Table 1.

Experimental layout for 3 variables and 3 levels response surface analysis

Treatment No	Syrup temp, °C	Syrup concentration, oBrix	Duration of osmosis, h
	T	C	θ
1	1 (50)	1 (70)	0 (5)
2	1 (50)	−1 (50)	0 (5)
3	−1 (30)	1 (70)	0 (5)
4	−1 (30)	−1 (50)	0 (5)
5	1 (50)	0 (60)	1 (6)
6	1 (50)	0 (60)	−1 (4)
7	−1 (30)	0 (60)	1 (6)
8	−1 (30)	0 (60)	−1 (4)
9	0 (40)	1 (70)	1 (6)
10	0 (40)	1 (70)	−1 (4)
11	0 (40)	−1 (50)	1 (6)
12	0 (40)	−1 (50)	−1 (4)
13	0 (40)	0 (60)	0 (5)
14	0 (40)	0 (60)	0 (5)
15	0 (40)	0 (60)	0 (5)

The data in parentheses indicate actual variables