No abstract

Four anti-hail and anti-insect nets (red, white and yellow anti-hail and Stop Drosophila Normal) were used on apple cv. 'Braeburn' grown in northern Croatia in order to evaluate their effect on fruit colouration that was measured with the colorimeter (expressed as: L* -lightness, a* -yellow/blue b* -green/red) on two sides of fruit ("green" side and "red" side), and also they were used in order to evaluate their effect on the coloured surface percentage, apart from their anti-hail and pest damage protection properties. The fruits were harvested on 12 th October 2015. Most differences were found between the fruit grown under the white anti-hail net and the fruit grown without the anti-hail net. Colour value "a*" was lower on the red side of the fruit under the white net in comparison with the red net. On the green side,"a*" value was lower and "L*" value was higher under the white net in comparison with control fruit. Different net colour had no influence on total colour difference. Regarding to the colouration, differences among the nets are found in classes 0-25% and 50-75% of skin coloured fruit. The fruit grown under the white nets had the higher percentage of fruit in class 0-25% than those grown without the net. The lower share of fruit in class 50-75% of skin colouration was recorded under the white net than under the red net or in the control fruit. Colouration index was lower in the fruit grown under the white net than in the control fruit. It can be concluded that the white anti-hail net promotes ripening, but at the same time it decreases red colouration. No significant differences in fruit colour have been found in the fruit grown under the red, yellow and Stop Drosophila Normal nets. Some accepted colour parameters such as a*/b* ratio are not appropriate for describing colour changes in 'Braeburn' apple in this study.

The present study was conducted with aim to test the effect of red photo-selective nets (Agritech S.r.l., Eboly, Italy) on 'Granny Smith' apple postharvest quality. The fruits have been harvested on optimal harvest date from orchard near city of Zadar where red photo-selective nets were used. Afterwards fruits were stored in regular air storage at 0°C for 4 months and then kept for 7 days at room temperature (shelf life). After harvest, cold storage and shelf life fruits grown under red net had significantly lower total soluble solid (SSC) content. After cold storage, superficial scald index and share of fruits with strong and very strong superficial scald severity were significantly higher in fruits grown under red net while for share of fruits with low superficial scald severity situation was opposite. After shelf life, fruits grown under red net had significantly higher titratable acidity (TA), but lower weight loss and SSC/TA ratio. It can be concluded that, due to greater susceptibility to superficial scald, prevention measures (optimal harvest time, 1-MCP and CA storage) should be applied when red photo-selective net is used on superficial scald-susceptible apple varieties.

The development of biodegradable materials as food packaging material is important not only due to the reduction in environmental pollution but also because of an improvement in the functionality. Rice husk-reinforced biopolymers have offered a possible solution to waste-disposal problems associated with traditional petroleum-derived plastics. Rice husk-reinforced low density polyethylene (LDPE)-based biocomposites have been of great interest for their use as food packaging material. In this work, the LDPE/RH biocomposites with different rice husk (RH) content (10, 20, 30, 40 and 50 wt.%) were prepared by the melt mixing process in a laboratory Brabender mixer. The effect of RH content on the physical, thermal and mechanical properties of LDPE was investigated. More importantly, this work aimed to research the biodegradation of the LDPE/RH biocomposites as well as their effect on ‘Granny Smith’ apples’ respiration. The results showed that the incorporation of RH into the LDPE decreased the thermal stability of LDPE, increased water vapour permeability and water absorption, and increased the degree of crystallinity. The incorporation of RH increased the biodegradability of LDPE as well as the postharvest quality of ‘Granny Smith’ apples. The addition of RH in LDPE film significantly decreased fruit respiration and increased firmness as compared to LDPE film. The composting results showed that after the LDPE/RH biocomposite films were biodegraded for 21 days, the biocomposite films with the highest content of rice husks were the most degraded.

GOSPODARSKE I ENOLOŠKE KARAKTERISTIKE OTPORNIH SORATA LOZA (VITIS SP.) U UVJETIMAZAGREBAČKOG VINOGORJA Sažetak S ciljem introdukcije i davanja preporuke za uvrštavanje na Nacionalnu listu priznatih kultivara vinove loze nekih od sorata s otpornošću na gljivične bolesti, na pokušalištu Agronomskog fakulteta "Jazbina" u Zagrebu, podignut je pokusni nasad sorata Bačka, Bianca, Merzling, Orion, Panonija, Phoenix, Sirius, Staufer i Regent. Istraživanja su provedena u periodu od 2007. do 2012. godine s osobitim naglaskom na gospodarske i tehnološke karakteristike koje sorte očituju na području Zagrebačkog vinogorja.Uvometrijskim mjerenjima i mehaničkom analizom grozda i bobice utvrđe-no je da su sve sorte s obzirom na randman tipično vinske, s visokim udjelom mesa u odnosu na čvrsti ostatak. Grozdovi su im mali do srednje veliki. Utvrđeni koeficijenti rodnosti pokazuju visok rodni potencijal istraživanih sorata, a kemijski sastav mošta ukazuje na njihov visok kvalitativni potencijal. Fizikalno-kemijska analiza vina i rezultati senzornih ocjenjivanja pokazuju kako su vina svih sorata bogata alkoholom, što je uz primjerenu kiselost i visoke količi-ne ukupnog ekstrakta rezultiralo dobrim ocjenama na senzornom ocjenjivanju. Kvalitetom su se osobito istaknule sorte Bianca i Regent s prosječnom ocjenom višom od 80 bodova, no i od ostalih sorata su u većini godina proizvedena vina koja su ocjenjivači svrstali u kategoriji kvalitetnih.Ključne riječi: vinske sorte s otpornošću na gljivične bolesti; međuvrsni križanci; gospodarske karakteristike; kvaliteta vina. UvodU drugoj polovici 19. st. iz Amerike u Europu, reznicama sjevernoameričkih vrsta podroda Euvitis, uneseni su filoksera (Viteus vitifoliae Fitch), pepelnica (Erysiphe necator) i plamenjača (Plasmopara viticola). Kako europska vinova loza (Vitis vinifera UDK: 634.8:582.783