Aquafeed ingredient production from herring (Clupea harengus) by-products using pH-shift processing: effect from by-product combinations, protein solubilization-pH and centrifugation force

•A new alternative to classic fishmeal production is proposed, using the pH shift method.•The pH shift process is proposed as an efficient method of working with high bone-low meat sources, such as fishery byproducts.•Protein yield is affected by the treatment that is applied during the pH shift process.•Proximate composition of the pH shift produced protein concentrates is also subject to treatment.