Ghee is the most widely used milk product in the Indian sub- continent. In besides having a rich and pleasant sensory profile, it is a valuable source of essential fatty acids and fat-soluble vitamins. People who are dishonest are drawn to adulterate it with less expensive foreign fats like vegetable oils, animal body fats, etc. due to its rising demand, high price, and unpredictable chemical composition. This is a bad course of action. Multiple techniques were created to detect the adulteration of ghee because it was previously mixed with foreign oils and fats. These techniques were based on variations in the major/minor components of ghee and adulterated fats/oils, as well as their nature and contents. The current methods for identifying foreign fats in milk fat are primarily based on the partial solidification behaviour, fatty acid profile, sterol analysis, and physico-chemical constants. All of these techniques, however, fall short when milk fat is tainted with a combination of body fats and vegetable oils. Additionally, tailored vegetable oils with R.M., P.V., and B.R. that are similar to milk fat are now readily available to unscrupulous individuals in an unspecified market for adulteration purposes. To counter this approach some methods can be handy in the testing laboratories.
Methodology: There are two methods for identifying milk fat that has been tampered with. The first strategy is based on traditional techniques like B.R. reading, R.M. value, and P.V. value. The second strategy relies on a number of quick and innovative techniques, including the furfural test for vanaspati, the opacity test, the crystallisation test, the number of carbons by GLC of triglycerides, the color-based test for the detection of vegetable oil, the apparent solidification time test, and the complete liquification time test. All cases involve testing the extracted fat, with the exception of the modified Gerber test, which makes use of a specially created dual-purpose Gerber butyrometer and measures the fat’s B.R. reading. Therefore, separating the fat is the first step before performing the test.
Butyro-refractometer: A butyro refractometer is an instrument used to measure the concentration of butyrate in a sample. Butyrate is a type of fatty acid that is found in ghee. The butyro refractometer is used to determine the amount of butyrate in a ghee sample. The reading on the butyro refractometer is expressed in terms of grams of butyrate per 100 grams of ghee.
Detection of vegetable oils by B.R. Reading: Apply petroleum ether to clean the prisms on the butyro-refractometer. Allow the ether to evaporate to dryness. By circulating water, keep the prisms’ temperature at 40°C. Apply a drop of fluid with a known B.R. to the B.R. apparatus to calibrate it and adjusting B.R. by moving the adjustment screw. Clean the prisms. Apply a drop of sample of clear fat obtained by and methods between the prisms. Before taking the reading, wait two minutes for the sample to reach a steady temperature of about 40°C.
B.R. reading changes with temperature, increasing and decreasing respectively. Normally, the temperature of observation should not deviate by more than 2°C. To obtain the corrected B.R. reading of the sample, a correction of 0.55 is added to the observed B.R. reading for each degree above 40°C or subtracted for each degree below 40°C. When fat is isolated using the Gerber method, B.R. is reduced because H2SO4 has a hydrolytic effect on the fat.
Therefore, observed B.R. reading is corrected as follows:
Corrected B.R. = 1.08 x observed B.R.
Any variation from the standard indicates that milk has been tampered with the vegetable oils. However, this method is limited in its ability to identify adulteration when two oils, namely coconut oil and palm oil, with properties similar to those of milk fat, are used.
Butyro refractometer is an important tool in the dairy industry used to measure the quality of ghee. The reading from the butyro refractometer provides information on the amount of butterfat present in ghee. Higher the reading, higher the amount of butterfat present. The amount of butterfat present in ghee is important because it affects the taste, texture, and quality of the product.
The main reason why we check butyro refractometer reading in ghee is to ensure that the ghee has been properly clarified. If the reading is too high, it means that there are still some water and milk solids present in the ghee. This can affect the flavor and quality of the ghee.
The butyro refractometer reading is an important quality control tool for ghee. It helps to ensure that the ghee is of the highest quality and that it will taste great.
Source : Team Safe Labs