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Development of the real-time PCR methodology for testing mycotoxigenic microorganisms in grape marc
2021
Sturza, Rodica | Mitin, Valentin | Mitina, Irina | Zgardan, Dan | Patras, Antoanela | Behta, Emilia
Agro-industrial waste management is an important problem of modern society as agriculture and food industry are important sources of waste. Wine production generates a considerable amount of winemaking waste (grape marc). Grape marc can be a source of natural dyes, antioxidants and could have various applications, if it is confirmed that it does not contain technogenic contaminants or unwanted microorganisms, for example, producers of mycotoxins. The paper developed the Real -Time Polymerase Chain Reaction (Real-Time PCR) methodology for testing the presence of potentially mycotoxogenic fungal species capable of producing ochratoxin A (OTA), which could be applied before grape marc processing. Based on the non-ribosomal peptide sequence of OTA, involved in ochratoxin biosynthesis, the primers have been developed for the detection of microorganisms potentially capable of producing ochratoxin A.
Показать больше [+] Меньше [-]Palynological, physico-chemical and biologically active substances profile in some types of honey in the Republic of Moldova
2021
Chirsanova, Aurica | Capcanari, Tatiana | Boistean, Alina
Three types of monofloral honey (rapeseed honey, buckwheat and lavender) from the Republic of Moldova were analyzed. The results of the palynological analysis showed that the samples had a dominant type of pollen (at least 45%). In the case of lavender honey, the pollen of the plant Lavandula angustifolia is present in an average value of 74.83 ± 0.3; in rapeseed honey - Brassica napus and for buckwheat honey -Fagopyrum esculentum in average values as follows: 56.07 ± 0.3 and 68.08 ± 0.2% respectively. The study of the content of biologically active substances showed that buckwheat honey is the richest in polyphenols (9.00 ± 0.11 mg gallic acid / kg) and carotenoids (4.24 ± 0.57 mg βcarotE / kg), and maximum content of flavonoids is in rapeseed honey (4.52 ± 0.28 mg catechin / kg). Thus, the obtained results confirm that the honey from the Republic of Moldova falls within the limits recommended by the international regulation assuming adequate working conditions, handling, collection and storage of honey by beekeepers from the Republic of Moldova.
Показать больше [+] Меньше [-]The role of berries in quality and safety ensuring of goat's and cow's milk yoghurt
2021
Cușmenco, Tatiana | Sandulachi, Elisaveta | Bulgaru, Viorica | Macari, Artur
The yogurt was obtained from a combination of 50% goat's milk and 50% cow's milk with the inclusion of scald fruits of aronia (Aronia melanocarpa), raspberries (Rubus idaeus), strawberry (Fragaria ananassa). Physico-chemical and microbiological indices were determined, according to standard methods, after manufacture and storage, after 1, 5, 10, 15 days. Compared to other samples, yogurt with aronia showed the best values of the dynamics specific to the development of microorganisms: 2.93.107 cfu/ml; the growth rate of lactic acid bacteria at fermentation 0.95 μ; physico-chemical indices: titratable acidity 85 ± 0.078⁰T, pH 4.28 ± 0.002, water activity 0.875 ± 0.025; total dry matter 18.45 ± 0.31%, viscosity 2500 ± 0.023 mPa s, ash content 0.89 ± 0.10% and the optical density 2.531 ± 0.054 nm. Yeasts and molds were not detected in any of the samples. From a physico-chemical point of view, in storage, in all fruit yogurt samples the titratable acidity showed increasing values, pH remaining in the range of permissible values. In storage fruits formed an association to control the microbiological risk and stability of yogurt. Fruit yogurt shows a synergism with Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactococcus lactis subsp lactis biovar diacetilactis. The overall Pearson coefficient (Pc = f(pH and MC) for all fruit yogurt samples is -0.95066.
