The characteristics of foam-mat dried red and purple roselle calyces powder prepared with commercial emulsifiers as the foaming agents

Figures & data

Figure 1. Red (a) and purple (b) of roselle flower.

Table 1. The composition and HLB of commercial emulsifier.

Symbol of Commercial Emulsifier	Composition	HLB Value
SSL	Sodium stearoyl lactylate	12.15 ± 1.52
SP	Sorbitol syrup, mono- and diglyceride, polyglycerol ester of fatty acid, propylene glycol, acid regulator, coloring agent yellow FCF CI No. 15985	14.09 ± 0.31
TBM	Monoglyceride, sorbitol, propylene glycol, polyglycerol ester, sorbitan monostearate, vanilla, tartrazine CI No. 19140	16.25 ± 0.91

Figure 2. The color foam mat dried red and purple roselle calyces powder with different foaming agents.

Table 2. The foaming properties of roselle calyces extract with different foaming agents.

Roselle Calyces	Foaming agent	Foam Expansion (%)	Foam Density (g/cm^3)
Red	SSL	36.97 ± 1.15^bc	0.17 ± 0.01^bc
	SP	33.61 ± 1.34^d	0.22 ± 0.02^a
	TBM	38.76 ± 1.15^b	0.13 ± 0.01^d
Purple	SSL	42.30 ± 1.02^a	0.14 ± 0.00^d
	SP	35.06 ± 0.84^cd	0.18 ± 0.01^b
	TBM	39.51 ± 0.42^b	0.14 ± 0.00^cd

All data expressed averages data from 3 replications ± standard deviations. The difference latter in the same column indicated a significant difference (p > .05) based on the turkey test.

Figure 3. Foam stability of roselle calyces water extract stabilized by different emulsifiers.

Table 3. Chemical properties of conventional and foam-mat dried roselle calyces powder with different foaming agents.

Roselle Calyces	Foaming agent	DPPH Assay		ABTS Assay		Total Phenolic Content (mg GAE/g)	Total Anthocyanins Content (mg/g)
		Antioxidant Activity (mg TE/g)	% DPPH Inhibition	Antioxidant Activity (mg TE/g)	% ABTS Inhibition
Red	SSL	0.37 ± 0.01^c	22.74 ± 0.68^c	2.44 ± 0.02^d	24.52 ± 0.21^d	2.66 ± 0.08^c	0.67 ± 0.05^c
	SP	0.35 ± 0.03^c	21.40 ± 2.01^c	3.45 ± 0.31^c	35.17 ± 3.25^c	2.27 ± 0.06^c	0.64 ± 0.01^c
	TBM	0.34 ± 0.00^c	20.81 ± 0.22^c	2.85 ± 0.21^cd	28.89 ± 2.26^cd	2.78 ± 0.04^c	0.65 ± 0.05^c
	Conventional Drying	15.02 ± 0.04	34.69 ± 0.35	10.05 ± 0.07	97.01 ± 0.69	23.28 ± 0.34	8.04 ± 0.00
Purple	SSL	0.60 ± 0.03^b	36.07 ± 1.89^b	6.38 ± 0.20^b	73.94 ± 2.47^b	4.22 ± 0.23^b	3.46 ± 0.05^ab
	SP	0.69 ± 0.01^a	41.26 ± 0.71^a	7.87 ± 0.46^a	83.40 ± 4.88^a	6.08 ± 0.47^a	3.10 ± 0.35^b
	TBM	0.70 ± 0.02^a	41.93 ± 1.00^a	8.51 ± 0.09^a	90.41 ± 0.99^a	6.13 ± 0.24^a	3.97 ± 0.37^a
	Conventional Drying	16.94 ± 0.06	88.31 ± 0.29	10.24 ± 0.04	98.83 ± 0.39	33.86 ± 0.32	38.61 ± 0.00

All data expressed averages data from 3 replications ± standard deviations. The difference latter in the same column indicated a significant difference (p > .05) based on the turkey test.

Figure 4. Particle size distribution of foam mat-dried red (a) and purple (b) roselle calyces powder.

Table 4. Functional properties and pH values of conventional and foam-mat dried roselle calyces powder with different foaming agents.

