Conjugation with alginate oligosaccharide via the controlled Maillard reaction in a dry state is an effective method for the preparation of salmon myofibrillar protein with excellent anti-inflammatory activity

The efficacy of the controlled Maillard reaction with alginate oligosaccharide (AO) in a dry state was examined for development of an anti-inflammatory compound from fish myofibrillar protein (Mf). Lyophilized Mf from spawned-out chum salmon was mixed with AO (half of the total protein weight) and incubated at 60 A degrees C and 35 % relative humidity for 0-6 h, followed by digestion with pepsin and trypsin. The anti-inflammatory activity of the digested peptide was improved with the progress of the AO conjugation, and dMSA4 (prepared from Mf-AO conjugate by reaction for 4 h, with 49.6 mu g/mg protein of AO attached) was most effective in inhibiting secretions of inflammation-related compounds in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Likewise, dMSA4 suppressed the LPS-induced gene and protein expression of inducible nitric oxide synthase, tumor necrosis factor-alpha, interleukin-6, and cyclooxygenase (COX)-2, while COX-1 expression was unaffected. Furthermore, oral administration of dMSA4 and the Mf-AO conjugate prior to proteolysis inhibited carrageenan-induced paw volume expansion in mice. These results indicate that AO conjugation using the controlled Maillard reaction in a dry state is a useful approach for enhancing the anti-inflammatory activity of salmon Mf as a nutraceutical food material.