Показать больше [+] Меньше [-]Microencapsulation of functional components in the food technology: partially optimistic view
2021
Baerle, Alexei
This work deals with the use of microencapsulation of biologically active compounds (BAC) as an alternative method of protection and prolongation of their functional properties in the food products. The main methods for the formation of microcapsules (MC) are considered. Biopolymer materials, suitable for MCs production, are outlined. Some technological solutions, suitable for microencapsulation and successfully used in other industries, present interest only for laboratory researches in the food science, but are not suitable for industrial scale food production. It is discussed why the methods of simple and complex coacervation, liposomal entrapment are thermodynamically advantageous for obtaining microcapsules in comparison with others. To achieve further progresses of microencapsulation in food technologies, the direct integration of the microencapsulation into the food production technological cycle is necessary. Products should initially have a texture and consistency that allow microcapsules to be resistant to premature aggregation. MCs should not exfoliate or break down, while execute their functions of protection and targeted delivery of biologically active compounds. Only high viscous colloidal systems, as traditional fermented dairy products (kefir, yoghurts, ice cream, curd and cheese) and fruit juices with pulp, are mostly suitable for supplementation of them by BACs using microencapsulation.
Показать больше [+] Меньше [-]Generic algorithm solution in estimation of the iron absorption potential from complex school meals
2021
Sturza, Rodica | Mija, Nina | Deseatnicov, Olga | Covaliov, Eugenia | Suhodol, Natalia
New analytical tools to study iron bioavailability are proposed in this article. An algorithm was devised to predict dietary iron abortion from school meals based on the contents of dietary factors that have the ability to promote or inhibit heme or non-heme iron absorption. The highest absorption rate of iron from representative meals was observed in the presence of ascorbic acid (27,73%) or meat ingredients (27,70%), and the lowest absorption rate – in the presence of Ca (12,40%), tannins (5,83%) and polyphenols (5,36%). Relationships between quantities of total iron intake from foods (dialyzable iron, in vitro assay) and the value of nutritional factors in those are described as exponential equations allowing calculations at any stationary state. In elaborated formula the rate of iron absorbance can be predicted considering one, two or three nutritional factors at the same time. The results emphasize the fact that it is important to understand the meal composition for the correct estimation of iron bioavailability.
Показать больше [+] Меньше [-]Physicochemical characteristics of unripe apples
2021
Crucirescu, Diana
Apple plays an important role in human health. The unripe apples, after physiological falls and the agricultural operation "regulation of the fruit load", are not used for food. The use of agricultural organic waste is a current problem. In the presented paper was approached the possibility of valorification on these unripe fruits to obtain natural products. Were studied the unripe apples of 4 varieties: Coredana, Golden Rezistent, Rewena and Reglindis. The fruits were harvested during development at 45th, 58th, 71st, 84th and 97th days after the full bloom. It was determined physico-chemical indices in fruits extracts. During the ripening of fruits, the diameter and mass increased continuously, the moisture content does not change significantly, but the pH values of the apple pulp increased non-essential. Dry matter content and total sugar increased considerably as the fruits were growing. There are unexpected increases in dry matter around the 84th day after the full bloom. The acidity decreased during the fruit development. Sensory evaluation was also effectuated. The results obtained provide informations regarding the optimal use of the unripe apple varieties researched in order to process and obtain different products (especially natural acidifiers).
Показать больше [+] Меньше [-]Quantifying deep cryogenic treatment extent and its effect on steel properties
2021
Funk, Paul A. | Kanaan, Ahmed | Shank, Christine | Cooke, Peter | Sevostianov, Igor | Thomas, Joe W. | Pate, Michael O.
Deep cryogenic treatment (DCT) has been known since the 1930s to improve hardness, fatigue resistance, and wear resistance of steel. While the effect of DCT on wear properties has been well documented, there is no consensus regarding the causal mechanisms, nor a widely accepted quantitative description of them. DCT transforms retained austenite into martensite and triggers the precipitation of fine carbides, among other things. We observed that DCT had a negligible effect on Young's modulus and the yield limit of high carbon spring steel. The observed microstructural changes (presence of specific dendritic inhomogeneities typical for inclusions of austenitic phase in non-treated specimens and homogeneous microstructure of treated ones) can serve for qualitative purposes only. However, we found that DCT led to a decrease in steel electrical resistivity which can be explained by noticeable differences between the resistivities of the martensitic and austenitic phases. We propose a micromechanical model for electrical resistivity which allows monitoring of the content of retained austenite and postulate that it can be used for other materials as well. We also observed increased resistivity after mechanical loading of the specimens, correlating with increased dislocation density caused by loading. This quantity can be used to assess the average dislocation density.
