Abstract:The main objective of this review is to summarize the present state of knowledge of different ways of processing cod, giving emphasis to salting, drying, and desalting steps. As an introduction, a description of the main characteristics of the Gadidae family and cod species, the general chemical composition of fresh cod, and a reference to farmed cod is included. Statistics on world fishery and aquaculture cod production are also reviewed. It is expected that this review will contribute to build a current picture of the technical and scientific knowledge on the cod processing situation, helping to move forward and to support future developments in this important seafood industry.

The objective of this work was to study the dependence of the heat transfer coecient (h) on the water loss rate of potato during frying. An indirect method was used where a metal piece with the same geometry of the potato pieces was placed on top of various potato samples at dierent frying times, and its temperature was recorded for 20±30 s. Another method consisted of direct recording of the temperature within a potato slice, close to the surface. Water loss rate was estimated by image analysis of bubbles. After immersion in hot oil, the potato temperature increases and water starts vapourising, leaving the surface in the form of bubbles that ow through the oil. The water loss rate increases until complete drying of the potato surface and then decreases till the end of frying. The h value showed the same behaviour increasing up by two times in relation to the values measured in the absence of bubbling, with maximum values depending on the oil temperature and potato geometry (443±750 W m À2 K À1 ). The percentage of heat transferred to the potato that is used for water evaporation showed an increase with time up to complete surface drying.

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Summary Light microscopy was used to study changes in cell size, blister formation and crust evolution during potato frying. Frying experiments with both French fries and crisps of different thickness (1–5 mm) were performed at temperatures of 140 and 180 °C. Thickness, volume and density changes were also measured. The formation of crust in French fries starts after the potato surface reached approximately 103 °C, and then the crust thickness increased linearly with the square root of frying time, this increase being faster at 180 °C. The potato volume decreased during frying, although in the late stages the volume may increase because of oil uptake and cell separation caused by entrapped water vapour. Shrinkage was adequately described by the Weibull model with a residual value, with shrinkage rate increasing with temperature and decreasing with potato thickness. The residual volume was not affected by temperature (65% for French fries and 59–30 for crisps, depending on thickness). Volume appeared to decrease mainly as the result of water loss, except for very low water content, and thus potato density changes were very small.

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