Changes in the Contents of Carbohydrates and Organic Acids in Fruit-Bodies of Shiitake-Mushroom [Lentinus edodes (Berk.) Sirg.] during Development and Post-Harvest Storage

Abstract

Changes in the contents of low molecular weight carbohydrates, polysaccharides and organic acids in pilei and stipes of fruit-bodies of Shiitake mushroom [Lentinus edodes (Berk.) Sing.] during development and post-harvest storage at 20°C were investigated. (1) The total free sugar content in pilei during development was found in the range of 2.3-7.0% in dry materials, and 2.9-4.5% in stipes, respectively, while the total sugaralcohol content 8.8-12.8% in pilei, and 12-5-23.3% in stipes, respectively. In this mushroom, trehalose, mannitol, arabitol, glucose and fructose were identified, and trehalose, arabitol and mannitol were found to be major among them. The contents of each element varied individually during the development, and there was remarkable difference between pilei and stipes. Especially the accumulation of trehalose was found in pilei, and that of arabitol in stipes during the last development. During post-havest storage, the contents of each element decreased without any exception. Especially the decrease in arabitol was marked. (2) The polysaccharide content in pilei during development was in the range of 38.8-40.2%, and 50.4-51.5% in stipes, respectively. The polysaccharide contents in stipes were 1.25-1.32 times as much as those in pilei. The five polysacchride fraction contents: formic acid-soluble fraction (R-glucan), alkali-soluble, acid-soluble fraction, hot alkli-soluble fraction, alkali-soluble, acid-insoluble fraction (S-glucan) and chitin had no change during development and post-harvest storage, but the content of acetic acid-solule fraction decreased during storage. (3) The contents of organic acids in pilei during development was found in the range of 1.8-3.0%, and in stipes 1.3-1.9%. The changing pattern of organic acid contents in pilei was different from that in stipes. The content of organic acid during post-harvest storage increased for the first three days, but it decreased from then on. In this mushrom, ten kinds of organic acids were identified. Malic, pyroglutamic, fumaric and citric acids were found to be major among them. The contents of each element varied individually during development, and the changing patterns of pilei and stipes were different. The contents of fumaric, pyroglutamic and citric acids during post-harvest storage increased for the first three days, but from then on they decreased. The contents of the rest decreased.