Formation of white spots in the shell of raw shrimps during frozen storage. Seasonal variation and effects of some production factors
✍ Scribed by Mikkelsen, Anni; Rønn, Birgitte; Skibsted, Leif H
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 289 KB
- Volume
- 75
- Category
- Article
- ISSN
- 0022-5142
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✦ Synopsis
During frozen storage of raw pink shrimps, Pandalus borealis, calcium carbonate tends to precipitate in the exoskeleton, giving the shrimps a spotted appearance. Seasonal variations in the formation of white spots and the inÑuence of shrimp size, production time, chemical treatment, and storage temperature on white spot formation was determined. A signiÐcant e †ect (P \ 0É003) of day of catch was observed and shrimps caught in the summer period showed a greater tendency of white spot formation than shrimps caught during the rest of the year. Treatment in a sulphite, a phosphate or a phthalate solution prior to freezing retards calcium carbonate crystallisation (P \ 0É05) while treatment in a borax solution promotes crystallisation (P \ 0É05). Prolonged time from catch to chemical treatment and increased storage time increase the risk of white spot formation. Storage temperature has a signiÐcant e †ect on white spot formation for which process the rate at di †erent temperatures was described by the Arrhenius equation with a high energy of activation of 90 kJ mol~1. The size (age) of the shrimps did not inÑuence white spot formation (P \ 0É69). From these Ðndings it is concluded that calcium carbonate precipitation resulting in white spots in shrimp shell can be retarded or possibly prevented by short production time, appropriate chemical treatment and very low storage temperature.