FSSAI issued a notice dated 22nd feb 2021, regarding the instruction for measuring the refractive index value in oil samples
Refractive Index (RI) or Butyro refractometer (BR) values are used to identify oils and its purity. Refractive Index(RI) of oil increases with increase in unsaturation and chain length of fatty acids. Different oils have their specific refractive index/BR values measured at a certain temperature. As the refractive index/BR value is greatly affected by temperature, the temperature of the refractometer is needed to be controlled during the process of analysis.
Hence FSSAI instructs all the laboratories to refer point 5.0 “Determination of Refractive Index” of FSSAI Manual of methods of Analysis of Foods (Oils & Fats) regarding the principle, apparatus to be used, instrument calibration, procedure, temperature correction etc., for measuring refractive Index/BR value of oils. Also, FSSAI directs the food testing laboratories to not use methods or apparatus other than one specified in the FSSAI Manual
Source: FSSAI
