Descriptive sensory evaluation of cooked stinging nettle (Urtica dioica L.) leaves and leaf infusions : effect of using fresh or oven-dried leaves

Abstract

Stinging nettles (Urtica dioica L.) have been known since ancient times as a wild source of food and a herbal medicine, but the plant remain underutilized. The aroma, flavour and colour of cooked stinging nettle leaves and leaf infusions prepared from the fresh or dried leaves, has not been researched. The effect of using fresh or oven-dried leaves in a cooked product or to prepare an infusion on sensory attributes were established. In addition, the effect of two infusion cycles on the sensory quality was determined. A trained descriptive sensory panel evaluated the sensory characteristics of cooked nettle and spinach leaves using 19 aroma and 26 flavour descriptors. Twenty aroma and 25 flavour descriptors were used for evaluating the leaf infusions. The L, a*, b* and ∆ E values of fresh, dried and cooked leaves were also measured. Although the colour changed, most of the characteristic green type aroma and flavour notes of fresh nettle leaves were preserved in cooked leaves and leaf infusions prepared from dried leaves. The two brewed infusions from fresh or dried leaves provided similar aroma and flavour intensities. Further consumer research will determine which sensory characteristics of the products from stinging nettles drive consumer liking or disliking. This research contributes to the understanding of the potential of stinging nettle for addressing food and nutrition security and well-being of consumers.