Deceleration of beer ageing by amino acid and Strecker aldehyde monitoring over the brewing process

2006 ◽  
pp. 265-268 ◽  
Author(s):  
Andreas Stephan ◽  
Helge Fritsch ◽  
Georg Stettner
Keyword(s):  
Amino Acid ◽  
Brewing Process ◽  
Strecker Aldehyde

scholarly journals Acrylamide Formation in Food: A Mechanistic Perspective

2005 ◽  
Vol 88 (1) ◽  
pp. 262-267 ◽  
Author(s):  
Varoujan A Yaylayan ◽  
Richard H Stadler
Keyword(s):  
Amino Acid ◽  
Carbonyl Compounds ◽  
Azomethine Ylide ◽  
Significant Progress ◽  
Acid Moiety ◽  
Sugar Moiety ◽  
Acrylamide Formation ◽  
Amino Acid Moiety ◽  
Strecker Aldehyde

Abstract Earliest reports on the origin of acrylamide in food have confirmed asparagine as the main amino acid responsible for its formation. Available evidence suggests that sugars and other carbonyl compounds play a specific role in the decarboxylation process of asparagine, a necessary step in the generation of acrylamide. It has been proposed that Schiff base intermediate formed between asparagine and the sugar provides a low energy alternative to the decarboxylation from the intact Amadori product through generation and decomposition of oxazolidin-5-one intermediate, leading to the formation of a relatively stable azomethine ylide. Literature data indicate the propensity of such protonated ylides to undergo irreversible 1,2-prototropic shift and produce, in this case, decarboxylated Schiff bases which can easily rearrange into E Decarboxylated Amadori products can either undergo the well known β-elimination process initiated by the sugar moiety to produce 3-aminopropanamide and 1-deoxyglucosone or undergo 1,2-elimination initiated by the amino acid moiety to directly generate acrylamide. On the other hand, the Schiff intermediate can either hydrolyze and release 3-aminopropanamide or similarly undergo amino acid initiated 1,2-elimination to directly form acrylamide. Other thermolytic pathways to acrylamide—considered marginal at this stage—via the Strecker aldehyde, acrolein, and acrylic acid, are also addressed. Despite significant progress in the understanding of the mechanistic aspects of acrylamide formation, concrete evidence for the role of the different proposed intermediates in foods is still lacking.

Composition Analysis of Litchi Juice and Litchi Wine

2008 ◽  
Vol 4 (4) ◽  
Author(s):  
Xin An Zeng ◽  
Xiao Dong Chen ◽  
Frank G.F. Qin ◽  
Lu Zhang
Keyword(s):  
Amino Acid ◽  
Amino Acid Content ◽  
Composition Analysis ◽  
Volatile Acid ◽  
Higher Alcohols ◽  
Interesting Phenomenon ◽  
Ethyl Octanoate ◽  
Long Time ◽  
Brewing Process ◽  
Grape Wine

In this study the total components of the litchi juice and litchi wine in the brewing process were analyzed with both a low temperature (13-16 °C) and a long time (8-10 days) for fermentation. 161.4 g/l total sugar, 2.2 g/l total acids and a high content of Vitamin C (354.12 mg/l) and K (1251.8 mg/l) were found in litchi juice and highly dried extract (25.6 g/l), low volatile acid (0.36 g/l) and low higher alcohols (0.048 g/l) were identified in the young litchi wine. The total free amino acid content in litchi wine (784.1 mg/l) was similar to that of grape wine (700-1300 mg/l). However the content of each single kind of amino acid in litchi wine was all at an average level (less than 50 mg/l). In total, 33 kinds of aroma compounds were identified in litchi wine by liquid-liquid extraction and GC/MS analysis, including 16 esters, 5 alcohols, 4 acids, 2 ketones, 1 phenol and 4 other chemicals. Ethyl octanoate (34.82%), ethyl decylate (15.41%), acetic ester (11.36%), ethyl hexoate (7.14%), acetic isopentyl ester (4.72%) and citronel ethyl acetate (1.94%) were the main constituents, which covered 75.39% and 93.03% of the total compounds and ester compounds, respectively. Content of higher alcohols was only 7.85%. A very interesting phenomenon was found in that no matter how much sulfurous acid was added and how much total SO2 content was observed in litchi juice or wine, the measured free state SO2 content was always below 10 ppm, which was quite different from that of grape wine.

Influence of amino acid content in seed mash on peptide uptake by yeast cells in main mash in sake brewing process

1999 ◽  
Vol 88 (6) ◽  
pp. 679-681 ◽  
Author(s):  
Yoshitsugu Iemura ◽  
Tasuku Yamada ◽  
Toshinari Takahashi ◽  
Keiji Furukawa ◽  
Shodo Hara
Keyword(s):  
Amino Acid ◽  
Acid Content ◽  
Amino Acid Content ◽  
Yeast Cells ◽  
Brewing Process ◽  
Peptide Uptake

scholarly journals The Roles of Amino Acids and Sugars in the Production of Volatile Materials in Microwave Heated Tobacco Dust Suspensions

1997 ◽  
Vol 17 (3) ◽  
pp. 75-95 ◽  
Author(s):  
WM Coleman ◽  
TA Perfetti
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Volatile Compounds ◽  
Reaction Pathways ◽  
Low Molecular Weight ◽  
Heat Treated ◽  
Strecker Aldehyde ◽  
Major Reaction ◽  
First Time ◽  
Volatile Materials

