Effects of harvest and post-harvest treatments on reduction of red discolouration in white asparagus

Research was carried out in 1995 and 1996 to investigate ways of reducing red discoloration of white asparagus spears (Asparagus officinalis L.). Spears were harvested from a raised bed system and were subjected to various harvest methods and post-harvest temperatures. Red discoloration varied significantly between years. The greatest increase in red discoloration took place between harvest and three days after harvest. Placement of spears directly in water on the field compared to the standard practice of placing the spears in plastic crates covered by damp sacks, significantly reduced red discoloration. No significant differences in red discoloration were recorded between water temperatures of 2 and 12 degrees C. Post-harvest discoloration could be reduced for up to seven days when spears were kept in a closed cooling system at 2 degrees C. To minimise red discoloration in asparagus farmers should place spears after being cut, directly in water on the field, bring the spears to the packing shed as quickly as possible but certainly within 2 hours and leave the spears at least 4 hours in water. After grading and packing the asparagus should be stored and transported in the dark at 2 degrees C without any intermittent rise in temperature.