One-Way Degassing Valve Behavior & Function in the Acceptability of Stored Coffee

Date and Time


Food Science lecture room 128



Final Examination for the Degree of MSc Food Science - JESSEY COWELL

Examining Committee
Dr. Yoshi Mine, Chair
Dr. Loong-Tak Lim, Advisor
Dr. Lisa Duizer, Advisory Committee Member
Dr. Donald Mercer, Department Member

TITLE: One-Way Degassing Valve Behavior & Function in the Acceptability of Stored Coffee

ABSTRACT: In this research, the opening/closing behavior of low-profile and button one-way degassing valves were examined with varying silicone oil viscosities (20, 70, 160 and 1100 mPa·s), valves were exposed to darkly roasted fine and coarse grind coffee degas. Furthermore, the degassing rates of fine and coarse coffees were approximated with two-component empirical models, enabling the simulation of CO₂ degas behavior via a programmable infusion pump. Oxygen ingress was measured in real-time while the valve was exposed to fine and coarse coffee degas to evaluate the effect of opening/closing behavior on the ingress of air. In addition, consumer acceptability and discrimination testing between reference and treated samples stored in fraction pouches with oiled low-profile and button valves, as well as un-oiled low profile and no valve samples, were conducted in 7 sensory evaluations over a 12-week duration. Headspace analysis of key volatile concentrations was also performed on the brewed coffee.

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