Darshan Lal

Development of a method employing reversed-phase thin-layer chromatography for establishing milk fat purity with respect to adulteration with vegetable oils

A systematic study was conducted using reversed-phase thin-layer chromatography wherein unsaponifiable matter of samples namely, pure cow and buffalo milk fats, vegetable oils (groundnut oil, soya bean oil and sunflower oil) and milk fats adulterated with vegetable oils (≥1%) were run along with the reference standards using two new solvent systems to detect adulteration in milk fat. The results of the study revealed that adulteration at even a 1% level could easily be detected using this rapid, reliable and reproducible method based on the presence of β-sitosterol as a marker and some additional spots ascribable to their occurrence in vegetable oils only.

A planar chromatographic method to detect adulteration of vegetable oils in ghee

Reversed-phase thin-layer chromatography (RP-TLC) is a sensitive, reliable, and reproducible technique, which can analyze a number of components simultaneously. This technique was exploited in the present study to identify the adulteration of vegetable oils (groundnut, soybean, and sunflower oil) in ghee, using the fact that β-sitosterol, an unsaponifiable matter, is present in vegetable oils, while absent in pure ghee. For this, RP-TLC of reference standards, unsaponifiable matter of pure ghee (cow and buffalo), pure vegetable oils, and the ghee adulterated with these vegetable oils (≥1%) was carried out on plates with different stationary phases, viz., RP-18, RP-8, and RP-2 plates using solvent system comprising of petroleum ether, acetonitrile, and methanol. The results revealed that adulteration of vegetable oils in ghee can easily be detected at a level of as low as 1 percent on RP-18 and RP-8 plates, while RP-2 plate did not offer any help in detection of adulteration. Thus, with the help of RP-TLC, a robust technique, the purity of ghee can be screened with respect to the presence of vegetable oils.

Detection of adulteration by caprine body fat and mixtures of caprine body fat and groundnut oil in bovine and buffalo ghee using differential scanning calorimetry

Differential scanning calorimetry was used to detect adulteration of pure ghee with caprine body fat when added singly (at 5, 10 and 15%) and in combination with groundnut oil (GNO) (at 5, 10 and 15%). Samples were analysed for transition behaviour in terms of crystallising and melting curves. When compared to pure ghee, adulterated ghee samples showed a shift in the midrange temperature of thermal curves, indicating the presence of foreign fats. The results revealed that the detection of adulteration was possible at the lowest level of the study (5%), irrespective of the nature of the adulterants.

Complete liquification time test coupled with solvent fractionation technique to detect adulteration of foreign fats in ghee

Complete liquification time (CLT) test (min:s) exploits the physical property of milk fat as the time required by solid fat to melt completely at a defined temperature. It has been used to detect adulteration of groundnut oil and goat body fat when added singly and in combination with ghee. The Complete liquification time test for samples containing a combination of adulterants was carried out before and after solvent fractionation. The results revealed that adulterants added individually could be detected at higher levels (15%, w/w, groundnut oil in cow ghee; and 10%, w/w, goat body fat in buffalo ghee), while fractionation reduced the detection limit to lowest level (10%, w/w) used in this study.