Optimization of Freeze-Drying Process Parameters for Qualitative Evaluation of Button Mushroom (Agaricus bisporus) Using Response Surface Methodology

Table 1

Experimental design (Box-Behnken) followed for freeze-drying of mushrooms.

Test number	Coded value of variables				Actual values of variables
					PDT; (°C)	SDT; (°C)	(mbar)	ST; (cm)
1	−1	−1	0	0	−8	25	0.07	0.5
2	1	−1	0	0	−2	25	0.07	0.5
3	−1	1	0	0	−8	31	0.07	0.5
4	1	1	0	0	−2	31	0.07	0.5
5	0	0	−1	−1	−5	28	0.04	0.2
6	0	0	1	−1	−5	28	0.1	0.2
7	0	0	−1	1	−5	28	0.04	0.8
8	0	0	1	1	−5	28	0.1	0.8
9	−1	0	0	−1	−8	28	0.07	0.2
10	1	0	0	−1	−2	28	0.07	0.2
11	−1	0	0	1	−8	28	0.07	0.8
12	1	0	0	1	−2	28	0.07	0.8
13	0	−1	−1	0	−5	25	0.04	0.5
14	0	1	−1	0	−5	31	0.04	0.5
15	0	−1	1	0	−5	25	0.1	0.5
16	0	1	1	0	−5	31	0.1	0.5
17	−1	0	−1	0	−8	28	0.04	0.5
18	1	0	−1	0	−2	28	0.04	0.5
19	−1	0	1	0	−8	28	0.1	0.5
20	1	0	1	0	−2	28	0.1	0.5
21	0	−1	0	−1	−5	25	0.07	0.2
22	0	1	0	−1	−5	31	0.07	0.2
23	0	−1	0	1	−5	25	0.07	0.8
24	0	1	0	1	−5	31	0.07	0.8
25	0	0	0	0	−5	28	0.07	0.5
26	0	0	0	0	−5	28	0.07	0.5
27	0	0	0	0	−5	28	0.07	0.5
28	0	0	0	0	−5	28	0.07	0.5
29	0	0	0	0	−5	28	0.07	0.5

-PDT: primary drying temperature.
-SDT: secondary drying temperature.
-: Vacuum pressure.
-ST: Sample thickness.