title: Membrane-Filtered Olive Mill Wastewater: Quality Assessment of the Dried Phenolic-Rich Fraction.
abstract: A current trend in olive mill wastewater (OMWW) management is to not only decrease environmental pollution but also to extract and utilize valuable by-products. Therefore, the objectives of this study were to explore different techniques for drying a phenolic-rich membrane filtration fraction of OMWW and compare the techniques in terms of the dried product quality and feasibility of the process. The OMWW from 2 (3-phase and 2-phase) California mills was subjected to a 2-step membrane filtration process using a novel vibratory system. The reverse osmosis retentate (RO-R) is a phenolic-rich coproduct stream, and the reverse osmosis permeate is a near-pure water stream that could be recycled into the milling process. Spray-, freeze-, and infrared-drying were applied to obtain solid material from the RO-R. Drying of the RO-R was made possible only with addition of 10% maltodextrin as a carrier. The total soluble phenolics in dried RO-R were in the range 0.15 to 0.58 mg gallic acid equivalents/g of dry weight for 2-phase RO-R, and 1.38 to 2.17 mg gallic acid equivalents/g of dry weight for the 3-phase RO-R. Spray-dried RO-R from 3-phase OMWW showed remarkable antioxidant activity. Protocatechuic acid, tyrosol, vanillic acid, and p-coumaric acid were quantified in all dried RO-R, whereas 3-hydroxytyrosol was found in 3-phase dried RO-R. This combination of separation and drying technologies helps to add value and shelf-stability to an olive oil by-product and increase environmental sustainability of its production.
authors.affiliation: Univ. of California, Davis, Olive Center, 392 Old Davis Rd, Davis, CA, 95616, U.S.A.
authors.forename: Ivana
authors.initials: I
authors.lastname: Sedej
authors.affiliation: United States Dept. of Agriculture - Agricultural Research Service, Healthy Processed Foods Research Unit, 800 Buchanan Street, Albany, CA, 94710, U.S.A.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Milczarek
authors.affiliation: Univ. of California, Davis, Olive Center, 392 Old Davis Rd, Davis, CA, 95616, U.S.A.
authors.forename: Selina C
authors.initials: SC
authors.lastname: Wang
authors.affiliation: Univ. of California, Davis, Olive Center, 392 Old Davis Rd, Davis, CA, 95616, U.S.A.
authors.forename: Runqi
authors.initials: R
authors.lastname: Sheng
authors.affiliation: United States Dept. of Agriculture - Agricultural Research Service, Healthy Processed Foods Research Unit, 800 Buchanan Street, Albany, CA, 94710, U.S.A.
authors.forename: Roberto
authors.initials: R
authors.lastname: de Jesús Avena-Bustillos
authors.affiliation: United States Dept. of Agriculture - Agricultural Research Service, Healthy Processed Foods Research Unit, 800 Buchanan Street, Albany, CA, 94710, U.S.A.
authors.forename: Lan
authors.initials: L
authors.lastname: Dao
authors.affiliation: United States Dept. of Agriculture - Agricultural Research Service, Healthy Processed Foods Research Unit, 800 Buchanan Street, Albany, CA, 94710, U.S.A.
authors.forename: Gary
authors.initials: G
authors.lastname: Takeoka
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D002140:California; D003373:Coumaric Acids / Q000032:analysis; D003890:Desiccation / Q000379:methods*; D005374:Filtration; D019649:Food Industry; D005707:Gallic Acid / Q000032:analysis; D062385:Hydroxybenzoates / Q000032:analysis; D007220:Industrial Waste / Q000032:analysis; D031658:Olea / Q000737:chemistry*; D000069463:Olive Oil; D010084:Oxidation-Reduction; D010636:Phenols / Q000032:analysis*; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives / Q000032:analysis; D010936:Plant Extracts / Q000302:isolation & purification; D011134:Polysaccharides; D011422:Propionates; D059027:Recycling; D014641:Vanillic Acid / Q000032:analysis; D062065:Wastewater
chemical_list: D000975:Antioxidants; D003373:Coumaric Acids; D005707:Gallic Acid; D062385:Hydroxybenzoates; D007220:Industrial Waste; D000069463:Olive Oil; D010636:Phenols; D010626:Phenylethyl Alcohol; D010936:Plant Extracts; D011134:Polysaccharides; D011422:Propionates; D014641:Vanillic Acid; D062065:Wastewater; C011867:4-hydroxyphenylethanol; C009091:protocatechuic acid; C008315:maltodextrin; C495469:p-coumaric acid
keywords: drying; membrane filtration; olive mill wastewater; phenolics