Abstract
To investigate the characteristics and food applicability of Ecklonia stolonifera inhabiting off the coast of Oham, Aomori Prefecture, seasonal changes in carbohydrates (laminaran, alginic acid, and fucoidan), amino acids, and polyphenols were determined between March 2008 and February 2009. Algal size reached the maximum (about 60cm) in June, whereas the minimum size (about 30cm) was noted in November. The laminaran content reached the maximum (about 200mg/g dry weight) in August and decreased thereafter. The minimum content (about 12mg/g dry weight) was noted in March, a 16-fold difference. The alginic acid content did not show a marked seasonal variation, and the content accounted for 20-30% of the dry weight. Fucoidan also showed no marked seasonal variation. Further, the following two types of fucoidan were noted: that containing xylose and mannose at a higher amount, and G-fucoidan. The main amino acids were alanine, aspartic acid, and glutamic acid. The alanine content was particularly high, reaching a maximum of 12mg/g dry weight in May-June and a minimum of 3mg/g dry weight in August-November. The polyphenol content reached the maximum (about 50mg/g dry weight) in November and decreased thereafter. Based on these findings, the timing of collection is important for the optimal use and application of the components of E. stolonifera.
