Influence of Ca2+, K+ and NO3− fertilisation on nutritional quality of pepper

A study was conducted in order to assess the effect of different fertilisation levels of Ca²⁺, K⁺ and NO₃^? on the bioactive nutrient content in red pepper (Capsicum annuum L) fruits. The experiment was carried out in a greenhouse, under hydroponic culture. Lycopene, β‐carotene, vitamin C, total phenolic compound, sugar, nitrate and potassium contents and antioxidant activity were determined. Increasing Ca²⁺ and NO₃^? concentrations in the root medium increased the lycopene and β‐carotene contents in pepper. Antioxidant activity was determined in the hydrophilic (HAA) and lipophilic (LAA) fractions. HAA was increased by intermediate and high Ca²⁺ concentrations in the culture medium. However, LAA was raised only by NO₃^? treatments. Vitamin C, sugar and total phenolic acid contents were not affected by Ca²⁺ or NO₃^? treatments. K⁺ treatments had no effect on nutritional quality of pepper. An increased supply of Ca²⁺ and NO₃^? in the culture medium could constitute a useful practice for improving the nutritional attributes of pepper as well as its commercial quality. Copyright © 2004 Society of Chemical Industry