Ultrasonic Assessment of Adulteration in Edible Oils Using Rheological Parameters

Non-destructive characterization methods using the ultrasonics become very important to characterize the oils and fats. It is used as a versatile tool in study of internal structure and inherent properties of fats and oils, since it does not change the properties of the structure of materials. The ultrasonic velocity is used as a valuable tool for the study of various physical and chemical properties of the matter. The variation of rheological and ultrasonic parameters in the binary mixtures of the oils are studied and reported in present paper. The adulteration in edible oil is a deep rooted social evil, can cause several problems in edible oils application and industry. Adulteration of low quality, cheap, non-edible and toxic substance in the edible oil leads to different disease to human. Six samples of mustard and olive oils, adulterated with cheaper oil by mixing them in different proportions, have been collected. The oil is subjected to frying temperature 200C repeatedly so that compositional changes take place in the fatty acids. The changes in the quality of sample oil are studied from the changes in the parameters such as viscosity, density, ultrasonic velocity, acoustic impedance, adiabatic compressibility and intermolecular free length, from which the adulteration in the oil can be easily perceived compared to analytical techniques. Fatty acids (FA), free fatty acids (FFA), peroxide value (PV) were used as chemical indicators of different quality of sample oil compared to ultrasonic measurements. The chemical changes are linked to changes in ultrasonic parameters, which show that ultrasound can be used to assess and monitor oil quality. The study demonstrated that edible oils are characterized in terms of their fatty acids and its flow behavior by ultrasonic and coupled with GC-MS.