Eva Ivanišová

The antioxidant and antimicrobial activity of essential oils against Pseudomonas spp. isolated from fish

Natural products of plant origin, which include essential oils (EO) could be used as a growth inhibitor of pathogenic and spoilage microflora in food. The objective of this study was to determine the antibacterial and antioxidant activity of 21 EO against 10 Pseudomonas species isolated from freshwater fish. The chemical composition of EO was determined by gas chromatography/mass spectrometry. The disc diffusion method and detection of minimum inhibitory concentration (MIC) were used for the determination of the antimicrobial activity. All the EO tested exhibited antimicrobial activity, however, Cinnamomum zeylanicum EO was the most effective against Pseudomonas spp. both according to the disc diffusion and MIC methods. The EOs of Cymbopogon nardus, Origanum vulgare, Foeniculum vulgare and Thymus serpyllum showed the highest antioxidant activity of 93.86 μg, 83.47 μg, 76.74 μg and 74.28 μg TEAC/mL. Application of EO could be an effective tool for inhibition of growth of Pseudomonas spp. on fish.

Antioxidant Activity of Milling Fractions of Selected Cereals

Antioxidant Activity of Milling Fractions of Selected Cereals The aim of this study was to evaluate antioxidant potential of four milling fractions of selected cereals grew in the year 2009 and 2010. Free radical scavenging activity of samples was measured using DPPH assay and reducing power was determined using FRAP assay. Secondary, total phenolic and flavonoid content of cereal extracts was evaluated. We found that flour fractions (break flour and reduction flour) showed the lower proportion of the total antioxidant potential than bran fractions (fine bran and coarse bran), which was balanced in observed years. Extract from barley had the highest values of antioxidant activity and polyphenol content.

Gluten-free bread with an addition of freeze-dried red and purple potatoes as a source of phenolic compounds in gluten-free diet

Abstract The basis for gluten-free diet is often gluten-free bread, which is usually characterized by a low-nutritional value, and lacks any pro-health properties. Only after an introduction of gluten-free raw materials, containing high level of bioactive compounds it would be possible to obtain the product with a pro-health potential. The aim of the study was to analyze the content of bioactive compounds (total phenolic content, phenolic acids, flavonoids, flavonols, anthocyanins and carotenoids) in gluten-free bread prepared with 5% addition of freeze-dried red and purple potatoes as well as to assess their antioxidant potential. Summarizing, among the analyzed gluten-free breads with an addition of freeze-dried red and purple potatoes, the best results could be obtained by using variety Magenta Love (red potato), which provided the highest levels of phenolic compounds and carotenoids and also antioxidant and antiradical activity.

Biological properties of black mulberry-derived food products ( Morus nigra L.)

BACKGROUND: Black mulberry is a good source of bioactive compounds and especially of anthocyanin. OBJECTIVES: The objective of this study was to evaluate the morphological, biochemical, technological and antioxidant properties of black mulberry fruit and fruit-derived food products. MATERIALS AND METHODS: Total anthocyanin content, total sugar content, ascorbic acid content, pH and antioxidant activity was analyzed in black mulberry juice, jam, jelly, syrup, liqueur, compote, wine and cake. All products were produced from selected genotypes of black mulberry grown in Slovakia. RESULTS: Reducing sugar content ranged from 6.50 mg.kg–1 FM in wine to 60.01 mg.kg–1 FM in jam, ascorbic acid content was from 0.27 mg.100 g–1 FM in wine to 1.10 mg.100 g–1 FM in fruits conserved in honey without sterilization. Content of anthocyanin varied from 21.4 in wine to 106.4 mg.dm–3 in fresh juice. Detected pH values ranged from 3.28 in jelly to 3.69 in liqueur. All tested samples had strong DPPH• radical scavenging activity with the best values in black mulberry compote with honey – 74.02% and jam 71.22% FM. Differences between the genotypes were significant and the content of the anthocyanin was significantly higher in genotypes with lower fruit weight (P ≤ 0.05). CONCLUSION: The results showed that black mulberry fruits and derived products are rich in biologically active compounds and can be used in food industry and human nutrition.

