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United States Department of Agriculture

Agricultural Research Service


item Wilkins, Mark
item Widmer, Wilbur
item Cameron, Randall - Randy
item Grohmann, Karel

Submitted to: Proceedings of Florida State Horticultural Society
Publication Type: Abstract Only
Publication Acceptance Date: 3/2/2005
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Approximately 10 million tons of oranges are processed in Florida each year, producing approximately 5 million tons of waste consisting of peel, seeds and segment membranes. Most of this peel is currently dried and pelletized to produce citrus pulp pellets, a low value cattle feed. Several researchers have converted orange peel waste into valuable sugars using both acid and enzymatic hydrolysis. After hydrolysis, many of these sugars can be utilized to produce ethanol, a valuable fuel, and other chemicals. This study focuses on the effect of harvest time and maturity on sugar yields from the enzymatic hydrolyses of Valencia orange peel. Valencia oranges were obtained from the same grove at three times during the 2005 harvest season, early March, early April and early May. A commercial juice extractor was used to extract juice and the processing waste collected for hydrolysis. Peel was comminuted to a size less than 0.7 mm in a food processor. Cellulose, hemicellulose and pectin were hydrolyzed using pectinase, cellulase and beta-glucosidase enzymes to produce sugars. Glucose, fructose, galactose, arabinose, xylose, rhamnose and galacturonic acid yields, as determined by HPLC both before and after hydrolysis over the season, are compared and will be discussed.

Last Modified: 06/27/2017
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