Potravinarstvo Slovak Journal of Food Sciences
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Bee stimulation to form protein food reserves
Get PDFWe have investigated different ways of bees’ stimulation to lay protein food while using artificial honeycombs. It has been proved that the use of artificial combs to get bee-bread upon the condition of the post-treatment processing of its elements by wax and honey syrup does not stimulate bees to lay and process protein food in their cells. It has been identified that upon the condition of the direct involvement of the working bees into the formation of bee-bread supplies the protein food has been mostly consumed. This proves that the working bees use the freshly-gathered pollen pellet for their own needs in the period of its active gathering. It has been determined that the most effective way of bee stimulation to reprocess pollen pellet into bee-bread is it's single densifying in artificial honeycombs with the follow-up processing of the upper layer of the feed by honey. This way encourages bees to form stocks of bee bread and decreases their activity of consuming protein food from cells of artificial honeycombs. The processing of thickened pollen pellet by honey probably oppresses the bees’ need to consume protein food from the packed cells redirecting them to other honeycombs of the bee family’s nest which has areas with bee-bread reserves
The Remnant photosynthetic pigments in tea dregs: identification, composition, and potential use as antibacterial photosensitizer
No full textThe production of tea dregs is continually increasing along with the growth of people's interest in ready-to-drink beverages. However, the recent development of research on the use of tea dregs is still very limited. The present study was aimed to identify the remnant photosynthetic pigments in tea dregs, determine their composition, and evaluate their potential use as natural antibacterial agents based on light-induced reaction (photosensitization). The tea dregs from six commercial teas, consisting of green and black teas, were analyzed using high-performance liquid chromatography (HPLC) with a photodiode array detector, and the spectroscopic data were analyzed from 350 to 700 nm. Pigment identification was performed based on spectral characteristics, and pigment composition in the extracts from the dregs was determined by a three-dimensional multi-chromatogram analysis method. The dominant pigment fractions in both tea types were pheophytin a and its isomers, as well as pheophytin b. Although the dregs of black teas generally contain fewer remnant pigments, they possess residual chlorophyll b, which is not found in the dregs of green teas. In thirty-minutes illumination under 50 W red light-emitting diode, the presence of pigments from tea dregs caused up to 0.87 and 0.35 log reduction of Staphylococcus aureus and Escherichia coli, respectively. The disparity of pigments composition among tea types does not strongly influence their photosensitization activity against both bacteria. Hence, upon further application, the amount of total remnant pigments in the dregs could be taken as substantial consideration instead of tea types
Incidence of hormonal growth stimulant and antibiotics residues in chicken meat
Get PDFThe purpose of this study is to determine the level of antibiotic residues in poultry meat sold in the city of Almaty, which is a megacity of Kazakhstan, and compare it with the Minimum Residue Level set by World Health Organization and Food and Agriculture Organization. Determination of hormonal growth stimulators (progesterone, testosterone, estradiol-17β) and antibiotics (tetracycline, chloramphenicol, and streptomycin) in poultry was carried out using immunoassay according to the manufacturer’s instruction. The results of monitoring showed that in the Almaty region annually wholesale deliveries of meat products from the USA, Belarus, Ukraine, and Russia are carried out regularly. On average in the region from 2016 to 2019, the specific weight meat imports averaged 47.9% of total consumption. A total of 105 samples were examined by us between 2019 and 2020, including 63-import meat and 42 samples of the meat of local production. Due to the particular importance of this problem, the main focus of the article`s goal is to conduct monitoring studies on imported and domestic meat for the residual content of hormones and antibiotics in poultry meat. As a result of the enzyme-linked immunosorbent assay of poultry meat, an excess level of maximum residue was detected in eight brands of imported meat
The system of monitoring of inhibitory drug residues in raw cows' milk in Slovakia
