45G-18 |
Respiration rate of fresh mushrooms |
Q. YUAN, V. A. Ghosh, S. Pandrangi, and R. C. Anantheswaran. Dept. of Food Science, Pennsylvania State Univ., 111 Borland Lab., University Park, PA 16802-2504 Modified atmosphere packaging (MAP) can be used to extend the shelf life of fresh mushrooms. The oxygen permeability of the film chosen for MAP should match the respiration rate of the fresh produce within the package. Previous studies in our laboratory on MAP of mushrooms offered evidence that the respiration rate of mushrooms might be varying with gas composition and time of storage. The objective of this study was to measure the respiration rate of fresh mushrooms under different gas compositions as a function of storage time. The respiration rate of mushroom was measured at 12C using the flow through method. A humidified gas mixture containing nitrogen and oxygen was fed into jar containing mushrooms at a flow rate of 100 cc/min. A gas sample was taken out of the inlet and outlet streams using a gas tight syringe at predetermined time intervals. The gas composition was determined using a Gas Chromatograph. The gas compositions used in this study were 5, 10, 15% and 21% (ambient air) v/v oxygen. It was found that the respiration rate during the first day of storage was 131 cc/(kg day) at 21% oxygen and 63 cc/(kg day) when the oxygen concentration was 10%. The respiration rate initially increased by 30% within a day and then decreased to a value lower than the initial respiration rate after three to five days of storage. Decreasing the oxygen concentration decreased the respiration rate. The variation in the respiration rate of mushrooms under different gas composition as a function of time can be modeled as a function of oxygen concentration and storage time. This model can be then be incorporated into MAP design in order to determine the in-package oxygen concentration during storage of mushrooms.
Session 45G, Fruit & Vegetable Products: Vegetables (Fresh)
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