不同温度条件下三文鱼中荧光假单胞菌生长预测模型的建立

摘要

Pseudomonas fluorescence SBW25 is a specific spoilage organisms (SSOs) that plays a leading role in the spoilage of salmon.Salmon meat and sterile fish sauce were chosen as growth media for Pseudomonasfluorescence.The modified Gompertz equation and Belehradek equation were used for titting kinetic models to predict the growth of P.fluorescence SBW25 at different temperatures.At the same time,the impact of protease activity in sterile fish juice on the growth kinetic parameters was explored,and the applicability of the models was evaluated.Results showed that the coefficients of determination (R2) of the modified Gompertz equations for shelf life prediction at all temperatures tested were up to 0.999,suggesting that the modified Gompertz model is suitable to describe microbial growth in salmon and sterile fish sauce.The maximum specific growth rate （μmax） increased and the lag phase of growth was shortened with the temperature increasing for both media.The R2 values of the Belehradek models between temperature and the square root ofμmax and lag phase duration in sterile fish sauce were up to 0.930 3 and 0.988 7,respectively,which were much higher than those in fish meat.In sterile fish sauce,protease activity andμmax at the same growth phase showed the same trend of change.The degree of deviation and accuracy of the Belehradek equation for sterile fish sauce at different temperatures were close to 1.00.The Belehradek model for SSOs growth in sterile fish sauce could reflect the shelf life of salmon at different temperatures.%荧光假单胞菌SBW25 (Pseudomonas fluorescence SBW25)作为三文鱼的特定腐败菌(specific spoilage organisms,SSOs),在三文鱼腐败过程中起着主导作用.实验选择以三文鱼的鱼肉和鱼汁为生长介质,采用修正的Gompertz方程和Belehradek方程拟合三文鱼特定腐败菌之一的荧光假单胞菌SBW25在不同温度条件下的生长动力学模型,同时探究鱼汁中蛋白酶活力对动力学参数的影响,并对模型的适用性进行评价.结果显示,修正的Gompertz方程所拟合出的各温度下货架期方程的决定系数(R2)都达到0.999,适用于描述三文鱼鱼肉和鱼汁中微生物的生长曲线.随着温度升高,鱼肉和鱼汁中的荧光假单胞菌的最大比生长速率和延滞期出现上升和缩短.鱼汁中温度和最大比生长速率、延滞期的Belehradek平方根方程取得较高的决定系数,分别达到0.930 3和0.988 7,高于鱼肉中取得的.在鱼汁中蛋白酶活力和对应时期荧光假单胞菌的最大比生长速率出现相同变化趋势.基于Belehradek方程的鱼汁不同温度模型偏差度和准确度都更接近于1.00,说明鱼汁中SSOs的生长曲线能较好地反映出各温度条件下的三文鱼货架期.