食品中柠檬酸快速检测试剂盒的研制

Development of rapid detection kit for citric acid in food

建立了一种酶法检测食品中柠檬酸含量的快速检测方法.将6UL-苹果酸脱氢酶、9.13 U L-乳酸脱氢酶、0.5 mg烟酰胺腺嘌呤二核苷酸、2 mg硫酸镁、3.783 mg海藻糖、5mg聚乙二醇6000在0.2 mL 0.082 g/mL双甘肽质量浓度下-60℃冷冻5h,室温条件下抽真空18h得到试剂Ⅰ,0.468U柠檬酸裂解酶在0.2 mL水体系冷冻干燥得到试剂Ⅱ.结果表明,该方法标准曲线线性关系良好,相关系数R2=0.995,线性范围1～80 μg/L;灵敏度0.25 mg/L;检测限0.5 mg/L;各样品回收率均在90％～110％.该试剂盒方法可以在20 min实现样品中柠檬酸的快速检测,方法灵敏度高、特异性高、快速简便,适合于食品生产企业对食品中的柠檬酸进行快速检测及对食品的质量和品质进行评价.

A rapid enzymatic detection method was developed for determination of citric acid in food. Reagent I was made by L-malate dehydrogenase 6 U, L-lactate dehydrogenase 9.13 U, nicotinamide adenine dinucleotide 0.5 mg, MgSO42 mg, trehalose 3.783 mg, PEG 6000 5 mg with 0.082 g/ml Gly-Gly 0.2 ml after freezing 5 h at -60 ℃, and then vacuumized for 18 h at room temperature. Reagent II was made by citrate lyase 0.468 U in 0.2 ml water system by freeze drying. Results showed the correlation coefficient of standard curve was 0.995, linearity range was 1-80 μg/L, the sensitivity of method was 0.25 mg/L, the limit of detection of method was 0.5 mg/L, and the recovery rate was 90%-110%. By this method, the citrate in the sample can be rapidly detected within 20 min. The method was simple and fast with high sensitivity and specificity, which was suitable for rapid detection of citric acid in food and evaluation of food quality.