ABSTRACT: This study was carried out to evaluate the effect of pretreatments prior different drying methods and temperatures on compositional quality of the dried mushroom. Oyster mushroom (Pleurotus ostreatus) was cultivated on rice substrate and collected samples were pretreated (steeped or blanched) by different solutions (0.1% sodium metabisulfite and 0.1 and 0.5% citric acid) and dried using oven at 50°C and 60°C, sun-drying at 30-35°C and microwave drying at 2.45 GHz until reached to constant weight. Rehydration ratio and browning index (color) of the dried oyster mushroom samples were the most effective parameter for judging and selecting the pretreatment and the drying process.Blanching pretreatment seems to elongate drying time compared
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are commonly called ‘Oyster mushrooms’. They are the second most popular mushrooms after button mushroom throughout the world (Adejoye et al., 2006, Amin et al., 2007 and Stojanova et al., 2016) and the most popular mushroom in Egypt. Oyster mushrooms grow over a range of temperature of 15-30oC and thus are suitable for cultivation under both temperate and tropical climatic conditions. Mushrooms are not only found to be medicinally effective as antitumor, antibacterial, antiviral and hematological agents and in immune modulating treatments (Weisburger, 1999 and Patel et al., 2012) but also found to possess significant antioxidant capacity (Prabu and Valli, …show more content…
Conventional air drying is one of the most frequently used techniques for mushroom dehydration, which involves thermal and /or chemical pretreatment and drying at temperature maintained between 50 and 70 oC. Due to long drying time and overheating of surface during hot air drying, the problems of darkening in colour, loss in flavour and decrease in rehydration ability occur. Drying of oyster mushrooms can lengthen their shelf life and retain their properties plus quality as close to the original sample as possible. Low heat air methods are recommended in reducing water activity and keeping proximate contents and quality (Aishah and Rosli, 2013 and Muyanja, et. al.,
are commonly called ‘Oyster mushrooms’. They are the second most popular mushrooms after button mushroom throughout the world (Adejoye et al., 2006, Amin et al., 2007 and Stojanova et al., 2016) and the most popular mushroom in Egypt. Oyster mushrooms grow over a range of temperature of 15-30oC and thus are suitable for cultivation under both temperate and tropical climatic conditions. Mushrooms are not only found to be medicinally effective as antitumor, antibacterial, antiviral and hematological agents and in immune modulating treatments (Weisburger, 1999 and Patel et al., 2012) but also found to possess significant antioxidant capacity (Prabu and Valli, …show more content…
Conventional air drying is one of the most frequently used techniques for mushroom dehydration, which involves thermal and /or chemical pretreatment and drying at temperature maintained between 50 and 70 oC. Due to long drying time and overheating of surface during hot air drying, the problems of darkening in colour, loss in flavour and decrease in rehydration ability occur. Drying of oyster mushrooms can lengthen their shelf life and retain their properties plus quality as close to the original sample as possible. Low heat air methods are recommended in reducing water activity and keeping proximate contents and quality (Aishah and Rosli, 2013 and Muyanja, et. al.,