
Panteley DenevUniversity of Food Technologies | UFTP · Organic chemistry
Panteley Denev
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Publications (155)
Interest in sucrose esters which are surfactants and environmental products, attracts the attention of researchers and manufacturers, due to the fact that renewable, easily available raw materials are used for their production. Sucrose esters are non-toxic, biocompatible and biodegradable products that are widely used in food technology, cosmetics...
Plasticizers are additives that increase the plasticity of polymers by increasing the flexibility of macromolecules. The selection of substances with a similar function is carried out in accordance with criteria that include requirements for non-toxicity, good miscibility, low migration ability, low volatility, etc. The plasticizers most used in pl...
Esters are used in the industry. The rapid increase in demand for esters in the food, cosmetics and pharmaceutical industries makes it mandatory to find alternative ways of synthesis instead of low-yield, expensive, energy-intensive and prolonged reactions. The production process for the synthesis of esters is based on chemical esterification of fa...
Plasticizers are additives that increase the plasticity of polymers by increasing the flexibility of macromolecules. The selection of substances with a similar function is carried out in accordance with criteria that include requirements for non-toxicity, good miscibility, low migration ability, low volatility, etc. The plasticizers most used in pl...
Green extraction methods present perspective approach for isolation of bioacticve molecules. Together with an ecofriendly approach for extraction there are many undervalued plants-a rich of source of prebiotics and phenolic compounds. Carlina acanthifolia L. roots possessed antimicrobial, anti-inflammatory, anti-ulcer properties due to the diverse...
The present study shows the results obtained in the ultrasonic synthesis of sucrose esters with lauric acid, the identification of products, and the study of their possible use as bio-additives with a plasticizing effect in the processing of plastics. Fourier transform infrared spectroscopy (FTIR) and NMR (1 H and 13 C NMR) were used to identify th...
The aim of this study is to demonstrate a simple and rapid "green" method for the ultrasound assisted synthesis of aliphatic esters of capric acid. The spectral characterization of esters was performed by IR and NMR spectroscopies. The impact of ultrasonic irradiation on the reaction in a comparison with the conventional method was analyzed based o...
The aim of the present study is to investigate the application of caprate aliphatic esters as co-plasticizers and biodegradable additives in polyvinyl chloride. i-Bu caprate was used in different proportions. The applicability of a mixture of esters as bio-plasticizers and bio-additives in polyvinyl chloride was studied. The influence of the ester...
The article presents a review of research and modern engineering solutions based on "green technologies" �for the synthesis of esters. Significant advantages of the method of transesterification of methyl caprate �with sucrose, leading to esters with potential biological activity such �as antifungal and antimicrobial agents, are highlighted.
The aim of this study is to demonstrate a simple and rapid "green" method for the ultrasound assisted synthesis of aliphatic esters by reacting isoamyl esters with saturated (capric, lauric, palmitic) acids. The spectral characterization of esters was performed by IR and NMR spectroscopies. The impact of ultrasonic irradiation on the reaction in a...
The aim of the present study is to investigate the application of a mixture of carbohydrate esters as co-plasticizers and biodegradable additives in polyvinyl chloride. Sucrose palmitate and inulin acetate were used in different proportions. The applicability of a mixture of carbohydrate esters as bio-plasticizers and bio-additives in polyvinyl chl...
Sucrose esters of higher fatty acids were obtained by ultrasound. The resulting esters are used as bioadditives in the processing of polyvinyl chloride. The addition of sugar esters causes a significant change in the physicomechanical properties of the resulting plastics, showing a plasticizing effect.
Sucrose is used as a renewable raw material for the preparation of esters in various fields such as detergents, whitening boosters, cosmetics, medicines, nutritional supplements, emulsifiers, stabilizing agents, etc. By transes-terification of all hydroxyl groups with fatty acids, the polysubstituted sucrose esters acquire specific physical and org...
An environmentally friendly and sustainable ultrasound-assisted esterification of long-chained inulin and sucrose with monounsaturated 10-undecylenic acid was performed. The obtained esters were characterized by thin-layer chromatography (TLC), Fourier transforms infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR) spectroscopy. The s...
