Yaguchi Shigenori

‘Hikoshima-haruna’ (Brassica rapa var. narinosa) is a local traditional vegetable in Shimonoseki (Yamaguchi, Japan). The mature leaves are edible and much of the harvest is processed into pickles for consumption in the Shimonoseki area. To expand the consumption of ‘Hikoshima-haruna’, we verified the use of ‘Hikoshima-haruna’ powder in fish paste products as a part of the utilization research. We prepared heated gels (Kamaboko) mixed with 0-10% ‘Hikoshima-haruna’ powder and measured their breaking strength. The Kamaboko containing 1.0-4.0% powder exhibited a bright green color, preserving the characteristics of ‘Hikoshima-haruna’ as a plant with bright green leaves. Although the breaking strength of the two-step heating (30℃ for 30 min followed by 85℃ for 20 min) gels tended to decrease with increasing powder concentration, the 1.0% powder concentration exhibited a slightly greater breaking strength than the other concentrations. Therefore, when applying ‘Hikoshima-haruna’ powder to fish paste products, its use as Kamaboko at a powder concentration of 1.0% was considered appropriate.

Mentaiko, a seasoned cod roe, is one of the main food products in produced from the ovary of Walleye Pollock in Japan. Walleye Pollock roe is predominantly used in the preparation of Mentaiko, with limited other applications. This study showed the processing procedure for an edible film from the Walleye Pollock roe. A few conditions were identified wherein the film could be prepared during processing of the roe. In the first step, water-soluble proteins were extracted from roe samples employing a pH 12.0 phosphate buffer. The pH of this mixture was subsequently adjusted to pH 6.0, mixed with 1.0% transglutaminase and heated at 70℃ for 20 min. Finally, the product was dried in silicon cases suitable for the preparation of edible films. Evaluation of the dried film indicated some improvement in terms of flexibility compared to similarly produced films. During the evaluation of various film-forming solutions, an increase in the amount of surface hydrophobic groups and/or surface sulfhydryl groups was associated with an increased film production. We showed that the edible film can be produced from the proteins of Walleye Pollock roe.