Processing citrus fruits into juice generates large amounts of by-products, mainly pomaces. This study aimed to perform a comprehensive analysis of the composition in phenolic compounds, carotenoids, and volatile organic compounds (VOCs) of juices and pomaces of four citrus fruits from Southern Italy, i.e., mandarin, lemon, orange, and bergamot. Juices were produced by squeezing the fruits into an electrical juicer, whereas pomaces were obtained as by-products of the juice extraction. The phytochemical content of the samples was studied by targeted LC and GC approaches. Results indicated that lemon provided the juice with the greatest phenolic content. It was abundant in eriocitrin (90.9 ± 10.8 mg kg⁻¹ FW), isorhamnetin 3-O-rutinoside (47.3 ± 8.03 mg kg⁻¹ FW), and rutin (78.9 ± 14.5 mg kg⁻¹ FW). Likewise, lemon pomace was the richest in phenolics, mostly narirutin (130 ± 14.7 mg kg⁻¹ FW). As regards carotenoids, mandarin and orange pomaces were equally (p > 0.05) prominent sources of the compounds, providing primarily lutein and β-cryptoxanthin. The phytochemical profile of lemon and mandarin pomaces was unknown up to date. Bergamot accumulated great amounts of VOCs. In particular, bergamot juice was rich in monoterpenes, e.g., α-pinene (375 ± 62.7 mg kg⁻¹ FW) and γ-terpinene (551 ± 67 mg kg⁻¹ FW). The study investigated for the first time the carotenoid and VOCs profiles of bergamot products, and of mandarin and lemon pomaces. Since, citrus pomaces contained great amounts of phytochemicals, they should find new applications in the food and cosmetic industries.

中文翻译：

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意大利南部四种柑橘类水果的汁液和果渣中酚类化合物，类胡萝卜素和挥发物的成分差异

将柑桔类水果加工成果汁会产生大量副产品，主要是豆荚。这项研究旨在对意大利南部四种柑桔类水果（普通话，柠檬，橙子和佛手柑）的汁液和豆浆中的酚类化合物，类胡萝卜素和挥发性有机化合物（VOC）的成分进行全面分析。通过将水果压入电动榨汁机中来生产果汁，而豆渣则是榨汁过程中的副产品。通过有针对性的LC和GC方法研究了样品的植物化学含量。结果表明柠檬为果汁提供了最大的酚含量。富含eriocitrin（90.9±10.8 mg kg ^-1 FW），异鼠李素3- O-芸香苷（47.3±8.03 mg kg ^-1）FW）和芦丁（78.9±14.5 mg kg ^-1 FW）。同样，柠檬渣是酚类中含量最丰富的，主要是纳鲁汀（130±14.7 mg kg ^-1 FW）。至于类胡萝卜素，普通话和橘子果肉是同样 重要的化合物（p > 0.05），主要提供叶黄素和β-隐黄质。迄今为止，柠檬和柑桔果肉的植物化学特征尚不清楚。佛手柑积累了大量的VOC。佛手柑汁尤其富含单萜，例如α-pine烯（375±62.7 mg kg ^-1 FW）和γ-萜品烯（551±67 mg kg ^-1FW）。该研究首次调查了佛手柑产品以及普通话和柠檬豆蔻的类胡萝卜素和VOCs分布。由于柑橘果肉含有大量的植物化学物质，因此它们应在食品和化妆品工业中找到新的应用。