Influence of temperature and brewing time of nettle (Urtica dioica L.) infusions on vitamin C content

ABSTRACT

Background: Stinging nettle (Urtica dioica L.) can be found in temperate climate zones of Europe, Africa and America Nettle may be a source of nutritional ingredients, mineral salts, vitamins and antioxidants. Objective: The aim of the study was to determine the effect of temperature and brewing time Urtica dioica L. infusions from different parts of this plant on vitamin C (ascorbic acid) content. Material and methods: Infusions of nettle leaf, stem and root were prepared at room temperature, 50°C, 60°C, 70°C and 80°C for 10 minutes. Leaf infusions were also brewed for 5, 10, 15 and 20 minutes at initial water temperature of 60°C. The amount of vitamin C was determined by the spectrophotometric method. Results: The best temperature of brewing nettle infusions, in terms of vitamin C concentration, is between 50 °C and 60 °C as it is sufficient to extract the substance, yet not high enough to destroy it. Conclusions: The optimal time of brewing appeared to be 10 minutes as the prolonged exposure to high temperature appeared to be detrimental for ascorbic acid as well.