β-Cyclodextrin inclusion complexes of combined Moroccan Rosmarinus officinalis, Lavandula angustifolia and Citrus aurantium volatile oil: production optimization and release kinetics in food models

Figures & data

Table 1. Central composite design with the yield of recovered powder, inclusion efficiency, and oil retention degree.

Ethanol/water ratio (v/v)	β-CD/RLC-VO ratio (w/w)	Starting material (g, db*)	Recovered powder (g, db*)	Recovery (%)	Inclusion efficiency (IE) (mg/g)	VO Retention degree in β-CD (%)
[1:1]	[10:90]	0.990	0.846 ± 0.038	85.455	45.436 ± 2.963	76.261 ± 0.725
[1:2]	[10:90]	0.990	0.969 ± 0.047	97.879	28.302 ± 2.575	85.358 ± 0.186
[1:1]	[20:80]	1.080	1.002 ± 0.076	92.778	80.514 ± 1.375	93.295 ± 1.332
[1:2]	[20:80]	1.080	0.955 ± 0.055	88.426	90.333 ± 1.764	62.336 ± 0.422
[1:1]	[15:85]	1.035	0.965 ± 0.024	93.237	66.804 ± 1.588	68.733 ± 1.361
[1:2]	[15:85]	1.035	1.001 ± 0.019	96.715	61.804 ± 0.811	61.381 ± 0.156
[1:1.5]	[10:90]	0.990	0.960 ± 0.014	96.970	34.620 ± 1.538	74.742 ± 0.357
[1:1.5]	[20:80]	1.080	1.003 ± 0.081	92.870	83.831 ± 1.139	70.857 ± 1.160
[1:1.5]	[15:85]	1.035	1.007 ± 0.016	97.295	62.710 ± 2.399	56.754 ± 1.517

Total amount of dry β-CD (0.900 g) plus essential oil combination used. db*: dry weight basis.

Table 2. Estimated regression coefficients for the second-order model and analyses of variance (ANOVA) for the experimental data.

Parameters	Y1 (recovered powder)		Y2 (VO retention degree)		Y3 (inclusion efficiency)
	Estimated coefficients	p-Value	Estimated coefficients	p-Value	Estimated coefficients	p-Value
Intercept	1.014	<0.001 ***	57.550	<0.001 ***	62.564	<0.001 ***
Linear
X1: Ethanol/Water ratio	0.019	0.024*	−4.869	0.003 **	−2.053	0.002 **
X2: β-CD/RLC- VO ratio	0.031	0.006**	−1.646	0.065	24.387	<0.001 ***
Quadratic
X1^2	−0.034	0.022 *	7.110	0.006 **	1.812	0.016 *
X2^2	−0.035	0.019 *	14.852	<0.001 ***	−3.266	0.003 **
Interaction
X1–X2.	−0.043	0.004 **	−10.014	<0.001 ***	6.738	<0.001 ***
Models
R^2	0.949		0.977		0.957
Adj R^2	0.983		0.999		0.995
Model p-value	0.007 **		0.001 **		<0.001 ***
Lack-of-fit F-value	115.010		17.690		9898.930
CV%	1.588		3.825		2.672

Significant terms. * p < 0.05, ** p < 0.01, *** p < 0.001, R² : coefficient of determination, CV: coefficient of variation.

Table 3. Fitting response model.

Response	Regression model
Y1(recovered powder)	= 1.014 + 0.019X1+0.031X2-0.034X1^2-0.035X2^2-0.043X1X2
Y2(oil retention degree)	= 57.550–4.869X1-1.646X2+7.110X1^2+14.852X2^2-10.014X1X2
Y3 (Inclusion efficiency)	= 62.564–2.053X1+24.387X2+1.812X1^2-3.266X2^2+6.738X1X2

X₁ : Ethanol/water ratio (mL/mL)), X₂ : β-CD/RLC-VO ratio (g/g).

Figure 1. Response surface 2D and 3D showing the interaction effects of X1 and X2 supsub1 Ethanol/water ratio (mL/mL)), supsub2 β-CD/RLC-VO ratio (g/g), respectively) on recovered powder a and a’, Inclusion Efficiency b and b’, and oil retention degree c and c’.

Figure 2. SEM Images of Recovered Powder from Experimental [1:1]; [10:90] a), [1:1]; [15:85] b) and [1:1]; [20:80] c) and Size Distribution Bar Chart of the Particles Measured from the Analysis of the SEM Images.

Figure 3. FTIR Spectra of the Inclusion Complexes Powders Recovered from Experiments [1:1]; [20:80] a), [1:1]; [15:85] b) and [1:1]; [10:90] c), β-CD d) and RLC-VO e).

