Natural compounds as environmentally friendly corrosion inhibitors of aluminium

The compounds of interest in the present study were the natural compounds rutin and quercetin, which are strong antioxidants and have beneficial effects on human health (Myake & Shibamoto, 1997). They are present in everyday foods and beverages and in this way they are used as an integral part of human diet. Therefore, it seemed interesting to investigate the influence of these valuable natural compounds on corrosion processes of aluminium, an ambalage material often used in food industry (Jovanovic et al., 1994). All the investigations were performed in 3% solution of sodium chloride, in aqueous rutin and quercetin solutions as well as in rutin and quercetin solutions in 3% sodium chloride solution. Concentrations of rutin and quercetin solutions used ranged from 10-2 to 10-5 mol dm-3, and investigations involved electrochemical methods. The results obtained showed that rutin and quercetin previously dissolved in 0.1 M NaOH and added to the 3% sodium chloride solution at concentrations of 10-4 and 10-5 mol dm-3 acted as aluminium corrosion inhibitors, while at higher concentrations (10-2 and 10-3 mol dm-3) their effects were opposite. The efficiency of the corrosion inhibition of aluminium by rutin and quercetin solutions was the result of forming protective film on the metal surface. Therefore, the diluted rutin and quercetin solutions could be used as corrosion inhibitors of aluminium

Ionske kapljevine – razvoj i izazovi industrijske primjene

Establishment of novel, highly productive, and sustainable processes for the production of industrially important compounds is becoming a growing area of research. Due to non-volatility, inflammability, great thermal, chemical and electrochemical stability and also recyclability, ionic liquids are extensively studied as possible green replacement for widely used conventional molecular solvents. Due to the extremely large number of possible chemical structures of ionic liquids, the ability to design ionic liquids for specific applications makes them unique solvents in electrochemistry, analytical chemistry, organic synthesis and (bio)catalysis, separation processes, as well as functional fluids (lubricants, heat transfer fluids, corrosion inhibitors etc.). This paper presents a review of the scientific and technical literature related to ionic liquids, their basic properties, preparation and application, as well as the challenges of their application on an industrial scale.Uspostavljanje novih visokoučinkovitih i održivih procesa proizvodnje industrijski važnih kemikalija predmet je brojnih znanstvenih istraživanja. Stoga se ionske kapljevine, zbog neznatne hlapljivosti, nezapaljivosti, velike toplinske, kemijske i elektrokemijske stabilnosti, te posebice mogućnosti regeneracije, posljednjih godina intenzivno proučavaju kao zelena zamjena za sveprisutna tradicionalna škodljiva otapala. Budući da je broj mogućih kemijskih struktura ionskih kapljevina iznimno velik, mogućnost dizajniranja ionskih kapljevina za specifične namjene čini ih jedinstvenim otapalima za raznovrsnu uporabu u elekrokemiji, organskoj sintezi i (bio)katalizi, analitici, separacijskim postupcima, ali i kao funkcionalnih kapljevina (sredstva za podmazivanje, akumulatori topline, inhibitori korozije i dr.). U ovom je radu dat pregled znanstvene i stručne literature vezane uz ionske kapljevine, njihova karakteristična svojstva, pripravu i primjenu, ali i izazove njihove primjene u industrijskom mjerilu

Distribution of glucosinolates in some raw and processed Brassica vegetables grown in Croatia

The interest in food with chemoprotective properties has been steadily increasing due to many epidemiological studies indicating the lower probability of acquiring some kinds of cancer (e.g. colon, prostate, breast, cervical) in populations, whose diet includes large quantities of Brassica vegetables. The biologically active compounds in Brassica vegetables are the breakdown products of glucosinolates, including isothiocyanates, nitriles, thiocyanates, indoles and oxazolidinethiones from which indoles and isothiocyanates in particular have been implicated to have anticarcinogenic properties. The object of the present study was to investigate glucosinolates distribution as well as their losses during blanching and cooking in edible parts of white cabbage, cauliflower, kohlrabi and collard. In all vegetable, only indole glucosinolates as precursors of anticarcinogenic compounds were identified, while glucoraphane was not detected. In cauliflower and collard, proportion of indole glucosinolates was more then 90%, followed by kohlrabi (>70%) and white cabbage (>50%). Analysis of glucosinolates losses during blanching and cooking showed substantial decrease in all vegetables. The major losses were observed for cauliflower, around 60%, for cooked vegetable, followed by white cabbage (55%), kohlrabi (53%) and collard (44%). The losses after blanching were approximately 15% less then in cooked vegetables

Comparison of selected bioactive compounds and antioxidative capacity in different broccoli cultivars

Numerous recent publications have compared different cultivars of broccoli and different cultivation conditions suggesting that great variations in the content of phytochemicals among cultivars are due to genetic, and many environmental factors. The purpose of the present work was the quantification of glucosinolates, phenolic compounds, carotenoids, and antioxidant capacity in the florescences of 13 genotypes from freshly harvested broccoli grown under uniform agroecological practices. The present results showed a significant variation in the level of bioactive compounds and consequently potential health benefits of broccoli (total glucosinolates 12.04–22.48 μmol g−1 d.w., the total phenolic content 15.54–26.92 mg g−1 d.w., total carotenoid content 0.19 mg g−1–0.46 mg g−1 d.w.). Studied cultivars were different in the level of the individual bioactive compounds, although some cultivars had higher content of all three analysed bioactive compounds such as Marathon, Ironman and General cultivar. In addition, these three cultivars showed excellent marketable properties and we choose them for the further breeding program in order to study variation among bioactive compounds in more details