Preparation Optimization, Characterization, and Antioxidant and Prebiotic Activities of Carboxymethylated Polysaccharides from Jujube

Table 1

Analysis of variance (ANOVA) for response surface quadratic model for the optimization of carboxymethylation conditions.

Source	Sum of squares	Degree of freedom	Mean of squares	F-value	-value	Significance
Model	0.0172	9	0.0019	14.37	0.0010
X1	0.0005	1	0.0005	3.90	0.0888	ns
X2	0.0010	1	0.0010	7.59	0.0283
X3	0.0003	1	0.0003	1.89	0.2116	ns
X1X2	2.500E-09	1	2.500E-09	0.0000	0.9967	ns
X1X3	0.0000	1	0.0000	0.1519	0.7083	ns
X2X3	0.0007	1	0.0007	5.41	0.0530	ns
	0.0002	1	0.0002	1.46	0.2655	ns
	0.0087	1	0.0087	64.91	<0.0001
	0.0048	1	0.0048	36.10	0.0005
Residual error	0.0009	7	0.0001
Lack of fit	0.0005	3	0.0002	1.34	0.3808	ns
Pure error	0.0005	4	0.0001
Total	0.0182	16

R² = 0.9487. Adjusted R² = 0.8826. Predicted R² = 0.5488. C.V.% = 6.17. Adeq. precision = 12.3571. X₁: concentration of NaOH solution, X₂: content of chloroacetic acid solution, and X₃: reaction temperature. Extremely significant difference ( < 0.01), significant difference ( < 0.05), and ns: nonsignificant.