Effect of drying conditions on quality of primed cabbage seeds and ethanol degradation as promising quality parameter

Seed drying is a common step during the processing of seeds. This paper presents a systematic study on the effect of drying on cabbage seed quality for which amongst others a new dryer system and a new quality indicator were developed. The new dryer system allows drying of seeds under highly controlled air conditions and automatically monitors mass and temperature change of seeds. Germination quality (GQ) and speed were determined via germination tests after drying and storage. Little or no effect of drying temperature on overall GQ (minimum 90%) was detected up to 55 °C. High-quality (i.e. 95% germination) was mostly reached with drying below 40 °C. For 70 °C, GQ decreased drastically. Relative humidity (RH) and time did not significantly influence GQ. To achieve high GQ after drying as well as after storage, the most optimal protocols were around 40 °C and 30% RH or 25 °C and 5% RH, with the latter protocol drying faster. In addition, the ethanol index (EI) was proposed as a faster and less laborious indicator for GQ by adapting a known ethanol method measuring ethanol headspace of cabbage seeds incubated with an ethanol solution. It correlated well with GQ (R2 = 0.93), thus being a promising quality indicator.