Document Detail

Determination of sulfur amino acids in foods as related to bioavailability.
MedLine Citation:
PMID:  18727553     Owner:  NLM     Status:  MEDLINE    
During the processing of feedstuffs and foods, methionine can be oxidized to methionine sulfoxide and methionine sulfone, and cysteine can be oxidized to cysteic acid. Methionine sulfone and cysteic acid are nutritionally unavailable, but methionine sulfoxide can be utilized, at least to some degree. The degree of utilization depends on the levels of methionine, cysteine, and methionine sulfoxide in the diet, but there is no consensus in the literature on the quantitative impact of these dietary constituents on methionine sulfoxide utilization. Methionine and cysteine are most often determined after quantitative oxidation to methionine sulfone and cysteic acid, respectively, using performic acid oxidation prior to hydrolysis. However, this method may overestimate the methionine content of processed foods, as it will include any methionine sulfoxide and methionine sulfone present. A selection of analytical methods has been developed to allow the separate determination of the 3 oxidized forms of methionine, the merits of which are discussed in this review. An additional consideration for determining methionine and cysteine bioavailability is that not all dietary methionine and cysteine is digested and absorbed from the small intestine. Selected methods designed to determine the extent of digestion and absorption are discussed. Finally, a concept for a new assay for determining methionine bioavailability, which includes determining the digestibility of methionine and methionine sulfoxide as well as the utilization of methionine sulfoxide, is presented.
Shane M Rutherfurd; Paul J Moughan
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Journal of AOAC International     Volume:  91     ISSN:  1060-3271     ISO Abbreviation:  J AOAC Int     Publication Date:    2008 Jul-Aug
Date Detail:
Created Date:  2008-08-27     Completed Date:  2008-09-25     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9215446     Medline TA:  J AOAC Int     Country:  United States    
Other Details:
Languages:  eng     Pagination:  907-13     Citation Subset:  IM    
Massey University, Riddet Institute, Private Bag 11 222, Palmerston North, New Zealand.
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MeSH Terms
Amino Acids, Sulfur / analysis*,  metabolism*
Cysteine / analysis,  metabolism
Food Analysis / methods*
Methionine / analogs & derivatives,  analysis,  metabolism
Nutritive Value*
Reg. No./Substance:
0/Amino Acids, Sulfur; 454-41-1/methionine sulfoxide; 52-90-4/Cysteine; 63-68-3/Methionine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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