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We compared physiological characteristics and responses to experimental freezing and thawing in winter and spring samples of the wood frog, Rana sylvatica, indigenous to Interior Alaska, USA. Whereas winter frogs can survive freezing at temperatures at least as low as -16°C, the lower limit of tolerance for spring frogs was between -2.5°C and -5°C. Spring frogs had comparatively low levels of the urea in blood plasma, liver, heart, brain, and skeletal muscle, as well as a smaller hepatic reserve of glycogen, which is converted to glucose after freezing begins. Consequently, following freezing (-2.5°C, 48 h) tissue concentrations of these cryoprotective osmolyteswere 44-88% lower than those measured inwinter frogs. Spring frogs formedmuchmore ice and incurred extensive cryohemolysis and lactate accrual, indicating that they had suffered marked cell damage and hypoxic stress during freezing. Multiple, interactive stresses, in addition to diminished cryoprotectant levels, contribute to the reduced capacity for freeze tolerance in posthibernal frogs. [ABSTRACT FROM AUTHOR]

• The effect of processing sequence on the quality of roe product was investigated. • Protein degradation of the eggshell was the cause of textural damage. • Cryoprotectants in seasoning solution prevented product quality deterioration. • The Seasoning-Frozen storage processed roe product superior quality. The quality of seasoned products of Alaska pollack (Theragra chalcogramma) roe declined dramatically during frozen storage. This research investigated the effects of processing sequence and frozen storage period on seasoned Alaska pollack roe product quality. In addition, the relationship between mechanical properties and protein composition of ovary membrane and eggshell was discussed. The seasoned roe product made by the Seasoning-Frozen storage process showed higher mechanical property values, better surface color and more stable protein composition. The results clarified that this process allowed endogenous transglutaminase to act before it had been denatured and effectively prevented protein degradation during frozen storage. The retardation of protein degradation was probably attributed to cryoprotective effects from components in seasoning solution. [ABSTRACT FROM AUTHOR]