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干豆腐掺假时有发生,而掺假物主要为玉米面,为了能在现场有效地快速检测出这种掺假、应用淀粉与碘作用生色反应的原理,研制出了一种干豆腐掺假的简易快速检验方法及检测装置。 取碘化钾1克溶于少量水中,然后用此溶液溶解结晶碘0.5克,待结晶碘完全溶解后,倒入100毫升容量瓶中加水至刻度即可。正常干豆腐(或纯豆粉)在常温下与碘不起反应,但玉米面中的淀粉在常温下则与碘反应呈现兰紫色。根据淀粉含量多少与反应强度的正变关系,而制做成含有不同比例玉米面的干豆腐,O/250g、1/250g、3/250g、5/250g、10/250g、25/250g、30/250g、35/250g、40/250g、50/250g、100/250g。然后将碘溶液分别滴加在各种干豆腐样品上,以观察显色强度。从1/250克剂量组开始即可看到碘与淀粉显色反应,
Dry tofu adulteration occurs from time to time, and adulteration is mainly cornmeal, in order to effectively detect this adulteration effectively in the field, the application of starch and iodine role of color reaction principle, developed a dry tofu adulteration Simple quick test method and testing device. Take potassium iodide 1g dissolved in a small amount of water, and then use this solution to dissolve crystalline iodine 0.5g until the crystal iodine is completely dissolved, into a 100mL volumetric flask add water to the mark. Normal dry tofu (or pure soy flour) does not react with iodine at room temperature, but the starch in cornmeal reacts with iodine at room temperature to show a purple-violet color. According to the positive relationship between the amount of starch and the reaction intensity, the dried tofu with different proportions of cornmeal is prepared, wherein the ratio of O / 250g, 1 / 250g, 3/250g, 5/250g, 10/250g, 25/250g, 250 g, 35/250 g, 40/250 g, 50/250 g, 100/250 g. The iodine solution was then dropped on various dried tofu samples to observe the color strength. From 1/250 g dose group began to see the color reaction of iodine and starch,