Abstract: The consumption of organic food has been growing all over the world. Clean soil environment and extensive methods of production make Poland particularly suitable for developing organic forms of farming. The nutritional quality of food grown by organic and conventional methods is the subject of much controversy. The nutritious quality of organic products is the subject of numerous scientific research. The study conducted in 2009 presents comparison of some nutritional values of juices made from organic and conventionally grown vegetables (carrot, red beet, celery). For the experiment 39 vegetable fields located in the south and east of Poland were chosen. All organic farms were certified according to UE Council Regulation no. 2092/91 and obtained valid certificates. Unclarified juices were obtained with cold press juicer. After microwave mineralization in HNO3 the following nutrient elements were measured: P, K, Mg, Ca, S, Fe, Zn, Mn, Cu, B as well as Na, Cd, Pb, and Ni. Moreover, ammonium N and nitrates content were evaluated using FIA method. Celery juices were the richest in P, K, Mg, Ca, Fe, Zn, B and heavy metals Cd, and Pb, while carrot juices were having the highest level of S and Na. Cultivation methods significantly differentiated Ca, Mg and Na content. Generally, the conventional farming method favored higher accumulation of N-NO3 (only in carrot), Mg and Na, whereas the higher Ca amounts were measured for bio juices. Significantly higher N-NH4 amounts were observed for all conventionally vegetable juices than for organic. Higher levels of Cd were found for conventional juices made from carrot and beet, however in the celery juice the values differences were not significant.
Reference: Domagala-Swiatkiewicz, Iwona and Gastol, Maciej. (2012). Comparative study on mineral content of organic and conventional carrot, celery and red beet juices. Acta Scientiarum Polonorum-Hortorum Cultus 11(2): 173-183