Why do stir fried mushrooms have a sour taste

The sour taste of stir fried mushrooms is usually related to their own characteristics or storage and processing methods. The main reasons include mushroom varieties containing natural organic acids, improper storage leading to spoilage, high-temperature cooking causing Maillard reaction, incomplete cleaning leaving acidic substances, and synergistic effects with acidic ingredients.

1. Characteristics of Mushroom Varieties

Some mushrooms such as Pleurotus ostreatus and Pleurotus eryngii contain high concentrations of natural organic acids, including oxalic acid and malic acid. These acidic substances will concentrate as water evaporates during the heating process, making the dish slightly sour. The sour substance content of wild mushrooms is usually higher than that of artificially cultivated varieties, which is closely related to their growth environment and metabolic processes.

2. Storage and deterioration

Mushrooms are prone to breeding spoilage bacteria in humid environments, and microbial decomposition of proteins produces metabolic products such as lactic acid and acetic acid. Mushroom cell walls that have been refrigerated for more than 3 days will rupture, accelerating the leakage of acidic substances. Especially when the surface of mushrooms appears sticky or yellowish in color, the degree of sourness is already quite obvious, and it is not recommended to continue cooking and consuming.

3. Maillard reaction

During high-temperature stir frying, the reducing sugars in mushrooms undergo complex reactions with amino acids, producing pyrazine and furan compounds. These substances not only impart aroma to dishes, but also generate small amounts of by-products such as acetic acid. When cooking with an iron pot, metal ions may catalyze the reaction, making the sour taste more prominent.

4. Cleaning residues

Mushroom folds are prone to residual acidic substances in the soil, which are difficult to completely remove by rinsing with tap water. Some merchants soak mushrooms in citric acid solution to extend their shelf life. If they are not thoroughly rinsed and cooked directly, the acidic solution will penetrate into the cap tissue and release a noticeable sour taste when heated.

5. When stir fried with acidic seasonings such as tomatoes and vinegar, the glutamate and other umami substances in mushrooms will combine with hydrogen ions to form glutamate, amplifying the perception of sour taste. Some mushrooms marinated in wine can also become sour due to the oxidation of alcohol to acetic acid, which is particularly evident when the juice is not fully harvested.

It is recommended to observe whether the mushroom cap is tight and full when purchasing, and to store it in kraft paper and refrigerate for no more than 2 days. Quickly blanching with salt water before cooking can remove some organic acids, and switching to ceramic cookware can reduce metal catalyzed reactions. Pairing with alkaline ingredients such as carrots, yams, etc. can neutralize the sour taste, and control the stir frying time within 3 minutes to avoid excessive carbonization. If the sour taste is accompanied by a pungent odor or a sticky texture, it should be stopped immediately to prevent food poisoning.