Hplc analysis of phenolic acids in mountain germander (Teucrium montanum L) extracts

The methanol, petroleum ether, chloroform, ethyl acetate, 1-butanol and water extracts were obtained by extraction of mountain germander (Teucrium montanum L). The total phenolic content in extracts was measured by Folin-Ciocalteu method. The 1-butanol extract had the highest phenolic content (296.00 mg/g). High performance liquid chromatography (HPLC) was employed to define qualitative and quantitative content of phenolic acids in mountain germander extracts. The largest number of phenolic acids were determined in ethyl acetate and 1-butanol extracts, while these acids were not present in petroleum ether extract. The highest content of phenolic acids (28.619 mg/g) had ethyl acetate extract and gentisic acid (14.432 mg/g) was its major component. Despite of a large number of phenolic acids in 1-butanol extract their content was only 3.740 mg/g

Elisa and HPLC analyses of deoxynivalenol in maize and wheat

Deoxynivalenol (DON) is a part of the family of mycotoxins called trichothecenes which are produced by a number of different Fusarium mold species. The presence of DON in 25 wheat and 25 maize samples was examined by Enzyme Linked Immunosorbent Assay (ELISA) and High Performance Liquid Chromatography (HPLC) methods. The presence of DON was detected and determined in 5 (20%) maize and 6 (25%) wheat samples by both of the methods. Correlation between ELISA and HPLC results was established, with the correlation coefficients (r) of 0.9691 and 0.9735 for wheat and maize samples, respectively. The results obtained by ELISA method were significantly higher than those obtained by HPLC method. This fact can be explained by the presence of conjugated or masked mycotoxins in the samples, especially DON-3-glucoside (DON-3-Glc), which could not be determined by HPLC method due to the lack of external standards. Contrary to this, being insufficiently selective towards masked DON, ELISA method measures total DON content of a sample. According to the obtained results, ELISA can be used as a reliable screening method, but the confirmation of positive results must be done by HPLC method

Characterization of extra-hard cheese produced from donkeys’ and caprine milk mixture

International audienceAbstractCheese cannot be produced solely from equine or donkeys’ milk, because of the unique physico-chemical properties of these milks. The purpose of this study was to characterize a novel dairy product, cheese produced from donkeys’ and caprine milk mixture (60:40% v/v), regarding its chemical, microbiological, textural and sensory properties. Fully ripened cheese was classified as a high-fat, extra-hard cheese, with high sodium (29.97 g.kg−1), magnesium (3.07 g.kg−1) and potassium (4.70 g.kg−1) content. The characterization by lab-on-a-chip electrophoresis revealed lysozyme, α-lactalbumin, immunoglobulins and casein fractions. Palmitic (C16:0) and oleic fatty acids (C18:2 n9-cis) with 25.11 and 24.70%, respectively, were found at the highest concentrations. The medium-chain fatty acids account 18.21% of the total fatty acid content in analysed cheese samples. Escherichia coli, Salmonella spp., Enterobacteriaceae, coagulase-positive staphylococci, Listeria monocytogenes, Bacillus cereus, Clostridium perfringens as well as moulds were under the limit of detection in all analysed samples. After 6 months of cheese ripening (0.94 aw, pH 4.71), total bacterial count, the counts of lactic acid bacteria and yeasts were 6.34 ± 0.03, 4.80 ± 0.10 and 5.81 ± 0.11 log CFU.g−1, respectively. The texture of mature cheese was moderately hard and crumbly. The cheese was described as very salty with strong pronounced creamy, fatty and acidic taste. The characterized donkey/caprine cheese could position this type of cheese as a high-quality functional product, thus having a potential impact on the market

