CO-laser-based photoacoustic trace-gas detection: applications in postharvest physiology

Abstract

A sensitive CO-laser-based photoacoustic trace- gas detector has been applied to study physiological pro- cesses in biological samples. A continuous flow-through sys- tem at atmospheric pressure leads the released trace gases from the sample to the photoacoustic resonator cells at flow rates where these processes can be studied with high time resolution. We focus here on transient effects that were found during fermentation of red bell peppers and apples, yielding in particular ethanol and acetaldehyde. Results are discussed also in the light of simultaneous O2 measurements using po- larographic oxygen sensors.