Changes in the Carbohydrates Contents in Fruit-Bodies of Hiratake-Mushrooms [Pleurotus ostreatus (Fr.) Quél] during Post-Harvest Storage

Abstract

Changes in the contents of carbohydrates in pilei, stipes and bases of stipes of Hiratake-mushroom [Pleurotus ostreatus (Fr.) Qué∫] during post-harvest storage at six storage temperatures (-20, 0, 5, 10, 20 and 30°C) and freeze drying process were investigated. (1) The shelf life of Hiratake-mushroom was 18-22 days at 0°C, 12-13 days at 5°C, 6-8 days at 10°C 3-4 days at 20°C and 2-3 days at 30°C. (2) In this mushroom, arabitol, mannitol, trehalose, glucose and fructose were identified, and trehalose and mannitol were found to be major among them. During the post-harvest storage, the contents of each element decreased except mannitol. Especially the decrease in trehalose was marked, which shows that trehalose is a major respiratory substrate. The trehalose consumption at 0°C are much less than 5°C and the storage at the below 5°C turned out to be an effective way of storing. (3) The five polysaccharide fraction contents : formic acid-soluble fraction (R-glucan), alkali-soluble, acid-soluble fraction, hot alkali-soluble fraction, alkali-soluble, acid-insoluble fraction (S-glucan) and Chitin had no change during the post-harvest storage, and had a role of composing elements of cell wall. The acetic acid-soluble fraction content of the post-harvest storage decreased, and it was storage carbohydrate. (4) The contents of free sugars, free sugaralcohols and polysaccharides of Hiratake-mushroom during the freeze drying process had no change.