Process parameters and pre-treatment methods influence on the drying kinetics and quality of sweet potato (Ipomea batatas L.) dried in the convective tray drier

Istraživanje kinetike sušenja batata (Ipomea batatas L.) provedeno je u konvekcijskom tunelskom sušioniku pri različitim temperaturama sušenja (50, 60, 70 i 80 °C), brzini strujanja zraka od 2,8 $ms^{-1}$ te različitim vrstama prethodne obrade svježih uzoraka. Primijenjeni fizikalno-kemijski postupci prethodne obrade uzoraka bili su: blanširanje u vreloj vodi, blanširanje na pari; uranjanje u: 0,5 %-tnu otopinu askorbinske kiseline, 0,15%-tnu otopinu 4-heksilresorcinola (4-HR) te 0,3 %-tnu otopinu L-cisteina (LC). Prethodna obrada s 0,15 %-tnom otopinom 4-HR rezultirala je značajnim skraćenjem ukupnog vremena sušenja i visokim rehidratacijskim omjerom, dok je prethodna obrada s 0,3 %-tnom LC rezultirala najmanjom ukupnom promjenom boje.The drying characteristics of sweet potato (Ipomea batatas L.) were investigated using a laboratory convective tray drier at different drying temperatures and pre-treatments. The drying temperatures were 50, 60, 70, 80 °C, and airflow velocity 2.8 $ms^{-1}$. Different physical and chemical pre-treatments of sweet potato samples were applied as follows: hot water and steam blanching; dipping in: 0.5% ascorbic acid solution, 0.15% 4-hexylresorcinol (4-HR) solution, 0.3% L-cysteine (LC) solution. Pre-treatment with 0.15% 4-HR resulted in the most reduced drying time and high rehydration ratio, while pre-treatment with 0.3% LC solution resulted in the minimum colour change

Arsenic in Eastern Croatia – problems and solutions

Groundwater in Eastern Croatia contains elevated concentrations of inorganic arsenic. The biggest well field in the area has an average arsenic concentration of 200 μg/L and it supplies the population of around 200,000 people with drinking water. Croatian Regulation has adopted guidelines from the European Council Directive for the maximum concentration limit (MCL) of 10 μg/L of As in drinking water. However, it has been estimated that almost 120,000 people drink water from that well field with a concentration of arsenic over 10 μg/L. To reduce the health risks associated with arseniccontaminated water intake in Eastern Croatia it is important to develop proper strategies that will use one of the following technologies for arsenic removal: oxidation, coagulation-flocculation, adsorption, ion exchange or membrane technologies

Water for all : Proceedings of the 7th international scientific and professional conference Water for all

The 7th International Scientific and Professional Conference Water for all is organized to honour the World Water Day by the Josip Juraj Strossmayer University of Osijek, European Hygienic Engineering & Design Group (EHEDG), Danube Parks, Croatian Food Agency, Croatian Water, Faculty of Food Technology Osijek, Faculty of Agriculture in Osijek, Faculty of Civil Engineering Osijek, Josip Juraj Strossmayer University of Osijek Department of Biology, Josip Juraj Strossmayer University of Osijek Department of Chemistry, Nature Park “Kopački rit”, Osijek- Baranja County, Public Health Institute of the Osijek- Baranja County and „Vodovod-Osijek“ -water supply company in Osijek. The topic of World Water Day 2017 was "Wastewater" emphasizing the importance and influence of wastewater treatments on global environment. The international scientific and professional conference Water for all is a gathering of scientists and experts in the field of water management, including chemists, biologists, civil and agriculture engineers, with a goal to remind people about the significance of fresh water and to promote an interdisciplinary approach and sustainability for fresh water resource management. The Conference has been held since 2011. About 300 scientists and engineers submitted 95 abstracts to the 7th International Scientific and Professional Conference Water for all, out of which 33 was presented orally and 62 as posters. 47 full papers were accepted by the Scientific Committee. 38 full papers became the part of the this Proceedings while 9 papers were accepted for publication in Croatian Journal of Food Science and Technology and Electronic Journal of the Faculty of Civil Engineering Osijek - e-GFOS

