Shellfish, organic acids

Man is capable of living on an all plant or all animal diet, although omnivory is most common in human societies. Animal foods may be divided into two major categories as far as we are concerned vertebrate and invertebrate. Although invertebrate animals may play a significant part in the diet of many human societies, there has been little work on invertebrate taste chemistry (except for shellfish) from a human consumption standpoint. Shellfish taste is primarily due to inorganic ions, organic acids, amino acids and nucleotides (44). 

Firstly, Takagi and Simidu (25) examined the correlation between the organic acid content of 9 species of shellfish and their taste, and found that the more palatable species were not necessarily richer in succinic acid, as exemplified by the hard clam, Meretrix lusoria. These results led them to conclude that succinic acid does not dominate the delicious taste of shellfish. Secondly, Konosu et al. (26) reported that the succinic acid content of the short-necked clam, Tapes japonica, when determined immediately after collection, was very low (20-40 mg/100 g of edible part) as compared with Aoki s value (330 mg), and that the flavor of a fresh sample was as good as that of a commercially available sample that had accumulated a large amount of succinic acid. 

Conditions causing hyperuricemia include the excessive synthesis of uric acid, the excessive synthesis of purine— precursor to uric acid—a high dietary intake of purine (shellfish, organ meat, anchovies, and wild game), diminished renal excretion of uric acid, and tissue destruction following injury or therapeutic irradiation. 

Determination of Mg in the hard tissues (shell and pearl) of shellfish by the ICP-AES method involves dissolution of the sample by hot concentrated nitric acid, hydrochloric acid and perchloric acid. However, the large excess of Ca in the matrix strongly interferes with the end analysis and causes damage to the torch. After adjusting the pH to 4.5, the Mg ions were extracted by a 0.01 M solution of 3-methyl-l-phenyl-4-trifluoroacetylpyrazol-5-one (16) in dibutyl ether and the ICP-AES analysis was carried out by direct injection of the organic solution. ... 

Domoic acid is a naturally occurring excitatory amino acid that was identified as the toxin responsible for an outbreak of amnesic shellfish poisoning that occurred in Canada in 1987 following consumption of contaminated blue mussels (Mytilus edulis) [1] as well as numerous other outbreaks worldwide. The parent compound is a tricarboxylic amino acid produced by certain marine organisms, the best characterized of which are the red alga Chondria armata and the planktonic diatom Nitzschia pungens, although other species are also known to produce domoic acid (for review, see Reference 2). 

Dietary copper intake is approximately 1-2 mg/day. Quoted copper contents of foods are unreliable. While some foods, such as meats and shellfish, have consistently high concentrations, others such as dairy produce are consistently low in copper. However, the copper content of cereals and fruits varies greatly with soil copper content and the method of food preparation. Estimates of copper intake should include water copper content, and the permitted upper copper concentration for drinking water is 2mg L. Approximately 10% of dietary copper is absorbed in the upper intestine, transported in the blood loosely bound to albnmin, certain amino acids and peptides. Finally, most of the ingested copper is taken np by the liver. Copper homeostasis is critically dependent on the liver becanse this organ provides the only physiologically relevant mechanism for excretion of this metal. 

---