Papers by Gabriela Bahrim
Antioxidants, Jan 13, 2024
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Annals of the University "Dunărea de Jos" of Galaţi, Nov 18, 2020
In this study two extraction methods, such as conventional solvent extraction (CSE) and microwave... more In this study two extraction methods, such as conventional solvent extraction (CSE) and microwave assisted extraction (MAE) were used for bioactive compounds extraction from red onion skins. The effects of several extraction parameters on the phytochemical content were investigated to discover which combination of parameters led to the highest concentration of phytochemicals. The results revealed that the optimal conditions for anthocyanin extraction (1.75±0.04 mg C3G/g DW) by CSE was achieved at 70% ethanol acidified with 0.1 N hydrochloric acid after 120 minutes of extraction at 25 °C. Also, the highest antioxidant activity (32.18±1.75 mM of Trolox/g DW) was obtained with 96% ethanol acidified with glacial acetic acid, after 3 hours of extraction at 25 °C. Meanwhile, for MAE the highest anthocyanin content of 1.60±0.05 mg C3G/g DW was found when using 50% ethanol acidified with 99.5% citric acid, at 735 W microwave power for 15 seconds of extraction. MAE with 96% ethanol and glacial acetic acid had the highest yield of antioxidant activity (33.41±0.59 mM of Trolox/g DW) at 315 W microwave power after 10 seconds of extraction. Therefore, the bioactive compounds from red onion skins might be available as a source of functional compounds useful in the pharmaceutical and food industry.
Antioxidant potential of the fungal dye, produced by a strain selected from the collection of Epi... more Antioxidant potential of the fungal dye, produced by a strain selected from the collection of Epicoccum nigrum bioresearch platform (acronym MIUG) was partially characterized in previous studies. However, the fungal dye antioxidant capacity compared with other potential colorant inhibitors of lipid peroxidation (e.g. cochineal dye) has not been fully elucidated, especially regarding its behavior in emulsions. In the present study, by a voltammetric technique, the antioxidant potential of yellow dye synthesized by fermentation in SSF system Epicoccum nigrum strain selected MIUG 2.15, after immobilization by emulsification in model food emulsions was evaluated. Fungal dye antioxidant activity in stable emulsions is correlated to its electrochemical behavior. Thus, to highlight the potential of oxidation of emulsions containing dyes the cyclic voltamograms (scan rate: 100 mVs-1) were determined. Corresponding oxidation peaks were observed more clearly, compared with the corresponding reduction, which were lower. Regarding the control emulsion, which relate to the antioxidant effect of dyes present in the system is properly noted the appearance of a little platinum electrode; the equilibrium potential is E 0 =-835 mV. From cyclic voltamograma peak of the emulsion with propyil gallate is notes the reduction in peak intensity for platinum electrode and the appearance of an anode peak (-589.3 mV), corresponding to the propyil gallate introduced in emulsion. Specifically in the case of emulsion containing the cochineal or fungal dye is the appearance of two second anode and cathode peaks in cyclic voltamogram, which means that in this case, there were several redox processes induced by this dyes in emulsions. On the other hand, the currents are small to very small. This is due to-OH groups and = C = a specific colour, which are largely responsible for its antioxidant activity. For fungal dye emulsion the cyclical voltamogram have less defined redox processes. However, small peaks can be assigned to oxidation conjugated double bonds systems present in flavonoids which are found in fungal dye, perhaps by producing a radical intermediate during the oxidation process.
