engleski

Influence of different pretreatments efficiency on plum fruit drying

Plum fruits are submitted to different pretreatments prior to drying in order to remove waxy layer from fruit skin with aim to foster dehydration and expedite drying time. The aim of the research was to determine the influence of pretreatments on drying period and organoleptic fruit quality of three plum cultivars: Hauszwetschge 'Schüfer', President and Topend. Sorted and pitted plum fruits were treated by following pretreatments: mechanically by abrasion on 5, 10 and 15 min ; submerging in water on 22 °C and 60 °C and chemically by submerging fruits in KOH solution diluted to 0, 5%, 1, 0% and 1, 5% on temperatures (22 °C, 60 °C) in 90 sec interval, along with untreated fruits as control sample. Pretreated fruits were dried to 35% moisture content in M. Buchner AG Typ 16B drier up to 30 kg capacity. Dried fruits were evaluated with quantitative descriptive organoleptic analysis on 1 to 7 scale by trained panelist. Drying time of plum fruits in this research in mechanical pretreatments was the shortest for abrasion in duration of 15 min and ranged from 28 (Bistrica, President) – 35 hours (Topend). Fruits submerged in KOH 1, 5% solution on 60 °C had the shortest drying time of chemical pretreatments and ranged from 26 (President) – 29 hours (Topend). Drying time of control sample was 74 hours. Cultivars significantly differed in organoleptic analysis with regards to colour, taste and aroma parameters (P ≤ 0, 05). KOH pretreatments on 60 C° were aggressive to fruit skin degradation and exhibited ununiformed drying of fruits. Correspondingly, they obtained lower scores for blue color intensity parameter (2, 61) in relation to other pretreatments (4, 24 ; 5, 00). Cultivars Hauszwetschge 'Schüfer' and Topend pretreated by abrasion in average scored the highest with regards to plum taste (4, 12 – 4, 24) and plum aroma (4, 27 – 4, 33) parameters.

plums ; pretreatment ; drying ; cultivars

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