牛初乳及原料奶、同一品牌不同阶段或同一阶段内不同厂家、不同国别的婴儿配方奶粉、不同保质期的液态奶、不同国别的超高温灭菌(UHT)奶和酸奶、国产复原乳中α- 乳白蛋白(α-Lac)、β- 乳球蛋白A (β-LgA)及β- 乳球蛋白B (β-LgB)的质量分数进行测定。结果表明：α-Lac、β-LgA 及β-LgB 的质量分数在乳清蛋白粉、牛初乳及原料奶中依次降低。液态奶中上述3 种蛋白的质量分数与保质期有关,一般保质期越久的产品,上述3 种蛋白的质量分数越低。大多数酸奶中α-Lac 的质量分数均高于UHT 奶。婴儿配方奶粉中α-Lac 质量分数随着阶段数的增加而增加,而且同一阶段内不同厂家不同国别配方奶粉中α-Lac 质量分数差异也较大,并非进口奶粉中α-Lac 质量分数均比国产奶粉高。     

毛细管区带电泳测定酪蛋白磷酸肽方法的研究

用毛细管区带电泳(CZE)对酪蛋白磷酸肽(CPP)进行了分离和测定。研究出的适宜电泳操作条件为:工作电压30KV、柱温25℃、毛细管长度50cm、内径70μm、进样量5sec(气压进样)、紫外检测波长200nm、缓冲液pH值9.2测定不同N/P样品的CPP含量分别为42.2％、50.0％、51.0％。     

肉制品中食盐含量测定方法的改进

目的建立肉制品中食盐含量测定的新方法。方法用共沉淀剂沉淀肉制品中蛋白质等干扰物质,用硝酸银标准溶液滴定样品提取液中的氯化钠,根据硝酸银的消耗体积计算样品中食盐的含量。结果样品测定相对标准偏差为2.11%,平均回收率为99.3%。与国标方法对比差异无统计学意义。结论本法适于肉制品中食盐的含量测定。     

Procedure for Soluble Collagen in Thermally Processed Meat Products

Methods to determine the extent of collagen solubilization during thermal processing in a product such as frankfurters may not be accurate. We modified existing procedures to separate soluble collagen from thermally processed meat samples without solubilizing more collagen. Water bath temperatures (36, 40, 44, 48, 52 and 56°C) and times (5, 10 and 15 min) were studied in a complete factorial design. Soluble collagen increased up to 48°C and 10 min, leveling off beyond that. In a 48–52°C water bath 10–15 min was sufficient to separate soluble collagen from thermally processed meat products without solubilizing more.     

优化毛细管电泳法测定山药淀粉中直链/支链淀粉

以市售新鲜怀山药为原料通过石灰水浸泡法制备山药粉,并通过正丁醇反复结晶法分离纯化直链淀粉与支链淀粉。利用碘做显色剂,使用毛细管电泳法测定山药淀粉中直链淀粉与支链淀粉的含量以及比率,本文分别对柠檬酸-磷酸盐缓冲液以及醋酸-醋酸盐缓冲液等不同缓冲液作为流动相进行了对比,实验发现醋酸-醋酸盐缓冲液对于分离测定直链淀粉与支链淀粉的效果较好。随后分析了不同p H条件下的醋酸-醋酸盐缓冲液进行的分离效果进行了比较,并测定其迁移率,当p H 4.8时分离效果最佳且其迁移率达到15.4。利用最佳条件使用纯的马铃薯直链淀粉与支链淀粉标准品,得出支链淀粉的保留时间约为1.8 min,而直链淀粉的保留时间约为2.9 min,对怀山药淀粉进行分析,从而得出怀山药中直链淀粉含量为19.49%。利用重复性试验以及回收率试验该方法的准确性与精确度能达到很好的效果。     

高效毛细管电泳法测定胭脂虫提取物中胭脂红酸

建立高效毛细管电泳法(HPCE)测定胭脂虫提取物中胭脂红酸含量的方法以含5% 乙腈、5% 乙二醇的40mmol/LNa2HPO4-Na2B4O7·10H2O 混合缓冲液(pH9.434)为背景电解质,60cm × 75μm 未涂层毛细管柱为分离泳道,分离电压20kV,0.5psi × 10s 压力进样,柱温25℃,检测波长239nm,此条件下,采用峰面积内标法定量;在选定的电泳条件下,胭脂红酸质量浓度在50～500mg/L 范围内线性关系良好,线性相关系数R=0.9958,加标回收率为100.86%,方法检出限(RSN=3)为5.00μg/mL。本方法测定胭脂红酸含量试剂用量少,简便、快速、准确,可应用于实际生产中胭脂红酸的测定。     

A Method for the Analysis of Tyramine in Meat Products: Its Content in Some Spanish Samples

A method is described for the analysis of tyramine in meat and meat products by sand column extraction eluted with ethyl acetate. Tyramine is determined quantitatively by fluorometry once the corresponding fluorophore has been formed by reacting the final extract with α-nitrous-β-naphthol Qualitative confirmation is carried out by spectrofluorometry and thin-layer chromatography. The average recovery was 88.80% and the relative standard deviation 6.35%. The method has been applied to 15 Spanish meat products, the amounts found oscillating between 0.13 and 301.2     

分光光度法测定鱼皮中羟脯氨酸含量

采用分光光度法测定鱼皮(鱿鱼皮和狗鲑鱼皮)中的羟脯氨酸(Hyp)含量.结果表明:两种鱼皮中羟脯氨酸的含量分别为0.823 %和2.247 %,平均回收率分别为98.47 %和98.39 %,变异系数分别为1.65 %和0.64 %.该法重复性好,可信度高,可作为判定鱼皮中胶原蛋白含量的一个定量指标.     

Development of a Reference Measurement Procedure and Certified Reference Material for the Determination of Hydroxyproline in Meat

The concentration of trans-4-hydroxy-l-proline has been traditionally employed as an estimate of collagen content in meat to assess meat quality. Conventional methods use chemical derivatization followed by UV–visible detection. However, complexity of the matrix may cause interferences due to lack of specificity and consequently bias quantification. On the contrary, liquid chromatography (LC) separation coupled to mass spectrometry (MS) detection overcomes these limitations, giving more accurate results. This study describes the development and validation of an exact matching-isotopic dilution mass spectrometry method for the determination of hydroxyproline in meat hydrolysates in the certification of a candidate meat reference material (CRM LGC7154). The method is not biased by changes in method conditions or by matrix load. Hydroxyproline concentrations and relative uncertainties for quality control samples revealed good agreement with the certified values. A mean hydroxyproline concentration of 1.78?±?0.28 g/kg (k?=?2) was found for the CRM LGC 7154 material.