As a by-product of the winemaking process, grape seeds have been receiving increased attention worldwide due to a number of beneficial nutritional properties. Moreover, grape seed oil has also been gaining prominence for its high content of unsaturated fatty acids, primarily linoleic acid (C18:2) (72-76%). The objective of this paper was to determine the influence of three different grape seed drying temperatures (20, 40 and 60 °C) on the quality of cold-pressed oils from five different grape varieties (Pinot noir, Pinot blanc, Muscat, Cabernet sauvignon and Graševina). The oils extracted were tested for the acid number (as an indicator of hydrolysis), the percentage of free fatty acids and the peroxide value (as an indicator of autoxidation). The peroxide values of the oil samples considered increased with the increasing drying temperature of grape seeds. The highest peroxide value was observed in the oil samples produced from the Graševina seeds (regardless of the grape seed drying temperature), whereas the Muscat oil samples exhibited the lowest peroxide values. The acid number and the percentage of free fatty acids of the oil samples considered were found to be variety specific and independent of the grape seed drying temperature.

The object of the mycorrhizal association between vine and fungus is to increase the absorption of water and/or nutrients from the soil. The aim of this research was to investigate the influence of mycorrhiza to the final product-wine. Besides, for the fermentation process authentic yeasts and four different commercial strains of yeasts were used. Grapes were grown in the wine growing region of Kutjevo, Croatia, in 2013. A typical variety from this region is Graševina. Obtained samples of wines were tested for alcohol, total acids, total polypfenol content (Folin-ciocalteu method), antioxidant activity (ABTS and DPPH method) and color hue. Sensory evaluation was done by professional tasters. Results showed that the usage of the different starter cultures of yeasts had different influences on wine depending on the mycorrhiza. Samples with mycorrhiza had a good extraction of polyphenols with the usage of authentic yeasts, while without micorrhiza starter cultures showed better results, which was evident in the physical and sensory properties as well.

The aim of the study was to determine the effect of a live mycorrhizal vaccine on the dynamics of grapevine’s plant nutrient supply. The experiment was performed on the Graševina variety (Vitis vinifera L.), grafted on an SO4 rootstock in the conditions of the Kutjevo Vineyards. The training system was Guyot, with a 10‐bud load. In the root system’s immediate vicinity, 20 ml of mycorrhizal suspension containing approximately 2,000 propagation units of a live mycorrhizal mycelium were inoculated. From the viticultural aspect, the research was conducted in two climatically very different years. The first research year (2014) was characterized by an abundant precipitation and less sunny days, resulting in a later technological grape maturity, amounting to 34 days when compared to the year 2015, which was extraordinarily warm and arid during the grape ripening period. In both research years, in the conditions of the soil’s low supply with the organic matter, phosphorus, and potassium, a mycorrhizal symbiosis influenced the higher content of phosphorus and potassium in the Graševina’s dry leaf matter. In a year experiencing more precipitation and less heat, a higher nitrogen content was found in the vine leaves manifesting a mycorrhizal symbiosis. In the dry and warm conditions, the calcium content was increased during the entire period of grape ripening, and a justifiably higher content of zinc, manganese, and iron was found in the period immediately preceding a technological grape ripeness. A positive influence of mycorrhiza on the yield, sugar content, and total acidity was not determined.

Cilj ovoga rada bio je utvrditi učinak gnojidbe dušikom (N) od 30 odnosno od 45 kg/ha, kao i trima komercijalnim dušičnim gnojivima, CaNO3 (15% N), KAN (27% N) i YaraMilaTM Cropcare (8:11:23), na agronomska svojstva: prinos, cijenu i vrijednost suhoga lista, kao i na šest morfoloških svojstava duhana tipa virdžinija. U poljski pokus, proveden u četiri okoline, bila su uključena tri hrvatska kultivara duhana. Gnojidba dušikom imala je signifikantan učinak samo na komponente prinosa: duljinu, širinu i površinu 9. lista, čije su vrijednosti kod gnojidbe s 45 kg N/ha bile za 2,2; 3,5 odnosno 5,8% veće u odnosu na gnojidbu s 30 kg N/ha. Tip korištenoga dušičnog gnojiva nije imao signifikantan učinak niti na jedno ispitivano svojstvo. Uzorak korelacija između morfoloških i gospodarskih svojstava bio je pod utjecajem okoline, kao i razine gnojidbe. Iako nije utvrđen učinak gnojidbe na gospodarska svojstva, signifikantno povećanje komponenata prinosa kod gnojidbe s 45 kg N/ha, u usporedbi s 30 kg N/ha, upućuje na višu razinu gnojidbe kao jamstvo osiguranja visokih i stabilnih prinosa te kvalitete osušenoga lista.

Iako klasična proizvodnja bijelih vina podrazumijeva fermentaciju mošta, suvremeni trendovi podrazumijevaju proizvodnju bijelih vina uz maceraciju, odnosno fermentaciju masulja. Cilj ovog rada bio je utvrditi utjecaj duge maceracije grožđa na kakvoću vina 'Graševina'. Istraživanje je provedeno tijekom 2021. godine u vinogradima i vinskom podrumu Veleučilišta u Požegi u vinogorju Kutjevo. Nakon berbe, kontrolni uzorak vina proizveden je klasičnim postupkom proizvodnje bijelih vina, te su provedena dva tretmana duge maceracije u periodu od 3 mjeseca - jedan uz sulfitiranje tijekom primarne prerade a drugi bez sulfita. U vinima su analizirani osnovni parametri kakvoće, koncentracija jabučne i mliječne kiseline, optička gustoća pri 280 nm, ukupni fenoli i antioksidativna aktivnost DPPH metodom. Statistički značajna razlika zabilježena je kod ukupnih fenola, kao i antioksidativnoj aktivnosti, s najvećim vrijednostima u maceriranom uzorku uz primjenu SO2. Organoleptičko ocjenjivanje uzoraka proveli su certificirani ocjenjivači, metodom 100 bodova. Najveću prosječnu ocjenu od 87 bodova dobilo je vino proizvedeno dugom mareracijom grožđa uz redovito sulfitiranje. Kontrolni tretman slabije je ocijenjen, sa 72 boda. Vino proizvedeno dugom maceracijom bez korištenja sulfita ocjenjeno je sa 66 boda uz napomenu pojedinih ocjenjivača o izraženoj oksidaciji.