Changes in the Organic Acids Contents in Fruit-Bodies of Shiitake-Mushrooms [Lentinus edodes (Berk.) Sing.] during Post-Harvest Storage

Abstract

Changes in the contents of organic acids in pilei and stipes of fruit-bodies of Shiitake-mushroom [Lentinus edodes (Berk.) Sing.] during post-harvest storage at six storage temperatures (-20, 0, 5, 10, 20 and 30°C), freeze-drying process and hot-air drying process were investigated. (1) In this mushroom, formic, acetic, lactic, oxalic, succinic, fumaric, malic, α-ketoglutaric, tartaric, pyroglutamic and citric acid were identified, and among them malic, citric, pyroglutamic, tartaric and fumaric acid were found to be major in pilei, and malic, citric, fumaric and pyroglutamic acid were found to be major in stipes. Organic acids compositions were different in pilei and 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 1. 4-3. 2% in dry materials, and 1.1-2.0% in stipes, respectively. The contents of organic acid during post-harvest storage increased for the first three days, but it decreased from then on. 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 organic acids decreased from the first day. As the storage temperature went higher, the changing pattern of organic acids in fruit-bodies advanced faster, and the storage method by low temperature turned out to be an effective way of storing. (3) The contents of organic acids during the freeze process and hot-air drying process had no change, and those two methods turned out to be an effective way of storing.