【作者】 孙丰梅；

【导师】 杨曙明；

【作者基本信息】 中国农业科学院 ， 农产品质量与食物安全， 2009， 博士

【摘要】 稳定同位素技术在地质学、考古学、医学、环境科学中很早就得到研究和应用,由于其特有的优点,近年来又被用于食品产地溯源的研究中。为了推动稳定同位素技术在我国食品科学中的应用和发展,本研究对其在牛肉溯源中的应用进行了探讨。为研究牛不同组织器官中不同稳定同位素的组成情况以及品种对同位素组成的影响,采集西门塔尔牛和夏洛来牛的里脊、外脊、腿部肌肉、臀部肌肉、牛尾毛、血液、肝脏、饲料等样品。利用同位素比率质谱仪测定了上述组织及饲料中的δ¹³C、δ¹⁵N、δ²H、δ³⁴S,肉品水中δ²H和δ¹⁸O,并借助SAS软件对检测结果进行了方差分析、多重比较分析。结果表明,牛组织中δ¹³C、δ¹⁵N、δ³⁴S值不受品种因素的影响,但δ²H值在牛两品种之间有差异;粗脂肪中的δ¹³C值远远低于其它组织,不同部位粗脂肪间差异不显著（P>0.05）,δ¹³C值在其它组织间也无显著差异（P>0.05）;肝脏中的δ¹⁵N值远高于其它组织;牛尾毛中的δ²H和δ³⁴S值与肌肉组织相比有极显著差异（P<0.01）,说明同位素在牛不同组织中的分馏效应是不一致的。肉品水中δ²H值和δ¹⁸O值存在着较强的相关关系（R2=0.83）,但各组织间的δ¹³C、δ¹⁵N、δ³⁴S、δ²H值相关关系不明显。因此在进行牛肉溯源的研究时,应根据研究目的、研究对象选择适宜的组织和成分。饲料碳同位素和氮同位素组成不同,影响动物组织中的δ¹³C和δ¹⁵N值。选择36头12-14月龄的青年牛作为试验动物,分为两个大组,分别饲喂C3、C4植物含量不同的日粮,探讨牛组织中δ¹³C值和膳食中C3、C4植物比例间的剂量响应关系。132天后将试验动物屠宰。利用同位素比率质谱仪测定牛尾毛、脱脂牛肉、粗脂肪、各种饲料原料的δ¹³C和δ¹⁵N值。结果表明,牛组织中碳同位素组成主要受饲料的影响,牛尾毛、脱脂肌肉、粗脂肪中的δ¹³C值随着C4植物含量在牛饲料中的比例增加而升高,随着C3植物含量在牛饲料中的比例增大而降低,并且均与C4、C3植物含量呈极显著的相关性（P<0.01）,用牛组织中的δ¹³C值可以调查牛饲料中的主要成分;牛组织中的氮同位素一定程度上受饲料因素的影响,但未随饲料组成成分的改变而呈现规律性变化;牛尾毛、脱脂肌肉相对饲料对13C的富集比例两组试验结果不一致,牛尾毛对15N的富集比例大于脱脂肌肉,富集比例约在3‰- 5‰,饲料种类、牛个体等因素对富集比例均有一定影响;牛尾毛、脱脂肌肉、粗脂肪中的δ¹³C值三者之间相关性达到极显著水平（P<0.01）。牛尾毛、脱脂肌肉、粗脂肪均可作为牛肉溯源的材料。为了探讨稳定同位素技术对我国牛肉产地溯源的可行性,采集不同来源的牛肉及饮水样品,分别测定脱脂牛肉中的δ¹³C和δ¹⁵N,牛粗脂肪中的δ¹⁸O及饮水中的δ¹⁸O。结果表明,不同地域来源脱脂牛肉中碳、氮同位素组成有显著差异,粗脂肪中的δ¹⁸O值也有显著差异,并且与各地饮水中的δ¹⁸O值高度相关,说明利用同位素技术可以区分不同产地来源的牛肉,同时用牛肉中的δ¹³C值可推断牛饲料的主要成分。本论文利用稳定同位素质谱技术研究了牛不同组织中δ¹³C、δ¹⁵N、δ²H、δ³⁴S、δ¹⁸O的组成变化情况,通过饲养试验确立了牛组织中δ¹³C值与饲料中C₄、C₃植物比例的关系,通过分析不同来源的牛肉样品,证明了利用同位素技术进行牛肉产地溯源是可行的,为稳定同位素技术在食品中的应用奠定了基础。更多还原