Roselle Calyces	Foaming agent	Dissolution time (s)	pH	Bulk Density (g/ml)	WAC (g/g)	OAC (g/g)	Mean Particle Diameter (µm)
Red	SSL	128.33 ± 2.89^a	2.67 ± 0.01^b	0.56 ± 0.00^b	0.46 ± 0.05^d	2.38 ± 0.23^a	3.56 ± 0.00^a
	SP	72.33 ± 2.52^c	2.41 ± 0.02^d	0.63 ± 0.00^a	0.53 ± 0.04^cd	2.09 ± 0.17^a	3.18 ± 0.00^c
	TBM	85.00 ± 2.65^b	2.42 ± 0.02^d	0.63 ± 0.00^a	0.56 ± 0.04^bc	2.13 ± 0.18^ab	3.50 ± 0.00^b
	Conventional Drying	undefined	4.27 ± 0.10	0.61 ± 0.02	2.70 ± 0.06	2.81 ± 0.01	n.a.
Purple	SSL	89.67 ± 1.15^b	2.72 ± 0.02^a	0.56 ± 0.00^b	0.33 ± 0.01^e	1.67 ± 0.06^bc	2.48 ± 0.01^d
	SP	87.00 ± 1.00^b	2.51 ± 0.01^c	0.63 ± 0.00^a	0.63 ± 0.02^b	1.47 ± 0.12^c	2.36 ± 0.17^e
	TBM	85.33 ± 1.15^b	2.49 ± 0.01^c	0.63 ± 0.00^a	0.77 ± 0.02^a	1.55 ± 0.13^c	2.23 ± 0.00^d
	Conventional Drying	undefined	3.71 ± 0.01	0.47 ± 0.01	2.20 ± 0.01	2.65 ± 0.08	n.a.

All data expressed averages data from 3 replications ± standard deviations. WAC (water absorption capacity) and OAC (oil absorption capacity). n.a: not analyzed. The difference latter in the same column indicated a significant difference (p > .05) based on the turkey test.

Table 5. Color value and index of conventional and foam-mat dried roselle calyces powder with different foaming agents.

Roselle Calyces	Foaming agent	L*	a*	b*	CI	VI	BI
Red	SSL	56.167 ± 2.48^b	+29.93 ± 2.06^a	+4.23 ± 0.32^a	0.26 ± 0.01^b	0.15 ± 0.00^b	0.47 ± 0.00^b
	SP	60.53 ± 0.67^a	+29.13 ± 0.50^a	+4.23 ± 0.15^a	0.28 ± 0.02^b	0.17 ± 0.01^a	0.55 ± 0.03^a
	TBM	60.37 ± 0.23^a	+28.53 ± 2.21^a	+4.36 ± 0.55^a	0.29 ± 0.01^b	0.17 ± 0.01^ab	0.55 ± 0.04^a
	Conventional Drying	51.43 ± 1.05	+18.53 ± 0.80	+8.30 ± 0.53	1.04 ± 0.08	0.05 ± 0.00	0.16 ± 0.00
Purple	SSL	45.60 ± 0.14^c	+24.97 ± 0.64^b	+3.20 ± 0.00^b	1.04 ± 0.12^a	0.09 ± 0.01^c	0.21 ± 0.02^c
	SP	48.61 ± 0.15^c	+27.73 ± 0.06^b	+3.80 ± 0.20^ab	1.20 ± 0.13^a	0.09 ± 0.00^c	0.21 ± 0.01^c
	TBM	48.51 ± 0.94^c	+27.03 ± 0.55^ab	+3.97 ± 0.21^ab	1.22 ± 0.05^a	0.09 ± 0.01^c	0.22 ± 0.02^c
	Conventional Drying	42.13 ± 0.25	+19.13 ± 0.23	+6.10 ± 0.10	5.14 ± 0.26	0.11 ± 0.00	0.28 ± 0.01

All data are expressed as averages from 3 replications ± standard deviations. CI (Color intensity), VI (violet index), and BI (browning index). The difference in the latter in the same column indicated a significant difference (p > .05) based on the Tukey test.