Esters are widely used in in-a-kind and are widely used in industry. The rapid increase in demand for esters in the food industry, cosmetics, pharmaceutical industry makes it imperative to find alternative ways of synthesis instead of reactions that have low yield, expensive, energy-intensive and long lasting. Also, long-chain esters of higher fatt...
The aim of the current study was to improve the nutritional value, rheological quality and sensory characteristics of yoghurt prepared with high-esterified citrus and celery pectins. Comparative studies of physicochemical characteristics of yoghurt with incorporated pectin isolated from celery (Apium graveolens var. rapaceum D. C.) tubers and comme...
The aim of this study is to demonstrate a simple and rapid "green" method for the ultrasound assisted synthesis of aliphatic esters by reacting isoamyl esters with saturated (capric, lauric, palmitic) acids. The spectral characterization of esters was performed by IR and NMR spectroscopies. The impact of ultrasonic irradiation on the reaction in a...
The increased consumption of resources and the increased requirements for environmental protection require the finding of alternative, more efficient, environmentally friendly methods for extraction and synthesis, as well as the reduction and recovery of industrial chemical waste. In chemical technologies, various methods and approaches are applied...
Undenicylic acid (10:1) is known as an antifungal agent and an active ingredient of many topical medicines [1-6]. The present research investigates the preparation of aliphatic esters of 10-undecylic acid with butanol and i-amyl alcohol by the conventional and ultrasound-assisted syntheses as well as the structural elucida-tion of the resulting com...
This study aims to demonstrate a simple and rapid "green" method for the ultrasound-assisted synthesis of t-aliphatic esters by reacting t-butanol with saturated (capric, lauric, palmitic) and unsaturated (oleic and undecylenic) acids. The spectral characterization of esters was performed by IR and NMR spectroscopies. The impact of ultrasonic irrad...
Microwave-assisted irradiation was performed for esterification of chicory
inulin with high degree of polymerization with acetic anhydride without a solvent
only with a catalyst. The resulting esters were characterized by melting point,
hydrophilic-lipophilic balance, thin-layer chromatography, ultraviolet spectroscopy,
Fourier transform infrared s...
Crab apple (Malus baccata (L.) Borkh) has been cultivated throughout Europe as an ornamental plant, but the nutritional properties of its edible
fruits were not fully revealed. The aim of the current study was to characterize the phytochemical composition of ripen crab apple fruits and to
evaluate their nutritional and antioxidant potentials. The f...
Crab apple (Malus baccata (L.) Borkh.) was mainly distributed in Europe as an ornamental plant, but the nutritional properties of its edible fruits were not fully revealed. The aim of the current study was to characterize the phytochemical composition of ripen carb apple fruits and to evaluate their nutritional and antioxidant potentials. The fruit...
The aim of the present work was to evaluate some phytochemical compounds in fresh, frozen, and processed yellow-coloured figs (Ficus carica L.). The moisture content, ash, titrable acidity, total chlorophylls, total carotenoids, total phenols, total flavonoids, total anthocyanins, as well as carbohydrates (fructose, glucose, and sucrose) were evalu...
A number of industrial technologies generate waste that creates a risk of environmental pollution. In this regard, research in recent years has focused on the search for new technological solutions for process intensification. For solution reactions, the use of ultrasound is effective. Ultrasound has been found to influence the rate of chemical rea...
Esters are widely used in a-kind and are widely used in industry. The rapid increase in demand for esters in the food, cosmetics, and pharmaceutical industries makes it imperative to find alternative ways of synthesis instead of reactions that have low yield, expensive, energy-intensive and long lasting. Also, long chain fatty acid esters are used...
Culinary herbs were known and applied from ancient times in food production and for culinary purposes, as flavor enhancers and food preservation, because of the bioactive substances with antimicrobial and antioxidant properties. Therefore, they can successfully use as sources of natural antioxidants that improve consumer health and the nutritional...
The effects of cooking methods (steaming, pressure-cooking, microwaving, frying and boiling) on total phenolic contents of Morchella esculenta mushrooms were evaluated. The best cooking method was microwaving with losses up to 2%, and the worst – boiling with losses amounting to 50%. The results of the study provided some information on the effects...
Jerusalem artichoke (Helianthus tuberosus L.) tubers are industrial crop considered as a promising source for inulin production. "Green" method was performed for accelerated inulin extraction from Helianthus tuberosus L. tubers by the application of microwave irradiation. Further pretreatment of the water extract with acetone and ethanol yielded in...
