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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Healthy Processed Foods Research » Research » Publications at this Location » Publication #315619

Research Project: New Sustainable Processing Technologies to Produce Healthy, Value-Added Foods from Specialty Crops and their Co-Products

Location: Healthy Processed Foods Research

Title: Sustainable technologies for olive mill wastewater management (abstract)

Author
item Sedej, Ivana - University Of California
item Milczarek, Rebecca
item Wang, Selina - University Of California
item Sheng, Runqi - University Of California
item Avena Bustillos, Roberto
item Takeoka, Gary

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/19/2015
Publication Date: 5/14/2015
Citation: Sedej, I., Milczarek, R.R., Wang, S.C., Sheng, R., Avena Bustillos, R.D., Takeoka, G.R. 2015. Sustainable technologies for olive mill wastewater management (abstract). University of California, Davis Postdoctoral Research Symposium.

Interpretive Summary: The California olive oil industry produces more than 600 million gallons of wastewater each year. Olive mill wastewater (OMWW) is considered a highly polluting effluent due to its high organic load and resistance to biological degradation. A current trend in OMWW management is to not only decrease environmental pollution but also extract and utilize valuable by-products. The objectives of this study were to develop an energy-efficient separation technology for OMWW treatment, and to extract health-promoting phenolic compounds. OMWW was filtered in 2 steps, using membranes of different pore sizes. The filtration stream that contained valuable compounds was subject to 3 different drying techniques (spray-, freeze-, and infrared-drying), resulting in a powder. Key quality metrics of this powder were measured, and the identities of several chemical compounds present in the powder were determined. Findings from this study confirm that the 2-step sequential membrane filtration process using a novel vibratory system can be successfully utilized in OMWW treatment. Drying of the filtered product, especially by spray drying, results in a powder that contains valuable chemical compounds. Further characterization of the dried material is needed for its possible applications in nutraceutical, feed or food industries. This combination of separation and drying technologies helps to add value to an olive oil by-product and increase the sustainability of its production.

Technical Abstract: The California olive oil industry produces more than 600 million gallons of wastewater each year. Olive mill wastewater (OMWW) is considered a highly polluting effluent due to its high organic load and resistance to biological degradation. A current trend in OMWW management is to not only decrease environmental pollution but also extract and utilize valuable by-products. The objectives of this study were to develop an energy-efficient separation technology for OMWW treatment, and to extract health-promoting phenolic compounds. The OMWW from two (3-phase and 2-phase) California mills was subjected to a two-step membrane filtration process using a novel vibratory system. The first step (ultrafiltration) permeate was submitted to a reverse osmosis (RO) membrane (40 Da pore size) filtration. The RO retentate (RO-R) is a phenolic-rich co-product stream, and the RO permeate is a near-pure water stream that could be recycled into the milling process. Different drying techniques (spray-, freeze-, and infrared-drying) were applied to obtain solid material from the RO-R. Drying of the RO-R was possible only with addition of 10% maltodextrin as a carrier, due to the low solids content. Physicochemical properties, total soluble phenolic content, and antioxidant activity of dried RO-R were determined. Furthermore, HPLC characterization and quantification of phenolic compounds in dried samples was accomplished. Findings from this study confirm that the two-step sequential membrane filtration process using a novel vibratory system can be successfully utilized in OMWW treatment. Drying of the RO-R stream, especially by spray drying, results in a powder that contains phenolics. Further characterization of the dried material is needed for its possible applications in nutraceutical, feed or food industries. This combination of separation and drying technologies helps to add value to an olive oil by-product and increase the sustainability of its production.