Effect of Different Storage Conditions and Treatments on the Content of Sodium Thiocyanate in Raw Milk
[Objective]The aim of this study was to explore the effects of different storage conditions and treatment methods on the content of sodium thiocyanate in raw milk samples.[Method]Raw milk samples were treated differently,including storage conditions(frozen at-20 ℃for 1,7 and 30 days,chilled at 0-6 ℃ for 4,8,24 and 48 h),thawing temperature(thawed at 25,40 and 60 ℃ after being frozen for 24 h),thawing frequency(frozen at 24 h,after thawed in water bath at 40 ℃ for 1,3 and 5 times respectively)and preservatives(sodium thiocyanate,potassium dichromate,sodium azide,propanediol bromide and formaldehyde).Then,sodium thiocyanate was detected in the sample,and the results were analyzed using One-Way ANOVA,principal component analysis,and recovery analysis to explore the impact of different treatments on the content of sodium thiocyanate in raw milk.[Result]After 1,7,and 30 days of frozen storage,there was no statistically significant difference in the content of sodium thiocyanate in milk(P＞0.05),with a recovery rate of 97.4％to 103.1％.After being chilled for 4,8,24,and 48 h,the content of sodium thiocyanate in milk showed a trend of first decreasing and then increasing,with a recovery rate of 94.5％to 102.1％.After 24 hours of freezing,there was no statistically significant difference in the content of sodium thiocyanate in milk at three different thawing temperatures(P＞0.05),with a recovery rate of 97.8％to 99.0％.The results of thawing 1,3 and 5 times after freezing showed that the content of sodium thiocyanate in milk decreased with the increase of thawing times,and the assay recoveries were 95.3％to 101.8％,which were in the acceptable range.There were significant differences in the content of sodium thiocyanate in milk with the addition of different preservatives(P＜0.05),in which the addition of sodium thiocyanate as a preservative led to high results,the addition of bromonitropropanediol led to low assay results,and the addition of formaldehyde led to non-detection of sodium thiocyanate.[Conclusion]When raw milk samples were frozen at-20 ℃ for 30 days,at 0 to 6 ℃ for 48 h,thawing temperature below 60 ℃ and thawing frequency less than 5 times,there was no effect on the content of sodium thiocyanate in raw milk samples.Sodium azide or potassium dichromate did not affect the content of sodium thiocyanate in raw milk samples.
raw milkpreservation timethawing temperaturethawing frequencysodium thiocyanate
万方数据
维普
