Selected Rheological Characteristics and Physicochemical Properties of Vegetable Oil Affected by Heating

Figures & data

TABLE 1 Viscosities (10⁻⁶ m²/s) of mustard and sesame oil at different temperature

Source of oil		Temperature °C
	25°C	35°C	45°C	55°C	65°C	75°C	85°C
Mustard oil unheated	71.45	56.17	47.41	30.49	21.12	17.71	13.91
Mustard oil heated	185.02	112.76	83.43	61.42	44.66	27.92	20.86
Sesame oil unheated	60.97	55.81	27.32	19.40	13.05	11.86	9.73
Sesame oil heated	143.10	98.77	53.69	44.79	25.24	20.49	16.31

TABLE 2 Values of constants obtained using different models and equations of mustard oil

Oil	Heating	Model	R^2 value	Constants	Standard error
Mustard	Unheated	ƞ = A e^Ea/KT (Arrhenius)	0.990	A = 1.103 B = 19.49	0.102
		ln ƞ = A + B* T (Andrade)	0.959	A = 3.554 B = –1.199	0.021
		ln ƞ = A + B*ln T (Andrade)	0.962	A = 3.537 B = 1.188	0.015
		log log (ƞ + 0.8) = A + B*log T (Walther)	0.995	A = 0.817 B = –0.379	0.043
		ln ln f (ƞ) = A + B*ln T (Wright ASTM)	0.943	A = 2.854 B = –0.418	0.046
		ln ƞ = A + B/T (Erying)	0.977	A = 2.170 B = 58.45	0.227
	Heated	ƞ = A e^Ea/KT (Arrhenius)	0.957	A = 1.312 B = 24.25	0.084
		ln ƞ = A + B*T (Andrade)	0.993	A = 4.378 B = –1.504	0.064
		ln ƞ = A + B*ln T (Andrade)	0.993	A = 4.357 B = 1.491	0.065
		log log (ƞ + 0.8) = A + B*log T (Walther)	0.956	A = 0.902 B = –0.382	0.036
		ln ln f (ƞ)= A + B*ln T (Wright ASTM)	0.944	A = 3.021 B = –0.412	0.025
		ln ƞ = A + B/T (Erying)	0.998	A = 2.630 B = 69.92	0.245

TABLE 3 Values of constants obtained using different models and equations of sesame oil

Oil	Heating	Model	R^2 value	Constants	Standard error
		ƞ = A e^Ea/KT (Arrhenius)	0.957	A = 0.852 B = 23.76	0.081
Sesame	Unheated	ln ƞ = A + B*T (Andrade)	0.992	A = 2.175 B = –0.016	0.029
		ln ƞ = A + B*ln T (Andrade)	0.995	A = 3.837 B = 1.462	0.084
		log log (ƞ + 0.8) = A + B*log T (Walther)	0.999	A = 0.918 B = –0.467	0.029
		ln ln f (ƞ) = A + B*ln T (Wright ASTM)	0.980	A = 3.094 B = –0.509	0.033
		ln ƞ = A + B/T (Erying)	0.947	A = 1.639 B = 66.32	0.164
	Heated	ƞ = A e^Ea/KT (Arrhenius)	0.952	A = 1.104 B = 26.73	0.104
		ln ƞ = A + B* T(Andrade)	0.987	A = 4.521 B = –1.683	0.055
		ln ƞ = A + B*ln T(Andrade)	0.991	A = 4.504 B = 1.672	0.086
		log log (ƞ + 0.8) = A + B*log T (Walther)	0.997	A = 0.985 B = –0.456	0.029
		ln ln f (ƞ)= A + B*ln T (Wright ASTM)	0.980	A = 3.207 B = –0.485	0.026
		ln ƞ = A + B/T (Erying)	0.946	A = 2.090 B = 77.47	0.193

TABLE 4 Physical properties of sesame and mustard oil

Sample	Time of heating (minutes)	Viscosity 10^–6 (m^2/sec)	Density × 10^3 (kg/m^3)	Conductance (μS)	Refractive index	Ultrasonic velocity × 10^3 m/s
Sesame	0	56.7 ± 0.26^b	1.04 ± 0.03^c	1.7 ± 0.04^b	1.466 ± 0.002^a	1.48 ± 0.04^b
	30	76.4 ± 0.08^b	1.09 ± 0.01^c	1.5 ± 0.03^c	1.468 ± 0.004^a	1.46 ± 0.05^b
	60	89.2 ± 0.11^a	1.10 ± 0.01^b	1.4 ± 0.06^b	1.47 ± 0.001^b	1.45 ± 0.02^c
	90	93.9 ± 0.35^b	1.11 ± 0.07^a	1.3 ± 0.01^a	1.471 ± 0.001^a	1.43 ± 0.02^a
	120	149.5 ± 0.28^b	1.12 ± 0.04^b	0.9 ± 0.02^c	1.474 ± 0.003^c	1.38 ± 0.04^c
Mustard	0	68.5 ± 0.41^b	0.97 ± 0.14^a	0.9 ± 0.05^b	1.464 ± 0.002^a	1.46 ± 0.03^c
	30	76.1 ± 0.37^a	0.97 ± 0.35^c	0.8 ± 0.02^b	1.467 ± 0.004^c	1.44 ± 0.04^a
	60	105.4 ± 0.07^a	0.98 ± 0.02^a	0.7 ± 0.04^a	1.468 ± 0.001^b	1.43 ± 0.02^a
	90	132.3 ± 0.13^b	0.99 ± 0.21^b	0.6 ± 0.04^c	1.47 ± 0.006^a	1.41 ± 0.02^a
	120	282.9 ± 0.08^c	1.02 ± 0.13^b	0.5 ± 0.02^a	1.472 ± 0.003^a	1.32 ± 0.01^a

Values are expressed by mean ± SD of three independent observations;

^ap-value < 0.001;

^bp-value < 0.01 are very significant;

^cp-value < 0.05 are regarded as significant.

TABLE 5 Chemical properties of sesame and mustard oil

Properties	Time of heating (minutes)	Saponification value	Acid value	Iodine value
Sesame	0	180 ± 0.3^c	5.5 ± 0.04^a	96 ± 0.07^a
	30	84.6 ± 0.05^a	5.2 ± 0.31^b	88 ± 0.09^a
	60	67.2 ± 0.24^c	4.7 ± 0.12^b	79 ± 0.04^b
	90	65.8 ± 0.01^a	4.2 ± 0.06^a	66 ± 0.04^a
	120	59.5 ± 0.14^b	3.9 ± 0.25^b	59.6 ± 0.09^b
Mustard	0	168 ± 0.23^b	5.7 ± 0.08^a	113.8 ± 0.01^a
	30	143 ± 0.17^b	5.1 ± 0.03^b	112.7 ± 0.03^c
	60	119.2 ± 0.08^c	4.8 ± 0.02^b	112.1 ± 0.01^a
	90	94.5 ± 0.03^a	4.2 ± 0.17^c	110.6 ± 0.02^b
	120	68.3 ± 0.09^a	3.2 ± 0.05^b	102.8 ± 0.07^b

Values are expressed by mean ± SD of three independent observations;

^ap-value < 0.001;

^bp-value < 0.01 are very significant;

^cp-value < 0.05 are regarded as significant.

Figure 1 Variation of IV and SV with time of heating for Sesame Oil B – variation of IV and SV with time of heating for Mustard Oil C – variation of viscosity and ultrasonic velocity with acid value for Sesame Oil D – variation of viscosity and ultrasonic velocity with acid value for Mustard Oil.