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Honey is the most important bee product. There are many secondary metabolites, carbohydrates, enzymes, and vitamins in honey, thus, honey has antimicrobial activity. In this study, in vitro antimicrobial activity of forty-two honey and eight propolis ethanolic extracts (PEE) were investigated against 16 microorganisms. Total phenolic content ranged between 20.00–124.10 mg GAE/100 g and 103–232 mg GAE/g for honey and raw propolis samples, respectively. Pine and oak honeydew honeys had higher antimicrobial activity than four different grades of Manuka Honeys up to 18 mm minimum inhibition zone diameters. The ethanolic propolis extracts showed much higher antimicrobial activity than the honey samples. Fungi species were inhibited by the propolis samples. Helicobacter pylorii (H. pylorii) was the most sensitive, whereas Streptococcus agalactiae was the most resistant bacteria among the studied microorganisms. Brazilian and Zonguldak propolis had the closest antimicrobial activity to ampicillin, streptomycin, and fluconazole. It can be concluded that both honey and propolis could be used in preservative and complementary medicine.

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Pollack Periodica
Authors: Peter Michalek, Jakub Kralovanec, and Jan Bujnak

Reactive powder concretes are a set of ultrahigh-strength concrete reinforced with fibers. Their compressive strength is greater than 100 MPa. For assuring connection of steel beams and a concrete slab, steel stud connectors are used. The investigation of that kind of shear connection efficiency, in the case of this higher strength concrete deck using standard push-out test specimens has been executed. The experimental results are presented in the paper.

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This study investigated the chemical properties of Durio zibethinus (Durian) in Malaysia. The cultivars included in the present study were D101, D197, and Kampung. A wide range of chemical properties such as proximate nutritional content, minerals, total phenolic content was analysed using established analytical methods. The antioxidant capacity in term of free radical scavenging activity was determined using colorimetric assay, whereas metabolite profiles of samples were analysed by hyphenated high throughput tool like GC-MS. The results showed that D197 durian had the highest content of ash, protein, fat, and carbohydrate, but the lowest moisture level. Potassium was found to be the highest mineral (8.68–11.36 mg g–1), followed by sodium (3.2–7.6 mg g–1), magnesium (0.86–1.88 mg g–1), and calcium (2.74–3.80 mg g–1) in the tested cultivars. The major sulphur containing compounds (% relative peak area) such as hydrogen sulphide (5.0–8.3%), methanethiol (0.5–1.0%), ethanethiol (20.7–35.0%), 1-propanethiol (2.7– 9.5%), and diethyl disulphide (0.6–1.9%), and esters, especially ethyl 2-methylbutanoate (10.0–15.0%), methyl 2-methylbutanoate (1.0%), and propyl 2-methylbutanoate (1.5%) were detected when fresh samples were heated in headspace GC-MS. However, those compounds evaporated during ultrasound assisted extraction and oven drying even at 40 °C.

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Modification of dairy products’ fat composition or replacement by other fats are common practices in the industry. Products in which milkfat is partially or wholly substituted by vegetable fats are defined as dairy analogues. This study delivers gap-filling information about sour cream analogues in nutritional aspects, focusing on the fat-related attributes. Analogue sour creams contained 29.6% less saturated fatty acids, 88.4% less cholesterol and 88.7% more mono- and poly-unsaturated fatty acids than the sour creams. Trans fatty acids were present in both products, which could not be linked to artificial hydrogenation in either case. Digestibility of the examined samples might be different, as sour creams had more short and medium chain fatty acids than the analogues. Overall, sour cream analogues, besides serving as an alternative to sour cream, have particular advantages based on their nutritional values.

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Chemical industry has a high demand for ethylene quantity, especially with high quality. This paper discusses dynamic simulation models of an ethaneethylene high-pressure cryogenic rectification column with Unisim Design process simulator software. Distillation is one of the most essential technologies in chemical industry, it is important that the operation of the procedure can be modeled not only in steady-state mode but also in a dynamic way. The goal during this study is to make simulations with system-controlling and to investigate the effect the disturbance on the behavior of the columns.