Показать больше [+] Меньше [-]THE MATHEMATICAL DESCRIPTION OF THE POSSIBILITY OF THE ELECTROCHEMICAL DETECTION OF INSUBOSINE ON CONDUCTING POLYMER-BASED SULFOACIDS
2021
Tkach, Volodymyr Valentynovych | V. Kushnir, Marta | G. Ivanushko, Yana | F. Moldianu, Anzhelika | C. de Oliveira, Sílvio | R. da Silva, Genílson | I. Yagodynets´1, Petro | V. Luganska, Olga
The possibility of Insubosin electrochemical determination on acid-group modified conducting polymers has been evaluated from the theoretical point of view. The correspondent mathematical model has been developed and analyzed by means of linear stability theory and bifurcation analysis. It was shown that the introduction of acid groups into the conducting polymer backbone makes more efficient the analyte immobilization, and that in general the modified conducting polymer is an excellent modifier for insubosin electrochemical determination. A base may be added in order to neutralize the general pH in the system, but not in excess, to avoid the electroanalytical inefficiency of steady-state stability. The possibility of the oscillatory and monotonic instability in this system has also been verified, and it was shown that it is more probable, than in general case, due to the possibility of the hydrogen bonding.
Показать больше [+] Меньше [-]OVEROXIDIZED POLYPYRROLE CHEMICAL AND ELECTROCHEMICAL N-OXIDATION.A THEORETICAL ANALYSIS OF AN INTERESTING POSSIBILITY
2021
Tkach, Volodymyr Valentynovych | Kushnir, MartaV | Alla V. Velyka, YanaG. Ivanushko, | Sílvio C. De Olive, Petro Ye. Kovalchuk, | Zholt O. Kormosh, Petro I. Yagodynets´, | Vaz dos Reis, Lucinda
For the first time, the possibility of overoxidized polypyrrole N-oxidation has been investigated from the theoretical point of view. The correspondent mathematical model has been developed and analyzed by means of the linear stability theory and bifurcation analysis. It was shown that the polypyrroleoveroxidation in the presence of peroxide compounds or at a slightly higher potential will yield a N-oxidized form, and its formation will be accompanied by the enhance of the oscillatory and monotonic instability realization probability. This enhance is among the factors, defining the resulting polymer morphology and conductivity.
Показать больше [+] Меньше [-]THE THEORETICAL DESCRIPTION FOR THE 4-4´-DIHYDROXYAZOBENZENE ELECTROANALYSIS, ASSISTED BY A COMPOSITE OF SQUARAINE DYE WITH CoO(OH) – CoO2 REDOX PAIR, ACCOMPANIED BY ITS ELECTROPOLYMERIZATION
2021
Tkach, Volodymyr Valentynovych | V. Kushnir, Marta | G. Ivanushko, Yana | V. Bocharov, Andrii | Ye. Kovalchuk, Petro | C. De Oliveira, Sílvio | I. Yagodynets´, Petro | O. Kormosh, Zholt | Vaz dos Reis, Lucinda
The theoretical description for 4-4´-dihydroxyazobenzene CoO(OH) – assisted electrochemical determination in mushroom pulp, food and biological liquids has been described. In this system, a squaraine dye is used as a Cobalt(III)oxyhydroxide stabilizer and electron transfer mediator. It is shown that, contrarily to the great part of the systems with cobalt (III) oxyhydroxide, this system will behave in a more stable manner, providing an efficient diffusion-controlled process. On the other hand, the oscillatory and monotonic instabilities, although possible, are caused by the double electric layer influences of either chemical or electrochemical stage.
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