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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Citrus and Other Subtropical Products Research » Research » Publications at this Location » Publication #315660

Title: Continuous Process for Release of Pectic Hydrocolloids and Phenolics from Citrus Processing Waste: Recovery, Characterization and Functionality

item Cameron, Randall - Randy
item Luzio, Gary
item Manthey, John

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/2/2015
Publication Date: N/A
Citation: N/A

Interpretive Summary: Converting one metric ton of dried citrus processing waste (CPW) to animal feed forgoes the opportunity to recover 200 kilograms of pectin, 35% of the available orange oil, and nearly all of the potentially health-benefiting bioactive flavonoids and other secondary metabolites. We aim to reclaim these resources and enable technologies for development of minimally processed functional materials, to utilize these resources for industrial, food and health-promoting applications and to enable a novel immunologically-based method for assessing pectin’s functional/structural properties. We are developing a pilot scale, continuous method to recover these valuable co-products using steam injection. Preliminary results indicate we can recover 75% of the available pectin which is comparable in size to commercially available pectins. We also will be presenting on phenolic recovery and pectin functionality.

Technical Abstract: Pectic hydrocolloids from citrus processing waste (CPW) are highly functional molecules whose utility and application have expanded well beyond their traditional use in jams and jellies. They are now finding applications in health, pharmaceutical and personal care products as well as functioning as emulsifiers, encapsulants, biobased film components, stabilizers, ion capture agents and generalized rheology modifiers of aqueous systems. Additionally, many phenolic compounds of CPW are candidate targets for biorefining. Research suggests direct involvement of the peel flavonoid components in confirmed health benefits. Current health benefits associated with these compounds are cardio protective, anti-arthritis (anti-inflammatory), prevention of diabetes and obesity, bone health, and others. Over 85% of the world’s marketed pectic hydrocolloids are isolated from citrus fruit peel, generally from Central and South America. Traditional extraction methods utilize harsh acidic extractions and alcohol precipitations. Approximately 4 million wet MT of sweet oranges were harvested and used for juice extraction in the U.S (Florida) during the 2013-2014 season leaving nearly 2 million wet MT of CPW. Over 1 million MT of CPW (wet and dry) was converted to value added products, mainly citrus peel pellets marketed as animal feed. The conversion of CPW failed to recover nearly 40,000 MT of pectin, 2,000 MT of flavonoids and related phenolics and 13,000 MT of limonene. We are developing an environmentally favorable continuous steam extraction process to recover these valuable coproducts. In a pilot scale facility we have demonstrated the recovery from CPW of approximately 75% of the available pectic hydrocolloids along with other polymeric hydrocolloids – arabinans (50% – 70% of available arabinose), galactans (70% – 85% of available galactose) and arabinogalactans. Molecular weights were comparable to commercially available pectins and suggested a relatively high degree of methylesterification based on weak gel results from rheological testing of calcium gels. Data also will be presented on phenolic recovery and pectin nanostructural characteristics.