Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Abstract Only
Publication Acceptance Date: 3/27/2014
Publication Date: N/A
Technical Abstract: As of 2010, the Louisiana Citrus Industry involved about 550 growers who produced roughly 1000 acres of citrus for an estimated gross farm value of almost $7.5 million; consisting predominately of Satsuma oranges, which have adapted well to the southern Louisiana growing conditions. Unfortunately, the Louisiana citrus industry is subdued by the immense commercial industry in Florida and other states. Estimates from local growers and farmers indicate that roughly 1/3 of the crop falls to the ground and rots yearly. Without methods to process and/or increase the shelf-life of Satsuma, both demand and incentive to grow local citrus is diminishing. Subsequently, we attempted to derive a rapid, convenient Satsuma juice (skipping traditional peeler, finisher and de-pulping machinery) to deliver an acceptable pilot plant, commercial-like, pressed juice product with minimal inputs as a viable means for local producers to begin finding alternative uses for this underutilized crop. Freshly harvested 2011 Satsuma from Plaquemines Parish were commercially sorted, washed, not waxed, and trucked to the Agricultural Research Service, Southern Regional Research Center in New Orleans. Fruit was washed in 100ppm NaOCl, rinsed in deionized water, air dried, then mechanically pressed as whole fruit (including peels) and peeled fruit. Four proprietary enzymes, and mixtures thereof, were specifically chosen to act on pectin, cellulose, protein, oil separation and bitterness/astringency that would be encountered when whole fruit were pressed with peels intact. These extractions were compared against peeled pressed fruit as well. Color, subjective flavor and astringency/sourness, and sedimentation were evaluated along with volatile headspace extraction. Herein, we report volatiles recovered via a DVB/Car/PDMS SPME performed with 10-ml juice in 20-ml vials for 12.5 minute exposure at 40°C, followed by injection into a HP6890/5973 GC-MS with a DB-5 column. Compounds were identified in triplicate runs by HP ChemStation software searched against the NIST, Wiley libraries, and authentic standards. Similar to previous Satsuma juice reports, we isolated limonene, '–terpinene, p-cymene, myrcene, a-pinene, ß-pinene, a-terpinolene, ß –caryophyllene, and valecene. Limonene completely saturated the MS profiles in whole fruit pressed with their peels, even when samples were diluted 10-fold. Limonene was also the predominant peak in all peeled juice samples. Removal of the peel indeed allowed for characterization of more subtle (non-terpenoid) compounds, such as, lower molecular weight alcohols and ketones. We are processing data to ascertain if enzyme treatments significantly altered the volatile profiles of peeled versus whole pressed juices.