title: Torrefaction of pomaces and nut shells.
abstract: Apple, grape, olive, and tomato pomaces as well as almond and walnut shells were torrefied at different temperatures and times in a muffle furnace. The fiber content and thermal stability of the raw byproducts were examined and the moisture and ash contents, elemental composition, and gross calorific values of the raw and torrefied samples were characterized. Response surface methodology and a central composite design were used to examine the effects of temperature and time on mass and energy yields of the torrefied byproducts. Raw apple pomace had the highest hemicellulose content, whereas raw grape pomace had the highest lignin content. Raw tomato pomace had the highest gross calorific value because of its high carbon content. Temperature had a larger effect on mass and energy yields than time. Grape pomace generally had the highest mass and energy yields. Also, energy yields of the byproducts could be predicted from mass loss values.
authors.affiliation: Bioproduct Chemistry and Engineering, U.S. Department of Agriculture, Albany, CA 94710, United States. Electronic address: bor-sen.chiou@ars.usda.gov.
authors.forename: Bor-Sen
authors.initials: BS
authors.lastname: Chiou
authors.affiliation: Bioproduct Chemistry and Engineering, U.S. Department of Agriculture, Albany, CA 94710, United States.
authors.forename: Diana
authors.initials: D
authors.lastname: Valenzuela-Medina
authors.affiliation: Bioproduct Chemistry and Engineering, U.S. Department of Agriculture, Albany, CA 94710, United States.
authors.forename: Cristina
authors.initials: C
authors.lastname: Bilbao-Sainz
authors.affiliation: Bioproduct Chemistry and Engineering, U.S. Department of Agriculture, Albany, CA 94710, United States.
authors.forename: Artur K
authors.initials: AK
authors.lastname: Klamczynski
authors.affiliation: Healthy Processed Foods Research, U.S. Department of Agriculture, Albany, CA 94710, United States.
authors.forename: Roberto J
authors.initials: RJ
authors.lastname: Avena-Bustillos
authors.affiliation: Healthy Processed Foods Research, U.S. Department of Agriculture, Albany, CA 94710, United States.
authors.forename: Rebecca R
authors.initials: RR
authors.lastname: Milczarek
authors.affiliation: Healthy Processed Foods Research, U.S. Department of Agriculture, Albany, CA 94710, United States.
authors.forename: Wen-Xian
authors.initials: WX
authors.lastname: Du
authors.affiliation: Bioproduct Chemistry and Engineering, U.S. Department of Agriculture, Albany, CA 94710, United States.
authors.forename: Greg M
authors.initials: GM
authors.lastname: Glenn
authors.affiliation: Bioproduct Chemistry and Engineering, U.S. Department of Agriculture, Albany, CA 94710, United States.
authors.forename: William J
authors.initials: WJ
authors.lastname: Orts
mesh_terms: D001709:Biotechnology / Q000379:methods*; D004602:Elements; D009754:Nuts / Q000737:chemistry*; D013696:Temperature; D013818:Thermogravimetry; D014866:Waste Products
chemical_list: D004602:Elements; D014866:Waste Products
keywords: Mass and energy yields; Nut shells; Pomaces; Response surface methodology; Torrefaction