Quality attributes of Pleurotus eryngii following gamma irradiation

Quality attributes (appearance, color, texture, weight, and volatile compounds) of irradiated (0,1, 2, and 3) king oyster (Pleurotus eryngii) mushrooms, packed in polystyrene trays and covered with polyvinylchloride (PVC) film, were evaluated over a storage period of 4 weeks at 5 +/- 1 degrees C. Hunter L values (lightness) increased upon irradiation and remained high throughout the storage period in 1 kGy-irradiated samples, whereas a values showed a slight decrease, and b values exhibited an increasing trend following irradiation. Mushroom texture decreased in firmness with increasing dose, but 1 kGy-irradiated samples maintained an overall better texture than all other samples. A similar trend was observed for weight loss during storage. The control samples developed mold, whereas 3 kGy-irradiated mushrooms were soft at the 3rd week of storage. Scanning electron microscopy showed micro-structural changes in the irradiated samples, which were probably the cause for increased weight loss and poor texture at the high 3 kGy dose. A principal component analysis of E-nose data showed dose-dependent differences in volatile profiles of all samples. Irradiation at 1 kGy was most effective for the extension of postharvest storage with added advantages. (C) 2011 Elsevier B.V. All rights reserved.