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建立了一种检测绿豆芽中亚硫酸盐的含量新方法。绿豆芽在充氮条件下进行蒸馏,挥发出来的SO2用氢氧化钠溶液进行吸收,吸收后的亚硫酸盐在室温下,p H值为6.6的介质中与铵盐、邻苯二甲醛反应生成强荧光物质,荧光强度与亚硫酸盐浓度(以SO2计)在0~9.60 mg/L范围内呈现良好的线性,线性方程为y=403.1x-147.41,相关系数为0.9996。该方法测定豆芽中的亚硫酸盐操作简单,选择性好,灵敏度高,所测结果与国标法(蒸馏滴定法)无显著性差别。同时对豆芽中亚硫酸盐的去除方法进行了研究,考察了水、醋酸水溶液、氯化钠溶液、碳酸钠溶液、洗米水对豆芽中亚硫酸盐的去除效果。结果表明洗米水和碳酸钠水溶液可以很好地去除豆芽中的亚硫酸盐。在65℃,绿豆芽在150.00 g/L洗米水和2.00 g/L的碳酸钠溶液中浸泡1.5 h,亚硫酸的去除率可分别达到66.41%~72.83%和67.07%~80.12%。
A new method for detecting sulfite content in mung bean sprouts was established. Mung bean sprouts under nitrogen conditions for distillation, volatile SO2 absorbed with sodium hydroxide solution, the absorbed sulfite at room temperature, p H value of 6.6 medium with ammonium salt, phthalaldehyde reaction generated Strong fluorescence, fluorescence intensity and sulfite concentration (SO2) in the range of 0 ~ 9.60 mg / L showed a good linearity, the linear equation was y = 403.1x-147.41, correlation coefficient of 0.9996. The method for determination of sulfite in bean sprouts has the advantages of simple operation, good selectivity, high sensitivity and no significant difference between the measured result and the national standard method (distillation titration method). At the same time, the removal of sulfite from bean sprouts was studied. The effects of water, acetic acid solution, sodium chloride solution, sodium carbonate solution and washing rice water on the removal of sulfite from bean sprouts were studied. The results show that washing water and sodium carbonate aqueous solution can well remove the sulfite in bean sprouts. At 65 ℃, mung bean sprouts were soaked in 150.00 g / L washing rice water and 2.00 g / L sodium carbonate solution for 1.5 h, the removal rates of sulfite reached 66.41% -72.83% and 67.07% -80.12%, respectively.