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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 #313046

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: Olive mill wastewater membrane filtration fraction: Drying techniques and quality assessment of the dried product (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: 2/23/2015
Publication Date: 7/13/2015
Citation: Sedej, I., Milczarek, R.R., Wang, S.C., Sheng, R., Avena Bustillos, R.D., Takeoka, G.R. 2015. Olive mill wastewater membrane filtration fraction: Drying techniques and quality assessment of the dried product (abstract). Institute of Food Technologists Annual Meeting, Chicago, IL July 11-14,2015.

Interpretive Summary: A current trend in olive mill wastewater (OMWW) management is to not only decrease environmental pollution but also utilize valuable co-products. Recovery of phenolics (antioxidant compounds) from OMWW could help olive oil processors add value to their co-product, increasing the sustainability of olive oil production. 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. We found that drying of the filtered OMWW is possible only with addition of 10% maltodextrin as a carrier, due to the low solids content. The highest recovery for OMWW from 2 different olive production processes was achieved with freeze-drying. Findings from this study show that drying of the membrane filtration stream of OMWW, especially spray drying, results in a powder which contains phenolics. Further characterization of the dried material is needed for its possible applications in nutraceutical, feed or food industries. Processing the OMWW in this way will help olive oil processors add value to their co-product OMWW stream.

Technical Abstract: A current trend in olive mill wastewater (OMWW) management is to not only decrease environmental pollution but also utilize valuable co-products. Recovery of phenolics from OMWW could help olive oil processors add value to their co-product, increasing the sustainability of olive oil production. 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 two California mills (2-phase and 3-phase) 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. The results of this experiment showed that drying of the RO-R is possible only with addition of 10% maltodextrin as a carrier, due to the low solids content. The highest recovery for both 2-phase and 3-phase RO-R was achieved with freeze-drying. The total soluble phenolics in dried RO-R were in the range 0.15 – 0.58 mg gallic acid/g of dry weight for 2-phase RO-R, and 1.38 – 2.17 mg gallic acid/g of dry weight for the 3-phase RO-R. Findings from this study show that drying of the membrane filtration stream of OMWW, especially spray drying, results in a powder which contains phenolics. Further characterization of the dried material is needed for its possible applications in nutraceutical, feed or food industries. Processing the OMWW in this way will help olive oil processors add value to their co-product OMWW stream.