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Introduction
Anhydrous milk fat, ghee, is by far the most ubiquitous indigenous fat-rich dairy product. It is a clarified form of milk fat. Ghee is defined as a product exclusively obtained from milk, cream or butter, by means of processes which result in almost total removal of water and non-fat solids, with an especially developed flavor and physical structure (Codex, 2006). Chemically ghee is an extremely complex mixture of triglycerides, together with diglycerides, monoglycerides, free fatty acids, phospholipids, cholesterol and several other compounds ranging from small to trace amounts (Safar et al., 1994; Che Man et al., 2005). Amongst all constituents of ghee, the glycerides constitute about 98 percent. Of the remaining constituents, sterols occur to the extent of about 0.5 percent (Ganguli and Jain, 1972). The principal variation in composition of fats and oils is the chain length and degree of unsaturation of the component fatty acids (Dupuy et al., 1996; Cabassi et al., 2013). Milk fat is undoubtedly one of the most complex of all dietary fats with variety of different fatty acids. It is mainly composed of saturated fatty acids, followed by monounsaturated fatty acids and small amounts of polyunsaturated fatty acids. It has more than 1,300 individual triacylglycerols (Nurrulhidayah et al., 2013). Ghee is the most valuable fat for human nutrition (Nurrulhidayah et al., 2013). It is the most widely used milk product in the Indian sub-continent and is now also gaining popularity in Australia, Arabian countries, the USA, the UK, Belgium, New Zealand, the Netherlands and many African and Asian countries (Illingworth et al., 2009; Khoshhesab, 2012).
The chemical methods for characterization of edible fats/oils require the use of chemicals and solvents especially chlorinated ones in large amounts, leading to potential health hazards and environmental pollution. GLC and HPLC employed for authenticity testing are costly, time consuming and involve hazardous chemicals as well as solvents. Moreover, some of these methods like GLC require extensive sample preparation including extraction, concentration and/or preliminary purification and/or derivatization of the target analytes, which may decrease the performance of the analytical technique (Karoui and Baerdemaeker, 2007, 2010; Capuano and van Ruth, 2012). Fourier transform-infrared (FTIR) spectroscopy has become an effective alternative to the traditional methods of analysis (Javidnia