33B-3 |
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K. SUNTHANONT1, M. R. Bennink2, and M. A. Uebersax2. (1) Food Science and Human Nutrition, Michigan State University, G.M. Trout Building, Room 204, E. Lansing, MI 48823, (2) Dept. of Food Science & Human Nutrition, Michigan State Univ., Suite 106 F. Malcolm Trout FSHN Bldg., East Lansing, MI 48824-1224 Two major classes of citrus phytochemicals, limonoids and flavonoids, have attracted considerable attention from science and industry because of their pharmacological properties. Large production of by-products accompanying orange juice production offers inexpensive starting materials for recovery of secondary metabolites with potential anticarcinogenic and cardioprotective activities. Our objective was to obtain distribution patterns for limonoids and flavonoids in orange juice and its by-products. Limonoid and flavonoid contents were determined in various by-products (seed, peel, peel press cake, rag, and peel press liquid) and orange juice from commercial orange varieties (Hamlin, Parson Brown, and Valencia). Twenty one compounds in these categories: limonoid aglycones (LA), limonoid glucosides (LG), flavanone glucosides (FG), and polymethoxylated flavones (PMF) were analyzed. There were significant differences (P £ 0.01) among fractions, varieties, and their interaction. Seeds had the highest content of LA and LG, while peel and peel press cake had the highest concentrations of FG and PMF. Peel press liquid contained more phytochemical content than juice (except LG). Water removal by pressing process extracted LG and PMF from the peel into peel press liquid, but concentrated LA in the peel press cake. Average g/100g dry weight of total contents in solid fractions from three varieties were 7.1 (FG), 4.1 (LG), 1.2 (LA), and 0.26 (PMF. Average g/100ml of that in liquid fractions were 0.150 (FG), 0.072 (LG), 0.009 (PMF), and 0.002 (LA). Valencia had highest phytochemical content, except for FG which was highest in Hamlin. FG were the predominant phytochemicals, followed by LG, LA, and PMF. LG are rich in edible orange fraction and are extracted into the juice. The results show that rags containing seeds are a good source for LA and LG, while peel and peel press cake are good sources for FG and PMF. Peel press liquid is a potential source for LG and PMF after evaporation to the molasses end-product. Orange juice is a good source of LG.
Session 33B, Citrus Products: General
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