Monitoring the formation of cholesterol oxidation products in model systems using response surface methodology

Table 2 The contents of COPs under different pH condition after storage at 4 °C for 10 days

Treatment COPs (mg)	Control	pH 5.8	pH 6.7	pH 7.6
7β-OH	Nd	nd	nd	nd
20α-OH^*	0.51 ± 0.07^a	0.43 ± 0.02^ab	0.37 ± 0.01^b	0.38 ± 0.06^b
25-OH^***	0.13 ± 0.01^a	0.07 ± 0.01^b	0.06 ± 0.00^b	0.06 ± 0.02^b
Triol^***	0.02 ± 0.00^a	n.d.^b	n.d.^b	n.d.^b
α-epoxide	0.04 ± 0.01	0.03 ± 0.01	0.03 ± 0.01	0.03 ± 0.00
7-keto	Nd	nd	nd	nd
Total amount of COPs/cholesterol (%) ^**	1.40 ± 0.17^a	1.06 ± 0.08^b	0.91 ± 0.05^b	0.95 ± 0.16^b

7β-OH 7β-hydroxycholesterol, 20α-OH 7α-hydroxy-cholesterol, 25-OH 25-hydroxycholesterol, Triol Cholestanetriol, α-epoxide 5,6α-epoxycholesterol, 7-keto 7-ketocholesterol
^*: P < 0.05, ^**: P < 0.01, ^***: P < 0.001
^{a, b} Means ± SE with different superscript in the same row differ significantly

ISSN: 1476-511X