Abstract
Changes in the contents of organic acids in pilei, stipes and bases of stipes of fruit-bodies of Hiratake-mushroom [Pleurotus ostreatus (Fr.) Quél] during post-harvest storage at six storage temperatures (-20, 0, 5, 10, 20 and 30°C) and freeze drying process were investigated. (1) In this mushroom, formic, acetic, lactic, glycolic, oxalic, succinic, fumaric, malic, α-ketoglutaric, pyroglutamic and citric acid were identified, and among them malic, pyroglutamic, citric, succinic and fumaric acid were found to be major in pilei and stipes, and malic, pyroglutamic, succinic and fumaric acid were found to be major in bases of stipes. Organic acids compositions were different in pilei, stipes and bases of stipes. (2) The total organic acid content in pilei during post-harvest storage at 20°C for 15 days was found in the range of 3.7-8.2% in dry materials, 4.5-8.4% in stipes and 6.0-10.4% in bases of stipes, respectively. During post-harvest storage, the contents of each element increased without any exception, but organic acids compositions had no change. The contents of organic acids in fruit-bodies during post-harvest storage at six storage temperatures increased with the elapse of storage days and the rise of storage temperatures, and the storage method by low temperature turned out to be an effective way of storing. (3) The contents of organic acids in fruit-bodies during the freeze drying process had no change, and the freeze drying method turned out to be an effective way of storing.
