Effect of Freeze-Thaw Cycles on Nutritional Quality and Texture Change of Ctenopharyngodon Idellus C.et V

In order to explore the effects of freeze-thaw cycles(0,1,3,5,7,and 10 cycles) on quality characteristics of Ctenopharyngodon idellus C.et V,the changes of basic eating quality,full textural properties,thiobarbituric acid-reactive substances(TBARS),total volatile base-nitrogen(TVB-N),protein carbonyl content,and total sulfhydryl content of treated samples were evaluated after repeated frozen-thawing in this paper.The results showed that with the increase of freeze-thaw cycles,thawing juice loss significantly increased(P< 0.05).Cooking loss and pressure filtration rate increased firstly and then decreased,however,the pH value was just opposite; L*value(brightness),whiteness,TBARS,TVB-N and protein carbonyl content increased gradually; a*value,b*value,hardness,springiness decreased gradually with freeze-thaw cycles.The microstructure of the samples had changed a lot,and the degree of tightness and fracture of myofibril increased as the number of freeze-thaw cycles increased.All the results demonstrated that freeze-thaw cycles could lower the quality of samples and this effect was positively related to the number of freeze-thaw cycles.