Extraction and preliminary characterization of polysaccharide from Umbilicaria esculenta cultivated in Huangshan Mountain

Figures & data

Table 1. Box–Behnken design and results of the extraction yield of HSSEP isolated from HSSE.

				Extraction yield (%)
Run number	Extraction temperature (°C)	Extraction time (h)	Liquid–solid ratio (mL/g)	Experimental	Predicted
1	0 (100)	0 (1)	0 (10)	27.66	27.61
2	−1 (90)	−1 (0.5)	0 (10)	22.74	22.87
3	1 (110)	1 (1.5)	0 (10)	23.73	23.60
4	0 (100)	0 (1)	0 (10)	27.63	27.61
5	0 (100)	1 (1.5)	1 (15)	24.14	24.35
6	0 (100)	0 (1)	0 (10)	27.70	27.61
7	0 (100)	0 (1)	0 (10)	27.41	27.61
8	0 (100)	−1 (0.5)	1 (15)	26.07	26.02
9	0 (100)	−1 (0.5)	−1 (5)	23.33	23.12
10	0 (100)	0 (1)	0 (10)	27.65	27.61
11	−1 (90)	0 (1)	1 (15)	23.70	23.63
12	−1 (90)	0 (1)	−1 (5)	21.47	21.55
13	−1 (90)	1 (1.5)	0 (10)	22.38	22.25
14	0 (100)	1 (1.5)	−1 (5)	24.83	24.89
15	1 (110)	0 (1)	1 (15)	23.49	23.41
16	1 (110)	0 (1)	−1 (5)	23.06	23.13
17	1 (110)	−1 (0.5)	0 (10)	22.75	22.88

Figure 1. Effect of extraction temperature (A), extraction time (B) and liquid–solid ratio (C) on the extraction yield of HSSEP.

Table 2. Analysis of variance of the fitted model.

Source	Sum of square (SS)	DF	Mean square (MS)	F-value	p-value	Significance
Model	75.7929	9	8.4214	248.7606	<0.0001	Significant
Residual	0.2370	7	0.0339
Lack of fit	0.1844	3	0.0615	4.6736	0.0852	Not significant
Pure error	0.0526	4	0.0132
Core total	76.0299	16
R^2	0.9969
Adj-R^2	0.9929

Note: Degree of freedom (DF); coefficient of determination (R²); adjusted determination coefficient (Adj-R²).

Figure 3. The 3D plots (A), (C) and (E) and 2D contour plots (B), (D) and (F) showing the effects of extraction temperature, extraction time and liquid–solid ratio on the extraction yield of HSSEP.

Note: The effect of extraction temperature and extraction time on the extraction yield of HSSEP at a fixed liquid–solid ratio of 10 mL/g (A) and (B); the effect of extraction temperature and liquid–solid ratio on the extraction yield of HSSEP at a fixed extraction time of 1.0 h (C) and (D); the effect of extraction time and liquid–solid ratio on the extraction yield of HSSEP at a fixed extraction temperature of 100 °C (E) and (F).

Figure 4. Preliminary characterization of HSSEP isolated from HSSE.

Note: UV spectra of HSSEP1 and HSSEP2 (A); monosaccharide composition of HSSEP1 (B); Monosaccharide composition of HSSEP2 (C); FT-IR spectra of HSSEP1 (D); FT-IR spectra of HSSEP2 (E).

Table 3. Preliminary physicochemical properties of HSSEP1 and HSSEP2.

	Total sugar content (%)	Protein content (%)	Uronic acid content (%)
HSSEP1	95.00±1.38	nd	0.73±0.026
HSSEP2	98.80±1.02	nd	0.54±0.030

Note: not detected (nd).