Evaluation of Occasional Nonresponse of a Washed Cod Mince Model to Hemoglobin (Hb)-Mediated Oxidation

• An emerging model to test antioxidants for application in seafoods is washed cod mince fortified withhemoglobin (Hb) as a catalyst. This system has been used to test the antioxidative activity of certainmuscle extracts and some pure compounds such as BHA, BHT, TBHQ, and propyl gallate during icestorage. However, the washed cod mince model has occasionally been resistant to Hb-mediatedoxidation. This has been in cases when the moisture of the model has been minimized by washesat the protein isoelectric point (pH 5.5) to allow for large additions of potentially antioxidative solutions.In this paper, noncontrollable and controllable factors for this intriguing occasional oxidation resistancewere studied. Compositional analyses (lipid content, alpha-tocopherol, and lipid hydroperoxides) andstructural analysis of a “normal” oxidizing model and a stable model were done to identify anydifferences among them. Some controllable factors related to the model preparation that were studiedincluded different washing pH values (5.5-6.6), Hb concentrations (7.2 and 13.5 íM), final modelmoisture contents (75, 81, and 90%), and light exposure during ice storage (0 h, 3-4 h, or 24 h oflight/day). Results revealed a 2-fold higher alpha-tocopherol content in the stable model than in theoxidizing model. Electron microscopy images showed a more and less disrupted myofibrillar structurein the stable and the oxidizing cod model, respectively. This indicated that “cold setting” (i.e., pregelation)of the stable model may have occurred and prevented Hb from diffusing freely in the model.Controllable factors that reduced lipid oxidation in the models were less Hb and lower moisture.

Ämnesord

LANTBRUKSVETENSKAPER  -- Lantbruksvetenskap, skogsbruk och fiske -- Livsmedelsvetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Agriculture, Forestry and Fisheries -- Food Science (hsv//eng)

Nyckelord

cod mince model

Antioxidant

moisture

hydroperoxides

washed

r-tocopherol

hemoglobin

lipid oxidation

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