Studies on Gloss of Hoshi-Nori, the Dried Laver, Porphyra yezoensis

摘要

On the quality of Hoshi-nori, the dried laver, Porphyra yezoensis, gloss is an important factor as well as color, luster and flavor. In this work, gloss of the Porphyra thallus dried on the vellum paper and Hoshi-nori was measured by a 45° reflective gloss meter, and the relation between gloss and occurrence of dead cells was also examined. When the Porphyra thallus was dried on the vellum paper, the wet thallus had no gloss at the beginning of the drying, but the half-dried thallus showed the highest gloss, and then fully dried one also showed good gloss. The dried Porphyra thallus with high gloss was found to be consist of the good smooth surface under the microscop, while the lusterless thallus had the rough surface which be caused by the coagulation of dead cells. Accordingly, the occurrence of coagulated cells in the drying process of Hoshi-nori was found to be mainly injured gloss of the dried thallus. Among the various grades of Hoshi-nori, higher grades showed generally good gloss, but a close relationship was not recognized between gloss and grades.