Table 2.

Identification of prenylflavonoids and hop bitter acids in surplus yeast

Peak No.	Compound	λmaxA			MW	RMD (ppm)C	MS (m/z)B			MS–MS fragment ions (m/z)B
		Found	Standard	Reported			Found	Std	Reported	Found	Standard	Reported/found
1	Isoxanthohumol	288 D	288	238/287a, 288b, 286c	354	3.4	355	355	355abcf	299, 235, 179	355, 299, 235, 179	299 [M + H–C4H8], 235 [M + H–C8H8O] 179 [M + H–C4H8–C8H8O] + f
2	8-prenylnaringenin	292	292	293/335d, 292/334c	340	3.5	341	341	341acg	341, 285, 165	341, 285, 165	285 [M + H–C4H8], 165 [M + H–C4H8–C8H8O]f
3	6-prenylnaringenin	292	292	292/334cd	340	3.5	341	341	341acg	341, 285, 165	341, 285, 165	285 [M + H–C4H8], 165 [M + H–C4H8–C8H8O]a
4	Cohulupone	256/324	–E	255/327e	318	0.9	317	–c	317eh	248, 233, 220, 205, 180	–	317 [M–H], 248 [M–H–C5H9], 205 [M–H–C5H9–C3H7], 180e
5	Xanthohumol	368	368	235/364a, 368bc, 272c	354	3.9	355	355	355abcf	299, 235, 179	355, 299, 235, 179	299 [M + H–C4H8], 235 [M + H–C8H8O], 179 [M + H–C4H8–C8H8O]bf
6	Hulupone	256/328	–		332	1.5	331	–	331eh	262, 247, 219, 205, 194, 166	–	219 [M–H–C5H9–C3H7]e, 262 [M–H–C5H9], 205 [M–H–C5H9–C4H9]
7	Adhulupone	256/324	–	–	332	1.2	331	–	331eh	262, 247, 205, 194, 166	–	219 [M–H–C5H9–C3H7]e, 262 [M–H–C5H9], 205 [M–H–C5H9–C4H9]
8	Unknown	–	–	–	–	–	302	–	–	302, 284	–	302
9	Trans-isocohumulone	228/272	228/272	257/271a	348	4.6	347	347	347af	329, 278, 251, 235, 233, 207, 181	347, 329, 278, 251, 233, 207, 182	347 [M–H], 329 [M–H–H2O], 278 [M–H–C5H9], 251 [M–H–C6H8O], 233 [M–H–C6H8O–H2O], 207 [M–H–C6H8O–C2H3O]af
9–1	Cis-isocohumulone	228/272	–	–	348	4.6	347	–	347af	329, 278, 251, 235, 207,181	–	347 [M–H], 329 [M–H–H2O], 278 [M–H–C5H9], 251 [M–H–C6H8O], 233 [M–H–C6H8O–H2O], 207 [M–H–C6H8O–C2H3O]af
11	Trans-isohumulone	228/280	228/280	257/277a	362	5.5	361	361	361af	343, 292, 265, 247, 235, 221, 196	361, 343, 292, 265, 247, 235, 221, 196	361 [M–H], 343 [M–H–H2O], 265 [M–H–C6H8O] 247 [M–H–C6H8O–H2O]af, 292 [M–H–C5H9], 196 [M–H–C6H8O–C5H9]
11–1	Cis-isohumulone	228/280	–	–	362	5.5	361	–	361af	343, 292, 265, 247, 235, 196	–	361 [M–H], 343 [M–H–H2O], 265 [M–H–C6H8O] 247 [M–H–C6H8O–H2O]af, 292 [M–H–C5H9], 196 [M–H–C6H8O–C5H9]
13	Trans-isoadhumulone	228/276	224/276	257/274a	362	5.5	361	361	361af	343, 292, 265, 247, 235, 196	361, 343, 292, 265, 247, 235, 196	361 [M–H], 343 [M–H–H2O], 265 [M–H–C6H8O], 247 [M–H– C6H8O–H2O]af, 292 [M–H–C5H9], 196 [M–H–C6H8O–C5H9]
