Umami, smaken av protein. [Arkiv] - Kolozzeum Forum - Sveriges största träningsforum

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samsam

2012-03-12, 17:20

Det senast upptäckta femte smak-elementet, umami, är proteinberoende (av glutamin, mer specifikt).
Kanske någon mer än jag som finner det intressant. :smash:

Abstract

The sensing of the nutritional level of the body fluid is pivotal for maintaining homeostasis in animals. However, it is not yet understood how the cells detect nutritional levels. In the present study, we examined the function of umami taste receptor, which has a dimeric protein structure composed of Tas1r1 and Tas1r3, as amino acid sensor in the cells. We found that deprivation of amino acids induced neurite outgrowth in N1E-115 cells. The neurite outgrowth was inhibited by almost all of the amino acids tested. To investigate the involvement of the umami taste receptor, siRNA against each of Tas1r1 or Tas1r3 was administered, resulting in suppression of the inhibitory effects of amino acids on neurite outgrowth. In addition, inosine 5'-monophosphate, which potentiates the response to amino acids in the taste cells, enhanced the inhibitory effect of glutamine on neurite outgrowth. These results suggest that Tas1r1 + 3 functions as an amino acid sensor in N1E-115 cells. Because glutamine increased intracellular cAMP concentration, we investigated the involvement of the Gαs subunit of the heterotrimeric G protein in signal transduction. The treatments to inhibit the Gαs subunit significantly suppressed the increase of intracellular cAMP concentration induced by glutamine and the inhibitory effect of amino acids on neurite outgrowth. In addition, the reagents for increasing intracellular cAMP concentration inhibited neurite outgrowth induced by deprivation of amino acids. We concluded that Tas1r1 + 3 functions as an amino acid sensor and activates the intracellular signaling pathway through the Gαs subunit in N1E-115 cells.
http://www.ncbi.nlm.nih.gov/pubmed/22189795

SeeYay

2012-03-12, 21:35

Umami är väl annars en sedan gammalt klarlagd smak? Orkar dock inte läsa igenom hela ditt "abstract". :)

Men 1985 för att vara specifik.
http://jn.nutrition.org/content/130/4/942.full.pdf

Det är väl en smak som du säger kopplad till protein, glutamat, "natriumglutamat".

Som man hittar i många buljonger och kryddor, tex. "aromat". Kinesiska köket (i väst) innehåller mycket glutamat tror jag .. inte säker dock.

Gober

2012-03-12, 22:43

olle lindblad

2012-03-12, 22:45

Kinesiska köket (i väst) innehåller mycket glutamat tror jag .. inte säker dock.
Det används en hel del rent glutamat som smaksättare även i Kina, inte bara i den västanpassade kinamaten.

Eddie Vedder

2012-03-13, 06:58

Som man hittar i många buljonger och kryddor, tex. "aromat". Kinesiska köket (i väst) innehåller mycket glutamat tror jag .. inte säker dock.

Jo därav "Kinarestaurangsyndromet". Jag håller på med en text om det just nu faktiskt. Finns en del intressanta blindstudier.

clavain

2012-03-13, 08:46

Har det framkommit något nytt om natriumglutamat annat än att en del drabbas av överkänslighets- allergireaktioner?

Eddie Vedder

2012-03-13, 09:12

Har det framkommit något nytt om natriumglutamat annat än att en del drabbas av överkänslighets- allergireaktioner?

En hypotes om samband med astmaproblematik vet jag att det finns. Men det är inte konstaterat.

Allen et al. (1987) conducted oral monosodium glutamate (MSG) challenges with 32 asthmatic volunteers and reported that 14 reacted to MSG. Another study by Moneret-Vautrin (1987) also reported MSG-induced asthma attacks in 2 of 30 asthmatic patients. Four additional studies have been conducted and none has confirmed the results of the above authors. These studies, by Schwartzstein et al. (1987), Germano (1991), Woods et al. (1998) and Woessner et al. (1999), challenged a total of 45 patients who gave a history of asthma attacks in oriental restaurants. None of these patients experienced asthmatic reactions after ingesting MSG (one-sided confidence interval of 0-0.066). Another 109 asthmatic patients, without a history of asthma in oriental restaurants, also did not react to ingestion of MSG (one-sided confidence interval of 0-0.027). With a confidence interval < 0.05 there is a >95% probability that MSG history-negative asthmatic patients are not sensitive to MSG. For the MSG history-positive asthmatics, 45 patients, in well-performed studies, underwent negative challenges to MSG, contrasting with two studies reporting positive challenges. Allen et al. (1987) and Moneret-Vautrin (1987), who reported positive MSG challenge results, performed studies with the following characteristics: 1) single blinded, conducted after discontinuing essential antiasthma medications; 2) used effort-dependent peak expiratory flow rate measurement of lung function; 3) added AM bronchodilators in some patients; 4) ignored wandering baselines on the placebo challenge days; and 5) conducted some challenges in the AM and some at night. In summary, the existence of MSG-induced asthma, even in history-positive patients, has not been established conclusively.

Monosodium glutamate and asthma. J Nutr. 2000 Apr;130(4S Suppl):1067S-73S.

clavain

2012-03-13, 09:56

Va bra, då behöver man inte lägga parmesanosten på hyllan alltså :)