Potravinarstvo Slovak Journal of Food Sciences
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Polyphenols and antioxidant capacity in different types of garlic
Get PDFGarlic contains important biologically active compounds such as phytoncides, antioxidants and others. There belong organosulfur compounds, allyl thiosulfinates and phenolic compounds (phenolic acids, flavonoids), vitamins (E and C) and some minerals, that all have several positive effects on human health. In the work five types of raw garlic (Allium sativum) of Czech, Chinese and Spanish origin, and bear's garlic (Allium ursinum), and two dried garlic products, were evaluated for polyphenols content and antioxidant capacity. The highest values of total polyphenols (TP), analyzed by spectrometric method with Folin-Ciocalteu reagent, had fresh samples of bear's and Spanish garlic; the lowest ones were evaluated for Czech garlic bulbs (92.2 - 119.6 mg GAE.100g-1 fw) and dry garlic products (70.1 - 84.5 mg GAE.100g-1). The total antioxidant capacity (TAC) was determined by spectrometric methods with DPPH and ABTS reagents. To types of fresh garlic with the best values of antioxidant capacity, evaluated by both methods, belong bear's and Spanish garlic, followed by Chinese and Czech garlic samples. These values are in agreement with polyphenols content in garlic bulbs. Dry garlic products had the highest values of TAC. Content of polyphenols and antioxidant capacity values were positively correlated, higher correlation value was detected for TP and TAC-ABTS (0.973) than for TP and TAC-DPPH (0.873). Bear's garlic and garlic belong to the vegetable types with high amount of biologically active compounds such as antioxidants
The morphological and antioxidant characteristics of inflorescences within wild-growing genotypes of elderberry (Sambucus nigra L.)
Get PDFThe aim of this study was to determine the basic morphological characteristics (weight, length) and antioxidant activity (using DPPH method) of elderberry (Sambucus nigra L.) inflorescences as well as some elderberry-derived food products prepared from fresh (honey, alcoholic extract, tea infusions) and dried inflorescences (syrup). For the study of problematic, it was used 113 wild-growing genotypes of elderberry from 56 locations in Slovakia growing at an altitude of 98.15 - 712.32 m. The weight of fresh inflorescences ranged from 0.45 to 57.59 g (75.65% coefficient of variation value), the total length of inflorescences ranged from 19.0 to 282.0 mm (22.42%), the length of inflorescence´s stems from 9.0 to 197.0 mm (31.51%), a number of petals predominated pentanumerous petals. Variability in primary and secondary branching reported a low to high degree of variability among as well as within the genotypes. Results showed significant differences in the shape of inflorescences and the colour of flowers among each genotype. Antioxidant activity by DPPH method in elderberry inflorescence water extract was between 85.12 and 89.29%. Activation of tea infusions and beverages was ensured using a mechanism Kalyxx based on galvanic effect. In beverages made from 10% diluted honey prepared from fresh inflorescences in the carbohydrate-based extract, anti-radical activity was determined in the range of 16.81 - 24.16%. In an alcoholic extract from fresh inflorescences, anti-radical activity was between 90.99 and 93.16%. In beverages acquired from the syrup of flowers, we identified antioxidant activity ranging from 37.92 (10%) to 62.82% (40%). Results indicated that elderberry inflorescences and elderberry-derived food products can be attractive to consumers and in future can increase the assortments of healthy products
Assesment of molecular diversity of internal transcribed spacer region in some lines and landrace of Persian clover (Trifolium resupinatum L.)
Get PDFClover which is an herbaceous, annual, and self-pollinated plant belongs to fabaceae family (legumes) and has become naturalized in Iran, Asia Minor and the Mediterranean eastern suburban countries. The aim of the present study is ITS molecular evaluation of the nuclear ribosomal genes of lines and landraces of Persian Clover. The sequences were aligned using ClustalW method and by MegAlign software and the dendrogram of different phylogenetic and matrix relationships between the sequences were drawn. The results showed little genetic diversity between the lines and the landrace. The conserved sequence of the analyzed gene in the Persian clover is 561 base. Totally, 740 loci (69 and 671 loci, respectively, with and without removal and addition), 9 Singletons, and 5 haplotypes were identified. The highest rate of transfer was observed in pyrimidine (%16.3). The numerical value of the ratio (dN/dS) was 0.86, and since it was less than 1, the pure selection on the studied gene happened. The lines and landraces were not separated based on their geographic locations. In general, the results indicated that the highest rate of the regional diversity belonged to the clover plants in Lorestan region. Moreover, ITS markers did not seem suitable enough for evaluating the intra- species genetic variation, but it was quite well- suited for inter-species or intergeneric evaluation
Relationship between viscosity and sugar content of must during ripening period of grapes
