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

100%

Walkowiak-Tomczak D.

Ecological Chemistry and Engineering S

2012

vol. 19

issue 1

89-96

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.

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.

Sewage Sludge-To-Energy Management In Eastern Europe: A Polish Perspective

80%

Werle S.

Ecological Chemistry and Engineering S

2015

vol. 22

issue 3

459-469

The Sewage Sludge Directive 86/278/EEC was adopted about 30 years ago with a view to encourage sewage sludge reuse in agriculture and to regulate its use. Meanwhile, some EU Member States have adopted stricter standards and management practices than those specified in the Directive. In particular, the majority of Member States has introduced more stringent standards for sludge quality, including stricter limits for most potentially toxic elements, organic contaminants and other elements. In general, untreated sludge is no longer applied and in several Member States it is prohibited. In some cases, stringent standards have resulted in an effective ban on use of sludge in agriculture. Moreover, the implementation of the Urban Wastewater Treatment Directive 91/271/EC should increase EU production of sewage sludge, thus enhancing problems related to sustainable sewage sludge management. Additionally, European legislation prohibits the landfill and water deposits of sewage sludge. The latest trends in the field of sludge management, ie combustion, pyrolysis, gasification and co-combustion, have generated significant scientific interest. This trend is specially strong visible in “new” EU Members countries which have to introduce strong EU Directive in their low system. Here the review the state of knowledge and technology in thermal methods for the utilization of municipal sewage sludge to obtain useful forms of energy such as pyrolysis, gasification, combustion, and co-combustion taking into consideration Poland situation is presented.

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2 Ecological Chemistry and Engineering S

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1 Walkowiak-Tomczak D.

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

Sewage Sludge-To-Energy Management In Eastern Europe: A Polish Perspective