Inventions, Oct 3, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
The fungal colorants produced by an Epiccocum nigrum selected strain showed a great potential as ... more The fungal colorants produced by an Epiccocum nigrum selected strain showed a great potential as an economical source of natural pigments reason of their edible characters and easiness for pigment biosynthesis, coupled with the attractive luminosity, chromo and hue of the pigments. The fungus Epiccocum nigrum was isolated from air and the cultivation of moulds for pigment biosynthesis was performed in solid state fermentation system, in darkness conditions. The fungal colorants were characterized through UV-visible spectroscopy; HPLC and colour attribute analysis (Tristimulus Colorimetry). This complex of pigments is rich in carotenoids and flavonoids. The carotenoids content was of 948.48 mg/100g powder and the flavonoids content was of 52 mg/100g powder. As a result of the same process were also some compounds known as poliphenols (the anthocyanins type). The colour characteristics (CIE L * , a * , b * , C * ab , h ab) of the pigments in extract solution were L * = 93.745, a * =-20.541, b * = 91.991, C * ab = 94.256 and h ab = 102.59. The oil-in-water emulsions with fungal colorant were instrumentally evaluated during storage at room temperature through UV-visible spectroscopy, microscopically observation, conductometric and turbidity measurements. The emulsions with these colorants are milkiness. The experimental results of colour differences and its components in the case of coloured emulsions (at pH = 7) were: ∆L * = 26.67, ∆a * = 0.33, ∆b * =-8.04, ∆C * ab =-7.99, ∆h ab =-4.9, ∆H * ab =-0.87 and ∆E * ab = 27.86. From the results presented in this paper, it should be noted that the colour shade of emulsions containing fungal colorants was stable during storage under normal light for 35 days, the colour of emulsions remaining almost unchanged.
Molecules, Aug 5, 2014
A series of bis-pyridinium quaternary ammonium salts (bis-PyQAs) with different aryl and heteroar... more A series of bis-pyridinium quaternary ammonium salts (bis-PyQAs) with different aryl and heteroaryl moieties were synthesized and their antimicrobial activity investigated. The inhibition effect of the compounds was evaluated against bacteria, molds and yeasts; the activities were expressed as the minimum inhibitory concentrations (MIC). The relationships between the structure descriptors (logP, polarizability, polar surface area (2D), van der Waals area (3D)) and the biological activity of the tested bis-PyQAs are discussed.
Innovative Romanian Food Biotechnology, 2010
Ethanol generation from lignocellulose materials provides an alternative energy-production system... more Ethanol generation from lignocellulose materials provides an alternative energy-production system. The objectives of this study were to identify the significant factors involved in the biotechnological process of waste cellulosic materials reusing bioconversion in the ethanol. The bioconversion process was conducted in two steps. The first one is the cellulose hydrolysis with the Trichoderma reesei commercial cellulase and the fermentation of reducing sugar with a Saccharomyces cerevisiae selected yeast strain with fermentative potential. By using the Plackett-Burman design of experiments model the optimized levels of significant factors for both biochemical steps were established. Based on results, the factors with positive effect are the solid/ liquid ratio, the pH, the enzyme concentration, the inoculum size, the fermentation temperature.
Green Processing and Synthesis
An efficient one-pot route leading to bis-indolizine symmetric compounds has been developed via a... more An efficient one-pot route leading to bis-indolizine symmetric compounds has been developed via a new approach from the dipyridinium heterocyclic compound, reactive halogenated derivative, and activated alkyne through biocatalysis. A set of local plants was evaluated for its catalytic potential in “one-pot” biocatalysis of these valuable fluorescent compound synthesis reactions. Most of these biocatalysts containing enzymes from the oxidoreductase class (peroxidase: 0.56–1.08 mmol purpurogallin‧g−1 fresh weight‧min−1, polyphenol oxidase (PPO) : 27.19–48.95 PPO units‧mg tissue−1, CAT: 3.27–21.71 µmol O2‧g−1 fresh weight‧min−1), were used as green catalysts in the multi-component cycloaddition reaction, in an aqueous buffer solution, for the production of bis-indolizine compounds in moderate to excellent yields (45–85%). The horseradish root (Armoracia rusticana) has been selected as the most promising biocatalyst source among the evaluated plants, and the obtained yields were greater...
