olive grind by MrsBrown on Pixabay

Olive Oil By-Products

The by-products of oil extraction are pomace and water. The three-phase system has separate out­lets for pomace and water, while the two-phase system mixes the pomace and water. Another major by-product is the wastewater from washing equipment and general cleaning of the facility.

California regulations require processors to carefully manage raw pomace and wastewater because the high chemical oxygen demand of these by-products may pollute groundwater, soil, and waterways by depleting available oxygen. We have ongoing research to identify efficient ways to separate the water-soluble phenols from pomace and wastewater, as the natural antioxi­dant and antibacterial properties of the phenols have value as supplements in processed food and cosmetics.


Some of our research findings are listed below:

Zhao, H., Kim; Y., Avena-Bustillos, R. J.; Nitin, N.,; Wang, S. C. LWT 2023, 180, 114677 “Characterization of California olive pomace fractions and their in vitro antioxidant and antimicrobial activities” 

Zhang, K.; Zhao, H.; Wang, S. C. Construction and Building Materials, 2022, 330, 127217 “Upcycle olive pomace as antioxidant and recycling agent in asphalt paving materials

Zhao, H.; Avena-Bustillos, R. J.; Wang, S. C. Foods, 2022, 11, 174 “Extraction, Purification and In Vitro Antioxidant Activity Evaluation of Phenolic Compounds in California Olive Pomace

Inzunza-Soto, M.; Thai, S.; Sinrod, A. J. G; Olson, D. A.; Avena-Bustillos, R. J.; Li, X.; Rolston, M. R.; Wang, S. C.; Teran-Cabanillas, E.; Yokoyama, W.; McHugh, T. H. J. Food Sci., 2021, 1-12: “Health benefits of first and second extraction drum-dried pitted olive pomace

Macedo, G. A.; Santana, A. L.; Crawford, L. M.; Wang, S. C.; Dias, F. F. G; Bell, J. M. LWT – Food Science and Technology, 2021, 138, 110621: “Integrated microwave-and enzyme-assisted extraction of phenolic compounds from olive pomace

Sedej, I.; Milczarek, R.; Wang, S. C.; Sheng, R.; Avena-Bustillos, R. J.; Dao, L.; Takeoka, G. I. J. Food Sci. Tech. 2016: “Spray Drying of a Phenolic-rich Membrane Filtration Fraction of Olive Mill Wastewater: Optimization and Dried Product Quality

Sedej, I.; Milczarek, R.; Wang, S. C.; Sheng, R.; Avena-Bustillos, R. d. J.; Dao, L.; Takeoka, G. J. Food Sci. 2016, 81, E889-E896: “Membrane-Filtered Olive Mill Wastewater: Quality Assessment of the Dried Phenolic-Rich Fraction