Get PDFThe relationship between dynamic viscosity and sugar content of the must is important indicator during the ripening of the vine grapes. For the experiment were selected and used only grape vine varieties. The grape vine varieties are divided into blue and white. The varieties of Blaufränkisch, Blauer Portugieser, and Cabernet Moravia were used in the blue varieties. Representatives of the white varieties were used Pinot Blanc, Pinot Gris, and Sauvignon. Country of origin was the Czech Republic, wine region Moravia (sub-region Slovácko). The grapes were collected and analyzed four times week after week during their ripening period. After grapes harvesting the individual berries were cut out of grape using the scalpel. These berries were then weighed and then the must was squeezed using a mechanical presser. Weight of berries, dynamic viscosity (in shear strain rate 100 s-1), sugar content, and density of must were measured and evaluated. From the values of berries weight it can be observed the variations in weight depending especially on the weather change - the water content in the berries. The observed sugar content did not change a lot during maturity, which can be explained by a more mature phase of the grapes. The results of viscosity and sugar content (for all varieties) demonstrate the viscosity dependence on the sugar content of must - with increasing viscosity of the must the sugar content of the must increase and conversely. The knowledge of the physico-mechanical properties os wine must is very important for for technocologists, producers, but also wine consumers
Nutrition marketing of honey: chemical, microbiological, antioxidant and antimicrobial profile
Get PDFHoney and all bee products have very good biological and chemical properties. They have been used in medicine for a long time. In our study we evaluated twenty polyfloral honey samples, the first ten were commercial honeys from a selected supermarkets with country of origin indicated "blend of EU and non-EU honeys" and represented imported honey. The second ten honeys were from a local beekeepers (Nitra region) and represented the Slovak origin. The aim of the study were to analyze chemical, microbiological, antioxidant, antimicrobial profile of honey and recommend marketing strategies for honey producers by applying nutrition marketing. From chemical point of view, the study examined mineral profile of honeys, antioxidant properties as antioxidant activity, total polyphenols, flavonoid and phenolic acid content and from microbiological view the study evaluated a total count bacteria, coliform bacteria and microscopic filamentous fungi. Results of minerals showed that the most dominant element in commercial honeys is sodium (30 mg.100g-1) followed by calcium, potassium, magnesium and phosphorus. Iron, arsenic and selenium are present only in trace amounts. In local honeys the most dominant element is potassium (84.181 mg.100g-1) followed by calcium, phosphorus, sulfur and magnesium. The presence of hazardous heavy metals (cadmium, lead and chrome) was not detected in either of the samples. Moreover, antioxidant activity determined by the DPPH method was slightly higher in local polyfloral honeys and vice versa the content of total polyphenol, flavonoid and the phenolic acid content was slightly higher in commercial polyfloral honeys. From the microbiological point of view, the total count of bacteria was found only in commercial polyfloral honeys while local honeys were without detectable microorganisms. The best antimicrobial activity was found against gram-negative bacteria such as Escherichia coli in both concentrations of honeys, and the local honeys reached better antimicrobial activity. All in all, honey has very good biological properties and mineral composition which opens opportunities for beekeepers to apply nutrition marketing and target new segments of consumers, e.g. sportsmen, people in convalescence, consumers following healthier lifestyle or seeking functional food. Moreover, educating consumers from a nutritional point of view will foster daily intake of honey and will increase annual consumption of honey in the future
Quantitative and qualitative parameters in Acorn squash cultivar in the conditions of the Slovak Republic
Get PDFThe species Cucurbita pepo includes several types of squashes; in Slovak Republic, well-known and oftenly grown squash types are patisson, zucchini, spaghetti squash, oil pumpkin etc. Several interesting squash types of Cucurbita pepo are grown abroad, including Acorn squash which is well-known mainly in USA. The aim of this study was to evaluate the important quantitative (yield per hectare, average fruit weight) and qualitative (total carotenoids, ascorbic acid, antioxidant activity, total soluble solids) yield parameters of Acorn squash fruits in comparison with patisson which is typical squash type of Cucurbita pepo in Slovak Republic. The field trial was realised in Košice-Šaca in 2016. Within experiment, four cultivars of Acorn type pumpkin were tested (Thelma Sanders; Jet Set; Table Gold; Cream of The Crop). The patisson 'Orfeus' was used as a comparative cultivar for evaluation of individual parameters of Acorn type pumpkin cultivars. Matured pumpkin fruits were harvested on the 7th September 2016. From aspect of yield quantity, Acorn cultivars are appeared as very interesting squash type with good yield potential for growing. The highest yield of squash fruits was found in the cultivar 'Cream of The Crop' (17.8 t.ha-1). In mentioned Acorn cultivar, the yield was higher about 87.4% compared to the tested patisson cultivar 'Orfeus' (9.5 t.ha-1). On the contrary, the average weight of squash fruits was reached in patisson cultivar 'Orfeus' (780.7 g). The qualitative parameters of fruits were expressively influenced by squash cultivar. The content of total carotenoids, ascorbic acid and total soluble solids was markedly higher in all Acorn cultivars, compared to the patisson cultivar 'Orfeus'. The highest content of total carotenoids (26.74 mg.kg-1 fresh weight) and ascorbic acid (238.79 mg.kg-1 f. w.) was found in the squash cultivar 'Table Gold'. The highest content of total soluble solids was determined in the cultivar 'Jet Set' (3.8 °Brix). On the contrary, the highest antioxidant activity (DPPH) was found in the patisson cultivar 'Orfeus' (10.80 %). On the basis of obtained results, it is possible to state that Acorn cultivars are very interesting squash type with promising yield potential for possible growing in conditions of Slovak Republic. In addition, Acorn squashes were expressed by higher content of several nutritional parameters compared to the typical squash type - patisson. Thus, these squashes could be an interesting vegetable for human nutrition
