Optimization of Extraction of Natural Pigment from Purple Sweet Potato by Response Surface Methodology and Its Stability

Table 4

Effects of metallic ion on PSPC stability.

Time (h)	Absorbance value (𝐴)
	Fe^3+	Zn^2+	Cu^2+	Pb^2+	Al^3+	Blank
0	0.752	0.752	0.752	0.752	0.752	0.752
24	0.750	0.721	0.745	0.744	0.749	0.746
48	0.748	0.710	0.742	0.743	0.748	0.745