Table 4. Kinetics constant and correlation coefficients of the RLC-VO release profile in different the hydroalcoholic and acidic systems.

β-CD/RLC-VO ratio	Models	First order		Korsmeyer-Peppa			Higuchi			Peppas Sahlin
		k	R^2 adj	k	n	R^2 adj	k	n	R^2 adj	m	K1	K2	R^2 adj
[10:90]	10 % Ethanol	0.0001 ± 0.0000	0.3878	0.0428 ± 0.0035	0.3944 ± 0.0108	0.7347	0.0188 ± 0.0000	0.5	0.9207	0.1972 ± 0.0054	0.0785 ± 0.0135	0.0428 ± 0.0035	0.4285
	3 % Acetic acid	0.0002 ± 0.0000	0.2449	0.0094 ± 0.0011	0.5682 ± 0.0152	0.7853	0.0160 ± 0.0001	0.5	0.9851	0.2597 ± 0.02382	0.0030 ± 0.0003	0.0450 ± 0.0061	0.4797
[15:85]	10 % Ethanol	7.9405E–05 ± 0.0000	0.6048	0.1416 ± 0.0231	0.2328 ± 0.0121	0.7706	0.0186 ± 0.0007	0.5	0.9164	0.0680 ± 0.0086	0.1047 ± 0.0135	0.3302 ± 0.0229	0.4723
	3 % Acetic acid	8.4225E–05 ± 0.0000	0.4528	0.0606 ± 0.0088	0.3466 ± 0.0150	0.7614	0.0185 ± 0.0009	0.5	0.9352	0.0408 ± 0.0062	0.0766 ± 0.132	0.4152 ± 0.0286	−0.8606
[20:80]	10 % Ethanol	0.0001 ± 0.0000	0.4113	0.0473 ± 0.0123	0.3762 ± 0.0317	0.7451	0.0176 ± 0.0005	0.5	0.9527	0.1881 ± 0.0001	0.0785 ± 0.0139	0.0473 ± 0.0012	0.4563
	3 % Acetic acid	0.0002 ± 0.0000	0.3161	0.0157 ± 0.0035	0.0223 ± 0.0291	0.7273	0.0165 ± 0.0003	0.5	0.9617	0.2401 ± 0.023	0.0022 ± 0.0003	0.0475 ± 0.0051	−1.2352

Table 5. Chemical composition of Rosmarinus officinalis, Lavandula angustifolia, and Citrus Aurantium VO and their relative contents before and after microencapsulation.

Components	RI	Relative content %
		RLC-VO	β-CD/RLC-VO
α-Pinene	930	7.0	3.1
Camphene	938	2.2	1.5
β-Pinene	963	1.4	0.9
β-Myrcene	975	1.1	0.4
p-Cymene	1003	1.6	0.8
1,8-Cineole	1005	35.3	34.7
Limonene	1009	1.0	0.8
cis-β-Ocimene	1017	0.1	0.2
trans-β-Ocimene	1027	0.5	0.3
cis-Linalool oxide (furanoid)	1045	0.8	0.3
trans-Linalool oxide (furanoid)	1059	0.7	0.3
Terpinolene	1064	t	0.2
Linalool	1074	9.5	12.8
1-Octen-3-yl acetate	1086	t	t
α-Campholenal	1092	0.2	t
Camphor	1102	13.5	15.2
trans-Pinocarveol	1106	t	0.2
cis-Verbenol	1113	t	t
Borneol	1134	5.2	8.6
Cryptone *	1143	0.8	0.9
p-Cymen-8-ol	1148	t	t
Myrtenal	1153	3.9	4.7
Linalyl acetate	1245	11.0	7.8
Neryl acetate	1353	0.7	1.6
β-Caryophyllene	1414	0.6	0.4
α-Santalene	1422	t	t
β-Caryophyllene oxide	1561	0.4	0.4
T-Cadinol	1616	0.7	0.2
% Identification		98.7	99.4
Grouped components
Monoterpene hydrocarbons		14.9	8.4
Oxygen-containing monoterpenes		81.6	89.2
Sesquiterpene hydrocarbons		0.9	0.6
Oxygen-containing sesquiterpenes		1.3	0.8
Phenylpropanoid			t
Others		t	0.4

RI: In lab calculated retention index relative to C₉-C₁₇ n-alkanes on the DB-1 column. * Identification based on mass spectra only. t: trace (<0.05 %).

Figure 4. (a) Powder X-Ray Diffraction Patterns of β-CD, (b) the Inclusion Complex Powder Recovered from Experiment [1:1]; [10:90].

Figure 5. The Release Profile of the RLC-VO in Different Media from ICs: The Inclusion Complexes Recovered Powder from Experimental (a) [10:90], (b) [15:85], and (c) [20:80].