Optimizing conditions for the extraction of polysaccharides of white tea

Figures & data

Table 1. Box–Behnken design matrix and the response values for the yield of WTPS.

Design point	Extraction temperature (X1, °C)	Ratio of water to material (X2, mL/g)	Duration of extraction time (X3, min)	Number of extractions (X4)	Extract yield (Y, %)
1	55 (−1)	12 (0)	120 (1)	3 (0)	0.8336
2	55 (−1)	12 (0)	60 (−1)	3 (0)	0.8066
3	60 (0)	12 (0)	90 (0)	3 (0)	0.9438
4	60 (0)	12 (0)	90 (0)	3 (0)	0.9509
5	65 (1)	10 (−1)	90 (0)	3 (0)	0.7245
6	60 (0)	14 (1)	90 (0)	4 (1)	0.9398
7	60 (0)	10 (−1)	120 (1)	3 (0)	0.9062
8	60 (0)	10 (−1)	60 (−1)	3 (0)	0.8765
9	60 (0)	12 (0)	120 (1)	2 (−1)	0.9372
10	55 (−1)	10 (−1)	90 (0)	3 (0)	0.7791
11	55 (−1)	14 (1)	90 (0)	3 (0)	0.8022
12	60 (0)	12 (0)	90 (0)	3 (0)	0.9564
13	60 (0)	12 (0)	90 (0)	3 (0)	0.9392
14	55 (−1)	12 (0)	90 (0)	2 (−1)	0.7772
15	65 (1)	12 (0)	90 (0)	2 (−1)	0.8253
16	60 (0)	12 (0)	90 (0)	3 (0)	0.9465
17	60 (0)	10 (−1)	90 (0)	4 (1)	0.9363
18	65 (1)	12 (0)	90 (0)	4 (1)	0.7494
19	65 (1)	12 (0)	60 (−1)	3 (0)	0.7377
20	65 (1)	12 (0)	120 (1)	3 (0)	0.7932
21	60 (0)	12 (0)	60 (−1)	2 (−1)	0.9062
22	60 (0)	10 (−1)	90 (0)	2 (−1)	0.9136
23	60 (0)	12 (0)	90 (0)	3 (0)	0.9601
24	60 (0)	12 (0)	60 (−1)	4 (1)	0.9416
25	65 (1)	14 (1)	90 (0)	3 (0)	0.7614
26	55 (−1)	12 (0)	90 (0)	4 (1)	0.892
27	60 (0)	14 (1)	90 (0)	2 (−1)	0.9054
28	60 (0)	12 (0)	120 (1)	4 (1)	0.9745
29	60 (0)	14 (1)	60 (−1)	3 (0)	0.8939
30	60 (0)	14 (1)	120 (1)	3 (0)	0.9181
31	60 (0)	12 (0)	90 (0)	3 (0)	0.9554

Table 2. Analysis of variance (ANOVA) for the response surface quadratic model.

Source	Sum of squares	df	Mean square	F-value	P-value	Significance
Model	0.181526	14	0.012966	166.14	<0.0001	***
X1	0.007460	1	0.007460	95.59	<0.0001	***
X2	0.000596	1	0.000596	7.64	0.0138	**
X3	0.003343	1	0.003343	42.84	<0.0001	***
X4	0.002372	1	0.002372	30.39	<0.0001	***
X1 × X2	0.000048	1	0.000048	0.61	0.4462
X1 × X3	0.000203	1	0.000203	2.60	0.1263
X1 × X4	0.009092	1	0.009092	116.49	< 0.0001	***
X2 × X3	0.000008	1	0.000008	0.10	0.7596
X2 × X4	0.000034	1	0.000034	0.44	0.5173
X3 × X4	0.000001	1	0.000001	0.01	0.9157
X1 × X1	0.151071	1	0.151071	1935.70	< 0.0001	***
X2 × X2	0.009275	1	0.009275	118.84	< 0.0001	***
X3 × X3	0.001604	1	0.001604	20.56	0.0003	***
X4 × X4	0.000318	1	0.000318	4.07	0.0606
Residual	0.001249	16	0.000078
Lack of fit	0.000909	10	0.000091	1.61	0.2903	Not significant
Pure error	0.000340	6	0.000057
Cor total	0.182774	30

Note: R² = 0.9932, Adj-R² = 0.9872; degree of freedom (df).

Figure 1. Response surface plots showing the interaction effects of extraction temperature, ratio of water solutions to material, extraction time and number of extractions on the yield of WTPS. Effects of different factors on the yield of WTPS: (a) effect of ratios of water solutions to the raw material and extraction temperatures, (b) extraction temperatures and extraction times, (c) extraction temperatures and number of extractions, (d) ratios of water solutions to raw material and extraction times, (e) ratios of water solutions to raw material and number of extractions, (f) extraction times and number of extractions.