Raman spectroscopy as a fast and nondestructive technique has been used to investigate heating effects on Desi ghee during frying/cooking of food for the first time. A temperature in the range of 140-180℃ has been investigated within which Desi ghee can be used safely for cooking/frying without much alteration of its natural molecular composition. In addition, heating effects in case of reuse, heating for different times, and cooking inside pressure cookers are also presented. An excitation laser at 785 nm has been used to obtain Raman spectra and the range of 540-1800 cm-1 is found to contain prominent spectral bands. Prominent variations have been observed in the Raman bands of 560-770 cm-1, 790-1160 cm-1, and 1180-1285 cm-1 with the rise in temperature. The spectral variations have been verified using classifier principal component analysis. It has been found that Desi ghee can be reused if heated below 180℃ and it can be heated up to 30 min without any appreciable molecular changes if a controlled heating can be managed.
Keywords: Desi ghee; Heating effects; PCA; Raman spectroscopy; Safe temperature range for cooking; principal component analysis.