UV light provoked stress can evoke antioxidant defence system and consequently induces the synthesis of several phytochemical compounds. The aim of the present study was to investigate the influence ...of UV-B light irradiation on surface colour and synthesis of some bioactive compounds in apples skin of cultivars ‘Elstar’ and ‘Jonagold’. Half of each apple was shaded with aluminium foil to compare irradiated and non-irradiated parts of skin. Apple fruits were exposed to constant UV-B light at 310 nm in chamber for 13 days at 8.5 °C. The UV-B light emitting diodes were positioned ca. 13 cm above the apple fruit and the average irradiance fruit received was 4.6 μW/cm2. Measurements of colour parameters (L*, a*, b*) were performed on the same spots of irradiated and non-irradiated surface of each apple fruit before and after 7, 10 and 13 days of storage constant UV-B light irradiation. All apple fruits started to develop red colour on the irradiated surface. The antioxidant potential, ascorbic acid content, total phenolic compounds, six flavonols and anthocyanin cyanidin-3-galactoside were quantitatively evaluated. Apple skins exposed to UV-B light irradiation contained significantly more total phenolic compounds and had higher antioxidant potential as compared to non-irradiated. UV light treated apple skin contained more cyanidin-3-galactoside and flavonols.
Modern and sustainable production of safe and healthy high quality vegetables for human consumption is nowadays the goal of many producers. Chicory (Cichorium intybus L.) has become an important crop ...used as food in many countries over the past decade. In this work field and glasshouse trials were conducted to compare phenolic profiles of hydroponically forced leaves and leaves produced as common agronomic practice of five chicory cultivars. Total phenolic content of hydroponically forced samples ranged from 60 to 140 mg/100 g fresh weight, and those of unforced grown leaves varied between 117 and 386 mg/100 g fresh weight. Red cultivar ‘Treviso’ shows the highest phenolic content for both, unforced and forced leaves extracts. In the unforced leaves a total of 33 and in those of forced a total of 44 compounds (peaks) were used for the discrimination study.
Svrha je ovoga rada bila ispitati utjecaj svjetlosti koje emitiraju LED svjetiljke na skladištenje nekoliko vrsta plodova. Jabuka, rajčica i paprika babura izlagane su žutoj svjetlosti valne duljine ...od 590 nm radi poboljšanja trajnosti plodova i povećanja udjela nekih bioaktivnih sastojaka. Određene su sljedeće vrijednosti: udjeli askorbinske kiseline, ukupnih fenola, ukupnih flavonoida i nekoliko pigmenata, te antioksidacijski potencijal plodova. Nakon sedam dana izlaganja plodova LED svjetlosti došlo je do znatnog povećanja udjela ukupnih fenola i antioksidacijskog potencijala u ekstraktima kore jabuke, povećanja udjela ukupnih fenola u plodu rajčice, te do povećanja antioksidacijskog potencijala ploda paprike babure. LED svjetlost nije utjecala na karakteristike boje, iako je donekle ubrzala razvoj boje plodova. Izlaganje jabuke LED svjetlosti uzrokovalo je mekšanje ploda. Ispitani su udjeli dvanaest pigmenata u plodovima, te je pronađeno znatno više β-karotena u jabuci i paprici baburi, više α- i γ-tokoferola u paprici, te više luteina u kori jabuke i plodu paprike babure nego u kontrolnim uzorcima. LED svjetlost je donekle ubrzala sazrijevanje plodova i utjecala je na sintezu nekih sekundarnih metabolita.
Svrha je ovoga rada bila utvrditi utjecaj sastava atmosfere na oksidaciju mljevenog oraha tijekom skladištenja pri 20 °C. Sedam je sorata oraha (Juglans regia L.) samljeveno i skladišteno 10 mjeseci ...na sobnoj temperaturi u hermetički zatvorenim posudama u atmosferi s povećanim udjelom kisika ili dušika, pri čemu su određivani sljedeći parametri: antioksidacijski potencijal, ukupni fenoli, sastav masnih kiselina i produkti oksidacije. Kultivar, sastav atmosfere, te interakcija između kultivara i sastava atmosfere bitno su utjecali na antioksidacijski potencijal. Sastav je ukupnih polifenola uvelike ovisio o kultivaru i sastavu atmosfere, a više je polifenola pronađeno u uzorcima skladištenim u atmosferi s povećanim udjelom dušika. Udjel se nezasićene linolenske kiseline smanjio u orasima pohranjenim u atmosferi s povećanim udjelom kisika, a statistički su značajne razlike primijećene jedino između pojedinačnih sorata. U atmosferi s povećanim udjelom kisika nastalo je više produkata oksidacije, pri čemu najviše hlapljivih produkata, i to heksanala, zatim 1-oktan-3-ola, oktanala, te smjese 2-oktenala i 1-okten-3-ola. Veće su koncentracije tih produkata utvrđene u uzorcima skladištenim u atmosferi s povećanim udjelom kisika, iako su bitne razlike pronađene jedino između pojedinih sorata.
