Integrated processes can turn industrial food waste into valuable food by-products and/or ingredients: The cases of olive mill and pomegranate wastes

• An integrated approach for olive mill wastewater utilization was developed.
• An integrated approach for pomegranate wastes utilization was developed.
• Fermentation, spray drying and encapsulation were applied to OMW.
• Olive paste spread, olive powder and encapsulated phenolics were produced from OMW.
• Encapsulated phenolics and seed oil were produced from pomegranate wastes.

Heavy food industry wastes present a constant threat to the environment and a serious operational problem for the respective food industries. While numerous research works are focused on the management of food wastes a lot of work has been done on several such wastes, process efficiency (i.e. extent of waste valorization) along with financial viability still remain serious drawbacks. This work deals with two difficult food wastes, the olive mill wastewater (OMW) and the pomegranate wastes (i.e. peels and seeds). It presents integrated approaches for complete utilization of these wastes in recovering valuable by-products and/or ingredients, while succeeding total depollution (zero waste). Specially designed fermentation, spray drying and encapsulation technologies were properly applied to OMW to produce a number of valuable by-products, such as olive paste spread or olive powder (to be included in food formulations) and encapsulated polyphenols. Clean water is the only remaining “waste stream” that can be reutilized in the olive mill plant, thus reaching total exploitation of the original OMW. In the case of pomegranate waste, an integrated approach is suggested for complete utilization of pomegranate seeds and peels based on ultrasound-assisted extraction of oil and phenolics from seeds and peels, respectively; optimized extraction is followed by isolated ingredient encapsulation using a suitable spray drying technique.