Optimization of sorbitol, fructooligosaccharides and sugar levels in the syrup based on physicochemical properties and sensory acceptance of healthy, sweet egg yolk drop (a traditional egg-based dessert) using response surface methodology

Figures & data

Figure 1. A variation in the characteristics of sweet egg yolk drops.

Table 1. Color and water activity properties of sweet egg yolk drops as affected by sorbitol with FOS ratio and percentage sugar reduction.

Experiments		Color			aw
Sorbitol : FOS	Sugar reduction (%)	L*	a*	b*
Control		95.17^b ± 0.62	4.28^b ± 1.27	83.32^c ± 2.95	0.837^d ± 0.001
25 : 75	25	95.88^a ± 0.15	5.62^a ± 0.22	86.04^ab ± 0.62	0.807^f ± 0.000
	50	95.94^a ± 0.08	5.66^a ± 0.22	86.43^a ± 0.22	0.819^e ± 0.004
	75	95.77^a ± 0.18	5.33^ab ± 0.50	85.68^abc ± 0.98	0.876^c ± 0.004
	100	95.56^ab ± 0.26	4.93^ab ± 0.50	84.95^abc ± 0.98	0.907^a ± 0.000
50 : 50	25	95.86^a ± 0.11	5.56^a ± 0.30	86.02^ab ± 0.15	0.800^g ± 0.000
	50	95.70^ab ± 0.04	5.19^ab ± 0.04	85.42^abc ± 0.04	0.820^e ± 0.000
	75	95.52^ab ± 0.11	4.91^ab ± 0.30	84.59^abc ± 0.15	0.839^d ± 0.001
	100	95.41^ab ± 0.15	4.72^ab ± 0.30	84.04^abc ± 0.52	0.893^b ± 0.001
75 : 25	25	95.78^a ± 0.09	5.41^a ± 0.18	85.80^ab ± 0.34	0.785^h ± 0.000
	50	95.73^a ± 0.20	5.37^a ± 0.36	85.54^abc ± 0.84	0.803^fg ± 0.003
	75	95.46^ab ± 0.34	4.79^ab ± 0.65	83.83^bc ± 2.05	0.803^fg ± 0.002
	100	95.40^ab ± 0.40	4.75^ab ± 0.74	84.40^bc ± 1.48	0.874^c ± 0.001

^a–hMeans ± SD of triplicate measurements with different superscripted letters in each column are significantly different (p ≤ .05).

Table 2. Physical properties of sweet egg yolk drops as affected by sorbitol with FOS ratio and percentage sugar reduction.

Experiments		Expansion ratio	Bulk density (g/cm^3)	Textures
Sorbitol : FOS	Sugar reduction (%)			Hardness (N)	Cohesiveness
Control		1.37^a ± 0.06	1.03^b ± 0.06	8.95^d ± 1.67	0.34^bcd ± 0.01
25 : 75	25	0.98^h ± 0.07	1.26^a ± 0.16	15.85^a ± 1.95	0.39^a ± 0.04
	50	1.06^g ± 0.07	1.12^ab ± 0.08	12.36^bc ± 1.68	0.38^ab ± 0.03
	75	1.17^de ± 0.05	1.12^ab ± 0.05	9.78^cd ± 2.10	0.33^bcd ± 0.03
	100	1.21^cd ± 0.08	1.05^f ± 0.11	5.46^abc ± 1.53	0.32^cd ± 0.04
50 : 50	25	1.79^gh ± 0.10	1.11^ab ± 0.12	13.11^b ± 1.99	0.34^abc ± 0.03
	50	1.81^fg ± 0.10	1.06^bc ± 0.09	10.22^cd ± 0.90	0.33^bcd ± 0.04
	75	1.91^cde ± 0.12	1.02^ef ± 0.05	5.78^abc ± 1.36	0.30^cd ± 0.05
	100	1.99^c ± 0.17	0.95^bc ± 0.07	3.85^fg ± 2.08	0.28^de ± 0.01
75 : 25	25	1.14^ef ± 0.09	1.05^bc ± 0.12	11.07^bcd ± 1.45	0.31^cd ± 0.03
	50	1.16^def ± 0.06	0.97^bc ± 0.08	8.29^de ± 1.66	0.29^cde ± 0.01
	75	1.30^b ± 0.10	0.97^bc ± 0.05	4.33^fg ± 1.62	0.25^ef ± 0.02
	100	1.36^ab ± 0.06	0.89^c ± 0.07	2.46^g ± 0.28	0.21^f ± 0.01

^a–hMeans ± SD of triplicate measurements with different superscripted letters in each column are significantly different (p ≤ .05).