Bee bread - perspective source of bioactive compounds for future

Bee bread is product with long history used mainly in folk medicine. Nowadays, bee bread is growing in commercial interest due to its high nutritional properties. The objective of this study was to determine biological activity of ethanolic extract of bee bread obtained from selected region of Ukraine - Poltava oblast, Kirovohrad oblast, Vinnica oblast, Kyiv oblast, Dnepropetrovsk oblast. The antioxidant activity was measured with the radical scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical as well as phosphomolybdenum assay. Total polyphenol content was determined with Folin-Ciocalteau reagent and total flavonoid content by aluminium-chloride method. Secondary was also evaluated antimicrobial activity in bee bread samples with disc diffusion method and minimum inhibitory concentrations . Antioxidant activity expressed as mg TEAC per g of dry weight (Trolox equivalent antioxidant capacity) was the highest in bee bread from Poltava oblast in DPPH and also phosphomolybdenum method. Samples of bee bread contained high levels of total polyphenols (12.36 - 18.24 mg GAE - gallic acid equivalent per g of dry weight) and flavonoids (13.56 - 18.24 μg QE - quercetin equivalent per g of dry weight) with the best values of bee bread from Poltava oblast. An elevated level of antioxidant potential in the bee bread determines its biological properties, which conditioned of the biological active substances. The best antibacterial activity of bee bred with disc diffusion method was found against Bacillus thuringiensis CCM 19. The antibacterial activity inhibited by the bee bread extract in the present study indicate that best minimal inhibition concentration was against bacteria Escherichia coli CCM 3988 and Salmonella enterica subs. enterica CCM 3807.

ANTIOXIDANT EFFECTS OF HERBAL EXTRACTS AND THEIR FOOD APPLICATION

Herbal extracts are considered as a good sources of antioxidant compounds. This work describes antioxidant effect of 15 kinds of herbs. Three different antioxidant assays were used, Trolox equivalent antiradical activity (TEAC), test based on deoxyribose oxidation and DPPH method. The TEAC values ranged from 0.38mM to 0.77 mM. Deoxyribose assay showed antioxidant activity of selected extracts expressed as the inhibition of formation of oxidative products of deoxyribose from 2.68 to 50.05 %. The DPPH method values ranged from 6.47 to 73.80 %. Extracts of Prunus spinosa L., Euphrasia rostkoviana Hayne were the best antioxidants confirmed by all methods. Scrophularia nodosa L. extract showed the weak antioxidant effect determined by all selected methods. Phenolic content was in relation to the antioxidant effect of herbs, very high significancy between DPPH and polyphenols content was found. To improve selected properties of apple juice (taste, smell, functional properties) by addition of medicinal herbs was achieved in this work. Antioxidant effect of apple juice variants with herbs additions determined by DPPH method was high and ranged from 73 to 78.49 %. Herbal extracts can be utilised in selected combinations to improve sensory and functional properties of some kinds of beverages. doi:10.5219/75

Evaluation of primary and secondary metabolites in selected varieties of potatoes.

The aim of study was to determine primary and secondary metabolites in selected varieties of potatoes. Potatoes ( Solanum tuberosum L.) are good source of bioactive compounds, mainly phenols as one of the most important components. The chemical composition with reducing sugar, starch, ascorbic acid, total polyphenol and flavonoid content were analyzed in five potato varieties (Agria, Marabel, Red Anna, Picasso, Princess). Values of dry matter content ranged from 20.34 to 23.64%. In terms of tubers storage, its content above 20% is required. The highest level of starch was detected in variety Princess (16.82%). The lowest reducing sugar content was recorded by variety Marabel (0.08%). Similarly, low values reached varieties Princess (0.12%), Agria (0.14) and Red Anna (0.16%). These would be appropriate to use for food processing and for production of fried potato chips or fries. Variety Red Anna reached the highest amount of vitamin C (73.72 mg.kg -1 ). The lower levels of this vitamin showed tubers of varieties Picasso (35.02 mg.kg -1 ) and Princess (36.89 mg.kg -1 ). The antioxidant activity was measured with radical scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical as well as phosphomolybdenic assay. Potato varieties contained high levels of total polyphenols (0.474 – 1.550 mg GAE per dry weight) and flavonoids (1.407 – 15.933 μg QE per dry weight). The consumption of potatoes can provide nutritional value along with antioxidant potential that can be helpful for proper functioning of the body physiological systems. Statistical evaluation by the single factor analysis of variance detected high significant impact of variety on the content of all the analytical parameters in evaluated varieties of potato tubers. Normal 0 21 false false false SK X-NONE X-NONE

