Extending Shelf Life of Sliced Mushrooms (Agaricus bisporus) by using Vacuum Impregnation and Electron-beam Irradiation

Mushrooms are one of the protein rich foods, however they have a short pro-harvest life (2 to 3 days) compared to most vegetables. The aim of this study was to evaluate whether applying an anti-browning solution using vacuum impregnation and then electron beam irradiation can be used to extend the shelf life of fresh-cut mushrooms (Agaricus bisporus).

Solutions made with (a) 2% ascorbic acid + 1% calcium lactate, (b) 2% citric acid + 1% calcium lactate, (c) 1% chitosan + 1% calcium lactate, and (d) 1% calcium lactate were used to impregnate mushroom slices at different vacuum pressures, vacuum pressure times, and atmospheric restoration times. Mushrooms were also irradiated at a dose of 1 kGy using a 1.35 MeV e-beam accelerator and their quality was evaluated in terms of color, texture, and microbial growth during 15 days storage at 4 degrees C.

The best vacuum impregnation treatment was the 2% ascorbic acid and 1% calcium lactate solution using a vacuum pressure of 50 mmHg for 5 minutes and an atmospheric restoration time of 5 minutes.

The control (not treated) and impregnated samples lost their structure (softening) during storage. The irradiated samples lost their firmness by day 4 of storage. The addition of calcium lactate to the samples during the treatment helped to keep the product?s texture during the 15 days storage time.

Color of the mushrooms changed during storage for all the control and impregnated samples and only the irradiated samples showed an acceptable color by the end of day 15.

Aerobics and psychrotrophics counts were significantly reduced by irradiation; while yeast and molds population increased by day 9 and were not completely inactivated with a dose of 1 kGy.

Sensory panelists preferred the treated samples over the controls. The best treatment was the combination of vacuum impregnation with irradiation according to the consumer studies.