Stability of lime essential oil emulsion prepared using biopolymers and ultrasound treatment

Figures & data

Figure 1. (a) pH and (b) Conductivity of Lime emulsions oils.

Figure 2. Size distributions of emulsions. (a) GA; (b) GA/WPI; (c) WPI; (1) 0 h and (2) after 4 h.

Figure 3. Microscopy images of emulsions prepared with GA and different essential oil concentration: (a) 5.0 g oil/100 g emulsion; (b) 7.5 g oil/100 g emulsion; (c) 10.0 g oil/100 g emulsion; (1) fresh and (2) after 4 h.

Figure 4. Apparent viscosity as function of shear rate for lime essential oil with GA (A), GA/WPI (B) e WPI (C).

Figure 5. Creaming index to lime essential oil emulsions after 4 h.

Table 1. Experimental design to lime essential oil emulsions.

	Biopolymer (g/100 g emulsion))
Assays	GA	WPI	Oil content (g/100 g emulsion)
E1	25	0	5
E2	12.5	12.5	5
E3	0	25	5
E4	22.5	0	7.5
E5	11.25	11.25	7.5
E6	0	22.5	7.5
E7	20	0	10
E8	10	10	10
E9	0	20	10

Table 2. Zeta potential by biopolymers solutions and emulsions at 0 and 4 h.

Emulsifier	Samples	Zeta Potential (mV)
		Solution (Water + Emulsifier)	0 h	4 h
GA	E1	−9.42 ± 0.60^g,B	−20.13 ± 0.01^e,A	−19.75 ± 0.29^e,A
	E4	−18.28 ± 1.88^c,C	−22.08 ± 0.12^d,A	−19.9 ± 0.55^e,B
	E7	−19.94 ± 0.90^b,B	−30.44 ± 0.30^c,A	−20.11 ± 0.09^c,C
GA/WPI	E2	−23.74 ± 0.54^e,A	−23.19 ± 0.10^d,A	−18.49 ± 0.08^e,B
	E5	−20.30 ± 0.64^d,A	−20.13 ± 0.24^e,A	−20.39 ± 0.13^e,A
	E8	−16.68 ± 1.33^a,C	−32.25 ± 0.08^b,A	−25.16 ± 0.52^d,B
WPI	E3	−26.50 ± 0.90^d,B	−31.92 ± 0.16^b,A	−29.55 ± 0.10^c,A
	E6	−18.54 ± 0.68^e,B	−32.52 ± 0.23^b,A	−31.52 ± 0.13^b,A
	E9	−17.32 ± 1.27^f,B	−33.93 ± 0.30^a,A	−33.99 ± 0.06^a,A

Same letter in same column (^a.b.c.d.e.f) or same line (^A,B) represents no significant difference (p > 0.05%). Results are presented as the mean ± standard deviation.

Table 3. Polydispersion index (PDI) and droplet size by emulsions at 0 and 4 hours.

Emulsifiers	Samples	PDI		Droplet size (µm)
		0 h	4 h	0 h	4 h
GA	E1	0.65 ± 0.05^a,A	1.31 ± 0.07^a,B	0.694 ± 0.024^a,A	0.709 ± 0.029^a,A
	E4	1.27 ± 0.03^b,A	1.77 ± 0.1^b,B	0.812 ± 0.032^a,A	0.792 ± 0.022^a,A
	E7	2.11 ± 0.05^c,A	2.48 ± 0.08^c,B	0.806 ± 0.098^a,A	1.037 ± 0.141^a,A
GA/WPI	E2	1.22 ± 0.05^b,A	1.45 ± 0.06^a,A	0.97 ± 0.016^b,A	1.622 ± 0.027^b,B
	E5	1.28 ± 0.02^b,A	1.71 ± 0.08^b,B	1.305 ± 0.075^c,A	1.968 ± 0.088^c,B
	E8	1.71 ± 0.04^d,A	2.2 ± 0.09^d,B	1.306 ± 0.017^c,A	1.634 ± 0.028^c,B
WPI	E3	0.94 ± 0.04^e,A	1.11 ± 0.05^a,A	0.282 ± 0.025^d,A	0.256 ± 0.01^d,A
	E6	1.34 ± 0.05^b,A	1.63 ± 0.09^b,A	0.288 ± 0.007^d,A	0.289 ± 0.001^d,A
	E9	1.54 ± 0.05^f,B	2.16 ± 0.13^d,B	0.294 ± 0.002^d,A	0.294 ± 0.002^d,A

Same letter in same column (^a.b.c.d.e.f) or same line (^A,B) represents no significant difference (p > 0.05%). Results are presented as the mean ± standard deviation.