Composition of fatty acids in selected vegetable oils

Plant oils and fats are important and necessary components of the human nutrition. They are energy source and also contain fatty acids - compounds essential for human health. The aim of this study was to evaluate nutritional quality of selected plant oil - olive, rapeseed, pumpkin, flax and sesame; based on fatty acid composition in these oils. Fatty acids (MUFA, PUFA, SFA) were analyzed chromatography using system Agilent 6890 GC, injector multimode, detector FID. The highest content of saturated fatty acids was observed in pumpkinseed oil (19.07%), the lowest content was found in rapeseed oil (7.03%), with low level of palmitic and stearic acids and high level of behenic acid (0.32%) among the evaluated oils. The highest content of linoleic acid was determined in pumpkinseed (46.40%) and sesame oil (40.49%); in these samples was also found lowest content of α-linolenic acid. These oils have important antioxidant properties and are not subject to oxidation. The richest source of linolenic acid was flaxseed oil which, which is therefore more difficult to preserve and process in food industry. In olive oil was confirmed that belongs to the group of oils with a predominantly monosaturated oleic acid (more than 70%) and a small amount of polysaturated fatty acid. The most commonly used rapeseed oil belongs to the group of oils with the medium content of linolenic acid (8.76%); this oil also showed a high content of linoleic acid (20.24%). The group of these essentially fatty acids showed a suitable ratio ∑n3/n6 in the rapessed oil (0.44).

Evaluation of Antioxidant Activities of Cereals and their Malts

Abstract The aim of this study was to determine the influence of malting on the antioxidant content in cereals such as wheat (PS Sunanka, Zaira, PS 57/11 and Vanda), oat (Dunajec) and barley (Laudis 550) harvested in 2013. Antioxidant and polyphenol contents of these cereals and malts were investigated. Secondary, technological parameters of prepared malts were evaluated and compared with malt from barley Laudis 550 used as reference material. Malting of selected cereals had an impact on antioxidant and polyphenol content and allowed a better extraction of these compounds from cereal matrix, except of barley malt, whose antioxidant and total polyphenol content remained comparable. For other cereal malts, antioxidant contents were 2.0, 1.8, 2.6, 2.9 and 3.2-fold higher and total polyphenol content were 1.8, 1.9, 1.9, 3.1 and 3.4-fold higher than in wheat (PS Sunanka, Zaira, PS 57/11, Vanda) and oat (Dunajec), respectively. From correlation analysis, the results showed that not all polyphenols released by malting have antioxidant activity. Technological parameters (friability, haze of wort, saccharification rate, filtration rate, extract and diastatic power) also indicated that good malt quality had oat Dunajec and wheat PS Sunanka and Zaira in comparison with reference material (barley Laudis 550).

MOLECULAR PROPERTIES OF SELECTED POLYSACCHARIDES DETERMINED BY SEC CHROMATOGRAPHY AND THEIR IMPACT ON WATER ABSORPTION OF WHEAT FLOUR

Chemical composition and solubility in water of selected polysaccharides as β-glucan, arabinoxylan and inulin preparation were determined. All these preparation were of good purity, they consist of at least 71% of polysaccharide of intrest. Solubility in water was the highest in the case of inulin and the lowest in the case of β-glucan. Molecular properties of examined preparations were determined by SEC chromatography. β-glucan and arabinoxylan were of much higher molecular mass than inulin. Molecular mass of examined polysacharides was corelated with increase of water absorption of the flour caused by 2% addition of each polysaccharide. doi:10.5219/173