Effect of Vacuum Impregnation on Drying Kinetics and Selected Quality Factors of Apple Cubes

Abstract

The possibility of using the vacuum impregnation as a pretreatment before drying apple cubes was investigated. The impregnation was carried out for 4.5 min with the vacuum pressure of 0.01 MPa. The sucrose solution or a mixture of sucrose and the citric acid were used as infiltration liquids. Apple cubes were dried by convective drying (CD) (at temperature of 50 and 70 °C) or microwave-vacuum drying (MVD) (at power of microwaves 120 and 480 W). The drying kinetics was determined and quality factors (anti-oxidant activity, mechanical–rheological properties and colour changes) were analysed. Studies proved that the vacuum impregnation causes increasing of the drying dynamics (12.50–28.57 % during CD and 12.50–18.48 % during MVD). All impregnated apples were darker, yellower and susceptible for deformation or cutting than non-impregnated. The highest level of anti-oxidant activity was observed when two-component impregnant before MVD by power of 480 W was used.

Effect of Different Drying Techniques on Dehydration Kinetics, Physical Properties, and Chemical Composition of Lemon Thyme

“…This phenomenon can also be observed when analyzing the changes of the constants in the Page Model: the parameter k rose with increasing temperature (from 1.1400 to 1.1576) and the constant n increased slightly (from 0.0130 to 0.0137) ( Table 1). A similar correlation between microwave power and the process time was observed in studies involving the MFB drying of apples 29 and soya. 30 MV drying was the fastest of all the tested methods for lemon thyme dehydration.…”

Influence of Pretreatments on Microwave Vacuum Drying Kinetics, Physicochemical Properties and Sensory Quality of Apple Slices

“…The lowest value was observed in OD samples while the highest value was observed in ST samples. Pasławska et al [2017] and Kowalska et al [2018] reported similar phenomenon of TA value decrease after fruit immersion in a sugar solution. The changes in TA may be attributed to the elution of organic acids from tissue during OD process [Kowalska et al, 2018].…”

“…The loss in V C was attributed to the thermal disruption and leakage of water-soluble V C during pretreatment [Wang et al, 2018;Horuz et al, 2017]. However, it was reported that the presence of sugar would stabilize vitamin C in fruits [Pasławska et al, 2017].…”

“…Dried apples are rich in dietary fi ber and bioactive components, and are convenient to handle, store, and utilize [Pasławska et al, 2017;Blanda et al, 2008]. They are a part [Zhang et al, 2006].…”

The Influence of Vacuum Impregnation on Nutritional Properties of Fluidized Bed Dried Kale (Brassica oleracea L. Var. Acephala) Leaves

“…Under conditions of reduced pressure, the material comes into contact with the impregnating liquid, and then atmospheric pressure is restored, while a solution of various components penetrates the material’s porous surface until a balanced pressure is achieved (impregnation stage) [ 22 ]. There is a large amount of literature focused on effects of VI conditions on mass transfer phenomena or structure and mechanical properties of impregnated material [ 20 , 21 , 22 , 23 , 24 , 25 ]. However, little is known about the chemical modifications induced by pressure changes and/or impregnated molecules influencing nutritional properties of processed vegetables.…”