乾のりの保蔵における水分とアスコルビン酸との関係〔乾のりの品質保持に関する研究-4-〕

概要

論文の詳細を見る
The infiuence of water activity (aw) on the destruction of reduced and oxidzed ascorbic acids (AH2, DH respectively) in a dried laver “Nori”, Porphya yezoensis, was examined in aw (0-0.8) during storage for 10 weeks at 13-15°C in both air and an oxygen-free atmospherr. Although BET's monolayer moisture value (ML) of Nori was corresponding to aw 0.11, the most suitable condition to keep AH2 was in aw 0.05 system. According to our estimation method, an optimum water content was at aw 0.02, which was also below BET's ML. This could be due to the difference of adsorption ability of a hydrophilic surface from that of a hydrophobic one. Both the surfaces could not be covered with the monolayer of water molecules at the same time because of the differences of surface-energy. This suggests that BET's ML is an apparent value which exceeds as a ML of the hydropgilic surface. DH increased at lower aw below 0.3 and decreased at higher aw. The ratio of DH to AH2 increased with the increase in aw and storage time. DH is considered to be stabler than AH2 with regrd to the influence of water. When oxygen was removed from the preservation systems, mol fraction <0.001, the destruction of AH2 and DH was reduced significantly but incompletely.
日本水産學會の論文