How to prevent rot and spoilage during storage of brine edible mushrooms
Brining edible mushrooms is an effective method of preserving wild mushrooms, which can improve quality and efficiency. However, they are prone to spoilage if management practices are not appropriate. After more than 3 months of storage, pickled mushrooms may become moldy film (or fungal flower), the upper layer of mushrooms rotten and smelly, slowly turn black, then the whole barrel of mushrooms become wax yellow, the juice is yellow and cloudy, acidic and tasteless, etc., causing losses.
(1) There are two types of mold film, one is a greyish white or creamy yellow film with wrinkles, which is produced by film-producing yeast and pseudo-yeast growing on the surface of the salt solution, and the other is a creamy white and smooth film, which is produced by hop yeast. These are aerobic, salt and acid resistant microorganisms that oxidise sugar, ethanol, acetic acid and lactic acid to produce carbon dioxide and water, which adversely affects the quality of brine mushrooms. There are two ways to control the growth of these micro-organisms: (i) fill the brine to the brim and screw the lid on tightly to isolate the air to form an anaerobic state. (ii) Raise the salinity of the brine to above 22 °Bé and lower the pH to below 2.5, or add a further 0.1% preservative (e.g. sodium benzoate).
(2) Rotting and stinking is due to the mushrooms rising to the surface of the liquid and coming into contact with the air, where the bacteria are active and produce toxic gases. The way to prevent rot and stinking is to use a bamboo curtain to press the mushrooms down to the surface of the liquid and keep them out of the liquid.
(3) Mushrooms slowly turn black because the tyrosine produced by protein degradation is oxidised by the enzyme tyrosinase in the mushroom tissue cells to produce melanin. In addition, amino acids in the cells interact with reducing sugars to produce a black substance that darkens the mushroom. This can be overcome by adding 0.4% citric acid, which will restore the mushroom to a light yellow colour.
(4) There are two reasons for mushrooms turning waxy yellow, cloudy juice and sour taste: one is excessive fermentation during the colour change process and the other is the low concentration of salt solution when pickling, caused by lactic acid bacteria, heterogeneous lactic acid bacteria and bacterial activity. The way to overcome this is to add salt to the marinade in time after the colour change and to check the degree of formation when storing, controlling it above 22 °Bé.
- Company News
- Industry News
- Product News
- Video
