Ozone Injection at Low Pressure: Decomposition Kinetics, Control of Sitophilus zeamais, and Popcorn Kernel Quality

ABSTRACT

This study aimed to characterize ozone gas (O₃) decomposition kinetics when injected at low pressure for controlling Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), and its effect on popcorn kernel quality. The ozonation of the kernels was conducted in a 70-L hypobaric chamber, using samples of 5.0 kg of grains packaged in woven polypropylene bags. Firstly, the internal pressure of the chamber was reduced to 250 hPa, and ozone was injected at concentrations of 5.0, 6.7, 8.5, and 13.0 mg L⁻¹ until reaching a pressure of 940 hPa. The ozone concentration decay inside both the chamber and package was continuously monitored. The quality parameters assessed included the expansion volume, moisture content, electrical conductivity, and color of the popcorn kernels. The decomposition kinetics followed a first-order model in all concentrations studied. The values of decomposition rate constant (k) ranged from 0.030 to 0.014 min⁻¹, inside the package, and from 0.030 to 0.015 min⁻¹, inside the chamber. The ozone half-lives ranged from 22.7 and 49.8 min, inside the package, and from 20.6 and 46.5 min, inside the chamber. Ozone applied in a low-pressure system at 13.0 mg L⁻¹ controlled 94.45% of the S. zeamais insects in the grain mass. The injection of ozone gas at low pressure did not change the expansion volume, moisture content, and electrical conductivity of the popcorn kernels.

KEYWORDS:

• Ozonation. agri-food applications
• hypobaric chamber
• Zea mays everta
• corn weevil
• storage

Acknowledgments

This study was funded by the National Council for Scientific and Technological Development (CNPq) [grant number: 164660]. The authors would like to acknowledge the support by the Minas Gerais State Research Support Foundation (Fundação de Amparo à Pesquisa do Estado de Minas Gerais, FAPEMIG) and the Coordination for the Improvement of Higher Education Personnel (CAPES) [grant number: 001]. The authors also would like to thank the technical support offered by the ozone generator manufacturer company Myozone.

Additional information

Funding

This work was supported by the Coordination of Improvement of Higher Education Personnel (CAPES) [Finance Code 001]; National Council for Scientific and Technological Development (CNPq) [grant number: 164660].