Table 2. Response surface methodology design to evaluate the effects of process conditions on bacterial change cycles, physicochemical properties and morphometric features.

Run	Factor				Response variable
					Bacterial change cycle			Physicochemical property					Morphometric feature
	A	B			N/(log CFU/g)			aw	w(moisture)/%	t(complete dissolution time)/s	Hygroscopicity/(g/100 g)	ρb/(g/mL)	d/μm	FDt
	t(outlet)/°C	p/MPa			After spray drying	Gastric pH	Bile salt
1	96	0.15			–3.53±0.03	–0.2±0.0	–0.02±0.00	0.18±0.01	0.8±0.0	127.5±7.7	49.03±0.00	0.30±0.01	8.04±0.02	2.55±0.05
2	110	0.08			–5.77±0.05	0.0±0.0	0.0±0.0	0.09±0.01	0.55±0.01	76.3±2.5	36.2±0.2	0.2±0.0	4.8±0.2	2.54±0.02
3	110	0.15			–6.4±0.1	0.0±0.0	0.0±0.0	0.09±0.01	0.45±0.01	68.1±3.1	28.9±0.8	0.2±0.0	8.0±0.2	2.55±0.01
4	110	0.116			–6.1±0.1	0.0±0.0	0.0±0.0	0.11±0.01	0.4±0.0	80.0±5.0	39.52±0.08	0.23±0.01	8.8±0.2	2.55±0.01
5	93	0.106			–2.0±0.3	–0.7±0.0	–0.5±0.0	0.2±0.0	0.93±0.01	156.1±12.7	34.7±0.06	0.33±0.01	10.5±0.2	2.50±0.03
6	96.7	0.084			–3.1±0.2	–0.2±0.0	–0.4±0.0	0.14±0.01	1.0±0.0	136.1±14.6	37.2±0.0	0.38±0.01	13.6±0.4	2.54±0.01
7	90	0.128			–1.9±0.1	–0.03±0.00	–0.5±0.0	0.19±0.02	0.66±0.06	119.1±18.6	35.1±0.2	0.32±0.01	13.8±0.3	2.57±0.01
8	101.3	0.11			–3.0±0.3	–0.9±0.0	–0.60±0.03	0.1±0.0	0.6±0.0	120.4±17.0	36.7±0.0	0.29±0.01	11.4±0.4	2.55±0.01
9	110	0.116			–6.5±0.0	0.0±0.0	0.0±0.0	0.1±0.0	0.3±0.0	78.3±9.8	41.4±0.2	0.29±0.01	11.8±0.4	2.54±0.03
10	101.3	0.11			–2.61±0.03	–0.91±0.01	–0.4±0.0	0.1±0.0	0.4±0.0	152.6±16.7	38.26±0.08	0.3±0.0	13.7±0.3	2.55±0.05
11	90	0.08			–2.8±0.2	0.0±0.0	0.0±0.0	0.19±0.06	0.83±0.01	146.1±13.1	48.65±0.01	0.2±0.01	13.4±0.3	2.54±0.02
12	103	0.137			–4.2±0.1	–0.78±0.01	–0.30±0.01	0.13±0.01	0.5±0.0	78.8±14.0	30.6±0.0	0.3±0.0	11.0±0.2	2.47±0.01
13	90	0.128			–1.92±0.2	–0.32±0.04	–0.46±0.01	0.19±0.01	0.8±0.0	113.3±18.6	35.89±0.01	0.32±0.01	11.4±0.4	2.48±0.03
14	101.3	0.11			–2.6±0.1	–1.2±0.0	–0.5±0.0	0.1±0.0	0.57±0.05	135.3±24.4	37.37±0.03	0.29±0.01	7.9±0.2	2.52±0.03
15	103.4	0.087			–4.50±0.09	0.0±0.0	–0.28±0.01	0.1±0.0	0.5±0.0	113.0±6.0	40.3±0.8	0.27±0.01	7.8±0.3	2.48±0.02
16	96	0.15			–2.5±0.1	–0.3±0.0	–0.1±0.0	0.13±0.02	0.7±0.0	127.7±24.6	44.9±0.1	0.30±0.01	16.4±0.4	2.56±0.02
p–value					<0.0001	0.013	0.0008	<0.0001	0.0043	0.003	0.0008	0.005	0.761	0.399
Optimal conditions	90.8 0.117			–2.0±0.2		–0.61±0.08	–0.2±0.0	0.065±0.001	4.4±0.2	127±6	36.57±0.05	0.6±0.0	4.6±0.7	2.54±0.01
Culture medium	90.8 0.117			–0.96±0.04		–0.58±0.08	–0.67±0.04	0.1±0.0	12.7±0.2	167±29	37.6±0.1	0.29±0.02	10.6±0.3	2.71±0.04

Results are expressed as mean value±standard deviation. FDt=fractal dimension texture, ρ_b =bulk density