Process parameters and pre-treatment methods influence on the drying kinetics and quality of sweet potato (Ipomea batatas L.) dried in the convective tray drier

Istraživanje kinetike sušenja batata (Ipomea batatas L.) provedeno je u konvekcijskom tunelskom sušioniku pri različitim temperaturama sušenja (50, 60, 70 i 80 °C), brzini strujanja zraka od 2,8 $ms^{-1}$ te različitim vrstama prethodne obrade svježih uzoraka. Primijenjeni fizikalno-kemijski postupci prethodne obrade uzoraka bili su: blanširanje u vreloj vodi, blanširanje na pari; uranjanje u: 0,5 %-tnu otopinu askorbinske kiseline, 0,15%-tnu otopinu 4-heksilresorcinola (4-HR) te 0,3 %-tnu otopinu L-cisteina (LC). Prethodna obrada s 0,15 %-tnom otopinom 4-HR rezultirala je značajnim skraćenjem ukupnog vremena sušenja i visokim rehidratacijskim omjerom, dok je prethodna obrada s 0,3 %-tnom LC rezultirala najmanjom ukupnom promjenom boje.The drying characteristics of sweet potato (Ipomea batatas L.) were investigated using a laboratory convective tray drier at different drying temperatures and pre-treatments. The drying temperatures were 50, 60, 70, 80 °C, and airflow velocity 2.8 $ms^{-1}$. Different physical and chemical pre-treatments of sweet potato samples were applied as follows: hot water and steam blanching; dipping in: 0.5% ascorbic acid solution, 0.15% 4-hexylresorcinol (4-HR) solution, 0.3% L-cysteine (LC) solution. Pre-treatment with 0.15% 4-HR resulted in the most reduced drying time and high rehydration ratio, while pre-treatment with 0.3% LC solution resulted in the minimum colour change

Oxidation of organic compounds : final thesis

Ovome radu bio je cilj obraditi oksidaciju organskih spojeva. Kako bi razumjeli njihovu oksidaciju prvo su postavljeni temelji ovoga rada stoga je on podijeljen u dva poglavlja. Prvi dio se odnosi na oksidaciju u anorganskoj kemiji. U ovome poglavlju razjašnjeni su pojmovi kao što je oksidacijski broj, njegovo pravilno odrađivanje te koliko je maksimalno moguć pozitivan, odnosno negativan oksidacijski broj nekog atoma. Također, obrađene su i redoks reakcije te je razjašnjeno što su oksidacijska i redukcijska sredstva te kako se može odrediti je li neki spoj dobro oksidacijsko odnosno redukcijsko sredstvo. U drugom poglavlju možemo vidjeti da i organski spojevi ulaze u redoks-reakcije, ali pri tom prijelaz elektrona najčešće nije potpun. Nastaju promjene u kovalentnom vezivanju među atomima različite elektronegativnosti stoga se ovaj tip reakcija koristiti za sintezu organskih spojeva kao što su aldehidi, ketoni i karboksilne kiseline.This papre deals whit oxidation of organic compounds. To fully understand their oxidation we need to first understand the redox-reactions, therefore we have divided him into two chapters. The first part refers to the oxidation in inorganic chemistry. In this chapter we introduce the terms such as oxidation number, its proper determination and as much as possible the maximum positive or negative oxidation number of an atom. Also, we have covered redox reactions and we have clarify what are oxidizing and reducing agents, how can we determine whether some compound is good oxidizing or reducing agent. In the second chapter we can see that the organic compounds are also included in the redox reaction, but at the same time transfer of electrons are not usually complete. That is because changes in covalent bounding are occurring between the atoms of different electronegativity, therefore this type of reactions are used for the synthesis of organic compounds such as aldehydes, ketones and carboxylic acids