Response surface methodology optimization of blended fruit nectar: cashew apple and açai

Figures & data

Table 1. Compositions of the mixed fruit nectars.

Formulations	Coded variable levels			Uncoded variable levels		Açai pulp (%)	Cashew apple pulp (%)
	X1	X2		X1	X2
1	−1		−1	0.8	34.4	15.3	19.1
2	1		1	3.5	34.4	26.8	7.6
3	−1		−1	0.8	55.6	24.7	30.9
4	1		1	3.5	55.6	43.3	12.3
5	-α		0	0.25	45.0	10.4	34.6
6	+α		0	4.0	45.0	36.0	9.0
7	0		-α	2.1	30.0	20.3	9.7
8	0		Α	2.1	60.0	40.6	19.4
9(C)*	0		0	2.1	45.0	30.5	14.5
10(C)*	0		0	2.1	45.0	30.5	14.5
11(C)*	0		0	2.1	45.0	30.5	14.5

X₁: Açai-to-cashew apple pulp ratio; X₂: Pulp content; (%); *(C): Central point

Table 2. Physicochemical analysis of pasteurized cashew apple and açai pulps.

Parameters*	Cashew apple pulp	Açai pulp
Titratable acidity (citric acid %)	0.6 ± 0.0	0.5 ± 0.0
pH	3.8 ± 0.0	3.7 ± 0.0
Soluble solids (°Brix)	10.0 ± 0.0	2.3 ± 0.0
Ascorbic acid (mg/100 mL)	151.3 ± 9.3	20.6 ± 6.9
Total phenols (mg gallic acid/100 g)	108.3 ± 5.6	98.5 ± 7.4
Total anthocyanins (mg/100 g)	-	13.2 ± 0.8
Total carotenoids (mg/100 g)	1.0 ± 0.1	2.4 ± 0.2
Reducing sugars (g/100 g)	3.5 ± 1.3	0.4 ± 0.0
Total sugars (g/100 g)	3.8 ± 0.2	1.1 ± 0.1

*Results represent mean values of triplicate determinations ± standard deviation (SD).

Table 3. Chemical characterization of blended tropical fruit nectars pasteurized composed of cashew apple and açai pulps (mean values of triplicate determinations ± standard deviation).

Uncoded variable levels		pH	Titratable acidity (% citric acid)	Reducing sugars (g/100 g)	Total sugars (g/100 g)	Total carotenoids (mg/100 g)	Color	Total phenols (gallic acid mg/100 g)	Ascorbic acid (mg/100 mL)	Total anthocyanin (mg/100 g)
X1	X2
0.8	34.4	3.98 ± 0.00	0.26 ± 0.00	9.20 ± 0.21	8.80 ± 1.34	0.28 ± 0.04	0.44 ± 0.03	38.70 ± 2.96	22.44 ± 4.53	1.71 ± 0.39
3.5	34.4	3.96 ± 0.00	0.19 ± 0.00	2.40 ± 1.17	9.30 ± 1.25	0.61 ± 0.10	0.72 ± 0.01	40.45 ± 0.212	6.41 ± 0.00	4.12 ± 0.00
0.8	55.6	3.92 ± 0.00	0.42 ± 0.042	7.90 ± 0.29	8.30 ± 0.82	0.98 ± 0.24	0.69 ± 0.01	58.30 ± 0.707	38.46 ± 0.00	3.18 ± 1.40
3.5	55.6	3.89 ± 0.00	0.36 ± 0.049	7.40 ± 0.35	8.30 ± 0.39	0.64 ± 0.5	1.12 ± 0.01	62.55 ± 1.626	9.62 ± 4.53	6.75 ± 0.25
0.25	45.0	3.96 ± 0.00	0.39 ± 0.00	10.00 ± 0.07	8.60 ± 4.53	1.34 ± 0.04	0.37 ± 0.00	50.60 ± 4.101	51.28 ± 0.00	1.71 ± 0.75
4.0	45.0	3.91 ± 0.00	0.36 ± 0.049	7.70 ± 0.48	8.70 ± 0.17	0.70 ± 0.02	0.92 ± 0.04	54.20 ± 0.848	9.62 ± 4.53	6.06 ± 0.14
2.1	30.0	3.96 ± 0.00	0.26 ± 0.00	7.90 ± 0.23	9.20 ± 0.18	1.14 ± 0.11	0.58 ± 0.03	32.40 ± 1.697	12.82 ± 0.00	2.93 ± 0.18
2.1	60.0	3.86 ± 0.00	0.46 ± 0.091	9.70 ± 0.14	8.90 ± 0.02	0.77 ± 0.03	1.05 ± 0.06	70.95 ± 3.040	28.85 ± 4.53	6.92 ± 0.43
2.1	45.0	3.87 ± 0.00	0.26 ± 0.00	11.50 ± 0.13	9.60 ± 0.05	0.51 ± 002	0.87 ± 0.03	54.50 ± 2.545	19.23 ± 9.06	5.47 ± 0.32
2.1	45.0	3.91 ± 0.00	0.26 ± 0.00	6.60 ± 0.58	8.50 ± 0.19	0.53 ± 0.05	0.78 ± 0.03	49.90 ± 0.707	16.03 ± 4.53	4.86 ± 0.25
2.1	45.0	3.92 ± 0.00	0.26 ± 0.00	6.60 ± 0.33	8.80 ± 0.25	1.01 ± 0.21	0.79 ± 0.02	54.25 ± 4.313	25.64 ± 0.00	7.36 ± 0.10

X₁: Açai-to-cashew apple pulp ratio; X₂: Pulp content; (%)

Table 4. Regression coefficients of the second-order polynomial and their significance.

