Stability enhancement of fish oil by its encapsulation using a novel hydrogel of cress seed mucilage/chitosan

Figures & data

Table 1. Suggested RSM design for production of fish oil loaded CSM/CS micro-hydrogel and some physicochemical properties.

Independent variables				Dependent variables
Run	CSM/CS ratio (X1)	Fish oil content (%) (X2)	Polysaccharide concentration (%) (X3)	Encapsulation load (%)	Encapsulation efficiency (%)	Particle size (nm)
1	1:1	0.2	30	24	80	1949
2	1:4	0.4	30	26.1	87	4161
3	1:1	0.6	30	25.8	86	5579
4	4:1	0.6	20	18.4	92	2846
5	4:1	0.2	20	17.8	89	1722
6	1:1	0.4	20	18.8	94	2171
7	1:1	0.4	20	18.7	93.5	2247
8	1:1	0.6	10	8.7	87	2981
9	4:1	0.4	30	27	90	1586
10	1:1	0.2	10	8.3	83	1737
11	1:1	0.4	20	18.85	94.25	2487
12	1:4	0.6	20	18.1	90.5	5203
13	1:4	0.4	10	8.78	87.8	3473
14	1:4	0.2	20	17	85	960.3
15	1:1	0.4	20	18.8	94	1524
16	1:1	0.4	20	18.65	93.25	1940
17	4:1	0.4	10	9	90	1844

Table 2. Final equation in terms of actual factors and R².

	Model parameters
Response variables	Intercept	A	B	C	AB	AC	BC	A^2	B^2	C^2	R^2
Encapsulation load (%)	−4.91122	0	+1.09121	+15.41633	0	0	0	0	−0.014219	−19.26625	0.9985
Encapsulationefficiency (%)	+49.56389	+0.071528	0	+105.52083	0	0	0	0	−0.051125	−117.18750	0.9920
Particle size (nm)	−550.86691	0	0	+6932.72917	0	−129.94583	0	0	0	0	0.8349

A is CSM/CS ratio, B is fish oil content and C is polysaccharide concentration

Table 3. Mean square errors of dependent factors.

Process variables	Degree of freedom	Encapsulation load (%)	Encapsulation efficiency (%)	Particle size (nm)
CSM/CS volume ratio	1	0.5	14.31**	4.204E+006
Fish oil content (%)	1	282.42**	2.88	1.312E+006
Polysaccharide concentration (%)	1	1.42**	42.78**	1.311E+007**

** Significant at P < 0.01

Figure 1. Effect of polysaccharide concentration and fish oil content on encapsulation load of micro-hydrogels.

Figure 2. Effect of polysaccharide concentration and CSM/CS volume ratio on encapsulation efficiency of micro-hydrogels.

Table 4. Optimized conditions and corresponding dependent data (model suggestion and experimentally determined).

Optimum condition				Optimum responses
No	CSM/CS ratio	Fish oil content	Polysaccharide concentration	EL (%) (mean ± SD)	EE (%) (mean ± SD)	Particle size (nm)
1	48/52	23	0.33	20.46	91.39	2327.63
2				20.47 ± 0.23	89 ± 1	2025

No1: Numerical optimized values proposed by RSM; No2: Experimental values; EL: encapsulation load; EE: encapsulation efficiency

Figure 3. SEM micrographs of micro-hydrogels loaded with fish oil.

Figure 4. FTIR spectra of CSM (cress seed mucilage), CS (Chitosan), fish oil and CSM/CS micro-hydrogel loaded with fish oil.

Figure 5. Oxidative stability of produced micro-hydrogel loaded with fish oil and pure fish at 40°C.

Table 5. Starting point, weight loss and thermal stability of CSM, CS and CSM/CS micro-hydrogels during thermal degradation in TGA and DTG.

Samples	Events	Starting point of weight loss (°C)	Weight loss (%)	Thermal stability (°C)
CSM	1st	48	7.02	315
	2nd	224	51.16
CS	1st	43	8.53	338
	2nd	252	46.78
CSM/CS	1st	28	3.91	355
	2nd	240	70.3
	3rd	460	19.77

CSM: cress seed mucilage; CS: chitosan; CSM/CS: cress seed mucilage/chitosan micro-hydrogel loaded fish oil

Figure 6. TGA curves of cress seed mucilage, chitosan, and cress seed mucilage/chitosan micro-hydrogel loaded with fish oil.

Figure 7. DTG curves of cress seed mucilage, chitosan, and cress seed mucilage/chitosan micro-hydrogel loaded with fish oil.