Foods, Jun 4, 2020
The impact of thermal treatment on the ability of lactoferrin (FL) to bind folic acid (FA) was in... more The impact of thermal treatment on the ability of lactoferrin (FL) to bind folic acid (FA) was investigated by employing fluorescence spectroscopy, molecular dynamics and docking tests. The structural and conformational particularities of LF upon heating at 80 • C and 100 • C were first estimated based on the intrinsic fluorescence changes in respect to the native protein. The emission spectra indicated gradual unfolding events accompanied by Trp exposure with increasing temperature. In agreement with the experimental results, molecular modeling investigations showed that the secondary and tertiary structure of LF are slightly affected by the thermal treatment. Some minor unfolding events related particularly to the α-helical regions of LF were observed when the temperature increased to 100 • C. The LF fluorescence quenching upon FA addition indicated that a static mechanism stands behind LF-FA complex formation. Regardless of the simulated temperature, the hydrogen bonds played an important role in regulating the interaction between the protein and ligand. FA binding to LF equilibrated at different temperatures occurred spontaneously, and all complexes displayed good thermodynamic stability. The obtained results support the suitability of LF as biocompatible material, for obtaining micro-and nanoparticles for delivery of dietary supplements or for enhancing the functionality of target delivery systems.
Inventions
Using a Central Composite Design, the extraction of bioactive compounds from red grape Băbească n... more Using a Central Composite Design, the extraction of bioactive compounds from red grape Băbească neagră peels was optimized by applying a conventional solvent extraction. On the anthocyanin content, total phenolic content, and antioxidant activity (using the DPPH method), the effects of extraction factors, including ethanol and citric acid concentrations, extraction temperature, and duration, were investigated. For each of the investigated parameters, a quadratic model was suggested. The maximum and minimum variables investigated in the coded form of the experimental plan are the concentrations of citric acid (0.10–2.64%), ethanol (38.06–96.93%), operating temperature (13.06–71.90 °C), and extraction time (11.36–78.63 min). The optimal mixture for recovering the most significant amount of polyphenol content and antioxidant activity was 85% ethanol, 0.85% citric acid, 52.14 min, and 57 °C. Based on the experimental approach, the anthocyanin content ranged from 1.71 to 2.74 mg C3G/g DW...
The Annals of the University Dunarea de Jos of Galati. Fascicle VI - Food Technology, 2021
The phenolic composition of the skin of the Băbească neagră grapes grown in south-eastern Romania... more The phenolic composition of the skin of the Băbească neagră grapes grown in south-eastern Romania was studied by two extraction techniques, i. e., ultrasound-assisted extraction (UAE) and enzyme-assisted extraction (EAE). This study aimed to analyze the grape skin bioactive compounds and the antioxidant potential using ethanol of three different concentrations 50%, 70%, and 96% and acidified with acetic, citric acid, or hydrochloric acid. This research aimed to maximize the extraction of bioactive compounds from red grape skin by using commercially available oenological enzyme preparations, varying the enzyme dosage, pH, temperature and extraction time. The results indicated that the highest total anthocyanin content was obtained when using 70 % ethanol extract acidified with 0.1 N hydrochloric acid, characterized by 4.29±0.04 mg C3G/g DW for ultrasound extraction and 2.54±0.13 for enzyme-assisted extraction. The results of antioxidant potential of the extracts investigated showed t...
Antioxidants, 2022
The present study focuses on heat-induced structural changes and the degradation kinetics of phyt... more The present study focuses on heat-induced structural changes and the degradation kinetics of phytochemicals and antioxidant activity of red grape skin extract. The thermal degradation of anthocyanins, flavonoids, polyphenols, and antioxidant activity followed a first-order kinetic model, increasing with temperature due to the intensification of the degradation process. The activation energy (Ea) highlighted this phenomenon. Likewise, the kinetic and thermodynamic parameters certified the irreversible degradation of the bioactive compounds from the skin of the Băbească neagră grape variety. Both temperature and duration of heating had a significant impact on the content of bioactive compounds. In addition, the red grape skin extract inhibited certain enzymes such as α-amylase, α-glucosidase, lipase, and lipoxygenase, which are associated with metabolic syndrome and inflammation. Further knowledge on the possible inhibition mechanisms exerted by the major anthocyanins found in red gra...