Svrha je ovog preliminarnog istraživanja bila pokazati da se analizom više elemenata, nekoliko omjera izotopa (13C/12C, 15N/14N, 18O/16O, 2H/1H) i odabranih fizikalno-kemijskih značajka (masa ploda, ...antioksidacijska aktivnost, udjeli askorbinske kiseline i ukupnih fenola) mogu razlikovati sorte slovenskih jabuka, te odrediti njihovo zemljopisno porijeklo i uvjeti uzgoja. Najvažnije su varijable za analizu bile omjer stabilnih izotopa u šećerima, pulpi, proteinima i vodi. Botaničko je porijeklo najviše utjecalo na δ13C i δ15N vrijednosti proteina te δ18O i δD vrijednosti vode. Zemljopisno je porijeklo točno utvrđeno pomoću δ18O i δD vrijednosti vode i masenih udjela Rb i S u soku jabuke. Najbitnije varijable za određivanje proizvođačke prakse (organski ili konvencionalni uzgoj) bili su omjer 15N/14N i antioksidacijska aktivnost. Osim toga, pronađene su i znatne razlike u udjelu askorbinske kiseline u plodovima.
U radu je istražen utjecaj različitih uvjeta skladištenja na kakvoću pakiranoga rezanog kupusa. Upotrijebljen je kultivar Fieldrocket koji je, nakon rezanja i pranja, pakiran u staklenke, ...polietilensku (PE) ili polipropilensku (PP) foliju. Kupus je pakiran pri različitoj početnoj atmosferi: 100 % N2, 5 % O2/95 % N2, 10 % O2/90 % N2, normalnoj atmosferi (NA), 70 % O2/30 % N2 i 100 % O2. Svi su uzorci skladišteni na 0 i 10 °C tijekom 7 dana. Intenzitet respiracije bio je veći u uzorcima skladištenim pri 10 °C, pakiranim u atmosferi sastava: 70 % O2 i 30 % N2. Snizivanje udjela O2 ispod 3–5 % i povećanje udjela CO2 iznad 2-5 % dovelo je do pojave anaerobnog metabolizma. Početna atmosfera od 100 % O2 i temperatura od 0 °C odgodila je pojavu anaerobnog metabolizma u usporedbi s ostalim sastavima atmosfere pri temperaturi od 10 °C. Ispiranje narezanog kupusa vodom smanjilo je nakupljanje acetaldehida i etanola. Veći intenzitet respiracije uzrokovao je jače nakupljanje anaerobnih metabolita, te je negativno utjecao na senzorska svojstva narezanog kupusa. Veća propustnost PE folije u usporedbi s PP folijom omogućila je bržu izmjenu CO2 i O2, a time i manje nakupljanje anaerobnih metabolita. Međutim, povećanje udjela O2 u atmosferi pakiranja negativno je utjecalo na boju svježe narezanog kupusa. Najbolji su rezultati postignuti pakiranjem svježe narezanog kupusa u PE foliju s početnom atmosferom od 100 % O2, pri temperaturi od 0 °C.
Spraying parameters are important factors when spraying wheat heads against fusarium head blight (FHB) to control the deoxynivalenol level in the grain and to obtain high and quality yields. In 2019 ...and 2020, field trials were conducted in order to establish the effect of the spraying pressure (2 bar, 4 bar, and 6 bar) of special nozzles with a variable flow rate Agrotop VR 1.5 on the head fungicide coverage, yield parameters, and the deoxynivalenol (DON) value in the grain. The coverage of the front and rear sides of wheat heads increased with the increase of spraying pressure from 2 to 6 bar. In 2019, when the infection with FHB was more severe, no significant differences appeared in the yield and the hectoliter weight at a lower spraying pressure, while the DON value at this pressure approached the maximum permissible level. In that year, the DON value exponentially fell with the increase of spraying pressure. In 2019, the thousand grain weight was higher at the spraying pressure of 6 bar than at the pressures of 2 and 4 bar. The results show that also a lower spraying pressure (2 bar) and a volume application rate (117 L/ha) below the recommended one suffice to retain the DON value in the grain below the maximum permissible level, even in years with more severe infection.
Simultaneous planting and final ridge formation using a deeper planting depth is necessary in order to achieve good soil cover of tubers and fewer green tubers. Three planting depths were used: ...planting depth 1 (the shallowest), planting depth 2 (the medium), and planting depth 3 (the deepest). Planting depth 3 led to the largest minimum distance of tubers from the ridge side, and the smallest percentage of tubers in the upper layer of the ridge (0 to 5 cm). However, the highest yield and percentage of green tubers and the smallest marketable yield occurred at the shallowest planting depth (1). The tuber cluster covers 80 to 90% of the area of the ellipse. Empty spaces surrounding the tuber cluster in the ridge also affect the percentage of green tubers in the ridge, which predominantly occur at planting depth 3 and are the rarest at planting depth 1.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Green tubers are often a problem in a modern potato production system. They can lead to a substantial reduction in marketable yield and potato quality. This study examined the effects of ridge top ...width on reduction of green potatoes, ridge geometry, soil cover of tubers, tuber position in the ridge and potato yield. Three different ridge top widths were analysed in the trial, i.e. 10, 28 and 38 cm. Final trapezoid-shaped ridges were formed simultaneously with planting. By increasing the width of the ridge top, especially to 38 cm, the horizontal distance between the tubers and the ridge side was increased. In the ridges with a 28- and 38-cm top width, a larger area between tuber cluster and ridge sides was achieved than in ridges with a 10-cm ridge top width. A 38-cm ridge top width led to the largest area of empty space between the tubers and the ridge sides. The increase in the ridge top width increased the cross-sectional area 0–5 cm below top of the ridge. The above-mentioned factors helped to decrease the weight and percentage of green tubers in the ridges with top widths of 28 and 38 cm compared to 10 cm, particularly by reducing greening of tubers at the ridge sides. The increase in ridge top width also increased the theoretical area of the ellipse that represents the largest possible area for the growth of tubers in a ridge. The area of the tuber clusters in the ridge was 220–360 cm
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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