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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Bioproducts Research » Research » Publications at this Location » Publication #308615

Research Project: Biorefining Processes

Location: Bioproducts Research

Title: Leaching behavior of water-soluble carbohydrates from almond hulls

Author
item Offeman, Richard
item Dao, Gloria
item Holtman, Kevin
item Orts, William - Bill

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/2014
Publication Date: 11/10/2014
Citation: Offeman, R.D., Dao, G.T., Holtman, K.M., Orts, W.J. 2014. Leaching behavior of water-soluble carbohydrates from almond hulls. Industrial Crops and Products. 65(65):488-495.

Interpretive Summary: Over 58% of the dry matter content of the hulls from the commercial almond is soluble in warm water extraction. The water-soluble extractables include useful amounts of fermentable sugars (glucose, fructose, sucrose), sugar alcohols (inositol and sorbitol), polysaccharides, and other components. The leaching characteristics of the almond hulls were determined, allowing development of a model for an ideal countercurrent extractor. The data indicate a solutes concentration of 18-20% dry matter in the concentrate liquid is attainable.

Technical Abstract: Over 58% of the dry matter content of the hulls from the commercial almond (Prunus dulcis (Miller) D.A. Webb) is soluble in warm water (50-70°C) extraction. The water-soluble extractables include useful amounts of fermentable sugars (glucose, fructose, sucrose), sugar alcohols (inositol and sorbitol), polysaccharides, and other components. Extraction rate data were taken over a range of temperatures and particle sizes (including whole hulls). Equilibrium concentrations and liquid retention data were taken over a wide solubles concentration range, enabling use of a standard leaching model for the calculation of stage-to-stage concentrations and flows in an ideal countercurrent extractor. The relations between recovery, product concentration, number of ideal stages, and ratio of solvent-to-feed were determined using the model. The data indicate that a solutes concentration of 18-20% dry matter in the concentrate liquid is attainable. Due to the nature of the native hulls to preferentially absorb water from dilute solutions, initial contact of hulls with the overhead liquid concentrate (if well below ~18% solutes) may result in a significant enhancement of overhead concentration.