Table 4. Correlation coefficient, residual mean square and Power Law model parameters for emulsions prepared with different biopolymers and lime essential oil.

Emulsifier	Assay	R^Citation2		E (%)		Consistency Index, k (Pa.s^n)		Flow Behavior Index, n
		0 h	4h	0 h	4h	0h	4h	0h	4h
GA	E1	0.994	0.996	2.319	1.437	0.391 ± 0.007ª	0.434 ± 0.016ª	0.984 ± 0.006^b	0.9923 ± 0.0065^b
	E4	0.994	0.995	3.361	3.303	0.699 ± 0.272^b	0.790 ± 0.230^b	0.946 ± 0.060^b	0.9320 ± 0.0403^b
	E7	0.999	0.997	0.828	3.632	0.800 ± 0.012^b	0.967 ± 0.293^b	0.992 ± 0.007^b	0.965 ± 0.048^b
GA/WPI	E2	0.994	0.979	0.509	1.122	0.089 ± 0.013ª	0.109 ± 0.008ª	0.972 ± 0.012^b	0.964 ± 0.005^b
	E5	0.984	0.999	1.724	0.248	0.203 ± 0.021ª	0.217 ± 0.025ª	0.950 ± 0.000^b	0.939 ± 0.020^b
	E8	0.989	0.983	42.293	4.491	1.848 ± 0.136^d	1.621 ± 0.577^b	0.770 ± 0.001ª	0.766 ± 0.048ª
WPI	E3	0.995	0.981	0.296	0.618	0.070 ± 0.004ª	0.077 ± 0.012ª	0.939 ± 0.002^b	0.933 ± 0.010^b
	E6	0.998	0.999	0.252	0.090	0.139 ± 0.007ª	0.130 ± 0.003ª	0.908 ± 0.001^b	0.909 ± 0.000^b
	E9	0.996	0.994	1.291	1.613	1.173 ± 0.083^c	1.179 ± 0.634^b	0.725 ± 0.015ª	0.749 ± 0.104ª

Same letter in same column (^a.b.c.d.e.f) represents no significant difference (p > 0.05%). Results are presented as the mean ± standard deviation.

Table 5. Apparent viscosity values at 100 s⁻¹.

Emulsifier	Assay	Apparent viscosity at 100s^−Citation1 (Pa.s)
		0 h	4 hours
GA	E1	0.3622 ± 0.01^a*	0.4177 ± 0.02 ^a
	E4	0.5347 ± 0.07 ^a	0.5574 ± 0.05 ^a
	E7	0.7698 ± 0.01 ^a	0.7987 ± 0.05 ^a
GA/WPI	E2	0.0791 ± 0.007 ^a	0.0929 ± 0.009 ^a
	E5	0.1612 ± 0.01 ^a	0.1622 ± 0.002 ^a
	E8	0.6405 ± 0.04 ^a	0.6278 ± 0.08 ^a
WPI	E3	0.0522 ± 0.002 ^a	0.0573 ± 0.006 ^a
	E6	0.0918 ± 0.007 ^a	0.0856 ± 0.002 ^a
	E9	0.3221 ± 0.006 ^a	0.3437 ± 0.013 ^a

*Same letters in the same line represent no significant difference (p < 0.05).

Gamarra, F.M.C.; Sakanaka, L.S.; Tambourgi, E.B.; Cabral, F.A. Influence on the Quality of Essential Lemon (Citrus aurantifolia) Oil by Distillation Process. Brazilian Journal of Chemical Engineering 2006, 23, 147–151.

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Rao, J.; McClements, D.J. Impact of Lemon Oil Composition on Formation and Stability of Model Food and Beverage Emulsions. Food Chemistry 2012, 134, 749–757.

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