Internal Pressure Profile in Semi-Rigid Food Packages During Thermal Processing in Steam/Air


  • The authors thank David Polvino (formerly with NFPA) for helping obtain the test system.


The internal pressure, during thermal processing of water and 3% starch solution in semi-rigid packages, was determined using steam/ air as heating medium, with different product temperatures (240, 250, and 260°F; 115.5, 121, and 126.7°C); initial temperatures (75, 100, and 130°F; 23.9, 37.8, and 54°C); initial vacuum (0, 3, 5, inch Hg) and headspace volume (15, 20, 25, and 30%). Data for water were fitted to an equation obtained from dimensional analysis. Exponents and coefficients of dimensionless groups were determined. The correlation developed for water also predicted pressure for 3% starch solution in semi-rigid food containers during different thermal processing conditions.