Results and Discussion Effects of water loss and low temperature storage on straw mushroom browning: Straw mushroom buttons develop browning rapidly after harvest. The browning symptoms are initially generated around the cap and cut surface within 6 h of storage at ambient conditions (Figs. 2A and B). The browning and shrivelling symptoms began at the middle part of the cap and became progressively more severe with increasing time in storage. The development of browning increased in parallel with the increase in weight loss (Fig. 3A). The decrease in L Hunter scales was highly correlated with the increase in browning severity (r2 = 0.9803) (Fig. 3B). It was apparent that browning was dependent on water loss. The critical point was reached after 6 h of storage (Fig. 2B), when weight loss increased to above 12% (Fig. 3B). A scanning electron micrograph (SEM) showed collapsed mycelium after 24 h of ambient storage (Fig. 2D) in contrast to the turgid appearance of the mycelium before storage (Fig. 2C). After 24 h storage, weight loss further increased to 40% (Fig. 3B), and the mycelium of the cap flattened and turned brown (Fig. 2D). The hypothetical mechanism of browning in straw mushrooms associated with a water- loss dependent reaction was apparent in a subsequent experiment of MA storage at various temperatures. Although the browning was delayed under the MA conditions with PVC film overwrapping, the scores reached 4 (30-50% browning) after 2 days of storage at 15ºC (Fig. 4A). The browning symptoms increased despite a low weight loss of only 3.6% (Fig. 4A) on day 3 of storage at 15ºC and 90-95% RH. This result suggests that the browning of straw mushrooms is not completely dictated by the rate of water loss. The optimum storage temperature was 15ºC, which kept the mushrooms for approximately 3 days. The straw mushrooms kept at 12ºCexhibited slight chilling injury (CI) (Fig. 4B). At 8ºC and 12ºC, the shelf life was less than 2 days. Decreasing the temperature to 4ºC further decreased the shelf life mainly due to more severe CI. The CI of the straw mushrooms exhibited water-soaking of tissues and browning. The shelf life was shortest at ambient conditions and at 4ºC (less than 1 day). The MDA content, a measure of lipid peroxidation, was highest at ambient conditions and at 4ºC on day 1 (Fig. 4C), indicating a rapid rate of cellular deterioration resulting in browning. Furthermore, the total protein contents in the mushrooms stored at high temperatures of 15ºC and ambient conditions (Fig. 4D) slightly increased from initial values (4.1%) during storage. As a tropical fungus, straw mushroom is highly sensitive to low storage temperatures compared with mushrooms grown in other zones, such as button mushrooms (5ºC) 10 and shiitake mushrooms (1ºC) 11, causing the storage life of straw mushrooms to be much shorter.