Get PDFThis article provides brief information on the system of monitoring raw cows’ milk for the presence of inhibitory veterinary drug residues in the Slovak Republic. We are describing in detail how the monitoring is carried out and what laboratory methods are used for this monitoring. We also deal with the issue of the disposal of contaminated milk. The presence of inhibitory veterinary drugs like antibiotics or residues of these drugs in milk in an amount exceeding maximal residual limits defined in legislation is illegal. Milk supplies containing detectable concentrations are not acceptable. The reputation of milk as a healthy and safe food should be protected. Dairy companies and consequently consumers want to be confident that milk and milk products are free of inhibitory veterinary drugs contamination. Small amounts of certain antimicrobial agents may affect antibiotic resistance in the human population, some percentage of the population is hypersensitive to antibiotics and other drugs. The presence of drug residues in milk affects the technological process of the production of fermented dairy products. Each country should implement a system of monitoring these drugs' residues in food. The system, which is applied in Slovakia, is effective, it can detect and the presence of these substances before milk processing in dairies. The total incidence of these substances in 2020 was 0.025% of all 12,181 samples tested in central testing laboratories. During the last 20 years
Development of the food act of the Slovak Republic from 1995 to 2021
Get PDFLegislation in food is quite fragmented, it includes several regulations, amendments due to the rapid development both in the studied area and the influence of European law. It is a legal branch of a relatively hybrid nature. It contains agricultural legislation that intersects with environmental law. It also affects administrative, financial, and criminal law as a branch of public law. Nor can commercial and civil law as the basis of private law be circumvented here. The legal norm has undergone a relatively interesting development, which is characterized by several amendments. During the more than 25 years of validity of this legal norm, a total of more than twenty amendments. This certainly does not contribute to the stability of the legislation, the legal certainty of the entities concerned, or its clarity and system. The article provides an overview of the development of the legal regulation of the Food Act in Slovakia from 1995 to 2021
The Citrus reticulata essential oil: evaluation of antifungal activity against penicillium species related to bakery products spoilage
Get PDFFungal food spoilage plays a key role in the deterioration of food products, and finding a suitable natural preservative can solve this problem. Therefore, antifungal activity of green mandarin (Citrus reticulata) essential oil (GMEO) in the vapor phase against the growth of Penicillium (P.) expansum and P. chrysogenum inoculated on wheat bread (in situ experiment) was investigated in the current research. The volatile compounds of the GMEO were analyzed by a gas chromatograph coupled to a mass spectrometer (GC–MS), and its antioxidant activity was determined by testing free radical-scavenging capacity (DPPH assay). Moreover, the disc diffusion method was used to analyze the antifungal activity of GMEO in in vitro conditions. The results demonstrate that the Citrus reticulata EO consisted of α-limonene as the most abundant component (71.5%), followed by γ-terpinene (13.9%), and β-pinene (3.5%), and it displayed the weak antioxidant activity with the value of inhibition 5.6 ±0.7%, which corresponds to 103.0 ±6.4 µg TEAC.mL-1. The findings from the GMEO antifungal activity determination revealed that values for the inhibition zone with disc diffusion method ranged from 0.00 ±0.00 (no antifungal effectiveness) to 5.67 ±0.58 mm (moderate antifungal activity). Finally, exposure of Penicillium strains growing on bread to GMEO in vapor phase led to the finding that 250 μL.L-1 of GMEO exhibited the lowest value for mycelial growth inhibition (MGI) of P. expansum (-51.37 ±3.01%) whose negative value reflects even supportive effect of the EO on the microscopic fungus growth. On the other hand, GMEO at this concentration (250 μL.L-1) resulted in the strongest inhibitory action (MGI: 54.15 ±1.15%) against growth of P. chrysogenum. Based on the findings it can be concluded that GMEO in the vapor phase is not an effective antifungal agent against the growth of P. expansum inoculated on bread; however, its antifungal potential manifested against P. chrysogenum suggests GMEO to be an appropriate alternative to the use of chemical inhibitors for bread preservation
The diversity of fungal population from grape harvest to young wine in Small Carpathian wine region
Get PDFThe study aimed to identify the filamentous fungi and yeast mycobiota found on the surface and in grapes, grape must, and wine obtained from four red grape varieties: Alibernet, Dornfelder, Blue Frankish, Cabernet Sauvignon, and four white grape varieties: Green Veltliner, Rheinriesling, Pinot Blanc, Sauvignon. Grapes from vineyard Vrbové located in southwestern Slovakia were used for the research in 2020. The identification of filamentous fungi was performed using the macroscopic and microscopic observations and yeasts were identified by MALDI-TOF Mass Spectrometer. A total of 642 isolates were obtained. Grapes were rich in diversity of filamentous fungi (13 genera) and must on yeasts (8 genera). Penicillium, Botrytis, and Hanseniaspora uvarum were identified in both grapes and must. Three of the fungal genera identified by conventional or molecular techniques from the surface of red grape varieties were predominant: Alternaria (26%), Botrytis (21%), and Issatchenkia terricola (13%), two from endogenous mycobiota: Hanseniaspora uvarum (45%) and Botrytis (17%), four from the surface of white grape varieties: Penicillium (25%), Botrytis (21%), Alternaria (16%) and Hanseniaspora uvarum (15%), and three from endogenous mycobiota: Botrytis (44%), Hanseniaspora uvarum (23%) and Alternaria (20%). Saccharomyces cerevisiae, Candida krusei, C. utilis, and Cryptococcus neoformans were identified only in wine