AbstractFor the first time, the role(s) of selected amino acids and sugars in the production of volatile compounds in microwave prepared heat treated tobacco suspensions (HTTS) has been unambiguously defined. The role can be expressed in two major reaction pathways:1) Strecker degradation of amino acids and 2) amino acid/sugar Maillard-type reactions. The mechanism of the Strecker degradation was confirmed by the addition of selected13C- labelled amino acids to the reaction suspension. The addition of the amino acid resulted in a dramatic increase in the concentration of the specific, appropriate, low molecular weight Strecker aldehyde in the headspace above the reaction suspension. The mechanism of the amino acid/sugar Maillard-type reactions was substantiated by: 1) adding a wide array of amino acids to the suspension;2) by employing15N-labelled amino acids; and3) employing13C-labelled sugars. Addition of amino acids to the suspension followed by heat treatment resulted in significant increases (2 ×) in the concentration of volatile pyrazines relative to the control. Most amino acids significantly increased the concentration of headspace pyrazines. Reactivity differences, as a function of sugars, was also demonstrated. Analysis of the headspace above suspensions incorporating15N-labelled amino acids and13C-labelled sugars revealed the15N and13C atoms to have been distributed throughout a wide array of volatile pyrazines. The distribution of the15N atoms within the pyrazines was unique to the amino acid and the distribution of the 13C atoms was linked to the type of sugar employed. These results have documented for the first time in a heat treated tobacco formulation the mechanisms of amino acids and sugars in the production of volatile compounds which have documented intense sensory characteristics.

The staining pattern of the tropomyosin sequence is displayed in a new paracrystal

1986 ◽  
Vol 44 ◽  
pp. 150-151
Author(s):  
M.K. Lamvik ◽  
L.L. Klatt
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Staining Pattern ◽  
Banding Patterns ◽  
Mass Thickness ◽  
New Form

Tropomyosin paracrystals have been used extensively as test specimens and magnification standards due to their clear periodic banding patterns. The paracrystal type discovered by Ohtsuki1 has been of particular interest as a test of unstained specimens because of alternating bands that differ by 50% in mass thickness. While producing specimens of this type, we came across a new paracrystal form. Since this new form displays aligned tropomyosin molecules without the overlaps that are characteristic of the Ohtsuki-type paracrystal, it presents a staining pattern that corresponds to the amino acid sequence of the molecule.

Electron probe x-ray microanalysis and electron microscopy of amino acid absorption and transport by the small intestine: inhibition by chemical poisons and correlation to the elemental composition of the epithelial cells

1986 ◽  
Vol 44 ◽  
pp. 134-135
Author(s):  
A. J. Tousimis
Keyword(s):  
Small Intestine ◽  
Amino Acid ◽  
Epithelial Cells ◽  
Elemental Composition ◽  
Isotope Labeling ◽  
Structural Components ◽  
X Ray ◽  
Human Small Intestine ◽  
Transport Studies

The elemental composition of amino acids is similar to that of the major structural components of the epithelial cells of the small intestine and other tissues. Therefore, their subcellular localization and concentration measurements are not possible by x-ray microanalysis. Radioactive isotope labeling: I131-tyrosine, Se75-methionine and S35-methionine have been successfully employed in numerous absorption and transport studies. The latter two have been utilized both in vitro and vivo, with similar results in the hamster and human small intestine. Non-radioactive Selenomethionine, since its absorption/transport behavior is assumed to be the same as that of Se75- methionine and S75-methionine could serve as a compound tracer for this amino acid.

Immunoelectron microscope detection of C-type natriuretic peptide in normal human atrial tissue

1993 ◽  
Vol 51 ◽  
pp. 388-389
Author(s):  
Chi-Ming Wei ◽  
Margaret Hukee ◽  
Christopher G.A. McGregor ◽  
John C. Burnett
Keyword(s):  
Amino Acid ◽  
Natriuretic Peptide ◽  
Vascular Tone ◽  
Cardiac Tissue ◽  
Ring Structure ◽  
Terminal Amino Acid ◽  
Amino Acid Peptide ◽  
Normal Human ◽  
Terminal Amino ◽  
The Brain

C-type natriuretic peptide (CNP) is a newly identified peptide that is structurally related to atrial (ANP) and brain natriuretic peptide (BNP). CNP exists as a 22-amino acid peptide and like ANP and BNP has a 17-amino acid ring formed by a disulfide bond. Unlike these two previously identified cardiac peptides, CNP lacks the COOH-terminal amino acid extension from the ring structure. ANP, BNP and CNP decrease cardiac preload, but unlike ANP and BNP, CNP is not natriuretic. While ANP and BNP have been localized to the heart, recent investigations have failed to detect CNP mRNA in the myocardium although small concentrations of CNP are detectable in the porcine myocardium. While originally localized to the brain, recent investigations have localized CNP to endothelial cells consistent with a paracrine role for CNP in the control of vascular tone. While CNP has been detected in cardiac tissue by radioimmunoassay, no studies have demonstrated CNP localization in normal human heart by immunoelectron microscopy.

Amino Acid Metabolism

1979 ◽  
Vol 7 (1) ◽  
pp. 261-262
Author(s):  
E. V. ROWSELL
Keyword(s):  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism
Sign in / Sign up

Export Citation Format

Share Document