The CODEX standard versus the enthalpy method: comparison of two techniques for determination of ice-glaze uptake on prawns

Glazing is the application of water (or sometimes a salt-sugar solution) to the surface of frozen foodstuffs, so that a layer of ice is formed. This p rocedure protects the product from the effect of dehydration and oxidation during long term storage. However, glaze is often applied in an uncontrolle d manner and considerable variation in the quantity of glaze may result. To day the CODEX standard is most widely used to determine the glaze-uptake of individually quick frozen (IQF) seafood products. However, the method exhi bits considerable variations with respect to accuracy and precision. We pro pose a conceptually totally different method for ice-glaze determination of cold-water prawns. The method is denoted the enthalpy method and is based on noncontact measurement of the prawn filet temperature elevation during g lazing. Comparisons of the CODEX and the enthalpy methods against weight re ference measurements of the glazing percentage show that the enthalpy metho d is superior, provided performance indices like precision and sampling rat e are used as evaluation criteria. (C) 1999 Elsevier Science Ltd. All right s reserved.