Effect of cooking and preservation on nutritional and phytochemical composition of the mushroom Amanita zambiana

The effect of different cooking and preservation methods on the nutritional and phytochemical composition of the mushroom, Amanita zambiana, was investigated. Fresh mushrooms were boiled in water, fried, or microwaved. In addition, fresh mushrooms were either air-dried for 7 days or frozen at -20°C for 14 days. The protein, lipid, carbohydrate, and phenolic content of the treated mushrooms were measured and compared to the fresh mushroom contents. Frying increased the protein (2.01% ± 0.2% [fresh mushroom] to 2.23% ± 0.09%), lipid (14.68% ± 0.9% to 15.56% ± 0.34%), and carbohydrate (0.89% ± 0.01% to 2.69% ± 0.03%) content, while microwaving increased the protein (2.01% ± 0.2% to 3.64% ± 0.08%) and carbohydrate content (0.89% ± 0.01% to 2.26% ± 0.09%). Boiling only increased the carbohydrate content (0.89% ± 0.01% to 1.71% ± 0.05%) of the mushroom and significantly decreased (p < .05) the phenolic content (8.77 ± 0.1 to 1.46 ± 0.2 mg gallic acid equivalent (GAE)/g mushroom). Drying resulted in significant increase (p < .05) in protein (2.01 ± 0.2% to 24.36 ± 0.09%), carbohydrate (0.89% ± 0.01% to 58.67% ± 3.29%), and phenolic contents (8.77 ± 0.1 to 119.8 ± 0.7 mg GAE/g mushroom), while freezing only increased the carbohydrate content (0.89% ± 0.01% to 1.77% ± 0.03%). From the three cooking methods studied, frying is recommended as the most effective cooking procedure in retaining or enhancing the mushroom nutrients, while drying is a better preservation method than freezing.