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This study assessed the application of an antibrowning solution using vacuum impregnation (VI) and then electron-beam irradiation as a means to extend the shelf life of sliced white button mushrooms (Agaricus bisporus). A preliminary study helped to determine the best antibrowning solution and VI process parameters. Mushroom slices were impregnated with 2 g/100 g ascorbic acid + 1 g/100 g calcium lactate; 2 g/100 g citric acid + 1 g/100 g calcium lactate; 1 g/100 g chitosan + 1 g/100 g calcium lactate; and 1 g/100 g calcium lactate at different vacuum pressures and times and atmospheric restoration times. Selection of the antibrowning solution and VI parameters was based on texture and color of the mushroom slices. Next, the slices were irradiated at 1 kGy using a 1.35-MeV e-beam accelerator. Physicochemical, sensory, and microbial quality of mushrooms was monitored for 15 d at 4 °C. The best impregnation process in this study was 2 g/100 g ascorbic acid and 1 g/100 g calcium lactate at 50 mm Hg for 5 min and an atmospheric restoration time of 5 min. The control (untreated) samples suffered structural losses throughout storage. Only the vacuum impregnated-irradiated samples had acceptable color by the end of storage. Sensory panelists consistently preferred the samples produced with VI and irradiation because exposure to ionizing radiation inhibited growth of spoilage microorganisms., (© 2013 Institute of Food Technologists®)

It is important to achieve dose uniformity in product box irradiated by gamma irradiators. To minimize lateral non-uniformity of absorbed dose, quantified as Dose Uniformity Ratio in a particular plane (DUR p), activities of source pencils need to be optimized. In present study, Simulated Annealing technique is used for this purpose and the same is described for a Low-Dose 60Co Blood Irradiator. An in-house computer program is developed that calculates DUR p and optimizes the activities of source pencils. The study demonstrates that only the primary component of dose is sufficient to determine DUR p. In the Simulated Annealing technique, several cooling parameters are tested and the most effective cooling schedule is selected to obtain optimized activity distribution. An improvement of 22% in DUR p value is observed after optimization as compared to each source pencil having the same activity. The methodology described in the paper is efficient as optimization of source activities using a trial-and-error approach will be tedious and time consuming. The optimization methodology described in the study is applicable to any irradiator geometry. However, geometry-specific dose calculation approach should be adapted. • Simulated Annealing capable of optimizing source activities to achieve uniform product dose in gamma irradiators. • Primary component of dose sufficient to determine lateral DUR. • Simulated Annealing algorithm more efficient than trial and error approach. [ABSTRACT FROM AUTHOR]