Relationships between quality parameters and content of glycerol galactoside and porphyra-334 in dried laver nori Porphyra yezoensis

Abstract

Glycerol galactoside (GG; floridoside + isofloridoside) and porphyra-334 (P-334) are contained in nori (Susabinori Porphyra yezoensis and Asakusanori Porphyra tenera). Glycerol galactoside has been found to have bifidogenic growth stimulator activity and P-334 is known to have ultraviolet-absorbing activity in the UVA region of sunlight. These substances have, respectively, potential for application to pre-biotic foods and in cosmetics as a sunscreen. In the present study, to investigate the relationships between GG and P-334 contents and the quality of nori, we measured the GG and P-334 contents with other components (total protein, chlorophyll-a, b-carotene and phycobillins) that are related to the quality of nori samples produced from different production areas and with different qualities. We found that the GG content was closely negatively correlated with the contents of other components, whereas P-334 was positively correlated with the other components. From these results, it is suggested that low-quality nori is a potential source of GG, and as a source for P-334, scraps of nori produced during nori processing should be suitable.

Effects of low and medium levels of red alga Nori (Porphyra yezoensisUeda) in the diets on growth, feed utilization and metabolism in intensively fed Nile tilapia,Oreochromis niloticus(L.)

“…However, the majority of the analysed samples range between 300 and 400 g kg −1 protein (Ishihara et al . ). An even higher protein content of 500 g kg −1 crude protein (CP) on a dry matter (DM) basis was reported by Noda ().…”

Prebiotic effect of glycerol galactoside isolated from color-faded nori in rats

“…The occurrence of color-faded nori is a heavy burden on the nori culture and processing industry. In our previous study, color-faded nori was found to contain over 10% GG by weight on a dry weight basis [9]. Although further human experiments are necessary to evaluate the prebiotic activity of GG in humans, we anticipate that the present data will contribute to the development of a new way of utilizing color-faded nori as a health-promoting foodstuff.…”

“…We recently found that color-faded nori contains large amounts of GG, more than 10% w/w in dry wt. [9]. In an in vitro study, we found that GG was a potential candidate for a prebiotic compound [10].…”

“…1) is known to be a component of nori [8]. Recently, we have found that low-quality nori (color-faded nori), which has a low protein content, contains a large quantity of GG [9]. From further studies, we have also found that GG exhibits prebiotic characteristics in vitro.…”

“…The resulting solution was freeze-dried. The residual colorless crystal was identified as glycerol galactoside (a mixture of floridoside, L-isofloridoside and D-isofloridoside, in proportions of 11, 62 and 27%, respectively) by nuclear magnetic resonance [10], and purity was assessed by HPLC ([95%) [9].…”