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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 #319559

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

Location: Healthy Processed Foods Research

Title: Spray drying of a phenolic-rich membrane filtration fraction of olive mill wastewater: Optimization and dried product quality

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
item Dao, Lan

Submitted to: International Journal of Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/4/2016
Publication Date: 6/30/2015
Citation: Sedej, I., Milczarek, R.R., Wang, S., Sheng, R., Avena Bustillos, R.D., Takeoka, G.R., Dao, L.T. 2015. Spray drying of a phenolic-rich membrane filtration fraction of olive mill wastewater: Optimization and dried product quality. International Journal of Food Science and Technology. doi: 10.1111/ijfs.13163.

Interpretive Summary: A current trend in olive mill wastewater (OMWW) management is to not only decrease environmental pollution but also utilize valuable co-products. A two-step membrane filtration process using a novel vibratory system was used for OMWW treatment, and recovery of phenolics. The objectives of this study were to explore different spray drying conditions for a phenolic-rich membrane filtration fraction of OMWW, and to optimize them in terms of the dried product quality and feasibility of the process. Using a response surface design, optimized conditions were achieved for 3-phase and 2-phase phenolic-rich membrane filtration fraction of OMWW. The powders obtained by spray drying under the optimum inlet temperature and feed pump speed were analyzed for physicochemical properties, including identification and quantification of phenolic compounds. The results show the possibility to obtain a phenolic-rich powder from an OMWW filtration fraction. Processing the OMWW in this way will help olive oil processors add value to their co-product OMWW stream.

Technical Abstract: Olive mill wastewater (OMWW) from two California mills (3-phase and 2-phase) was subjected to a two-step membrane filtration process using a novel vibratory system. The obtained reverse osmosis retentate (RO-R) is a phenolic-rich co-product stream, and the reverse osmosis permeate is a near-pure water stream that could be recycled into the milling process. A pilot scale spray dryer was used for the production of RO-R powder. Different inlet temperatures and feed pump speeds were tested in order to optimize the dried product quality and feasibility of the process. The RO-R powders were analyzed for moisture content, water activity, total soluble phenolics, and antioxidant capacity. Process recovery and energy consumption were also determined. Using a response surface design, optimized conditions were achieved for 3-phase and 2-phase RO-R. The powders obtained by spray drying under the optimum composite desirability inlet temperature/feed pump conditions were analyzed for physicochemical properties, including identification and quantification of phenolic compounds. The results show the possibility to obtain a phenolic-rich powder from an OMWW filtration fraction. This will lead toward better usage of by-products from olive oil production, an increase in the feasibility of the production, and lowering of the environmental impact.