PCR技术在肉类成分定量分析中的应用研究进展

PCR技术具有特异性强、灵敏度高、可同时分析大量样本的特点,在鉴别和定量分析食品中肉类成分上应用广泛。本文介绍了PCR扩增产物分析、实时荧光PCR和微滴数字PCR三种应用于肉类定量的技术,通过检出限、定量限和定量范围等数据分析这三种方法在肉类成分定量分析中的应用效果,并对其定量的局限性进行阐述,为进一步完善PCR定量技术提供参考。

多重PCR技术在食品中4种肉类成分快速鉴别中的应用

目的:探究多重PCR技术在食品中4种(猪肉、牛肉、羊肉和鸡肉)肉类成分快速鉴别中的应用。方法:采用DNeasy试剂盒提取法、SDS-蛋白酶K法与CTAB-蛋白酶K法提取肉类中总DNA,比较三种方法的效率及纯度,确定最优方式。在动物线粒体细胞色素b基因的差异性位点,设计两套多重PCR引物。建立并优化多重PCR反应体系,根据电泳检测扩增产物分子量差异以快速鉴别4种肉类。结果:DNeasy试剂盒法、SDS-蛋白酶K法提取DNA效率显著优于CTAB-蛋白酶K法,P<0.05。在优化反应条件下选择特异性高、序列长的多重PCR引物可有效快速鉴定食品中猪、牛、羊与鸡源性成分,检测灵敏度为皮克级。结论:多重PCR方法应用于食物中多动物源性成分鉴别,精确稳定快速。

常见肉类成分荧光PCR检测试剂盒的比较

目前市场上肉类成分检测试剂盒种类繁多。为了评价不同厂家试剂盒的应用效果,选取当前市场上4个品牌的5种肉类成分荧光PCR检测试剂盒,对其特异性、灵敏性及效率成本进行了分析比较。结果显示:4个品牌的5种肉类成分荧光PCR检测试剂盒特异性均较好,不同肉类之间没有交叉反应;但检测同一种肉类的不同品牌试剂盒及同一品牌检测不同肉类的试剂盒灵敏性存在差异;不同品牌的试剂盒检测时间和成本也有区别,A品牌耗时最短,D品牌价格最高。结果表明,不同品牌试剂盒的灵敏性、检测耗时和检测成本各有特点,使用者可根据使用目的及经费预算选择合适的试剂盒。

Chemical Composition of Meat in Castrated Male Brahman Cattle in Venezuela

Chemical composition of Brahman cattle was studied and determined in this study. Fifty males had been castrated at birth, farmed semi-intensively on the Venezuelan plain and then slaughtered at the age of 31 months with an approximate weight of 500 kilograms. The average pH value of beef was 5,84 after obtained for 24 hours after staughtering, which matches the ~atue found in similar studies made on the same breed in Venezuela （5.8）. The moisture, crude protein and ash contents correspond to the expected values of cattle, while the intramuscular fat values are slightly higher than those of the different breeds ofBos indicus. The total collagen values found in this study are either similar or lower than those found by other researches from the different breeds ofBos indicus and their crossbreeds, while the collagen solubility value （39%） was higher than the one found in other studies on the Brahman breed.

Fisher判别法确定肉类寒热性的物质基础

运用Fisher判别分析理论,根据寒热性肉类的化学成分,针对寒热性的寒性、平性、热性进行判别分类,分别建立Fisher的线性判别函数模型和典则判别的函数模型,并对它们进行判别分析,将所建得的肉类寒热性识别的Fisher判别模型应用于其他肉类和食品予以验证。研究结果表明:该模型利用回代估计法所得到的误判率小,并具有较强的判别能力。运用该模型进行判别分析,简易方便,分类效率高,对寒热性肉类具有快速、有效地判别;该模型适用性强,有广阔的应用前景。

Quantification of seven phenylpropanoid compounds in Chinese Cinnamomi Cortex and Ramulus by HPLC

In the present study, we developed and validated a high-performance liquid chromatography method for the simultaneous determination of seven phenylpropanoid compounds （2-hydroxyl cinnamaldehyde, coumarin, cinnamyl alcohol, cinnamic acid, 2-methoxy cinnamic acid, cinnamaldehyde and 2-methoxy cinnamaldehyde） in Cinnamomi Cortex and Cinnamomi Ramulus. The levels of seven phenylpropanoid compounds in Cinnamomi Cortex and Cinnamomi Ramulus were compared using this method. A total of 48 samples （27 Cinnamomi Cortex and 21 Cinnamomi Ramulus） were purchased in China and analyzed. Quantities of seven phenylpropanoid compounds ranged from 17.5 to 61.6 mg/g in Cinnamomi Cortex and ranged from 9.91 to 23.4 mg/g in Ciunamomi Ramulus. The level of 2-methoxy cinnamic acid in the Cinnamomi Cortex samples was below the LOD, whereas it ranged from 0 to 0.119 mg/g in the Cinnamomi Ramulus samples. The （cinnamyl alcohol＋cinnamic acid）/cinnamaldehyde ratios （R346） of Ciunamomi Cortex and Cinnamomi Ramulus ranged from 0.0121 to 0.0467 and 0.0598 to 0.182, respectively. This ratio could be used to discriminate Cinnamomi Cortex （〈0.05） and Cinnamomi Ramulus （〉0.05）. The extraction rates （Dn） of seven compounds in boiling water were different, with the lowest dissolution for cinnamaldehyde （〈3%） and the highest for cinnamic acid （about 60%）.