氢、氧稳定同位素在新疆库尔勒香梨中的分布及分馏机制

The Xinjiang Korle Pear(XJKP) is the international famous product of geographical indication, which are wide concern by consumers for its quality and safety. It is the prerequisite for the government to supervise the safety by tracing the original production region and confirming the authenticity and effectiveness of product information. Compound-specific isotope analysis has a good application prospect on traceability and authenticity of food origin. δD and δ18O isotope is one of key effective isotope for agro-food geographical origin traceability. Although the isotope has been used to trace the origin of XJKP, but the corresponding relationship between the environmental factors such as surface water and the compound-specific (such as carbohydrate, organic acid) of isotopic fingerprint characteristic of XJKP is not clear, as well as the isotopic fractionation effects. It is an urgent scientific problem which related to the accuracy, reliability, stability of the traceability application. The project take the XJKP as the research material, the δD and δ18O isotope fingerprint of XJKP and the corresponding environmental samples such as surface water et al from different origins were analyzed. The project aims to (1)to explore the fraction characteristic of δD and δ18O isotope in XJKP, (2)to reveal the variation law of δD and δ18O isotopes in different compound-specific of fruit of XJKP, (3)to elucidate the corresponding relations between the environmental factor such as surface water and the fruit of XJKP of δD and δ18O isotopes. The innovation of the project is to reveal the mechanism of traceability of XJKP by the δD and δ18O isotope fingerprint, which can provide theoretical basis for traceability and authenticity of XJKFP geographical origin.

库尔勒香梨是国际知名的地理标志产品，其质量安全受到消费者的普遍关注。追溯香梨原产地并确证产品信息的真实有效性是政府部门实施监管的前提条件。单体稳定同位素分析在食品产地溯源与确证方面具有很好的应用前景。氢氧稳定同位素是产地溯源与确证的重要同位素。尽管已被用于香梨产地溯源研究，但环境因子与香梨各单体组分（如糖、有机酸等）中氢氧稳定同位素指纹特征、对应关系及分馏效应并不清楚，这是氢氧稳定同位素成为准确、稳定、可靠的产地溯源指标亟待解决的关键科学问题。本项目拟以库尔勒香梨为研究材料，分析不同产地来源香梨及对应环境样品的氢氧稳定同位素组成；探讨氢氧稳定同位素在果实中的分布规律及分馏特征；揭示氢氧稳定同位素在香梨各单体组分中的变化规律；明确果实与环境因子氢氧稳定同位素的对应关系。项目创新点在于揭示氢氧稳定同位素在香梨果实中分馏的机理，旨在为香梨产地溯源与确证提供理论依据。

氢（H）和氧（O）是构成植物体重要成分，δ2H、δ18O是产地溯源与确证的重要指标，尽管已被广泛用于瓜果真实性鉴别与溯源研究，但环境因子与瓜果中稳定同位素指纹特征、对应关系及分布规律等均不清楚，这是H、O稳定同位素成为准确、稳定、可靠的产地溯源指标亟待解决的关键科学问题。项目通过研究新疆库尔勒市、阿克苏市和甘肃酒泉市等产区香梨中的H、O稳定同位素组成及在香梨果实不同部位中的变化规律，发现库尔勒香梨果实不同部位H、O稳定同位素存在显著的差异（分馏），且来自新疆、甘肃、陕西三个产区香梨果实中的H、O稳定同位素值及其与产地环境水样中的δ2H、δ18O值存在显著差异，借助同位素质谱联用技术探索了香梨果实中特定化合物的稳定同位素组成，发现了H、O等多种稳定同位素指纹信息在香梨果实不同部位、不同组分中的变化规律，明确了香梨果实的产地指纹特征，发现香梨果实H、O稳定同位素明显受到年际效应和地理因子的影响。通过稳定C、N、H、O同位素指纹，建立了基于稳定同位素判别香梨产地的判别模型，筛选出了与产地密切相关的稳定同位素，探讨了H、O稳定同位素在果实不同部位及特定化合物中分馏的原因，为揭示库尔勒香梨同位素指纹溯源机理奠定了基础，同时，通过本研究，将进一步探讨单体稳定同位素在库尔勒香梨产地溯源中的应用开辟了蹊径，为特定化合物稳定同位素产地溯源研究提供了理论支撑。