Food Inspection and Quarantine Center, Shenzhen Customs, Shenzhen 518033, China; School of Life and Marine Sciences, Shenzhen University, Shenzhen 518055, China.
Food Inspection and Quarantine Center, Shenzhen Customs, Shenzhen 518033, China.
Food Chem. 2022 Mar 30;373(Pt B):131535. doi: 10.1016/j.foodchem.2021.131535. Epub 2021 Nov 5.
Not-from-concentrate (NFC) juice has better nutrition, flavor and higher price than reconstituted juice. Accordingly, NFC juice is prone to adulteration and is an ongoing industry problem that has not yet been resolved. Undeclared addition of water and sugar are the main forms of NFC juice adulteration. This paper investigates the carbon and oxygen stable isotope ratios (δC and δO values) of the bulk juice and different juice components from 21 fruit and vegetable juices, and qualitatively and quantitatively analyzes the addition of water and sugar in NFC juices. The results show that the use of fruit pulp can help to qualitatively and quantitatively indicate the presence of C4 plant sugars in NFC juice, and can reliably detect added C4 plant sugars above 7 %. Sugar-specific isotope analysis (SSIA) technology was used to determine the δC values of different sugars (sucrose, glucose and fructose) and carbon content to qualitatively infer C3 plant sugar addition. Pulp extracted from juice had a good linear relationship with the juice water δO values (R >0.90). The addition of water to NFC juice can also be determined by comparing δO values of extraneous water, pulp and filtered juice. Stable isotope technology confirmed NFC juice adulteration of in-market samples using the pulp as an internal reference and was found to be a useful tool to detect adulteration of in-market NFC juice.
非浓缩还原（NFC）果汁比复原果汁具有更好的营养、风味和更高的价格。因此，NFC 果汁容易被掺假，这是一个持续存在的行业问题，尚未得到解决。未申报的加水和加糖是 NFC 果汁掺假的主要形式。本研究调查了 21 种果蔬汁的原浆和不同果汁成分的碳氧稳定同位素比值（δC 和 δO 值），并定性和定量分析了 NFC 果汁中加水和加糖的情况。结果表明，使用果肉有助于定性和定量指示 NFC 果汁中 C4 植物糖的存在，并能可靠地检测出添加的 C4 植物糖含量高于 7%。糖的稳定同位素分析（SSIA）技术用于确定不同糖（蔗糖、葡萄糖和果糖）的 δC 值和碳含量，以定性推断 C3 植物糖的添加。从果汁中提取的果肉与果汁水 δO 值之间具有良好的线性关系（R>0.90）。NFC 果汁加水也可以通过比较外来水、果肉和过滤汁的 δO 值来确定。稳定同位素技术证实了市场上 NFC 果汁掺假的情况，使用果肉作为内部参考，是一种检测市场上 NFC 果汁掺假的有用工具。
