Changes of proximate composition and extractive components in narezushi, a fermented mackerel product, during processing

ABSTRACT:   During the processing of mackerel narezushi , the fish body was strongly dehydrated by permeation of salt, the low pH of fish meat, and pressure applied to the fish and rice mixture. In the proximate components, moisture, protein and lipid flowed out from the fish meat into the rice mixture, and sugar permeated from the rice mixture into the fish meat. That the total amount of outflow was larger than that of permeation into the fish is thought to contribute to the decrease in fish body weight during processing. In the extractive components, although the nucleotides completely decomposed, free amino acids and peptides increased remarkably because of the decomposition of proteins in fish meat during processing. Especially, six kinds of free amino acid, Glu, Asp, Gly, Ala, Leu, and Ile, which are thought to be the taste components in marine resources, increased. Organic acid increased remarkably because of the fermentation of rice and permeation into the fish meat. The marked increase of the extractive components is thought to contribute to the umami taste and the sour taste of narezushi .     

Anthocyanins from purple sweet potato Ipomoea batatas cultivar Ayamurasaki suppress the development of atherosclerotic lesions and both enhancements of oxidative stress and soluble vascular cell adhesion molecule-1 in apolipoprotein E-deficient mice

We evaluated the protective potential of anthocyanins from purple sweet potato Ipomoea batatas cultivar Ayamurasaki (APSP) against low-density lipoprotein (LDL) oxidation in vitro and atherosclerotic lesion development in apolipoprotein E-deficient mice given a cholesterol- and fat-enriched diet with or without 1% APSP for 4 weeks. APSP protected LDL against oxidation more potently than other anthocyanins and l-ascorbic acid in vitro. In mice, APSP significantly lowered the atherosclerotic plaque area to about half of the control, the liver level of thiobarbituric acid-reactive substances as an oxidative stress marker, and the plasma level of soluble vascular cell adhesion molecule-1 (sVCAM-1). However, APSP showed no effects on body weight and cholesterol and lipid levels in the plasma. The results suggest that APSP can suppress the development of atherosclerotic lesions and both enhancements of oxidative stress and sVCAM-1 independently of the changes in cholesterol and lipid levels in mice.