Mineral composition of potatoes (Solanum tuberosum L.) on the market of the city of Zagreb

Mineralni sastav krumpira uvelike ovisi o sorti, agroekološkim čimbenicima i sustavu proizvodnje. Cilj ovoga istraživanja bio je utvrditi mineralni sastav uzoraka krumpira te usporediti preporučene dnevne potrebe minerala za čovjeka. Prikupljanje prosječnih uzoraka krumpira provelo se u triplikatu u gradu Zagrebu u 3 trgovačka lanca, na 3 tržnice i u 3 trgovine ekološkim proizvodima. Nakon pripreme uzoraka u laboratoriju fosfor je određen spektrofotometrijski, kalij plamenfotometrijski, a kalcij, magnezij, željezo, cink, mangan i bakar atomskom apsorpcijskom spektrometrijom. Dušik je određen metodom po Kjeldahlu. Statistička analiza podataka napravljena je pomoću SAS programa prema modelu analize varijance. Suha tvar u krumpiru kretala se od 16,09 do 19,48 %. Utvrđene količine elemenata uzorcima krumpira u suhoj tvari iznosile su 1,50-2,04 % N, 0,27-0,30 % P, 0,73-2,20 % K, 0,02-0,03 % Ca, 0,05-0,10 % Mg, 48,10-67,23 mg Fe/kg, 1,00-15,33 mg Mn/kg, 14,13-17,10 mg Zn/kg i 6,93-10,37 mg Cu/kg. Utvrđene količine elemenata u svježoj tvari (mg/100 g svježe tvari) iznosile su 291,71-326,73 N, 44,13-56,70 P, 139,35-406,96 K, 3,17-4,01 Ca, 9,86-18,33 Mg, 0,183-1,051 Fe, 0,134-0,224 Mn, 0,258-0,291 Zn i 0,111-0,209 Cu. Uspoređujući preporučene dnevne unose i utvrđene vrijednosti minerala, krumpirom iz ovoga istraživanja moguće je zadovoljiti 6,28-8,10 % P, 6,96-20,47 % K, 0,46-0,55 % Ca, 2,54-4,94% Mg, 6,45-8,45 % Fe, 6,67-11,17 % Mn, 0,77-1,1 % Zn, 11-21 % Cu od dnevnih potreba.The mineral composition of potatoes largely depends on the variety, agroecological factors and production system. The aim of this research was to determine the mineral composition of potato samples and to compare the recommended daily intake of minerals for humans. The collection of average potato samples was carried out in triplicate in the city of Zagreb in 3 retail chains, 3 markets and 3 organic products stores. After preparing the samples in the laboratory, phosphorus was determined by spectrophotometry, potassium by flame photometry, and calcium, magnesium, iron, zinc, manganese and copper by atomic absorption. Nitrogen was determined using the Kjeldahl method. Statistical analysis of the data was done using the SAS program according to the variance analysis model. Dry matter in potatoes ranged from 16,09 to 19,48%. The determined contents of elements in the dry weight were 1,50-2.04 % N, 0.27-0.30 % P, 0.73-2.20 % K, 0.02-0.03 % Ca, 0.05-0.10 % Mg, 48.10-67.23 mg Fe/kg, 1.00-15.33 mg Mn/kg, 14.13-17.10 mg Zn/kg and 6.93-10.37 mg Cu/kg. The determined contents of elements in the fresh weight (mg/100 g FW) were 291.71-326.73 N, 44.13-56.70 P, 139.35-406.96 K, 3.17-4.01 Ca, 9.86-18.33 Mg, 0.183-1.051 Fe, 0.134-0.224 Mn, 0.258-0.291 Zn and 0.111-0.209 Cu. Comparing the recommended daily intakes and established values of minerals, it is possible to meet 6.28-8.10 % P, 6.96-20.47 % K, 0.46-0.55 % Ca, 2.54-4.94% Mg, 6.45-8.45 % Fe, 6.67-11.17 % Mn, 0.77-1.1 % Zn, 11-21 % Cu of the daily needs with the potatoes from this research