Neutralization of Soybean Oil Deodorizer Distillate for Vitamin Supplement Production

Table 1

Levels and ranges of the independent variables (Na₂CO₃ concentration, temperature, and time) employed in the first and second experimental designs.

First experimental design
Independent variable	Levels and ranges
	−1		0	+1
Na2CO3 concentration (N)	2		3	4
Temperature (°C)	25		37.5	50
Time (min)	2		4	6
Second experimental design
Independent variable	Levels and ranges
	−1.68	−1	0	+1	+1.68
Na2CO3 concentration (N)	2.66	3	3.5	4	4.34
Temperature (°C)	25	30	37	44	49
Time (min)	1.67	2	2.5	3	3.33