Table 4.
Regression coefficients of second degree polynomials for yield, color value and total anthocyanin contents of purified anthocyanin from Bokbunja byproducts.
| Parameters | Estimate |
| HCl | TFA |
| Yield | Color value | Total anthocyanin contents | Yield | Color value | Total anthocyanin contents |
| Intercept | 114.467263 | -5.714338 | 20.163333 | 113.252593 | -2.079614 | 14.616667 |
| X1 | -0.678601 | 1.352870 | 2.695000 | -1.833333 | 1.372284 | 2.840000 |
| X2 | -1.221926 | 0.157112 | 3.556667 | -1.789407 | 0.063359 | 0.001667 |
| X1 * X1 | -0.3292018 | -0.474074 | -2.815000 | 1.407407 | -0.0353086 | -2.000000 |
| X1 * X2 | 0.017037 | -0.006981 | -0.512500 | 0.007407 | -0.009148 | -1.645000 |
| X2 * X2 | 0.006170 | -0.00981 | -5.220000 | 0.005956 | -0.000399 | -1.845000 |
X1: Concentration of HCl or TFA
X2: Concentration of ethanol