Table 3. Chemical properties of sweet egg yolk drops as affected by sorbitol with FOS ratio and percentage sugar reduction.

Experiments
Sorbitol : FOS	Sugar reduction (%)	Moisture content (% wb)	Soluble Fiber (g/100 g)	Reducing sugar (as invert sugar g/100 g)	Sucrose (g/100 g)	Energy (kcal)
Control		30.28^d ± 0.03	ND	0.68^b ± 0.03	43.10^a ± 0.56	351.28^a ± 1.07
25 : 75	25	23.18^h ± 0.06	0.19^a ± 0.01	0.73^a ± 0.04	31.95^c ± 0.64	331.76^b ± 0.92
	50	28.82^f ± 0.08	0.15^b ± 0.01	0.59^b ± 0.01	25.10^e ± 0.57	322.31^c ± 1.89
	75	29.55^def ± 0.31	0.15^b ± 0.01	0.54^b ± 0.02	16.80^g ± 0.56	321.31^c ± 2.02
	100	37.25^b ± 0.21	0.13^c ± 0.01	0.53^c ± 0.01	1.17^h ± 0.07	288.86^f ± 1.52
50 : 50	25	25.72^g ± 0.19	0.16^b ± 0.01	0.68^b ± 0.01	33.30^b ± 0.28	329.35^b ± 2.37
	50	29.13^ef ± 0.00	0.15^b ± 0.01	0.52^a ± 0.01	24.65^e ± 0.21	322.62^c ± 0.75
	75	31.14^c ± 0.36	0.13^c ± 0.01	0.51^b ± 0.01	17.95^f ± 0.21	301.92^e ± 0.13
	100	40.57^a ± 0.63	0.09^d ± 0.00	0.45^b ± 0.01	0.88^h ± 0.22	270.77^g ± 2.72
75 : 25	25	25.42^g ± 0.42	0.12^c ± 0.00	0.53^c ± 0.04	32.40^c ± 0.14	328.82^b ± 1.14
	50	29.72^de ± 0.06	0.10^d ± 0.00	0.49^b ± 0.01	26.65^d ± 0.21	314.24^h ± 0.64
	75	29.09^ef ± 0.19	0.09^d ± 0.01	0.47^c ± 0.01	17.35^fg ± 0.22	315.75^d ± 0.93
	100	40.40^a ± 0.55	0.09^d ± 0.00	0.42^b ± 0.01	0.71^h ± 0.01	268.56^g ± 1.31

^a–hMeans ± SD of triplicate measurements with different superscripted letters in each column are significantly different (p ≤ .05).

Table 4. Sensory properties of sweet egg yolk drops as affected by sorbitol with FOS ratio and percentage sugar reduction.

Experiments		Appearances	Yellowish-orange	Overall flavor	Sweetness	Juiciness	Firmness	Overall liking
Sorbitol : FOS	Sugar reduction (%)
Control		6.5^abc ± 1.0	6.8^abc ± 1.2	6.2^bc ± 1.6	6.5^abc ± 1.3	6.5^ab ± 1.7	6.1^abcd ± 1.8	6.6^ab ± 1.3
25 : 75	25	6.0^cde ± 1.7	6.2^bcd ± 1.6	6.4^abc ± 1.6	6.0^bcd ± 1.5	5.7^bc ± 1.7	6.1^abcd ± 1.8	6.0^bc ± 1.5
	50	7.3^a ± 1.0	7.3^a ± 1.1	7.2^a ± 1.1	7.0^a ± 1.1	6.6^ab ± 1.5	6.8^b ± 1.6	7.2^a ± 0.9
	75	7.1^a ± 1.0	7.1^a ± 1.0	6.9^ab ± 0.9	6.8^ab ± 1.7	6.7^ab ± 0.9	7.0^a ± 1.2	6.6^ab ± 1.0
	100	5.5^def ± 1.8	6.2^bcd ± 1.5	6.5^abc ± 1.8	5.6^cde ± 2.0	5.6^bc ± 2.3	5.2^de ± 1.8	5.3^cd ± 1.8
50 : 50	25	6.5^abc ± 1.4	7.4^a ± 1.2	6.8^ab ± 1.6	6.0^bcd ± 1.4	6.6^ab ± 1.7	6.4^b ± 1.8	6.0^b ± 1.2
	50	7.0^a ± 1.2	7.0^ab ± 1.3	6.2^bc ± 1.4	6.2^abcd ± 1.5	6.4 ^ab ±1.5	6.0^abcd ± 2.2	6.5^ab ± 1.3
	75	7.2^a ± 1.0	6.1^bcd ± 1.1	6.0^bc ± 1.3	6.0^bcd ± 1.1	6.3^ab ± 1.5	6.2^abcd ± 1.2	7.0^a ± 0.7
	100	5.2^ef ± 1.4	5.9^cd ± 2.0	6.0^bc ± 1.7	4.5^f ± 1.2	6.0^b ± 2.0	5.8^abc ± 2.0	5.1^de ± 1.5
75 : 25	25	6.1^bcd ± 0.7	7.2^a ± 1.4	6.8^ab ± 1.5	6.2^abcd ± 1.6	7.2^a ± 1.4	6.1^abcd ± 1.0	6.0^b ± 1.0
	50	6.7^abc ± 1.1	6.7^abc ± 1.5	6.2^bc ± 1.6	6.2^abcd ± 1.2	6.5^ab ± 1.2	6.4^abc ± 1.5	6.7^ab ± 0.9
	75	6.8^ab ± 0.9	6.7^abc ± 1.9	6.8^ab ± 1.2	6.0^bcd ± 1.7	6.6^ab ± 1.9	5.5^cd ± 2.0	6.2^d ± 0.7
	100	5.0^f ± 1.8	5.4^d ± 1.7	5.7^c ± 1.8	5.0^ef ± 2.1	4.9^c ± 2.2	4.2^e ± 2.0	4.5^e ± 1.7

