Quality Characterisation of Mustard (Brassica Nigra) Oil and Its Blends with Argemone (Argemone Mexicana) Oil under Varying Dielectric Frequency and Temperature

Physical properties of edible oil are a decisive factor for the characterisation of its quality. Adulteration of pure mustard oil (MO) with argemone oil (AO) is common and rampant. In this study, the effect of dielectric frequency (200, 1000 Hz) on the physical properties such as specific gravity, viscosity, refractive index, and colour of MO blended (0, 25, 50, 75, 100%) with AO was investigated at five (10 - 50 °C) levels of temperature is reported. The individual and interaction effects of frequency, blend ratio, and temperature indicated that there was no significant effect (p≤0.05) on the physical properties of oil samples due to the dielectric frequency. However, the effects of blend ratio on all measured parameters were highly significant (p≤0.01). The effect of temperature was significant (p≤0.05) for all parameters, except refractive index. Viscosity and specific gravity correlated with temperature and blend ratio in third-degree polynomial regression model (R²>0.9) for MO and AO blends. The findings of this study established that dielectric spectroscopy can be used for detection of adulteration in MO without affecting its physico-chemical properties.