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Plodovi grejpfruta značajno se ističu bogatim nutritivnim sastavom, posebice sadržajem vitamina C, polifenolnih spojeva i snažnom antioksidacijskom aktivnosti. Sastav i sadržaj fitokemikalija uvelike ovisi o genetskim svojstvima vrste odnosno sorte. Stoga je i cilj ovog istraživanja bio utvrditi fizikalno-kemijska svojstva, sadržaj bioatkivnih spojeva i antioksidacijski potencijal plodova grejpfruta dviju različitih sorti: 'Marsh Seedless' i 'Natzumikan'. Obje sorte grejpfruta ubrane su u nasadu agruma na području Opuzena. Istraživane sorte ne razlikuju se značajno u sadržaju ukupne suhe tvari (prosječna utvrđena vrijednost 11,55%), topljive suhe tvari (prosječna utvrđena vrijednost 9,89%) kao ni u sadržaju vitamina C (prosječna utvrđena vrijednost 42,92 mg/100 g svježe tvari). No, značajnije razlike utvrđene su u sadržaju polifenolnih spojeva prilikom čega su kod sorte 'Natzumikan' utvrđene čak 66% više vrijednosti ukupnih fenola, 76% više ukupnih flavonoida i 54% više ukupnih neflavonoida u usporedbi sa sortom 'Marsh Seedless'. Također, sorta 'Natzumikan' imala je i značajnije veći antikodiacijski kapacitet (1,68 mmol TE/L). Temeljem svega može se zaključiti kako su plodovi grejpfruta značajan izvor vrijednih fitokemikalija, značajnih za ljudsko zdravlje., The fruits of grapefruit are characterised by a rich nutritional composition, especially the vitamin C content, polyphenolic compounds and a strong antioxidant activity. The composition and phytochemicals largely content depend on the genetic characteristics of the species or cultivar. Therefore, the aim of this study was to determine the physicochemical properties, bioactive compound content and antioxidant potential of grapefruit fruits of two different cultivars: 'Marsh Seedless' and 'Natzumikan'. Both grapefruit cultivars were harvested from a citrus orchard in the Opuzen region. The studied varieties did not differ significantly in the total dry matter content (average determined value 11.55%), total soluble solids (average determined value 9.89%), as well as in the of vitamin C content (average determined value 42.92 mg/100 g fresh matter). However, significant differences were found in the polyphenolic compounds content, with the variety 'Natzumikan' having as much as 66% more total phenols, 76% more total flavonoids and 54% more total non flavonoids compared to the variety 'Marsh Seedless'. Moreover, the cultivar 'Natzumikan' had significantly higher antioxidant capacity (1.68 mmol TE /L). From all this, it can be concluded that grapefruit fruit is a significant source of valuable phytochemicals important for human health.

Voštana prevlaka površine kožice ploda šljive ključna je prepreka gubitku vode prilikom postupka sušenja te ju je nužno ukloniti. Cilj ovog rada bio je istražiti utjecaj primjene različitih predtretmana, kemijskog (primjenom lužine), fizikalnog (primjenom abrazije) i toplinskog (ugrijanom destiliranom vodom) na vrijeme sušenja plodova šljive sorte 'President'. Također, varirani su i ključni parametri svakog pojedinog predtretmana poput temperature otopine prilikom toplinskog (22 i 60 °C), koncentracije (0,5, 1 i 1,5% v/v) i temperature (22 i 60 °C) lužine (KOH) kod kemijskog i vremenskog perioda abrazije (5, 10 i 15 min) kod fizikalnog. Prema dobivenim rezultatima, kemijski predtretman lužinom koncentracije 1 i 1,5% temperature 60 °C bio je najučinkovitiji, vrijeme sušenja iznosilo je svega 27 sati, adok je samo 2 sata dulje (29 h) trajalo sušenje plodova predtretiranih abrazijom u vremenu od 15 min. Temeljem svega, može se zaključiti kako je fizikalni predtretman abrazijom izrazito učinkovit u uklanjanju voštane prevlake, time i u skraćivanju vremena sušenja plodova šljive, a isto tako treba naglasiti kako primjenom abrazivnog predtretmana značajno utječemo na smanjenje onečišćenja okoliša, ali i na zdravlje ljudi, s obzirom da nema ostataka kemijskih sredstava koja nakon primjene treba adekvatno zbrinuti, jer potencijalno mogu negativno utjecati na čovjeka i okoliš., Wax coating from the surface of the plum fruit skin is a key barrier to water loss during the drying process and it is necessary to remove it. Therefore, the aim of this study was to examine the impact of the application of different pre-treatments, i.e. chemical (using alkali solution), physical (using abrasion) and thermal (heated distilled water) on the drying time of plum fruits cv. 'President'. Also, the key factors of each pre-treatment varied, such as the temperature of the solution in the thermal pre treatment (22 and 60 °C), the concentration (0.5, 1 and 1.5% v/v) and the temperature (22 and 60 °C) of the alkali solution (KOH) in the chemical and time duration of abrasion (5, 10 and 15 min) in the physical pretreatment, while the influence of each pre-treatment was researched. According to the obtained results, chemical pre-treatment with alkali solution concentration of 1 and 1.5% temperature of 60 °C was most effective in shortening the drying time of plums, lasted only 27 hours, while only 2 hours longer (29 h) lasted the drying of plums pre-treated by abrasion of 15 min. Based on all mentioned, it can be concluded that the physical pre-treatment by abrasion is extremely effective in removing the wax coating thus affecting shortening the drying time of plum fruits, and it should be emphasized that the application of abrasive pretreatment significantly affects the reduction of environmental pollution, but also human health, given that there are no chemical residues that after application should be adequately disposed of, which can affect humans and environment.