Particle size characteristics of buriti oil microcapsules produced by gelatin-sodium alginate complex coacervation: Effect of stirring speed

Figures & data

Table 1. Formulation and processing conditions during microencapsulation of buriti oil in alginate-gelatin coacervates.

Sample^1 Code	Gelatin (g/100 g)	Alginate (g/100 g)	Buriti oil (g/100 g)	Shear rate (1/s)	Yield stress (mPa)	Consistency index (mPa⋅s^n)	Flow behavior index	r^2	Reynolds number
3G1A600	3	1	2	90.8	3.48	0.71	1.10	0.999	32648
3G1A950	3	1	2	144.6	7.14	0.78	1.17	0.999	66873
3G1A1300	3	1	2	198.8	5.45	0.48	1.18	0.998	70778
3G1A1650	3	1	2	251.0	0.56	0.25	1.39	0.991	73795
3G1A2000	3	1	2	305.9	0.99	0.27	1.31	0.996	77635
6G2A600	6	2	4	90.8	13.28	0.21	1.40	0.999	13338
6G2A950	6	2	4	144.6	19.26	0.05	1.64	0.994	34928
6G2A1300	6	2	4	198.8	7.14	0.90	1.18	0.996	41009
6G2A1650	6	2	4	251.0	27.26	0.07	1.14	0.999	62842
6G2A2000	6	2	4	305.9	21.72	0.03	1.70	0.998	75433

¹G = gelatin; A = alginate; the numbers indicate the stirring speed (rpm) applied in each treatment.

Figure 1. Optical micrographics (bar = 200 μm) of sample coded as 3G1A600 (3:1 g/100 g gelatin:alginate at 600 rpm) (a) after coacervation, (b) freeze-dried, and (c) rehydrated.

Table 2. Particle size, encapsulation efficiency (%EE), brightness (L*), chroma (C*), and hue angle (h) of buriti oil microcapsules.

Sample Code^1	D[4,3] (µm)	span	%EE	L*	C*	h
3G1A600	443.83 ± 54.95^ab	0.85	81.74 ± 0.63^a	79.26 ± 0.35^a	55.98 ± 0.85^f	80.12 ± 0.09^b
3G1A950	274.93 ± 23.99^c	1.00	81.36 ± 0.82^a	78.48 ± 0.22^b	54.88 ± 0.63^f	80.57 ± 0.24^a
3G1A1300	168.89 ± 6.93^d	0.81	81.15 ± 1.43^a	77.57 ± 0.34^c	55.85 ± 0.38^g	80.24 ± 0.23^b
3G1A1650	186.76 ± 15.67^d	1.00	81.24 ± 0.24^a	75.68 ± 0.62^de	61.89 ± 0.88^bc	79.55 ± 0.23^c
3G1A2000	189.04 ± 7.25^d	0.83	80.71 ± 0.49^a	74.30 ± 0.49^g	62.48 ± 0.31^ab	78.84 ± 0.21^de
6G2A600	490.20 ± 63.17^a	1.32	81.17 ± 1.14ª	75.31 ± 0.50^ef	61.84 ± 0.48^bc	78.83 ± 0.09^de
6G2A950	360.93 ± 30.66^b	1.29	81.28 ± 1.06ª	76.31 ± 0.50^d	60.49 ± 0.55^d	78.90 ± 0.05^d
6G2A1300	254.85 ± 39.78^c	1.25	81.08 ± 0.44ª	74.66 ± 0.54^fg	59.57 ± 0.23^e	78.76 ± 0.05^de
6G2A1650	148.26 ± 33.12^d	0.91	80.62 ± 1.47ª	73.40 ± 0.39^h	61.21 ± 0.42^cd	78.60 ± 0.11^e
6G2A2000	132.06 ± 2.92^d	0.93	80.94 ± 1.63ª	72.73 ± 0.14^i	62.90 ± 0.47^a	78.64 ± 0.06^e

¹G = gelatin; A = alginate; the numbers indicate the stirring speed (rpm) applied in each treatment.

Figure 2. Optical micrographics (bar = 200 μm) of microcapsules produced with 3:1 g/100 g gelatin:alginate, at different stirring speeds: (a) 600 rpm; (b) 950 rpm; (c) 1300 rpm; (d) 1650 rpm; (e) 2000 rpm.

Figure 3. Correlation between Reynolds number and mean particle size of microcapsules produced with (∎) 3:1 g/100 g gelatin:alginate and (·) 6:2 g/100 g gelatin:alginate.

Figure 4. FTIR spectra to sample coded as 3G1A600 (3:1 g/100 g gelatin:alginate at 600 rpm) and pure gelatin, alginate, and buriti oil.