Submitted to: Proceedings of Florida State Horticultural Society
Publication Type: Proceedings
Publication Acceptance Date: December 5, 2010
Publication Date: December 29, 2010
Citation: Bai, J., Ford, B.L., Manthey, J.A., Baldwin, E.A. 2010. A comparison of processed and fresh squeezed ‘Hamlin’ orange juice - nutrients and phytonutrients. Proceedings of Florida State Horticultural Society. 123:207-212.
‘Hamlin’ orange juices were extracted using one of following methods: 1) freshly squeezed with a commercial food service squeezer (fresh), 2) freshly squeezed + pasteurized (fresh/pasteurized), and 3) processed with industrial extractor and pasteurized (processed). Samples were taken directly after juice extraction and again after 4 days of storage at 5 °C for analysis of flavonoids, limonoids, alkaloids, carotenoids, ascorbic acid and total phenolic content. Processed juice had higher levels of insoluble solids, but lower levels of peel oil in comparison with fresh juices regardless of pasteurization. The majority of flavanones including hesperidin, narirutin, narirutin 4'-glucoside, 6,8-di-C-glucosyl apigenin and isosakuranetin rutinoside, which are rich in albedo and segment membranes, exhibited high levels in the processed juice. On the other hand, flavones associated with peel oil, such as quercetagetin hexamethyl ether, sinensetin, nobiletin, tetramethylscutellarein, heptamethoxyflavone and tangeretin had high contents in the fresh juices. Limonoids (limonin glucoside, limonin aglycone, nomilin glucoside, nomilinic acid glucoside, and nomilin aglycone), alkaloids (ferulyol putrescine and an unknown alkaloid) and carotenoids (zeaxanthin, lutein, ß-cryptoxanthin, a-carotene and ß-carotene) had higher contents in the processed juice than in the fresh juice regardless of pasteurization. The processed juice had higher total phenolic contents but lower ascorbic acid content than in the fresh juices. Thermal pasteurization increased contents of flavones, but decreased contents of carotenoids. During 4 d storage at 5 °C, 20-80% flavanones, including hesperidin, narirutin, narirutin 4’-glucoside and isosakuranetin rutinoside, precipitated in the processed juice but not the fresh juice.