Effect of temperature on the physical changes and drying kinetics in plum (Prunus domestica L.) Pozegaca variety

Abstract

In this study, drying kinetics of autochthonous variety Požegača plum was examined in a laboratory dryer at three temperatures. The whole plum fruits, together with the kernels were subjected to the drying process. The effect of drying has been examined at temperatures of 55, 60 and 75 °C, with a constant air velocity of 1.1 m s -1 . The corresponding experimental results were tested using six nonlinear regression models. Coefficient of determination (R 2 ), standard regression error (SS E ), model correlation coeficient (V y ), as well as the maximum absolute error (ΔY) showed that the logaritmic model was in good agreement with the experimental data obtained. During drying of plums, the effective diffusivity was found to be between 5.6×10 -9 for 55 °C and 8.9×10 -9 m 2 s -1 at 75 °C, respectively. The physical characteristics of fresh (length 39.64 mm and width 29.15 mm) and dried (length 37.52 mm and width 22.85 mm) plum fruit were determined. Finally, by chemical analysis, the contents of micro-and macro-elements (Fe, Mn, Cu, B and N, F, K, Ca, Mg and S) in the skin and flesh of the dried product, prunes, has been established.Prunus domestica is the most numerous and diverse group of fruit tree species [1], but the extent of fundamental investigations concerning the prunes production is not appropriate to its importance. However, production of prunes has a long-established tradition in Serbia. The second part of the nineteenth and the begining of the twentieth century are considered to be the golden years for the export of prunes to the world markets. At that time, the plum fruit of the Požegača species were dried in primitive dryers operating on wood fire [2]. At that time, it was traditional that the optimal parameters for the ripeness of plum fruit were estimated on the basis of long term experience of fruit pickers. However, recent investigations show that, for successful prunes production, anthocyanin content, as well as the change in fruit colour in the last plum ripening stage, should be monitored [3].

The effect of processing method on drying kinetics of Petrovská klobása, an artisan fermented sausage

“…In order to determine the moisture content as a function of drying time, non-linear mathematical models in Table 1 were used by several authors [7,[10][11][12][13][14][15][16][17] to describe the thin layer drying of various fruits, vegetables, olive pomace, algae and fish. In order to determine the moisture content as a function of drying time, non-linear mathematical models in Table 1 were used by several authors [7,[10][11][12][13][14][15][16][17] to describe the thin layer drying of various fruits, vegetables, olive pomace, algae and fish.…”

Influence of different pre-treatments on the content of bioactive compounds of dried plum fruits

“…Drying time is influenced by air-drying temperature, product type, raw material preparation, application of pretreatments and type of dryer used, and in average lasts between 16 and 30 hours (Okos et al, 1992;Cvejanov et al, 2004;Grabowski et al, 2003;Živković, 2011).…”

Drying of oil palm frond particles in a fluidized bed dryer with inert medium

“…Examples of semi-theoretical models are the Lewis Several studies have been reported on mathematical modelling of agricultural products. The logarithmic model was shown to be suitable to describe the drying kinetics of plum [17], apple pomace [18], radish [19], hull-less seed pumpkin [20], plum [21] and figs [22]. The Henderson and Pabis model was found to be most suitable for describing the drying curves of banana, mango and cassava [16].…”