Application of modern pre-treatments in plum drying

The purpose of this study is to determine the influence of abrasive pre-treatments on plum drying time compared to the conventional ones. The mechanical pre-treatment examined included the abrasion at three different cylinder rotation times: 5, 10 and 15 min. The chemical pre-treatment under consideration included the immersion of plums in alkaline solution (KOH) of different concentrations (0.5, 1 and 1.5% (v / v)) at 60 °C for one minute. The thermal treatment performed included the immersion of fruits in distilled water at 60 °C for one minute. As a control (untreated) sample, fruits with waxy lawyers were used. According to the results obtained, the drying time of plums was significantly reduced compared to the control sample (97 h): in the samples treated with distilled water (thermal treatment) drying time was reduced by 21 h, whereas the drying time reduction of up to 68 h was reorded using a KOH solution of 1.5%. In the samples pre-treated by abrasion for 15 min, the drying time recorded was also reduced by 68 h compared to the control samples, thus proving the exceptional efficiency of abrasive pre-treatment in plum drying.