EFFECT OF DIFFERENT DRYING METHODS ON THE PHYSICOCHEMICAL CHARACTERISTICS AND VOLATILE COMPOUND PROFILE OF Pleurotus ostreatus

ABSTRACT Pleurotus ostreatus is considered a functional food with benefits for human health. However, its shelf life is very short even when refrigerated. This study compared the effects of five drying treatments on the water activity, color, microstructure, hardness, rehydration index, total polyphenol (TP) content and volatile compounds of P. ostreatus. The drying treatments included lyophilization (T1), forced air oven drying (T2) and refractive window (RW) drying at 60 °C (T3), 70 °C (T4) and 80 °C (T5). Bromatological analysis showed that the samples contained high concentrations of proteins and carbohydrates, with values of 29.28 g/100 g and 47.80 g/100 g, respectively. Microstructural analysis revealed less cell shrinkage and damage under T1 than under the other treatments. This finding was corroborated by the texture analysis results, which indicated a lower hardness value for T1 (5.07 N) than for T2 (8.94 N). The TP content varied between 4.62 and 6.82 mg GAE/g. Some parameter values of samples treated by RW at 80 °C were similar to those of lyophilized samples, showing that RW, which presents advantages over lyophilization, such as a lower cost and processing time, is very suitable for dehydrating P. ostreatus.