Flavor Constituents in Savory Seafood: Dried Kelp ( Kombu), Scallop, and Dried Bonito ( Katsuobushi)

Abstract

Omission tests of the synthetic water extract of dried kelp (Kombu-dashi) revealed that the water solution prepared by mannitol, monosodium glutamate (MSG), potassium chloride (KCl), and sodium chloride (NaCl) represented the whole taste characters of the synthetic extract. Succeeding study suggested that the characteristic Kombu-dashi like kokumi flavors (continuity, mouthfulness, and thickness) were generated by flavor interaction among mannitol, MSG, and KCl. Some studies of taste interactions among NaCl, KCl, sweet amino acids, and 5¢-inosinate (IMP) showed that NaCl strengthened umami and sweetness of some amino acids and also suggested that IMP enhanced umami of Gly, L-Ser, and L-Ala synergistically. The sulfur-containing compounds in garlic and onion, such as alliin, S-propenyl-L-cysteinesulfoxide and reduced glutathione (GSH), had no tastes by themselves but they gave rise to kokumi flavors in umami solution or soups. Scallop and beef contained a high amount of GSH and the peptide strengthened kokumi flavors of synthetic extracts of these foods. The examination of volatile compounds in dried bonito by using GC-MS and GC-sniffing methods revealed that acetol and 2,3- pentandione reacted with amino acids or protein in boiled bonito meat, generated pyrazines. Straight-chain aldehydes might be involved in the deterioration of crushed dried bonito. Hydrogen sulfide, one of the key flavor components, decreased during preservation of crushed dried bonito catalytically by the complex of Fe3+ and histidine. This study, including new findings, would lead to improve the quality of processed foods and contribute to future studies of taste phisiology and flavor chemistry