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1

Drying of red beetroot after osmotic pretreatment: Kinetics and quality considerations

100%

Kowalski S. J., Łechtańska J. M.

Chemical and Process Engineering

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2015

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vol. 36

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issue 3

345-354

EN

This article presents experimental studies on drying kinetics and quality effects of red beetroot (Beta vulgaris L.) after convective drying with a preliminary osmotic pretreatment. The effects of the osmotic agent (NaCl) concentration and the osmotic bath time on the product colour and nutrient content preservation, the water activity, and rehydration ability after drying were analysed. Osmotic dehydration curves and Solid Gain (SG), Water Loss (WL), Weight Reduction (WR) were determined. It was proved that drying of beetroot with osmotic pretreatment contributes to shorter drying time, smaller water activity, higher retention of betanin, better colour preservation, and a greater degree of water resorption.

2

Drying of red beetroot after osmotic pretreatment: Kinetics and quality considerations

88%

Kowalski S. J., Łechtańska J. M.

Chemical and Process Engineering

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2015

|

issue 3

3

Influence of preliminary osmotic dehydration on drying kinetics and final quality of carrot (Daucus carotaL.)

88%

Kowalski S., Mierzwa D.

Chemical and Process Engineering

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2011

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vol. 32

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issue 3

185-194

EN

This paper concerns convective drying of carrot preliminary dehydrated in aqueous solutions of three types of osmotic agents (sucrose, fructose, glucose). Three solution concentrations (20, 40 and 60%) were examined to work out efficient conditions of osmotic dewatering. The parameters such as water loss (WL), solid gain (SG) and osmotic drying rate (ODR) indicating the real efficiency of osmotic dehydrations (OD) were determined. The samples dehydrated with osmotic solutions underwent further convective drying to analyze influence of dehydration process on drying kinetics and final products quality. The quality of products was assessed on the basis of visual appearance of the samples and colorimetric measurements. It was found that osmotic pretreatment improves significantly the final product quality as the samples were less deformed and their colour was better preserved compared to samples, which had not been preliminarily dehydrated. Preliminary dehydration, however, did not influence significantly the overall drying time of the samples.

4

Ultrasound-assisted osmotic dehydration and convective drying of apples: Process kinetics and quality issues

75%

Mierzwa D., Kowalski S. J.

Chemical and Process Engineering

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2016

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vol. 37

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issue 3

5

Influence of preliminary osmotic dehydration on drying kinetics and final quality of carrot (Daucus carota L.)

75%

Kowalski S., Mierzwa D.

Chemical and Process Engineering

|

2011

|

issue 3

6

Quality Aspects of Fruit and Vegetables Dried Convectively with Osmotic Pretreatment

75%

Kowalski S. J., Łechtańska J. M., Szadzińska J.

Chemical and Process Engineering

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2013

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issue 1

7

Quality Aspects of Fruit and Vegetables Dried Convectively with Osmotic Pretreatment

75%

Kowalski S. J., Łechtańska J. M., Szadzińska J.

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vol. 34

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issue 1

51-62

EN

This article presents a quality analysis of convectively dried fruits and vegetables with preliminary osmotic dehydration. Tests were carried out on banana fruit and red beetroot samples. Hypertonic solutions of fructose for the banana and those of sucrose for the red beetroot were used, each one at three different concentrations. After osmotic dewatering treatment conducted at different time intervals and after osmotic dehydration the samples were dried convectively until an equilibrium with the surroundings was attained. Osmotic dehydration and convective drying curves were determined. The values of Solids Gain (SG), Water Loss (WL) and Weight Reduction (WR) were measured and changes in the samples’ colour and shape after convective drying with and without osmotic pretreatment were assessed.

8

Determination of Chemical Composition of Plums During Pre-Treatment and Drying

63%

Walkowiak-Tomczak D.

Ecological Chemistry and Engineering S

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2012

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vol. 19

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issue 1

89-96

EN

Thanks to drying, fruits are available on the market throughout the year. Parameters of drying conditions affect eg the content of bioactive compounds in the product. The aim of the study was to investigate the effect of pretreatment conditions and the applied drying method on changes in the chemical composition of plums. Analyses were conducted on plums cv. 'Valor', which were subjected to pre-treatment including blanching, drilling and osmotic dehydration. Next they were dried by the convection method at air temperature of 60°C and flow rate of 1.5 m/s. Dehydration was run in a 61.5% sucrose solution at a temperature of 50°C for 1 or 2 h. Convection-dried plums, with no osmotic dehydration applied, constituted the reference sample. In fresh, dehydrated and dried fruits determinations included dry matter, polyphenols by colorimetry with the Folin reagent and contents of sugars by colorimetry using 3,5-DNS acid. As a result of blanching and dehydration the content of dry matter increased. Water loss after dehydration amounted to as much as 1.45 g H2O/g d.m.0 after 2 h in comparison with blanched plums. As a result of dehydration total contents of sugars and polyphenols in plums decreased (mg/100 g d.m.). In convection-dried prunes the content of polyphenols was by 30÷50% higher than in the raw material, but lower than in the reference sample.

PL

Suszenie owoców pozwala na utrzymanie ich dostępności na rynku przez cały rok. Parametry warunków suszenia wpływają m.in. na zawartość związków bioaktywnych w produkcie. Celem pracy było badanie wpływu procesów obróbki wstępnej i metody suszenia na zmiany składu chemicznego śliwek. W badaniach wykorzystano śliwki odmiany 'Valor', które poddano obróbce wstępnej, obejmującej blanszowanie, drylowanie i odwadnianie osmotyczne. Następnie poddano je suszeniu metodą konwekcyjną przy temperaturze powietrza 60°C i przepływie 1,5 m/s. Odwadnianie prowadzono w 61,5% roztworze sacharozy, w temperaturze 50°C, w czasie 1 lub 2 godzin. Jako próbkę odniesienia przyjęto śliwki suszone konwekcyjnie z pominięciem odwadniania osmotycznego. W owocach świeżych, odwadnianych i suszonych oznaczano zawartość suchej substancji, polifenoli metodą kolorymetryczną z odczynnikiem Folina oraz zawartość cukrów metodą kolorymetryczną przy użyciu kwasu 3,5-DNS. W wyniku blanszowania i odwadniania zwiększyła się zawartość suchej substancji. Ubytek wody po odwadnianiu, w porównaniu do śliwek blanszowanych, wyniósł do 1,45 g H2O/g s.s.0 po 2 h. W wyniku odwadniania w śliwkach obniżyła się ogólna zawartość cukrów oraz polifenoli (mg/100 g s.s.). W śliwkach dosuszonych konwekcyjnie zawartość polifenoli była wyższa o 30÷50% niż w surowcu, ale niższa niż w próbce odniesienia.

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Drying of red beetroot after osmotic pretreatment: Kinetics and quality considerations

Drying of red beetroot after osmotic pretreatment: Kinetics and quality considerations

Influence of preliminary osmotic dehydration on drying kinetics and final quality of carrot (Daucus carotaL.)

Ultrasound-assisted osmotic dehydration and convective drying of apples: Process kinetics and quality issues

Influence of preliminary osmotic dehydration on drying kinetics and final quality of carrot (Daucus carota L.)

Quality Aspects of Fruit and Vegetables Dried Convectively with Osmotic Pretreatment

Quality Aspects of Fruit and Vegetables Dried Convectively with Osmotic Pretreatment

Determination of Chemical Composition of Plums During Pre-Treatment and Drying