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Yoghurt is considered as a healthy food. Thus, it could convey functional and bioactive ingredients. Chia seeds are of great interest due to their ability to improve consumer health. In this study, chia seeds were added to stirred yoghurt at different doses (1.5, 3, 4.5, or 6%). The effects of chia seeds on physicochemical, microbiological, and sensory qualities were assessed during 28 days of refrigerated storage. The results showed that chia seeds slightly decreased post-acidification, the lowest value was obtained in yogurt with 3% chia seeds (24°D), but syneresis rose significantly (P<0.05) when 6% of chia seeds was added. Furthermore, chia seeds promote viability of yoghurt bacteria, and antioxidant activity reached 62.20±0.02% in yoghurt added with 1.5% chia seeds. However, proteolysis is not affected. The effects of chia seeds were not dose dependent as 4.5% and 6% did not follow trend. These findings were affirmed by sensory characteristics. Thus, stirred yoghurt containing 1.5 or 3% of chia seeds proved to be the most adequate choices.

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This study describes the antistaphylococcal mechanism of the ethanolic extract of Algerian propolis on Staphylococcus aureus ATCC 25923. To investigate the underlying mechanism of action of the ethanolic extract of propolis, bacteriolysis, bacterial death, leakage of potassium, proteins, nucleic components, and scanning electron microscopic studies were conducted. The results showed that the minimum inhibitory concentration (MIC) of ethanolic extract of propolis against Staphylococcus aureus ATCC 25923 was 39 μg ml–1. The extract displayed significant bactericid activity against S. aureus in a time and concentration dependant manner. Its mode of action was evident from the increase of K+ efflux and nucleotide leakage. These results were confirmed by Scanning Electron Microscopy (SEM) that showed remarkable morphological and ultrastructural changes in S. aureus after exposure to 1MIC and 2MIC concentrations. The overall study contributed to the understanding of the antistaphylococcal mechanism of ethanolic extract of propolis. It emphasizes its potential to be used as an important natural bio-preservatives in food products.

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In this study, thirty onion (Allium cepa L.) genotypes grown in sub-tropical region of India were analysed for different physico-chemical attributes. There were significant differences among genotypes, and the onion genotypes showed a tendency to be classified according to different colours. The cultivars of the same colour exhibited similar tendencies in terms of accumulating most of the analysed components. About 1.78 fold variation in dry matter (%) and 2 fold variation in fresh weight per bulb were recorded among coloured onions. Red genotype D-888-B possessed maximum contents of TS and NRS, while the yellow coloured genotype POH-5 accumulated highest RS and lowest NRS contents. Maximum values of fructans (3.68 g/100 g DW), AIS (6 g/100 g DW), protein (10.61 g/100 g DW), and FAA (4.24 g/100 g DW) were also found in red coloured genotypes D-715-B, D-97-B, PR-305, and D-PS-121-B, respectively. Proline content in different genotypes was found to vary about 6.9 fold. The correlation studies showed a positive relationship between most of the quality parameters. Our results suggested that red group genotypes were better than yellow and white groups for all the studied parameters except for RS, which makes red genotypes more suitable for processing purposes.

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Acta Alimentaria
Authors: D. Koren, B. Hegyesné Vecseri, and G. Kun-Farkas

There are numerous scientific publications about the folate content of several types of beers available in commercial trade, but there is limited information about the effect of raw materials and technological steps of brewing on folate content. In this study the aim was to investigate different raw materials and the evolution of folate content during laboratory and pilot scale brewing. For the determination of folate content of different malts, three types of barley malts (Pilsner, Caramel, and Coloring), wheat malt, rye malt, and oat malt were analysed. For the study of the evolution of folate content during the brewing process, worts were produced on laboratory and pilot scale. Among malts, Pilsner type barley malt had the highest folate content (44.7 μg/100 g d.m.). During brewing the protein rest seemed to dissolve the majority of the folate content, and with the increasing temperature of the β- and α-amylase rests there was a further dissolution. Filtration and sparging did not have negative effect on folate concentration related to the extract content of the wort. Hop boiling had no negative effect on folate content, folate seemed to be stable during the one-hour boiling. Natural folate of barley malt seemed to be stable through the technological steps of brewing, offering the possibility to produce a foodstuff with high natural folate content.

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