Justification of thermodynamic efficiency of the new air heat pump in the system of redistribution of energy resources at the enterprise
Get PDFThe article evaluates the energy resources of the components of the environment and the prospects for their use on the redistribution with the creation of local zones of cooling and heating. The physical basis of the principle and systems of redistribution and transformations of energy resources of environments with coverage of the role of compensation processes is given. The use of closed energy circuits with intermediate energy sources, which are subject to phase transitions of evaporation and condensation, and data of energy potentials of ambient air, which are practically achievable for use on this basis, is proposed. The article shows the advantages of arranging systems for redistribution of thermal potentials based on the use of phase transitions of material media. Determination of energy balances of energy redistribution systems is carried out with the indication that in the end, such a method is the most energy-efficient. Upon completion of technological tasks, local areas with different energy potentials and temperatures degrade in dissipation processes and transform to the level of environmental indicators. This means interfering with the environment only at the level of energy costs in compensation processes. The article shows the transition to secondary recovery systems of energy resources based on the use of primary energy sources in environmental transformations at the levels of increasing their energy potentials and providing phase transitions with appropriate mathematical formalizations. A regression analysis of the feasibility of using primary energy potentials is given. It is proved that in the heat pump due to the generated mechanical energy the heat return at the level of the lost one. The estimation of the general condition of processes at power effects is given. The offered air pump and system of realization of a refrigerating cycle are considered. The redistribution of energy potentials of natural, forcibly created environments or systems and the synthesis on this basis of powerful heat fluxes in combination with advanced control methods, allows you to control their values of thermodynamic parameters
Development of nutritional meals and gruels from blends of pro-vitamin a cassava grits and African yam
Get PDFThe potentials of underutilized African yam bean (AYB) and pro-vitamin A cassava in the development of nutritious food products with acceptable sensory properties were studied. Grits were produced from freshly harvested yellow root pro-vitamin A cassava by peeling, washing, cutting, soaking, dewatering, roasting, sieving, and milling to obtain yellow root cassava grits while AYB flour was obtained by cleaning, roasting, dehulling, milling, and sieving (425 µm). A simple lattice design was used to obtain formulations of blends (100:0; 90:10; 80:20; 70:30; 60:40 and 0:100) of yellow root cassava grits and AYB flour. Gruels were prepared from these formulations using 4:5 w/v in boiling water while meals were prepared using 1:1 w/v of blend in boiling water for 5 min. Moisture, fat, ash, protein, crude fibre, carbohydrate, β-carotene and calorific content of the blends were in the ranges of 4.66 – 7.92%, 2.20 – 2.82%, 2.16 – 2.66%, 2.72 – 20.43%, 1.15 – 1.40%, 68.65 – 83.23%, 1.33 to 3.97 μg/g and 348.37 – 358.96 kcal/100 g, respectively. Saponin, tannin, trypsin inhibitor, hemagglutinin, starchyose, raffinose, phytate and Hydrogen Cyanide ranged from 0.039 – 0.087%, 0.11 – 0.15%, 1.24 – 3.15 mg/g, 1.47 – 3.49 mg/100 g, 1.51 – 1.81%, 0.38 – 0.45%, 0.82 – 2.69 mg/g, 0.07 – 4.47 mg/kg, respectively. The sensory evaluation revealed that the meal and the gruel samples had acceptable sensory attributes. The developed products have the potentials in alleviating the problem of protein malnutrition in developing countries
The nutritional profile of indonesian salmon van Java mahseer T. soro species
Get PDFT. soro, in Indonesia called salmon van Java is of high economic value, and due to high demand, its culture has been intensively studied and developed. This study aimed to assess the nutritional value of wild and cultured T. soro. The fish’s proximate compositions, minerals, as well as amino and fatty acid profiles were analyzed. A t-test analysis was used to identify differences between treatments. Results showed that the fat content of wild T. soro was higher than that of cultured fish, but the protein, water, and ash contents between the two groups were not significantly different (p >0.05). T. soro was considered a lean fish with higher concentrations of PUFAs (polyunsaturated fatty acids) than MUFAs (monounsaturated fatty acids). The amino acid profile was dominated by lysine, phenylalanine, and allo-isoleucine. Both groups of fish were a good source of macro- (Na, K, Ca) and microminerals (Zn, Fe), except for selenium (Se). The two groups were not significantly different (p >0.05) in ω3, ω6, and PUFAs, indicating that culturing T. soro in proper ways could substitute for wild T. soro