Four specimens of Rishiri-kombu, Laminaria ochotensis, differing in growth were collected from Oniwaki in the Rishiri Island, Hokkaido. They were arranged by their degrees of growth as follows: 1) One-year-old plants, 2) one- or two-year-old plants (the plants were not discriminated as to whether they were one- or two-year-olds), 3) two-year-old plants, second grade, and 4) two-year-old plants, first grade.
The base and the central parts of the blade were collected separately from each specimen: One half obtained from one side of the blade was used for chemical analyses (amino acid pool, total extractive nitrogen, extractive amino nitrogen, and thickness), and the other half from the other side for the sensory test,
The results with the exception of the, sensory test are shown in Table 1. From the table, the following results were drawn: The amounts of glutamic and aspartic acids in one-year-old plants were higher than the two-year-old plants. The ratio of glutamic acid to aspartic acid was about 1:1 in one-year-old plant and one- or two-year-old plant, while it was about 2:1 in the two-year old plants (first and second grade). Proline contents decreased according to the growth of the plant. Cystine was found in one-year-old plants, while it was absent in the two-year-old ones. The presence of tryptophan was quite opposed to the cystine. Two peaks of unknown ninhydrine reactive substances were found on the chromatogram; the one (U2) was between valine and methionine, and the other (U3) between leucine and tyrosine (Fig. 1). The thickness increased with growth.