2007 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).
Colorimetric Method for Estimating Limonoid Concentrations. Citrus limonoids is one of the last remaining families of compounds important to citrus quality, human health and possessing potential health-promoting properties, detection methods for which are lacking. Researchers in the Processed Foods Unit, Albany, CA, filled a critical need by developing and subsequently disseminating a simple, rapid and inexpensive method for estimating total limonoid concentrations in juices. This method will allow researchers and citrus producers alike to evaluate the quality and value of their citrus products. This research supports NP306, Component I, Quality Characterization, Preservation and Enhancement, d) Preservation and/or Enhancement of Quality and Marketability.
Robust and Green Method for the Isolation of Limonin Glucoside. Methods that overcome the hindrances to commercialization of citrus due to limonin glucoside are critical to U.S. agriculture. Researchers in the Processed Foods Research Unit, Albany, CA, have developed a robust and green method for the isolation of limonin glucoside. The utility and robustness of the method was demonstrated on a pilot scale as it was used to obtain, from a variety of sources and without modification, over 350 grams of high purity material (greater than 98%). Methods designed to utilize readily scalable food grade materials and minimize the number of steps and waste are now available. This research supports NP306, Component II, New Processes, New Uses, and Value-Added Foods and Biobased Products, d) New and Improved Processes and Feedstocks.
Pilot Scale Removal of Limonin. After learning that the limonin glucoside containing beverages to be used for the human study were too bitter for consumption due to the presence of limonin (less than 1%), a compound in the same family as limonin glucoside, but structurally different, researchers in the Processed Foods Research Unit, Albany, CA, quickly developed a pilot scale chromatographic method for removing residual limonin. Purity of the material treated by this polishing method increased by 1.5% to 99.5% with only a minimal loss of the starting material. The two-step process uses only ethanol and water as the solvents and affords a readily-scalable to a production scale method that may be used by producers whose customer requirements include increased purity. This research supports NP306, Component II, New Processes, New Uses, and Value-Added Foods and Biobased Products, d) New and Improved Processes and Feedstocks.
Production Scale Quality Control Methods Developed. Methods are needed that can accurately evaluate potential feed-stock and isolated material for their limonoid glucoside content and character. Researchers in the Processed Foods Research Unit, Albany, CA, have developed analytical methods and implemented these methods as quality control processes in support of their pilot scale isolation of limonin glucosides. Methods, based on HPLC-MS and NMR, have been successfully utilized. The availability of ARS-developed methods, in light of the considerable public interest in the contents and character of food products, especially processed foods and supplements, will directly assist commercial enterprises pursuing the commercial scale isolation of limonoid glucosides by alleviating cost associated with in-house development of quality control methods. This research supports NP306, Component I, Quality Characterization, Preservation and Enhancement, d) Preservation and/or Enhancement of Quality and Marketability.
5.Significant Activities that Support Special Target Populations
|Number of active CRADAs and MTAs||7|
|Number of non-peer reviewed presentations and proceedings||2|
Breksa III, A.P., Ibarra Jr, F.G. 2007. Colorimetric Method for the Estimation of Total Limonoid Aglycones and Glucoside Contents in Citrus Juices. Journal of Agricultural and Food Chemistry. (Article) 55(13):5013-5017.
Breksa III, A.P., Manners, G.D., Jacobs, R.A., Hasegawa, S. 2006. Citrus Limonoid Bioavailability in Humans. In: ACS Symposium Series No. 936, Potential Health Benefits of Citrus; Patil, B.S.; Turner, N.D.; Miller, E.G.; Brodbelt, J.S. Washington, DC: American Chemical Society. p. 95-101.