Anserine and carnosine are dipeptides that have antioxidant properties and are found in the skeletal muscle of mammals and fish. Anserine and carnosine are water soluble and are removed through the washing process in surimi production. We hypothesized that the two dipeptides are identifiable, recoverable and can be converted into an antioxidant extract from surimi wash water.
Our objective is to determine the concentration of anserine and carnosine in surimi wash water at all stages of surimi processing and undertake preliminary methods to remove and concentrate the two dipeptides.
Wash water samples were collected from a local surimi plant. The samples were centrifuged, heat treated, filtered, vacuum packed and frozen at -80 degrees C. A second set of samples were heat treated at 60 degrees C, filtered with a 50K cutoff membrane and filtered again through a 10K cutoff membrane. The supernatant was vacuum packed and frozen at -80 degrees C. The concentration of the two dipeptides were analyzed using High Performance Liquid Chromatography (HPLC) with a fluorescent detector.
Tests showed that anserine and carnosine are present in high concentrations (greater than 200mg/L) in the first two stages of surimi processing. Treatment of the samples by ultrafiltration removed the majority of the large MW proteins in the washwater but caused some reduction in dipeptide concentrations. Tests showed that heat treated samples followed by ultrafiltration had values of 203 and 61 mg/L of carnosine and 176 and 49 mg/L of anserine, respectively, for the first and second wash.
Anserine and carnosine are antioxidants that help reduce lipid oxidation which affects flavor, aroma, texture, color and nutritional composition. Presence of these compounds in surimi wash water and their partial recovery is the first step in demonstrating their potential use as antioxidants.