^a–hMeans±SD of triplicate measurements with different superscripted letters in each column are significantly different (p≤ .05).

Table 5. Predictive regression models for response variables of sweet egg yolk drops.

Dependent variables (Y)		Predictive models	R^2	Lack of fit (p-value)
Physical properties:
	Expansion ratio (Y1)	−1.237 + 0.115X1 +0.002X2-0.001X1^2-2.984E-18X1X2 +0.000008X2^2	0.98	>0.05
	Hardness (Y2)	23.808–0.180X1-0.161X2 +0.001X1^2 +0.000X1X2 +0.000X2^2	0.97	>0.05
Chemical property:
	Energy value (Y3)	333.907–0.782X1 +0.858X2 +0.008X1^2-0.004X1X2-0.011X2^2	0.93	>0.05
Sensory properties:
	Appearances (Y4)	3.2417 + 0.027X1 +0.1245X2-0.0003X1^2-0.0001X1X2-0.001X2^2	0.86	>0.05
	Sweetness (Y5)	6.1583–0.088X1 +0.0875X2 +0.0009X1^2-0.0002X1X2-0.0007X2^2	0.86	>0.05
	Overall liking (Y6)	3.4333 + 0.017X1 +0.1177X2-0.0001X1^2-0.0002X1X2-0.001 X2^2	0.78	>0.05

Independent variable: X1 = sorbitol (%), X2 = percentage of sugar reduction in syrup (%).

R2 = correlation coefficient of determination.

Second-order polynomial regression model: $Y={\beta }_0+{\beta }_i{X}_i+{\beta }_j{X}_j+{\beta }_{ii}{X}_i^2+{\beta }_{jj}{X}_j^2+{\beta }_{ij}{X}_i{X}_j$

Figure 2. RSM contour plots of expansion ratio (a), hardness (b), energy values (c), and sensory liking score of appearances (d), sweetness, (e) and overall liking (f).

Figure 3. The optimal condition in the shaded area for development of sweet egg yolk drop.

Table 6. Predicted and experimental values of the sweet egg yolk drop under selected conditions for verification of optimized region.

Properties			Formulation of syrup		Predicted values^a	Experimental values	RMSE^b
			Sorbitol : FOS (%)	Sugar reduction (%)
Expansion ratio			25 : 75	60	1.10	1.55	0.41
			25 : 75	65	1.11	1.65
			30 : 70	65	1.41	1.32
Hardness (N)			25 : 75	60	10.27	9.65	0.86
			25 : 75	65	9.47	8.17
			30 : 70	65	8.84	9.21
Energy values (kcal)			25 : 75	60	325.24	328.04	1.78
			25 : 75	65	322.15	321.44
			30 : 70	65	319.14	320.23
Appearances			25 : 75	60	7.4	7.5	0.18
			25 : 75	65	7.4	7.6
			30 : 70	65	7.5	7.2
Sweetness			25 : 75	60	7.0	6.8	0.17
			25 : 75	65	6.9	7.0
			30 : 70	65	6.7	6.9
Overall liking			25 : 75	60	7.0	7.2	0.28
			25 : 75	65	6.9	7.3
			30 : 70	65	6.9	7.0

^aValues derived from the predictive regression model (Table 5).

^bRMSE = Root mean squared error between predicted and experimental values.

Data availability statement

Data included in article/supplementary material/referenced in article..