赤藓糖醇对南美白对虾肉玻璃化转变温度与状态图的影响

南美白对虾肉（PV）冻藏期间极易出现蛋白质变性,为提高虾肉贮藏稳定性,研究了PV与按虾肉质量添加5%赤藓糖醇的虾肉（PV-E）的吸附等温线;测定了PV与PV-E的玻璃化转变温度（Tg）和冻结点温度（TF）。采用Gordon-Taylor方程与Chen’s方程拟合数据,探讨添加赤藓糖醇对虾肉状态图的影响。结果表明,PV与PV-E水分吸附均为III型等温线,GAB模型为描述虾肉水分吸附特性的最适模型。PV与PV-E的Tg随着湿基含水率升高而降低;相同含水率时,PV-E的Tg高于PV。PV与PV-E的TF随着固形物含量的增加而降低。PV与PV-E最大冷冻浓缩溶液时的玻璃化转变温度T’g分别为-77.09℃和-62.23℃,与之对应的溶质含量分别为0.672 g/g和0.686 g/g。赤藓糖醇可作为一种新型抗冻剂,用于提高虾肉冻藏期间的贮藏稳定性。 

Effects of erythritol on the glass transition temperature and state diagram of Penaeus vannamei meat

Protein denaturation is liable to occur during frozen storage of Penaeus vannamei( PV) meat.The effect of addition of erythritol on the glass transition temperature( Tg) and state diagram of Penaeus vannamei meat were investigated to improve the storage stability of Penaeus vannamei meat. Moisture adsorption isotherms of PV and Penaeus vannamei meat with addition of 5%( w / w) erythritol( PV- E) were determined at 25 ℃ by the gravimetric method. Differential scanning calorimetry was used to determine the Tgand freezing point( TF) of samples equilibrated at various water activities.Gordon- Taylor equation and Chen's equation were employed to model the data of Tgand TF,especially.The adsorption behavior of PV and PV-E displayed III type isotherms.The GAB model satisfactorily described the adsorption behavior of PV and PV- E. Tgof PV and PV- E decreased with increasing moisture content and TFdecreased with increasing solid content. At a given moisture content,Tgof Penaeus vannamei meat increased with the addition of erythritol.The state diagram yielded maximally- freeze- concentrated solutes at 0.672 g / g and 0.686 g / g solids with the characteristic temperature of glass transition being-77.09 ℃ and-62.23 ℃ for PV,and PV- E,respectively.Erythritol could be used as a novel cryoprotective agent and the storage stability and shelf life of Penaeus vannamei meat could be observably improved by the addition of erythritol.