13–1	Cis-isoadhumulone	228/276	–	–	362	5.5	361	–	361af	343, 292, 265, 247, 235, 196	–	361 [M–H], 343 [M–H–H2O],265 [M–H–C6H8O], 247 [M–H–C6H8O–H2O]af, 292 [M–H–C5H9], 196 [M–H–C6H8O–C5H9]
15	Cohumulone	236/284/ 320	236/284/ 320	283/320a, 236/282/322c	348	4.6	347	347	347af	347, 329, 278	347, 329, 278	347 [M–H], 329 [M–H–H2O], 278 [M–H–C5H9]afi
16	Humulone	236/284/320	236/284/320	283/320a, 236/282/322c	362	5.5	361	361	361af	361, 292, 249	361, 292, 249	361 [M–H], 292 [M–H–C5H9], 249 [M–H–C5H9–C3H7]af
17	Adhumulone	236/282/320	236/282/320	283/320a, 236/282/322c	362	5.5	361	361	361af	361, 292, 249	361, 292, 249	361 [M–H], 292 [M–H–C5H9], 249 [M–H–C5H9–C3H7]af
18	Prehumulone	228/288	–	–	376	2.7	375, 363	–	375a	357, 306	–	306 [M–H–C5H9]a
19	Postlupulone	288	–	–	386	1.0	385	–	385af	316, 273, 261, 248, 205	–	273 [M–H–C5H9–C3H7], 316 [M–H–C5H9]af, 261, 248, 205f
20	Adprehumulone	228/288	–	–	376	3.5	375	–	375a	357, 306	–	306 [M–H–C5H9]a
21	Colupulone	276/332	276/332	275/332ae, 278/336c	400	3.3	399	399	399aefi	330, 287, 262, 219	399, 330, 287, 262, 219	399 [M–H], 287 [M–H–C5H9–C3H7], 330 [M–H–C5H9]aefi
22	Lupulone	276/332	276/332	274/331ae, 274/332c	414	5.6	413	413	413aef	344, 301, 233	413, 344, 301, 233	413 [M–H], 301 [M–H–C5H9–C3H7], 233 [M–H–C5H9–C3H7–C5H8]aef, 344 [M–H–C5H9]
23	Adlupulone	280/332	276/332	280/332ae, 276/328c	414	5.6	413	413	413aef	344, 301, 233	413, 344, 301, 233	413 [M–H], 301 [M–H–C5H9–C3H7], 233 [M–H–C5H9–C3H7–C5H8]aef, 344 [M–H–C5H9]
24	Prelupulone	288	–	–	428	1.6	427	–	427a	383, 358, 315, 303, 290, 247, 222	–	315 [M–H–C5H9–C3H7]a, 358 [M–H–C5H9]
25	Adprelupulone	288	–	–	428	1.6	427	–	427a	383, 358, 315, 303, 290, 247, 222	–	315 [M–H–C5H9–C3H7]a, 358 [M–H–C5H9]

^AA gradient mobile phase of acetonitrile and phosphoric acid in water (pH 1.6) was used

^BDeterminated by HPLC–ESI–MS–MS in the positive ion mode. A gradient mobile phase of acetonitrile and formic acid in water (pH 1.6) was used

^CRelative mass difference = 10⁶ × (m_true-m_measured)/m_true

^DMaximum absorption wavelength was marked as underline

^E“-”: Data not available

^aBased on a reference by Intelmann et al.¹⁵

^bBased on a reference by Stevens et al. (2003)

^cBased on a reference by Kao and Wu (2013)

^dBased on a reference by Wilhelm and Wessjohann (2006)

^eBased on a reference by Haseleu et al. (2009)

^fBased on a reference by Česlova et al. (2009)

^gBased on a reference by Rong et al. (2012)

^hBased on a reference by García-villalba et al. (2006)

ⁱBased on a reference byVanhoenacker et al. (2004)