LACTIC ACID FERMENTATION OF MUSHROOM (AGARICUS BISPORUS) FOR PRESERVATION AND PREPARATION OF SAUCE

摘要

Introduction of lactic acid fermentation into mushroom (Agaricus bisporus) and preparation of sauce from fermented mushrooms was studied as a method of extension of its postharvest life. Mushrooms (blanched or unblanchcd) with dry salting, similar to the sauerkraut preparation, did not undergo lactic acid fermentation. The amount of acid produced was negligible (0.03 - 0.04%) and the pH did not reduce below 4.39 and it was higher than the microbiologically critical value (pH 4.1). Mushrooms of all these treatments got spoiled within 24 h with microbial count ranging from 4.0 x 10~4 to 1.5 x 10~8. Even the addition of lactose didn't stimulate lactic acid fermentation in dry salting procedure. Mushroom-in--brine inoculated with lactic acid bacteria produced more acid than the uninoculated mushroom. Amongst the bacteria tried, Lactobacillus plantarum produced the highest amount of acid (0.59%) after 5 days of fermentation. The bacterium sharply decreased the pH to less than 4.0 in one day. Two % salt supported the higher acid production than 3%. Fermentation softened slightly the spongy texture of mushrooms without altering the colour and flavour of fermented mushrooms. The fermented mushroom along with brine could successfully be converted into sauce of desirable physico-chemical characteristics, sensory qualities and shelf life. The method of preparation and quality characteristics of mushroom sauce are also described.