Screening of mycotoxins in animal feed from the region of Vojvodina

This paper shows the results of screening of mycotoxins in animal feed originating from the region of Vojvodina. Permanent screening is needed on all levels of production and storage, as well as the use of known methods to reduce mould contamination or toxin content in feedstuffs and feed. A total of 56 representative samples were collected from feed companies from the region of Vojvodina. Samples were collected during February 2009. The collected samples included 41 samples of feedstuffs (soybean, soybean meal, soybean grits, soybean cake, maize, sunflower meal, barley, wheat feed flour, rapeseed meal, dehydrated sugar beet pulps, alfalfa meal, yeast, dried whey, fish meal, meat-bone meal) and 15 samples of complete feedingstuffs. The amounts of aflatoxins, ochratoxin A, zearalenone, fumonisin and deoxynivalenol were determined. Screening method for the analysis was done using Neogen Veratox® testing kits. The test itself is a competitive direct enzyme-linked immunosorbent assay (CD-ELISA). Mycotoxins were present in 71.4% of the samples, but the values determined were below the maximum allowed limits for both Serbian and EC reference values. Zearalenone was found with the highest incidence (57.1% of samples), followed by ochratoxin A (37.5%), fumonisin (33.9%), deoxynivalenol (14.3%) and aflatoxins (3.6%)

Catalyst design for Rh-catalysed arene and alkane C-H borylation : the NHC affects the induction period and indenyl is superior to Cp

The authors would like to thank the Royal Society of Chemistry (Undergraduate Summer Research Bursary to A.L.B., Research Fund grant R21-6824221494) and the EPSRC (DTP PhD studentship award to P.A.M., Vacation Internship to L.S., and EP/M024210/1 for supporting B.E.T.) for funding. A.P. thanks the Institute of Chemical Sciences for the award of a bursary to support a summer research project. The authors would also like to thank Johnson Matthey plc for the award of platinum group metal materials used in their research (loan of RhCl3, PGMAS38).In order to establish design criteria for Rh C-H borylation catalysts, analogues of the successful catalyst [Rh(Ind)(SIDipp)(COE)] (Ind = η5-indenyl, SIDipp = 1,3-bis(2,6-diisopropylphenyl)-4,5-dihydroimidazol-2-ylidene, COE = cis-cyclooctene) were synthesised by changing the indenyl and carbene ligands. [RhCp(SIDipp)(COE)] (1) formed alongside the C-C activated, cyclometallated by-product [RhCp(κ2CAr,Ccarbene-SIDippʹ)(iPr)] (rac-2; SIDippʹ = 1-(6-isopropylphenyl)-3-(2,6-diisopropylphenyl)-4,5-dihydroimidazol-2-ylidene). Computational modelling of COE dissociation showed that both C-C and C-H activation of the SIDipp aryl group is thermally attainable and reversible under experimental conditions, with the C-C activation products the more thermodynamically stable species. Oxidative addition of 1 with SiH(OEt)3 gave the Rh silyl hydride [RhCp(H){Si(OEt)3}(SIDipp)] (rac-3). [Rh(Ind)(IDipp)(COE)] (4; IDipp = 1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene), the carbonyl analogue [Rh(Ind)(IDipp)(CO)] (5; νCO = 1940 cm-1, c.f. 1944 cm-1 for [Rh(Ind)(SIDipp)(COE)]) and [Rh(Ind)(IMe4)(COE)] (6; IMe4 = 1,3,4,5-tetramethylimidazol-2-ylidene) were also characterised, but attempts to synthesise Rh carbene complexes with fluorenyl or 1,2,3,4-tetrahydrofluorenyl ligands were not successful. For the catalytic C-H borylation of benzene using B2pin2, 1 was inactive at 80°C, and [Rh(Ind)(SIDipp)(COE)] was superior to all other complexes tested due to the shortest induction period. However, addition of HBpin to precatalyst 4 eliminated the induction period. Catalytic n-alkane C-H borylation using [Rh(Ind)(NHC)(COE)] gave yields of up to 21% alkylBpin but [RhCp*(C2H4)2] was the better catalyst.Peer reviewe

Uticaj različitih hemijskih sredstava i uslova skladištenja na mikrobiološki profil semena industrijske konoplje (Cannabis sativa L.)

