Effect of Different Saccharides on the Quality of Peeled Shrimp During Frozen Storage with Freeze-thaw Cycles

To investigate the effects of different saccharides on the quality of frozen shrimp(Litopenaeus vannamei)under freeze-thaw cycles conditions,the cryoprotective effects of 3% xylooligosaccharide,3% carrageenan oligosaccharide,3% trehalose,and 3% alginate oligosaccharides(the 3% sodium pyrophosphate treatment as positive control)on peeled shrimp during the circulated freezing-thawing(-55~4 ℃)process was investigated by monitoring the thawing loss rate,L^* value,texture characteristics,myofibrillar protein content,sulfhydryl content,and Ca²⁺-ATPase activity. The results showed that the thawing loss and L^* value of control shrimp significantly increased to 46.2% and 11.7%,while the chewiness,hardness,myofibrillar protein content,Ca²⁺-ATPase activity,and total sulfhydryl content decreased significantly by 57.5%,43.8%,14.0%,29.7%,and 23.4%(P<0.05)after 6 cycles of the repeated freezing and thawing. Compared with the distilled water group,the saccharides soaking showed good water holding capacity and inhibition effects on the protein denaturation in frozen shrimp. After 6 cycles of treatment,the thawing loss and L^* value of shrimp muscle treated with 3% carrageenan oligosaccharide increased to 5.65% and 47.35,while the chewiness,hardness,myofibrillar protein content,Ca²⁺-ATPase activity,and total sulfhydryl content maintained at 5.43 mJ,1.28 mm,95.24 mg/g,0.093 U/mg and 7.31 mmol/L,respectively. The protection on the quality characteristics of the shrimp was better than the other saccharide treatments. In conclusion,the saccharides treatments played important roles in the peeled shrimp during frozen storage with temperature fluctuations,which provided a theoretical basis for the quality assurance of frozen shrimp.