Effect of some thermal and chemical pre-treatments on smoked oyster mushroom quality

The effect of different thermal and chemical pre-treatments on quality and enzyme activities of smoked mushroom was investigated. Mushrooms were blanched (water and steam) and dipped in different concentrations of SO₂, H₂O₂, ethylenediaminetetraacetic acid (EDTA) and citric acid for 10 min before smoking. Enzyme activities, colour characteristics, microbiological and sensory examinations were carried out every 2 weeks up to 8 weeks of storage at 4 °C. Smoked mushroom pre-treated with sulphites (SO₂), H₂O₂ and steam blanching had the best colour values, better scores for all sensory characteristics and lower non-enzymatic browning compared with the other pre-treatments. Pre-treatment against total aerobic bacteria, yeast and moulds was the most effective when using citric acid, EDTA and steam, followed by smoking of mushroom. The most effective pre-treatments on quality and safety of smoked mushrooms were those using H₂O₂ and steam. It can be concluded that thermal and chemical treatments followed by smoking of mushroom reduce enzyme activities and are suitable for preserving mushrooms.