Effects of stress on taste and constituents of carrots

Carrots can be exposed to stress in the field by insect pests, pathogens, drought, high or low temperature, UV-light, mechanical stress from hail as well as by post-harvest handling or changes in atmosphere in storage rooms or packaging. Our studies deal with how carrots change quality during field cultivation, grading, washing, packaging and storage. Definition of quality in carrots and the evaluation on how quality can be altered by many different factors in reviewed.

harvest of carrots
Harvesting of carrots by Asa-Lift harvesting equipment. Photo: Randi Seljaasen / NIBIO
Contacts
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Washing line for carrots. Photo: Randi Seljåsen / NIBIO.
Pre-harvest stress conditions for carrots can be affected by soil or cultivation area and season. Hot climate conditions or stress from pests should be avoided to optimize sensory quality. When it comes to factors affecting the carrots after harvest, mechanical stress at grading and washing as well as storage conditions and packaging conditions were found to be important. Mechanical stress and ethylene should be minimized and oxygen content in packaging must not be too low. Low temperature during distribution and marketing reduce the effect of stress.

Our studies have been carried out together with colleges at NOFIMA and NIBIO over the last decades. Focus has been investigations on how stress affects sensory quality and the related chemical compounds in carrots. The results from our scientific studies are utilized towards assignments for farmers or industry actors on how to control quality in the production and marketing chains.
 

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Abstract

The effect of different degrees of attack by carrot psyllid (Trioza apicalis) on quality parameters of carrots was studied in field experiments for two years. Treatments were different degrees of physical insect protection by floating row cover. An increasing attack level of psyllids showed an enhancement effect on the antioxidant capacity (ORAC), content of falcarindiol, 6-methoxymellein, and terpenes, and scores for bitter taste, chemical flavor, terpene flavor, and toughness. Carrot psyllid attack decreased the yield, total sugar, fructose, glucose, and sensory attributes sweet taste, color hue, color strength, crispiness, and juiciness. Carrot plants at 8−10 weeks of age tolerated attack by psyllids at low levels (2% leaves with curling or discoloration).