Temporal variations in the glaze uptake on individually quick frozen prawns as monitored by the CODEX standard and the enthalpy method

Determination of the ice-glaze content of fish and other seafood products d epends today on batch samples from the production line. A non-contact schem e (denoted the enthalpy-method), based on infrared measurement of temperatu re changes of the product, has previously been introduced in the literature . In this paper the method is compared to the conventional CODEX procedure during regular online production. Especially, the ability to detect unwante d temporal variations in the glazing percentage is focused on. Two cases ar e studied. Firstly, the glazing process is monitored during stationary cond itions. Secondly, an abrupt change in the glazing level is induced and the steady-state and dynamic properties of both methods are investigated. It is concluded that the enthalpy method is superior to the CODEX procedure and has the potential to be a key element in an automatic control system for th e glazing percentage of cold-water prawns. (C) 2001 Elsevier Science Ltd. A ll rights reserved.