Han Leng, Cheng Yujiao, Zhang Tenghui, Zhou Qi, Zhang Wanchao, Li Yongan, Li Guijie
Citrus Research Institute, National Citrus Engineering Research Center, Southwest University, Chongqing, China.
Chengdu Centre Testing International Group Co., Ltd., Chengdu, China.
Front Nutr. 2022 May 23;9:897982. doi: 10.3389/fnut.2022.897982. eCollection 2022.
Profiles of citrus juice oxygenated heterocyclic aglycones (OHAs), which are notable marker secondary metabolites, were used to assess the authenticity of sweet orange and grapefruit juices in situations where mandarin and pomelo juices might be adulterants. Thirty-nine known OHAs, including 10 methoxyflavones, 13 coumarins, and 16 furanocoumarins, as well as 13 tentatively screened OHAs, were analyzed in orange, mandarin, grapefruit and pomelo juices using our newly developed high-resolution HPLC-UV and fluorescence detection method. Quantitative OHA profiles from 158 pure juice samples were obtained to establish a purity discriminant model using an omics strategy. Reduction of OHA variables showed that three important methoxyflavones, i.e. isosinensetin, tangeretin and sinensetin provided the best discrimination ability between sweet orange and mandarin juices. There are two subtypes of pomelos, Shatianyou Group and Wendan Group, of which juices should be separately compared to grapefruit juice. Five OHAs, namely meranzin, 3,5,6,7,8,3',4'-heptamethoxyflavone, osthole, 6',7'-epoxybergamottin, and bergamottin were found to discriminate Shatianyou Group of pomelo juice from grapefruit juice; whereas three OHAs, namely bergaptol, isomeranzin, and 6',7'-dihydroxybergamottin were able to discriminate Wendan Group of pomelo juice from grapefruit juice. The established partial least squares discriminant analysis (PLS-DA) models were capable of detecting as little as 10% mandarin juice in sweet orange juice and 10% pomelo juice in grapefruit juice, allowing for fast prescreening of excess addition with good reliability (root mean square error of prediction, RMSEP < 5%).
柑橘汁氧化杂环苷元（OHAs）是显著的标志性次生代谢产物，其谱图被用于评估在可能存在掺假的情况下，甜橙汁和葡萄柚汁中是否掺有柑桔汁和柚汁。使用我们新开发的高分辨率HPLC-UV和荧光检测方法，对橙汁、柑桔汁、葡萄柚汁和柚汁中的39种已知OHAs（包括10种甲氧基黄酮、13种香豆素和16种呋喃香豆素）以及13种初步筛选的OHAs进行了分析。通过组学策略，从158个纯果汁样品中获得了定量的OHA谱图，以建立纯度判别模型。减少OHA变量显示，三种重要的甲氧基黄酮，即异川陈皮素、橘红素和川陈皮素，对甜橙汁和柑桔汁具有最佳的区分能力。柚有两个亚型，即沙田柚组和文旦组，其果汁应分别与葡萄柚汁进行比较。发现五种OHAs，即橙皮苷、3,5,6,7,8,3',4'-七甲氧基黄酮、蛇床子素、6',7'-环氧佛手柑内酯和佛手柑内酯，可区分沙田柚组柚汁与葡萄柚汁；而三种OHAs，即补骨脂酚、异橙皮苷和6',7'-二羟基佛手柑内酯，能够区分文旦组柚汁与葡萄柚汁。所建立的偏最小二乘判别分析（PLS-DA）模型能够检测出甜橙汁中低至10%的柑桔汁和葡萄柚汁中低至10%的柚汁，从而能够以良好的可靠性（预测均方根误差，RMSEP<5%）对过量添加进行快速预筛选。