Coefficients	Ph	Titratable acidity	Reducing sugars	Total Sugars	Total carotenoids	Color	Total phenols	Ascorbic Acid	Total anthocyanin
β0	3.90	0.26	8.27	8.99	0.68	0.82	52.88	20.30	5.90
β1	−0.02	−0.02	−1.31	0.10	−0.11	0.19	1.39	−12.97	1.52
β1^2	0.02	0.04	−0.19	−0.18	0.08	−0.08	−0.75	3.47	−1.12
β2	−0.03	0.08	0.78	−0.24	0.03	0.17	12.03	5.24	1.22
β2^2	0.01	0.03	−0.24	0.00	0.05	<0.01	−1.11	−1.34	−0.60
β12	<0.01	<0.01	1.57	−0.12	−0.17	0.04	0.62	−3.21	0.29
R^2	0.88	0.88	0.51	0.50	0.27	0.99	0.96	0.92	0.90
R^2 ajust.	0.75	0.77	0.03	<0.01	<0.01	0.98	0.93	0.83	0.81
F	39.48	46.68	5.76	5.21	2.04	497.50	151.11	58.23	52.19
(F/F5%)reg	7.82	9.24	1.14	1.03	0.40	98.51	29.92	11.53	10.33
Flof	2.97	<0.01	5.35	2.14	27.82	1.51	17.30	18.08	1.74
(F/F5%)lof	0.15	<0.01	0.28	0.11	1.45	0.08	0.90	0.94	0.09

β_0: mean; β₁: proportions of açai/cashew apple pulps; β₂: pulp content.

Figure 1. Response surface of blended tropical fruit nectars composed of cashew apple and açai pulps: (a) ascorbic acid content; (b) pH; (c) titratable acidity; (d) total anthocyanins; (e) color (e) and (f) total phenols.

Table 5. Sensory attributes of blended tropical fruit nectar composed of cashew apple and açai pulps (mean values of triplicate determinations ± standard deviation).

Uncoded variable levels		Açai pulp (%)	Cashew apple pulp (%)	Flavor	Overall impression	Purchase intention
X1	X2
0.8	34.4	15.31	19.09	6.1 ± 1.7	6.0 ± 1.5	3.2 ± 1.0
3.5	34.4	26.76	7.64	5.5 ± 2.0	5.6 ± 1.9	2.8 ± 1.2
0.8	55.6	24.74	30.86	4.7 ± 2.1	4.9 ± 2.0	2.5 ± 1.1
3.5	55.6	43.26	12.34	5.1 ± 2.2	5.2 ± 2.1	2.7 ± 1.2
0.25	45.0	10.40	34.6	5.2 ± 2.1	5.2 ± 2.0	2.8 ± 1.2
4.0	45.0	36.00	9.00	5.9 ± 2.0	5.8 ± 1.9	3.2 ± 1.2
2.1	30.0	20.31	9.69	6.6 ± 1.6	6.5 ± 1.7	3.4 ± 1.1
2.1	60.0	40.62	19.38	4.5 ± 2.0	4.8 ± 1.9	2.4 ± 1.1
2.1	45.0	30.46	14.53	5.7 ± 2.0	5.9 ± 1.9	3.1 ± 1.2
2.1	45.0	30.46	14.53	5.5 ± 2.1	5.6 ± 2.0	3.0 ± 1.2
2.1	45.0	30.46	14.53	5.7 ± 1.9	5.7 ± 1.8	3.0 ± 1.2

X₁: Açai-to-cashew apple pulp ratio; X₂: Pulp content.

Table 6. Regression coefficients of the second-order polynomial and their significance.

Coefficients	Flavor	Overall Impression	Purchase intention
β0	5.71	5.77	3.07
β1	0.10	0.09	0.03
β1^2	−0.13	−0.14	−0.06
β2	−0.60	−0.50	−0.28
β2^2	−0.12	−0.10	−0.09
β12	0.25	0.19	0.15
R^2	0.89	0.9	0.81
R^2 adj.	0.78	0.79	0.62
Freg	44.77	47.63	23.53
(F/F5%)reg	8.87	9.43	4.66
Flof	121.47	57.04	284.53
(F/F5%)lof	6,.4	2.98	14.85

β_0: mean; β₁: proportions of açai/cashew apple pulps; β₂: pulp content.

Figure 2. Response surface for sensorial attributes of blended tropical fruit nectars composed of cashew apple and açai pulps: (a) taste; (b) global impression and (c) purchase intention.