Compsn. for determining degree of oxidn. of fats - contains alcoholic base and redox indicator

摘要

Compsn. for colourimetric determination contains an alcoholic base, esp. KOH, and a redox indicator. The indicator may be Bromophenol blue, (I), Thymol blue, Xylenol orange, Bromocresol purple, Methylene violet, (colour index no 52041); Methylene green (colour index no 52020) or Patent blue (colour index no 42051). Compsn. is used for testing freshness of frying fats. Used also for fat contg. foods. Test is quick, simple and accurate. In an example, 6 drops 25% KOH soln. and 1 ml molten fat were added, with shaking, to 3 ml 4:1- n-propanol/benzyl alcohol mixt. 0.05 ml of a 0.1% aq soln. of (I) was added drop by drop, with shaking. After 2 min, colour obtd. was compared with a calibrated colour scale.