Goat milk fat is known for the higher content of shortand mediumchain fatty acids, which have ant... more Goat milk fat is known for the higher content of shortand mediumchain fatty acids, which have antibacterial and antifungal properties. By solid state enzymatic hydrolysis of goat milk fat, using different Candida lipolytica strains as lipase sources, were obtained hydrolysate products with antimicrobial activity. The antimicrobial properties of hydrolysates against some spoilage microorganisms, bacteria (Bacillus subtilis, Bacillus cereus) and fungi (Saccharomyces cerevisae, Candida mycoderma, Rhodotorula glutinis, Aspergillus niger, Penicillium spp. and Geotrichum candidum) were evaluated. Hydrolysate extracts produced by hydrolysis activity of Candida lipolytica G.01.3.1strain exerted inhibitory effect against bacteria, as well as fungi. The results of this study could be considered promising for developing new natural preservatives that could be used in food industry in order to reduce food contamination, increase the shelf life and for food safety assurance.
During conservation, the probiotic bacteria currently used in food industry have been shown to ha... more During conservation, the probiotic bacteria currently used in food industry have been shown to have less viability in the matter of fermented products microbiota and also to present lower levels of colonization and survival in vivo. This study describes a new way of improving the behavior and functionality of Lactobacillus acidophilus LA 5® commercial strain by using buckwheat flour (Fagopyrum esculentum) and oat bran (Avena sativa) as fermentation ingredients, in view of their high content of bioactive compounds that have a great impact both on fermentation microorganisms and consumers’ health. The effect of these two raw vegetal products on LA 5® strain was studied by cultivation on MRS broth and on milk. The supplementation of the fermentation medium with 4.0% 6.0% of buckwheat flour or oat bran, respectively, had a positive effect on metabolic activity and viability of lactic acid bacteria. Thus, the rapid decrease of the pH and the increase of the multiplication rate were obser...
Innovative Romanian Food Biotechnology, 2011
Inulinases are hydrolysis enzymes that act on the β-2,1 linkage of inulin, resulting fructose, gl... more Inulinases are hydrolysis enzymes that act on the β-2,1 linkage of inulin, resulting fructose, glucose and inulooligosaccharides as reaction products. Microorganisms are the best sources for inulinases production, as they are easy to be cultivated and produce high yields of enzymes. Inulinases have a molecular weight over 50.0 kDa, an optimal pH between 4.5-7.0 and an optimal temperature between 30°C and 60°C, depending of their producers, moulds, bacteria or yeasts. Purified enzymes are activated in the presence of some ions (like Ca, K, Na), while other metallic ions act like inhibitors (Mg or Ag). Inulinases are widely used for ultra-high-fructose syrup and oligofructans production from inulin, for bioethanol production from inulin rich feedstock, citric acid, single cell protein and other chemicals obtaining. In this article, inulinases obtaining and their properties characterization, as well as their potential applications are reviewed.
Anthocyanin is a water-soluble pigment existing in plants, and has various health benefits to hum... more Anthocyanin is a water-soluble pigment existing in plants, and has various health benefits to humans. As far as that goes, the number and location of the hydroxyl groups of the parent nucleus have significant effects on the anthocyanin activities. This review summarizes anthocyanin content in fruits, the importance of anthocyanin in relation to human health, some aspects of anthocyanin biochemistry and their bioavailability, the distribution in some fruits, the biosynthetic pathway, different extraction, separation and purification methods, and also identification methods. Beneficial effects of anthocyanin pigments are reported in the scientific literature and these compounds are nowadays recognised as potentially therapeutic. The lack of antioxidant defense mechanisms in humans is associated with the cardiovascular and coronary artery diseases, cancer and diabetes, besides others.
