Emulsion stability of clove oil in chitosan and sodium alginate matrix

Figures & data

Table 1. Chemical composition of Indonesian clove oil. The sequences in the table are from the lowest to the highest tr.

No.	Compounds	Concentration (%)
1	Chavicol	0.32
2	α-cubebene	0.05
3	Eugenol	43.66
4	β-elemene	0.05
5	Iso-eugenol	0.15
6	Caryophyllene	29.17
7	α-guaiene	0.01
8	Humlene	16.98
9	Allaromadendrene	0.06
10	β-selinene	0.12
11	δ-guaiene	0.05
12	L-calamenene	3.60
13	4,10 dimetyl-7-isopropyl(4,4,0)-bicyclo-1,4-decadiene	0.05
14	α-cadinene	0.02
15	β-caryophylene epoxide	0.89
16	Diepicedrene 1-oxide	0.83
17	Humulene 1,2-epoxide	0.44
18	Cubenol	0.04
19	Caryophyllene oxide	0.36
20	Un-identified traces	3.16

Figure 1. Typical GC-histogram of Indonesian clove leaf oil.

Figure 2. Viscosity profile of chitosan and sodium alginate solutions. (

) denote 1% (w/w) chitosan (up ramp), (

) chitosan (down ramp), (

) 2.5% (w/w) sodium alginate (up ramp) and (

) sodium alginate (down ramp).

Table 2. ζ-potential of hydrocolloids solutions and the emulsion systems.

Sample	ζ-potential (mV)
Chitosan	27.78 (±2.12)
Sodium alginate	– 27.46 (±1.42)
CC emulsion	32.07 (±0.47)
CA emulsion	– 49.80 (±5.06)

Table 3. Clove oil in chitosan (CC) and sodium alginate (CA) matrix parameters with reference to homogenization speeds and storage time. (a) The influence of homogenization speeds and (b) storage time.

Table 3(a)
Emulsion type	CC emulsions Homogenization speed (rpm)				CA emulsions Homogenization speed (rpm)
Parameters	5,000	10,000	15,000	20,000	5,000	10,000	15,000	20,000
Average diameter (μm)	1.996^a	1.997^a	2.047^a	2.046^a	2.457^a	2.565^a	2.378^a	2.302^a
Stability (%)	96.363^a	96.000^a	96.182^a	95.909^a	93.581^a	93.219^ab	92.800^bc	92.364^c
Eugenol (%)	80.436^a	79.114^a	80.538^a	80.622^a	84.296^a	80.854^a	80.678^a	81.282^a
Caryophyllene (%)	15.842^a	16.589^a	15.657^a	16.890^a	12.590^a	15.453^a	15.612^a	15.131^a
Humulene (%)	3.725^a	4.298^a	3.806^a	4.220^a	3.110^a	3.692^a	3.709^a	3.586^a
Table 3(b)
	CC emulsions					CA emulsions
Emulsion type	Storage time (days)					Storage time (days)
Parameters	0/1*	7/8*	14/15*	21/22*	28/29*	0/1*	7/8*	14/15*	21/22*	28/29*
Average diameter (μm)	2.071^ab	2.150^a	1.954^bc	1.918^c	2.015^abc	2.382^ab	2.640^a	2.509^ab	2.350^ab	2.246^b
Stability (%)	100.000^a	98.180^b	96.701^c	94.094^d	91.593^e	97.384^a	94.093^b	91.820^c	91.090^d	90.569^d
Eugenol (%)	83.409^a	74.174^c	85.158^a	77.274^bc	80.874^ab	84.435^a	86.635^a	86.568^a	84.719^a	66.531^b
Caryophyllene (%)	13.593^c	20.986^a	12.399^c	18.514^b	15.731^bc	12.314^b	10.786^b	10.619^b	12.366^b	27.398^a
Humulene (%)	3.431^bc	5.600^a	2.821^c	4.215^b	3.994^b	3.248^b	2.579^b	2.813^b	2.913^b	6.070^a

The values with the same superscript letters (a, b, c, etc.) are not significantly different.

*The first numbers are the time in days at which the size and stability were measured.

Figure 3. Microscopy images of clove oil emulsions prepared at various homogenization speeds (a) chitosan and (b) sodium alginate. The scale bar is 10 μm.

Figure 4. Droplet size and distribution of clove oil emulsions in chitosan (CC) and sodium alginate (CA) matrix. (a) Typical size distribution of CC and CA emulsions. (

) denote CC emulsions at day 0, (

) CC emulsions at day 28, (

) CA emulsions at day 0, and (

) CA emulsions at day 28. (b) Average droplet diameter of the emulsions as function of homogenization speed. (

) denote CC emulsions, and (

) denote CA emulsions droplet size.

Figure 5. Stability of emulsions during 28 days of storage. Solid lines show CC emulsions, and dotted lines show CA emulsions. (

) denote 5000 rpm, (

) 10,000 rpm, (

) 15,000 rpm, and (

) denote 20,000 rpm.

Figure 6. Average droplet diameter of CC and CA emulsions during 28 days of storage. The images show the course of emulsion coalescence. Solid lines show CC emulsions, and dotted lines shoe CA emulsions. (

) denote 5000 rpm, (

) 10,000 rpm, (

) 15,000 rpm and (

) denote 20,000 rpm.