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United States Department of Agriculture

Agricultural Research Service

Related Topics

Research Project: IMPROVING CITRUS NUTRITIONAL PROPERTIES AND QUALITY TO BENEFIT HUMAN HEALTH AND ENHANCE CITRUS UTILIZATION

Location: Healthy Processed Foods Research

2008 Annual Report


1a.Objectives (from AD-416)
The primary goals of this research project are to establish the role of naturally occurring biologically active citrus phytochemicals, in particular citrus limonoids, in human health and nutrition, to enhance citrus co-product utilization and to utilize molecular level methods to improve citrus quality and optimize important biologically active phytochemicals in new citrus varieties.


1b.Approach (from AD-416)
1) Characterize naturally occurring phytochemicals, in particular limonoids, isolated from citrus fruit and juice, and assess their biological activity, determine their potential contribution to the improvement of human health and nutrition, and establish the nature and scope of their action in biological systems. .
2) Develop and refine methodology to reclaim pure biologically active citrus limonoids important to human health and nutrition from citrus processing co-products. .
3) Determine the origins and modulating chemical and biochemical factors for natural phytochemicals in citrus and develop molecular level strategies to modify and/or enhance the character or amount of these compounds to achieve improve citrus quality, increased consumer acceptance and optimized nutritional value of citrus. Replaces 5325-41430-008-00D (01/2005).


3.Progress Report
Efforts in support of this project have been directed at the continued isolation of limonin glucoside from available starting materials and the evaluation of alternative starting materials. Concurrent with our isolation efforts, a 200-day study examining the stability of limonin glucoside in beverage matrices was completed. Results from this study provided evidence that limonoid glucoside is stable in common beverage matrices and resistant to degradation into limonin. Of the matrix components tested, only vitamin B2 was found to be detrimental. In addition, the human study portion of the project has commenced and six participants have already completed the study regime.

In addition, we determined the synephrine concentrations found in the juices of Satsuma mandarin fruits obtained from 10 different orchards located in Placer County, CA, USA. The 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. Results for some samples suggests that the consumption of one standard cup of juice could provide a dose of synephrine in the upper range of those available in oral weight loss supplements. The data also revealed 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. This research supports NP306, Component II, New Processes, New Uses, and Value-Added Foods and Biobased Products, d) New and Improved Processes and Feedstocks.


4.Accomplishments
1. Isolation and Identification of the First C-17 Limonin Epimer - Epilimonin. Secondary metabolites, including limonoids, directly or indirectly contribute to or detract from the marketability of juice and in order to fully assess the contributions of these compounds, they must first be isolated individually. Researchers in the Processed Foods Research Unit, Albany, CA, have isolated and characterized the first C-17 epimer of limonin. The epimer, named epilimonin, was isolated as a byproduct of our efforts to isolate limonin glucoside. This compound will be an invaluable resource to those undertaking studies probing the structural-activity relationships of limonoids. This research supports NP306, Component II, New Processes, New Uses, and Value-Added Foods and Biobased Products, Problem d) New and Improved Processes and Feedstocks.

2. Stability of Limonoid Glucoside in Beverage Matrices Demonstrated. Prior to the formulation and commercialization of beverages containing limonin glucoside as their health-promoting component, the stability of limonin glucoside in beverage matrices must be demonstrated. Researchers in the Processed Foods Research Unit, Albany, CA, completed a study over a 200-day period examining the stability of limonin glucoside formulated into three beverage matrices. Results from this study demonstrated that the stability of limonin glucoside formulated into beverages exceeds six months and that limonin glucoside is resistant to degradation into limonin. This research supports NP306, Component II, New Processes, New Uses, and Value-Added Foods and Biobased Products, Problem d) New and Improved Processes and Feedstocks.

3. Pilot Scale Clarification of Frozen Orange Juice Concentrate. Efficient and economically viable methods are needed for the large-scale isolation of limonoid glucosides from citrus process streams. Researchers in the Processed Foods Research Unit, Albany, CA have demonstrated that continuous flow centrifugation may be used to generate concentrates suitable for immediate processing by solid phase extraction or column chromatography. In comparison to methods that rely on the use of standard floor centrifuges, this method yields a significant reduction in processing time and opens to manufacturers an opportunity to use frozen orange juice concentrate as a starting material for the isolation of health-promoting and functional food components from citrus. This research supports NP306, Component II, New Processes, New Uses, and Value-Added Foods and Biobased Products, Problem d) New and Improved Processes and Feedstocks.


5.Significant Activities that Support Special Target Populations
None.


6.Technology Transfer

Number of Non-Peer Reviewed Presentations and Proceedings3
Number of Newspaper Articles and Other Presentations for Non-Science Audiences4

Review Publications
Breksa III, A.P., Dragull, K.D., Wong, R.Y. 2008. Isolation and Identification of the First C-17 Limonin Epimer, Epilimonin. Journal of Agricultural and Food Chemistry. 56:5595-5598.

Breksa III, A.P., Manners, G.D., Ibarra, Jr., P. 2008. Clarification of reconstituted frozen orange juice concentrate by continuous flow centrifugation for limonin glucoside solid phase extraction. Journal of the Science of Food and Agriculture. 88:2213-2218.

Breksa III, A.P., Hidalgo, M.B., Wong, R.Y. 2008. Stability of Limonin Glucoside in Beverage Matrices. Journal of the Science of Food and Agriculture. 88:2194-2200.

Last Modified: 9/22/2014
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