Optimization of Head Space Pressure Using Liquid Nitrogen in Hot-packed BBQ Sauce

BBQ sauce was hot-filled at 54°C (130°F) in plastic PET, 567 g (20 oz) bottles. The PET bottles paneled, due to the temperature and pressure of the hot-fill process. Liquid nitrogen was used as a processing aid to optimize the headspace pressure to prevent paneling. The objective of the research was to eliminate paneling of the PET bottles due to hot-filling. A micro dosing system was used to inject nitrogen into the container just after filling and immediately prior to capping. Headspace pressure was measured using a custom-designed pressure sensor. Nitrogen dosage time was plotted against headspace pressure. The relationship between nitrogen dosage time and headspace pressure was linear, with a coefficient of determination of 0.84, and slope of 1.36 kPa/ms, with an intercept of -12.21 kPa. Results were analyzed using analysis of variance. Visual inspection of the bottles for defects resulted in the determination of the optimum headspace pressure of 30 kPa (4.4 psi).