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

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%)

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

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

Effect of Packaging Methods and Storage Time on Oxidative Stability of Traditional Fermented Sausage

In this paper influence of packaging method (vacuum and modified atmosphere packaging) on lipid oxidative stability and sensory properties of odor and taste of the traditional sausage Petrovská klobása were examined. These parameters were examined during storage period (7 months). In the end of storage period, vacuum packed sausage showed better oxidative stability. Propanal content was significantly lower (P<0.05) in vacuum packed sausage compared to these values in unpacked and modified atmosphere packaging sausage. Hexanal content in vacuum packed sausage was 1.85 µg/g, in MAP sausage 2.98 µg/g and in unpacked sausage 4.94 µg/g. After 2 and 7 months of storage, sausages packed in vacuum had the highest grades for sensory properties of odor and taste

Antioxidant activity of wheat and buckwheat flours

Antioxidative activities of wheat flours (type 500 and wholegrain) and buckwheat flours (light and wholegrain) were tested using 1,1-diphenyl-2-picrylhydrazyl (DPPH·)-scavenging activity, reducing power and chelating activity on Fe2+. Also, the content of the total phenolics of ethanolic extracts was estimated. Polyphenolics content (expressed as gallic acid equivalent, GAE) in wheat flours varied between 37.1 and 137.2 μg GAE/g extract, while its content in buckwheat flour were at least four time higher and ranged between 476.3 and 618.9μg GAE/g extract. Ethanolic extracts of buckwheat flours exhibited higher antioxidant activities in all the assays, except for chelating activity. Regarding all the obtained results, it can be concluded that bakery products produced with buckwheat flour could be regarded as potential functional foods

Antioxidant activity of white grape seed extracts on DPPH radicals

Composition and antioxidant activity of grape seed extract (GSE) obtained from red grape varietes are very well documented, in contrast to the white varietes. This paper presents the results of polyphenols content of ethyl acetate extract of grape seeds, obtained from two white grape varieties, Italian Riesling and Župljanka, and their antioxidant activity on the stable DPPH radical. The influence of the addition of GSE to raspberry juice on the DPPH radical was also examined. Content of total polyphenols in GSEs ranged between 81.6 and 82.8% (w/w), and the contetn of flavan-3-ols between 66.2 and 91.0% (w/w). HPLC results showed that the most abundant components in the extract were (+)-catechin and (-)-epicatechin for both grape varieties. All tested GSEs exhibited good antioxidant activity. IC50 values for the GSEs of Italian Riesling and Župljanka were 0.79 and 0.95 mg sample/mg DPPH radical, respectivelly. Since the GSE of Italian Riesling possesed stronger antioxidant activity, it was used for further experiments. The IC50 value for raspberry juice was 4.18 mg raspberry juice/mg DPPH. The raspberry juice with addition of 0.60 μg/mL of GSE showed antioxidant activity of 39.2%. The same juice with the threefold concentration of vitamin C (1.81 μg/ml) exhibited similar antioxidant activity (33.9%). Antioxidant activity of the same amount of juice without added antioxidants was lower (15.7%). The results showed that the GSE of white varietes could be considered as a good functional food ingredient

Effect of mint (Mentha piperita L.) and caraway (Carum carvi L.) on the growth of some toxigenic aspergillus species and aflatoxin B1 production

An inhibitory effect of various concentrations (0.0, 0.5, 1.0, 1.5 and 2,0%) of mint (Mentha piperita L.) and caraway (Carvum carvi L.) on the growth of A. fumigatus, A. flavus and A. ochraceus was examined during 10 days of cultivation in YES medium at temperature of 25°C. Mint showed stronger inhibitory effect than caraway. Total dry weight (g/l) after 10 days of the growth of A. fumigatus in YES medium with 0.5% of mint decreased by about 95%, A. flavus by 97% and A. ochraceus by about 82%. Addition of higher concentrations of mint (1.0, 1.5 and 2.0%) reduced the growth of all tested species. It was poor and hardly visible. pH values of the media increased with the increase of mint concentrations. A. fumigatus showed the highest sensitivity towards caraway and A. flavus the lowest. Total dry weight (g/l) after 10 days of growth of A. fumigatus in medium with 0.5% of caraway decreased by about 72% in comparison to the control. In media with higher concentrations of caraway, its growth was found to be very poor. Concentration of 1.0% of caraway reduced A. flavus growth by 15% and of 1.5% by 92%, in regard to the control. In medium with 2.0% of caraway the growth of A. flavus was observed as poor and hardly visible. The growth of A. ochraceus in medium with 0.5% of caraway decreased by about 85% comparing with control and further decrease was noticed by the increase of concentrations. In medium with 1.5% of caraway a reduction of about 95% of growth was found and under 2.0% of caraway it was poor. pH of the media also increased with the increase of caraway concentrations. Applied concentrations of mint and caraway inhibited completely the production of AB1 by A. flavus

Mycotoxins in maize: Annual variations and the impact of climate change

The presence of aflatoxins (AFs), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), and fumonisins (FUMs) was examined in maize samples from the Republic of Serbia. The maize samples were collected during the period 2012-2016, and analyzed every year after harvest using validated Enzyme Linked Immunosorbent Assay (ELISA) method. The obtained results were considered regarding the weather conditions parameters recorded during the investigated maize growing seasons. Significant differences in weather-related parameters recorded in the five-year period resulted in different mycotoxin profiles between the investigated years. Obtained results indicate that the presence of ZEA and DON in maize is characteristic of years with abundant precipitation, while AFs and OTA mainly occur in maize during hot and dry years. Furthermore, FUMs were detected with different contamination frequency in maize samples from every year. Based on the findings obtained in this study, as well as on noted changes in weather conditions in the recent years it could be assumed that maize from Serbia may become susceptible to problems concerning mycotoxins. Therefore, there is a necessity for monitoring and research related to the mycotoxins occurrence in maize from Serbia