凍結乾燥卵白の加熱による栄養価の変化 (その2)

“有効性リジン” 量ならびにin vitroでのプロテアーゼによる分解率の変化

抄録

When freeze dried egg white is autoclaved at 100°C, for 30min. or at 120°C, for 30min., its digestibility by rat remarkably decreases. Changes in DNP-available lysine and in vitro digestibility with several proteases were studied for the autoclaved freeze dried egg white samples. DNP-available lysine in the freeze dried egg white decreased by autoclaving but the decrease of available lysine was not sufficient to explain the severe depression of nutritive value of the freeze dried egg white in the feeding experiment with rats. Maximum digestibilities of the freeze dried egg white by several proteases in vitro was generally observed when the samples were autoclaved at 100°C, for 3 to 5min., and the longer autoclaving sharply depressed the digestibilities. However, the digestibilities of the freeze dried egg white autoclaved at 100°C, for 30min. were not lower than those of the values obtained with unautoclaved sample except for pepsin. Only digestibility by pepsin significantly decreased by autoclaving. It was discussed whether the low digestibility of autoclaved freeze dried egg white in vivo is mainly due to the resistance for pepsin or not.