ANALYSIS OF THE ANTIOXIDANT CAPACITY OF LETTUCE GROWTH AT DIFFERENT FERTILIZER REGIMES

Increasing consumer demand for healthier foods produced using organic farming practices has led to the rapid expansion of organic farming. Numerous studies have clearly shown the importance of vegetables as the richest potential source of natural antioxidants and highlight the need to increase the proportion of these products in the human diet. The purpose of this study was to compare the antioxidant profile in three lettuce varieties (Leaf lettuce (two types Lactuca sativa L. var. crispa L.) type Batavia variety Maritima and type Lolo Rossa variety "Tuska"; one type Head lettuce (Lactuca sativa L. var. capitata L.) variety "Winter butterhead") grown in greenhouses, non-fertilized or fertilized with: bird manure Italpollina; mix of bovine, horse and chicken manure Arkobaleno; lumbricompost made by Red Californian worms Lumbrical; biofertilizer composed with beneficial microorganisms EKOprop. The content of bioactive compounds (total phenols and flavonoids, water- and lipid-soluble metabolites with antioxidant activity), total antioxidant activity measured by radical scavenging activity and ferric reducing antioxidant power, as well as antioxidant enzyme activity were monitored. The enzyme antioxidant activity was influenced by lettuce morphotype, as well as by the type of fertilization - conventional chemical NPK fertilizers, bio fertilizers of microbial origin, or organic fertilizers of bovine, horse and chicken manure. The parameters associated with non-enzymatic antioxidant activity were lowest in non-fertilized plants and increased with different types of fertilization.