Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/2/2008
Publication Date: 9/5/2008
Citation: Dragull, K.D., Breksa III, A.P., Cain, B.R. 2008. Synephrine Content of Juice from Satsuma Mandarins (Citrus unshiu Marcovitch). Journal of Agricultural and Food Chemistry. 56:8874-8878.
Interpretive Summary: After overcoming some initial chromatographic challenges we faced due to matrix effects, we determined by HPLC the synephrine concentrations found in the juices of Satsuma mandarin fruits obtained from ten different orchards located in Placer County, CA, USA. The HPLC analyses for synephrine were complemented with physiochemical characterization of the juices. Synephrine concentrations found in Satsuma mandarins were on average higher than those reported for sweet and sour oranges, and in a range similar to other mandarins or tangerines. Consumption of one standard cup of juice from some samples could provide a dose of synephrine in the upper range of those available in oral weight loss supplements. The present data also reveal an up to 2-fold difference among groves in the same county suggesting that factors including microclimate or localized agricultural practices may influence synephrine concentrations.
Technical Abstract: Synephrine, the main protoalkaloid in Citrus species, is commonly analyzed as the active component in citrus peel-containing herbal supplements, but the edible parts of mandarins have been largely ignored. We determined the synephrine concentration in the juices of C. unshiu mandarins harvested from ten different groves located in a major growing region in California. For comparison, the physicochemical properties of the juices, including pH, conductivity, soluble solid content and titratable acidity were also measured. The synephrine values among ten groves ranged from 73.3 to 153.1 mg L –1. Repeat sampling of fruit from the ten locations showed that the intra-grove variability in synephrine concentrations ranged from 1.0 to 27.7%CV and were grove dependent. Among the physicochemical properties, titratable acidity weakly correlated with synephrine and for one sample a low maturity index was linked to high synephrine content. The overall mean synephrine concentration of 92.8 mg L-1 is up to six-fold higher than the values previously determined for orange juices and suggests that mandarin juice may constitute a significant dietary source of synephrine. Furthermore, the results suggest that grove location affects synephrine content.