INFLUENCE OF AGRICULTURAL PRODUCTION SYSTEMS ON INTERNAL QUALITY OF LETTUCE

Potrošniki dandanes dajejo vse večji poudarek na poreklo in način pridelave zelenjave. Zelenjava lokalnega porekla, pridelana na ekološki (EKO) ali biodinamični (BD) način, naj bi imela prednosti pred zelenjavo tujega porekla in pridelano na integrirani (IP) ali konvencionalni (KONV) način. V poljskem poskusu v letu 2015 je bil preverjen vpliv prej omenjenih različnih pridelovalnih sistemov in kontrolnega obravnavanja (KONT) na vsebnost določenih notranjih parametrov (nitratov, nitritov, vitamina C, sladkorjev in suhe snovi) pri dveh sortah solate (\u27Comice\u27 in \u27Leda\u27) z analizami v laboratoriju in s hitrimi testi. Pri različnih pogojih skladiščenja so bile z dekompozicijskim testom preverjene razlike v skladiščni sposobnosti solate iz različnih pridelovalnih sistemov. Solata ekološkega in biodinamičnega izvora vsebuje večjo količino sladkorjev in vitamina C ter nižjo vsebnost nitratov in nitritov. Hitri testi so v primerjavi z laboratorijskimi analizami uporabna metoda za določanje vsebnosti nitratov in askorbinske kisline (vitamina C). Zaznan je bil trend višjih vsebnosti posameznih parametrov v sorti \u27Comice\u27. Povprečne vsebnosti nitratov pri meritvah s hitrimi testi so znašale 229,92 mg/l, nitritov 2,45 mg/l, askorbinske kisline 85,16 mg/l in skupnih sladkorjev 2,31 oBrix. Vzorci sveže solate so imeli najvišjo vsebnost suhe snovi pri integrirani pridelavi (6,39 %), vzorci, hranjeni na sobni temperaturi, iz konvencionalne pridelave (3,52 %), pri vzorcih iz hladilnice pa iz integrirane (6,07 %). Izguba mase solate med skladiščenjem je bila najnižja pri vzorcih iz BD pridelovalnega sistema. Solato je na podlagi rezultatov na sobni temperaturi smiselno skladiščiti do največ enega tedna. Vsebnost vitamina C se je na sobni temperaturi povišala, v hladilnici pa zmanjšala. Uspeli smo potrditi, da vzorci EKO in BD izvora vsebujejo nižjo vsebnost nitratov in nitritov, medtem ko za ostale notranje parametre kot tudi za tržno kakovost nismo popolnoma potrdili prednosti teh dveh pridelovalnih sistemov.Consumers today place increasing emphasis on the origin and production method of of vegetables. Vegetables of local origin produced organically (ECO) or in biodynamic (BD) production system are expected to have advantages over vegetables of foreign origin produced in the integrated (IP) or conventional (CONV) production systems. In the field experiment we did in 2015, we verified the influence of the aforementioned various production systems and the control treatment (CONT) on the presence of certain internal parameters (nitrates, nitrites, vitamin C, sugars and dry matter) in two varieties of lettuce (\u27Comice\u27 and \u27Leda\u27) using laboratory analyzes and rapid tests. With different storage conditions and decomposition test we verified the difference in market quality of lettuce of different production systems. Lettuce of organic and biodynamic origin contained a larger amount of sugars and vitamin C and lower content of nitrates and nitrites. Rapid tests can be compared to laboratory analysis and can be a useful method fort he determination of nitrate and ascorbic acid (vitamin C). There was a trend of higher levels of individual parameters in the variety \u27Comice\u27. Average levels of nitrates in measurements with rapid tests amounted to 230 mg/l, levels of nitrite to 2,45 mg/l, levels of vitamin C (ascorbic acid) to 85 mg/l and levels of total sugars to 2,31 oBrix. Samples of fresh lettuce had the highest dry matter content in integrated production (6,39 %), samples stored at room temperature from conventional production system (3,52 %) and those stored in the cold were from the integrated system (6,07 %). The loss in the weight of lettuce during storage was lowest in the samples from BD production systems. Optimal duration of lettuce storage based on our results is up to one week. Vitamin C content was increased during storage at room temperature and reduced during storage at cold. We were able to confirm, that the samples of ECO and BD origin contain lower levels of nitrate and nitrite but we couldn\u27t fully acknowledge the advantages of these two production systems on the levels of other internal parameters as well on the market quality of lettuce