【Abstract】 Stable isotope technology was applied in the fields of geology, archeology, medical and environmental science in early time. In recent years, stable isotope analysis is applied in the traceability of food geographical origin thanks to its virtue. The objective of this article was to push forward its application and development into food science and it was studied in beef traceability.In order to research on different stable isotope composition in the different beef tissues, as well as the breed, longissimus muscle, psoas major muscle, leg muscle, buttock muscle, cattle tail hair, blood, liver and feed were collected, which were belonging to simmental and charolais cattle under the same culture conditions. Theδ¹³C,δ¹⁵N,δ²H,δ³⁴S values of above tissues,andδ²H,δ¹⁸O of muscle tissue water were determined using isotope ratio mass spectrometry（IRMS）. Then the data were performed using multivariate analysis including ANOVA with the help of SAS Package for windows. The results showed thatδ¹³C,δ¹⁵N,δ³⁴S values of cattle tissues exceptδ²H values were not different between breed. Theδ¹³C values of crude fat were far lower than those of other tissues, but it had not significant difference between different fat sources and the same as other defatted tissues （P>0.05）. However,δ¹⁵N values of defatted liver, andδ²H,δ³⁴S values of cattle tail hair were significantly higher than those of muscle tissues （P<0.01）. So these results indicated that isotope fractionation in the various tissue was discrepant. Theδ²H andδ¹⁸O values of muscle tissue water were positively correlated （R2=0.83, P<0.01 ）, but these values varied in a large range. Theδ¹³C,δ¹⁵N,δ³⁴S,δ²H values between each tissue were not significantly correlated, so the proper tissue or component should be selected according to the purpose and object in the beef traceability study.Previous studies had shown that the stable carbon and nitrogen composition of diets influenced theδ¹³C andδ¹⁵N values of animal tissue. 36 （12 to14 months old） young bulls were selected and assigned to 2 large groups fed with a diet consisting of different content of C3、C4 plant with the aim of developing a quantitative relationship between the dietary C4 and C3 plant intake andδ¹³C of bovine tissues. All animals were slaughtered after feeding for 132 days. Theδ¹³C andδ¹⁵N values of cattle tail hair, defatted muscle, crude fat and each feed material were determined by isotope ratio mass spectrometry （IRMS）. It was shown that the stable carbon isotope composition of beef tissue was primarily dependent on the diet the animals were fed,meanwhile theδ¹³C values of cattle tail hair, defatted muscle and crude fat all enhanced with the increment of the proportions of C4 constituents in diet, but those values were on the contrary with the enhancement of the proportions of C3 constituents. Moreover, allδ¹³C values of different tissues were significantly correlated with the content of C4 and C3 plant material. So, the main component of cattle feed could be investigated with the help ofδ¹³C values. Theδ¹⁵N values of beef tissues were affected by feed composition to some extent, but it had no regularity. The cattle tail hair and defatted muscle enriched in 13C to their feeds gave different results between the two groups, but cattle tail hair enriched in 15N much more than defatted muscle and in the proportion of 3‰- 5‰, plus, cattle variety and individual had effect on the proportion of enrichment. Theδ¹³C values between cattle tail hair, defatted muscle, crude fat were significantly correlated （P< 0.01）, which suggested that all of them could be used for beef traceability.For exploring the feasibility of stable isotope technique for cattle geographical origin, the beef samples and drinking water samples were collected from different regions, then theδ¹³C,δ¹⁵N values of defatted muscle andδ¹⁸O values of crude fat and drinking water were determined. The results showed that the stable carbon and nitrogen isotope composition of beef were significantly different, and the same as theδ¹⁸O values of crude fat, but also they were highly correlated with theδ¹⁸O values of drinking water. Therefore, stable isotope technique can distinguish cattle from different regions, and also the main component of cattle feed can be inferred using theδ¹³C values of beef.This article studied the stable carbon, nitrogen, sulfur, hydrogen and oxygen composition of beef different tissues with IRMS, and established the relationship between the dietary C4, C3 plant proportion andδ¹³C of bovine tissues by the animal experiment. At the same time, the stable isotope technique was proved for cattle geographical origin by analyzing beef samples from different regions.These results provided theoretical basis in the food traceability for the stable isotope technology.更多还原