The effect of pH on the formation of aroma compounds produced by heating a model system containing l-ascorbic acid with l-threonine/l-serine

2010 ◽  
Vol 119 (1) ◽  
pp. 214-219 ◽  
Author(s):  
Ai-Nong Yu ◽  
Ai-Dong Zhang
2013 ◽  
Vol 781-784 ◽  
pp. 1811-1817 ◽  
Author(s):  
Xing Zhi Yang ◽  
Ai Nong Yu

Aroma compounds from the Maillard reaction of the l-ascorbic acid and l-methionine system were investigated. The mixture was heated while stirring at 142±2°C for 2 h in an oil bath at five different pH values (5, 6, 7, 8, or 9). Analysis of the reaction mixture was performed by headspace-SPME–GC–MS technique, and further use of LRI. 27 Components, comprising 11 pyrazines, 5 thiophenes, 6 aliphatic S compounds, 4 furans (non-S-containing) and 1 phenol, were identified. The studies showed that furans (non-S-containing), 4-hydroxybenzo[b]thiophene and 2,3,5-trithiahexane were formed mainly at acidic pH. In contrast, higher pH values could promote the production of pyrazines, acylthiophenes, 2-(isopropylthio)thiophene, methyl butanedithioate and 2,4-di-tert-butylphenol. The effect of pH on the formation of other compounds did not follow a consistent pattern.


Chemosphere ◽  
2019 ◽  
Vol 218 ◽  
pp. 670-679 ◽  
Author(s):  
Zidan Yuan ◽  
Guoqing Zhang ◽  
Jinru Lin ◽  
Xiangfeng Zeng ◽  
Xu Ma ◽  
...  

1965 ◽  
Vol 97 (1) ◽  
pp. 7-16 ◽  
Author(s):  
E Boyland ◽  
P Sims

1. Benz[a]anthracene was hydroxylated by rat-liver homogenates on the 3,4-,5,6- or 8,9-bond to yield phenols and dihydrodihydroxy compounds. Metabolic action at the 7- and 12-positions was also detected. 5,6-Epoxy-5,6-dihydrobenzanthracene was converted into a phenol that is probably 5-hydroxybenzanthracene and 5,6-dihydro-5,6-dihydroxybenzanthracene. Both substrates yielded a product that is probably S-(5,6-dihydro-6-hydroxy-5-benzanthracenyl)glutathione. 2. Dibenz[a,h]anthracene was hydroxylated by rat-liver homogenates to yield products that are probably 3- and 4-hydroxydibenzanthracene, 1,2-dihydro-1,2-dihydroxydibenzanthracene, 3,4-dihydro-3,4-dihydroxydibenzanthracene and 5,6-dihydro-5,6-dihydroxydibenzanthracene. There was no evidence for metabolic action at the 7- and 14-positions. 5,6-Epoxy-5,6-dihydrodibenzanthracene was converted into a phenol that is probably 5-hydroxydibenzanthracene and 5,6-dihydro-5,6-dihydroxydibenzanthracene. Both substrates yielded a glutathione conjugate that is probably S-(5,6-dihydro-6-hydroxy-5-dibenzanthracenyl)glutathione. 3. The synthesis of 5,6-epoxy-5,6-dihydrodibenzanthracene is described and the reactions of this epoxide and 5,6-epoxy-5,6-dihydrobenzanthracene with water and thiols have been investigated. 4. The oxidation of dibenzanthracene in the ascorbic acid-Fe(2+) ion-oxygen model system is described.


1981 ◽  
Vol 46 (4) ◽  
pp. 1218-1236 ◽  
Author(s):  
M. S. POEI-LANGSTON ◽  
R. E. WROLSTAD

2013 ◽  
Vol 19 (10) ◽  
pp. 3119-3121
Author(s):  
Kanjana Narkprasom ◽  
Pi-Jen Tsai
Keyword(s):  

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