Global rheological approach to the quality of the rollers pumping of dough
Get PDFAn analysis was made of the model approximations of three-phase medium and its behavior under deformation impacts in the rollers bulk feed, the lack of reliability of their operation was noticed and regularities and reasonable geometric parameters was determined. The influence of engineering rheology on the medium was considered and on its basis was derived an analytical mechanical model for determining the optimum value of shift deformation in order to ensure reliable operation of the rollers injection mechanism. A new design and method of determining the geometrical parameters of the pumping unit rollers were proposed and the yeast dough state was examined after cyclic action of the rollers
Sauvignon wine quality as affected by its processing and storage
Get PDFThe colour and limpidity are the first sensory attributes of wines that are appreciated by consumers, predisposing their acceptance or rejection. The aim of this work was to monitor the effect of harvest, processing (different clarification and treatment of must) and storage on the quality of Sauvignon wine. The wines were stored for two years in the wine cellar at 12°C and 70 % of humidity, in the bottles. The acid content, residual sugar and alcohol content among chemical parameters and sensory profile of wines were observed. Sensory quality of wines was evaluated by the aromatic profile (profile method). Based on acquired results, two years of wine storage significantly affected the total acid content of wines and alcohol content. Different treatments of must affected residual sugars, the variant with the maximum dose of the clarification preparation (highly pure cellulose, polyvinylpolypyrrolidone, gelatin and mineral adsorbents) showed statistically the highest content of residual sugars. From the sensory point of view, sensory profiles of wines were different compared to the first and second harvest of grape, sensory profiles of wines were changed also after two years of storage. The fourth variant appeared to be the best stable, treated with the addition of clarification preparation at the dose of 30 g. 100 L-1 must. Because from the same variety Sauvignon were produced wines of different chemical and sensory qualities, some gastronomy recommendations were done as well
A thaumatin-like genomic sequence identification in Vitis vinifera l., stormy wines and musts based on direct pcr
Get PDFDirect polymerase chain reaction method was use to amplify a thaumatin-like sequence of Vitis vinifera L. in grapes as well as in stormy wines and musts. Thaumatin-like proteins (TLPs) of Vitis vinifera possess beside its function in abiotic and biotic stress response another one - they are able to cause protein haze in wine unless removed prior to bottling. Direct PCR is an approach where omission of DNA extraction is typical prior the amplification of the target site of plant genome. Crude extract or small pieces of plant tissues are used in the analysis directly without steps of extraction and purification of gDNA. The biological material that was used in analysis was collected during August - October 2017 in local stores and winery Sabo and comprises from cultivars Iršai, Muškát, Savignon Blanc, Svätovavrinecké, Dornfelder and Pálava. Direct PCR was performed by a cutted piece of grape tissue and a dilution buffer was use in 1:2 for stormy wine or must, respectively. Direct amplification of thaumatin-like protein sequence of Vitis vinifera was performed along with the control reactions with the primers for conserved region of plant chloroplast. Possitive amplification of thaumatin-like allergen sequence resulted in 570 bp amplicon. The most abundant amplicons were amplified in stormy wines, followed by musts and the amplicons from grapes were weaker when comparing them to others. The amplicon specificity checking of obtained PCR product of thaumatin-like allergen was performed by restriction cleavage by Psi I and resulted in restriction amplicons of the 80 bp, 81 bp, 94 bp and 315 bp in length. Confirmation of the amplicon specificity by restriction cleavage support the potential of direct PCR to become a reproducible method that will be fully applicable in routine analysis of not only plant genomes in the future, but it was demonstrated, that it works in liquids, too.
Effect of different storage conditions on the microbiological characteristics of insect
Get PDFWhen introducing a novelty food, its safety needs to be monitored. One of the safety aspects of human health is microbial contamination. In this work, microbiological parameters of long-term stored edible insect material - mealworm (Tenebrio molitor), lesser mealworm (Alphitobius diaperinus), field cricket (Gryllus assimilis), and migratory locust (Locusta migratoria) were evaluated. The monitored indicators (colony forming units, enterobacteria, lactic acid bacteria, yeasts and moulds) were evaluated using common microbiological methods. All samples of stored insect were determined as safe for human consumption, except for the lesser mealworm sample from 2016, in which case the limit was exceeded. Sample of adult field cricket seems to be suitable for long-term storage, as it contained the lowest amount of microorganism. Sample of dried Gryllus assimilis from 2014 had the lowest microbial contamination. Further results suggest that, for long-term storage, the most suitable way of preparation is killing with boiling water, drying at 103 °C for 12 hours and subsequent hermetic packaging