The Annals of the University Dunarea de Jos of Galati Fascicle VI – Food Technology, 2019
The importance of lavender as a source of essential oils has been well recognized. This study rep... more The importance of lavender as a source of essential oils has been well recognized. This study reports the phytochemical profile of lavender extract in terms of chlorophylls, total carotenoids, polyphenols and flavonoids, related to antioxidant activity. The extract displayed a high polyphenolic and flavonoids content, with an antioxidant activity of 2.28±0.18 mMol Trolox/g D.W. The fractional conversion and first order kinetic models were found suitable for predicting the changes that occur in the selected phytochemicals. Kinetic and thermodynamic parameters were calculated confirming the irreversible degradation of phytochemicals. Both the temperature and duration of heating significantly impacted the content in bioactive compounds.
Journal of Food Science and Technology, 2015
Linoleic acid (LA) is the precursor of bioactive oxidized linoleic acid metabolites and arachidon... more Linoleic acid (LA) is the precursor of bioactive oxidized linoleic acid metabolites and arachidonic acid, therefore is essential for human growth and plays an important role in good health in general. Because of the low water solubility and sensitivity to oxidation, new ways of LA delivery without compromising the sensory attributes of the enriched products are to be identified. The major whey protein, β-lactoglobulin (β-Lg), is a natural carrier for hydrophobic molecules. The thermal induced changes of the β-Lg-LA complex were investigated in the temperature range from 25 to 85°C using fluorescence spectroscopy techniques in combination with molecular modeling study and the results were compared with those obtained for β-Lg. Experimental results indicated that, regardless of LA binding, the polypeptide chain rearrangements at temperatures higher than 75°C lead to higher exposure of hydrophobic residues causing the increase of fluorescence intensity. Phase diagram indicated an all or none transition between two conformations. The LA surface involved in the interaction with β-Lg was about 497 Ǻ 2 , indicating a good affinity between those two components even at high temperatures. Results obtained in this study provide important details about heat-induced changes in the conformation of β-Lg-LA complex. The thermal treatment at high temperature does not affect the LA binding and carrier functions of β-Lg.
Due to its important environmental benefits, bioethanol promise to be a good biofuel substitute f... more Due to its important environmental benefits, bioethanol promise to be a good biofuel substitute for gasoline. To make it competitive with other fuels, the production costs should be reduced by using alternative raw materials. Inulin rich feedstock, like dahlia (Dahlia hortensis) and Jerusalem artichoke (Helianthus tuberosus) tubers or chicory (Cichorus intybus) roots would be a cheap and convenient source for fermentable sugars for bioethanol production. These are suitable crops for European countries and in low-requirements environmental conditions. Two processes were studied for conversion of inulin rich feedstock to fermentable sugars:"acid-based" and "enzymebased" hydrolysis. The fermentable sugars (mainly fructose and low amounts of glucose) are then fermented using different alcohol-tolerant Saccharomyces cerevisiae yeast strains. Direct fermentation of inulin to ethanol was also performed, as some Kluyveromyces spp. yeast strains were found to have the ability to ferment inulin. This paper highlights the ongoing developments in fuel ethanol bioproduction from inulin rich feedstock, with focus on inulin hydrolysis which is the major problem of the overall process.
Bioethanol serves as liquid fuel or gasoline enhancer in many countries in response to the progre... more Bioethanol serves as liquid fuel or gasoline enhancer in many countries in response to the progressive depletion of the world's energetic resources. Production of bioethanol from inulin rich raw materials has been a subject of great interest for many years due to the large amount of existing and not completely developed technologies. The aim of this work was to study three different methods for hydrolysis and fermentation of pure inulin and Jerusalem artichoke flour: separate hydrolysis by A. niger MIUG 1.15 strain as active producer of inulinase, in stationary phase and under agitation, followed by fructose fermentation and simultaneous hydrolysis and fermentation of inulin and Jerusalem artichoke flour respectively, in order to increase the yield of biotransformation of substrate into ethanol. The highest amount of ethanol was formed during simultaneous hydrolysis and fermentation, for both pure inulin and Jerusalem artichoke (Helianthus tuberosus) tubers used as raw materials, of 16.2 g•L-1 and 28.1 g•L-1 respectively.
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Papers by Gabriela Bahrim