This study aimed to test different chemical agents to obtain microbiologically safe industrial hemp seeds that could be used for further food processing (with the reduced total number of microorganisms, total number of moulds and yeasts, and total number of Enterobacteriaceae). In order to obtain seeds applicable for food consumption, optimal storage temperature conditions (room temperature, refrigerator, freezer), method of seed packaging (vacuum/without vacuum), and the application of various chemical treatments (ethanol, sodium hydrogen carbonate, sodium hypochlorite) were tested on the certified industrial hemp seeds, produced in two consecutive years. Optimal storage conditions differed for different microorganisms, and the most optimal storage was at room temperature, for seeds produced in 2018, in the treatment to reduce the total number of Enterobacteriaceae and the total number of microorganisms. When storing seeds from 2018 in order to reduce the number of yeasts and moulds, a slightly lower number was spotted when seeds were stored in a vacuum-sealed bag, at the refrigerator/freezer temperature. For hemp seeds produced in 2019, the most optimal storage conditions were at the refrigerator (for reduction of the total number of Enterobacteriaceae) and freezer temperature (for reduction of the total number of microorganisms). For the reduction of the total number of moulds and yeasts, optimal conditions were at room temperature. Ethanol (75%, v/v) was the most effective disinfectant among the tested chemicals regardless of the initial number of microorganisms, with log reduction of 3.2 (for the total number of Enterobacteriaceae), 2.9 log (for the total number of microorganisms), and total reduction of the total number of yeasts and moulds after 10 minutes, for the seeds harvested in 2019, which were far more contaminated than the seeds harvested in 2018. Considering the price of the disinfection method with ethanol, sodium hypochlorite may be a better solution for the reduction of the number of microbiota on the seeds.Cilj ovog istraživanja bio je ispitivanje različitih hemijskih sredstava za dobijanje mikrobiološki bezbednog semena industrijske konoplje, koje bi se moglo koristiti za dalju preradu u hranu (sa smanjenim ukupnim brojem mikroorganizama, ukupnim brojem kvasaca i plesni, i ukupnim brojem enterobakterija). Da bi se dobilo seme primenljivo za ishranu, optimalni temperaturni uslovi skladištenja (sobna temperatura, frižider, zamrzivač), način pakovanja semena (vakuum/bez vakuuma) i primena različitih hemijskih tretmana (etanol, natrijum hidrogen karbonat, natrijum hipohlorit) su testirani na sertifikovanom semenu industrijske konoplje, proizvedenom u dve uzastopne godine. Optimalni uslovi skladištenja su se razlikovali za različite mikroorganizme, a najoptimalnije skladištenje je bilo na sobnoj temperaturi, za seme iz 2018. godine, a u cilju smanjenja broja enterobakterija i ukupnog broja mikroorganizama. Pri skladištenju semena iz 2018. godine u cilju smanjenja broja plesni i kvasaca primećen je nešto manji broj datih mikroorganizama kada je seme čuvano u vakuumski zatvorenoj vrećici, na temperaturi frižidera/zamrzivača. Za seme konoplje iz 2019. godine najoptimalniji uslovi skladištenja su bili na temperaturi frižidera (za redukciju broja enterobakterija) i u zamrzivaču (za redukciju ukupnog broja mikroorganizama). Za smanjenje ukupnog broja plesni i kvasaca, optimalni uslovi su bili na sobnoj temperaturi. Etanol (75%, v/v) je bio najefikasnije sredstvo za dezinfekciju među ispitivanim hemijskim sredstvima, bez obzira na početni broj mikroorganizama, sa log smanjenjem od 3,2 (za ukupan broj enterobakterija), 2,9 log (za ukupan broj mikroorganizama) i ukupnim smanjenjem broja kvasaca i plesni nakon 10 minuta delovanja, za seme proizvedeno 2019. godine, koje je bilo mnogo više kontaminirano u odnosu na seme iz 2018. godine. Uzimajući u obzir cenu metoda dezinfekcije etanolom, natrijum hipohlorit može biti bolje rešenje za smanjenje broja mikrobiota na semenu