Comparison of Extractive Components between Raw and Salted Alaska Pollack Roe (“Tarako”)

Abstract

Alaska pollack roe and its salted product (“Tarako”) were analyzed extensively for nitrogenous and nonnitrogenous extractive components to elucidate their changes during salting. The change in proximate composition was also examined. The results obtained are summarized as follows.
1) The protein content decreased somewhat, but the lipid content hardly changed during the salting. The content of ash increased remarkably due to salting, and the extractive nitrogen increased to some extent.
2) As for the nitrogenous extractive components in the roe, free amino acids, especially Tau, Ala, Glu, and Leu, were predominant. Considerable amounts of creatine, trigonelline, and trimethylamine oxide were also found. The levels of nucleotides and related compounds were rather low.
3) Among the analyzed nonnitrogenous extractive components in the roe, lactic acid and inorganic ions, such as Na⁺, K⁺, Cl^-, and PO₄^3-, were dominant. It is noticeable that a relatively large amount of sugar alcohols was detected.
4) The most striking changes in extractive components during the salting were the large decrease in Tau and the large increase in Na⁺ and Cl^-.
5) Free amino acids and inorganic ions were found to constitute the most part of extractives from “Tarako”, suggesting that they were the principal contributors to its flavor.