Table 4.

Factors and levels for the BBD.

Variable No.	Factors	Unit	Lower Level(−1)	Higher Level(+1)
X1	EPC/SSa-SSd	g/g	10	40
X2	EPC/Chol	g/g	4	10
X3	Water bath temperature	°C	40	70
Fixed	pH of PBS	-	7.4
Fixed	Ultrasound time	min	15