Primjena fizikalnog predtremana abrazije u postupku sušenja šljive

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.