The paper presents the findings of an experimental study on the microwave synthesis (MW) of inulin acetate and its possible application as bio-additive in poly(vinyl chloride) (PVC). The obtained inulin acetate has been identified and characterized by spectroscopic methods. Advantages of the MW compared with the conventional synthesis were defined....
Petkova N. and P. Denev, Chemical structure and functional properties of fructan isolated from Echinacea purpurea roots by microwave-assisted extraction, Proceedings of the 14th International Conference on Polysaccharides-Glycoscience 2018, 58-64. Petkova N. and P. Denev, Chemical structure and functional properties of fructan isolated from Echinac...
The aim of the study was to improve the nutritional properties of breads by the incorporation of wheat and Jerusalem artichoke flours. Total phenols, total flavonoids, selenium and inulin content were also evaluated in the samples. Breads prepared with mixture of wheat and Jerusalem artichoke tubers flours possessed higher antioxidant activity 576...
The main industrial sources of pectin are apple pomace and citrus peels. Pectins obtained from other plants, such as sugar beet, pumpkin and tropical fruits1, watermelon rind2 or papaya peel3 also gain interest. Pectin consists of homogalacturonan, rhamnogalacturonan I, rhamnogalacturonan II which form the main building blocks of polymers. Homogala...
The "green" methods as microwave (MAE) and ultrasound-assisted extraction (UAE) have been applied for simultaneous isolation of inulin from dahlia tubers. The inulin yield was 42% dw, fructose content 90-95% and reducing groups was 4.3-4.6%, respectively. The structure of dahlia inulin was confirmed by IR-FT and 1 H and 13 C NMR spectroscopy. IR-FT...
Undenicylic acid (10-) is known as an antifungal agent and an active ingredient of many topical drugs. The present research investigates the preparation of aliphatic esters of 10-undecylic acid with butanol and i-amyl alcohol by the conventional and ultrasound-assisted syntheses as well as the examination of the structure of the resulting compounds...
The aim of this study is to demonstrate a simple and rapid method for “green synthesis” of t-aliphatic esters by reacting t-butanol with saturated (capric, lauric, palmitic) and unsaturated (oleic and undecylenic) acids by ultrasound irradiation. Additional spectral characterization of esters was performed by IR and NMR spectroscopy. The impact of...
Enrichment of food with bioactive compounds improved significantly their functinal and nutritional properties
[1,2]. The Jerusalem artichoke flour is rich source of phenolic compounds and inulin and could be successfully
used in bread production [3, 4]. The aim of the current study was to improvement the nutritional potential of
breads by the incor...
In the present work eleven of the most widely used culinary herbs (parsley, dill, lovage, thyme, savory, oregano, basil, peppermint, spearmint, rosemary and fenugreek leaves) in the Bulgarian traditional kitchen were analyzed for biologically active substances as total phenolic content, derivatives of caffeic acids, total flavonoids content, natura...
9-ТА НАЦИОНАЛНА КОНФЕРЕНЦИЯ ПО ХРАНЕНЕ, 31 май-3 юни 2018 Катедра "Органична химия и неорганична химия" Университет по хранителни технологии-Пловдив
The chemical composition of honeybees (Apis mellifera) was analyzed. Proteins accounted for the highest percentage of the detected substances (56.2%), followed by carbohydrates (11.3%), and lipid components (10.4 %). The mineral content was very low (0.5%). Thirteen fatty acids were identified, the main ones being oleic (56.0%), palmitic (22.6%), a...
Moraceae is very common in the Mediterranean region and in the countries with dry and warm climate. Since ancient times the figs have been used for human consumption, but it was only recently that their nutritive and pharmacological value has been investigated. The aim of the current study was to investigate the metabolites profile of the different...
A comparative investigation of n-hexane soluble compounds from aerial parts of dandelion (Taraxacum officinale Weber ex F.H. Wigg.) collected during different vegetative stages was carried out. The GC-MS analysis of the n-hexane (unpolar) fraction showed the presence of 30 biologically active compounds. Phytol [14.7% of total ion current (TIC)], lu...
Mushroom samples were collected in 2017 and 2018 from the Batak mountain by the authors themselves. The aim of this study was to determine phospholipids composition of species wild edible mushrooms (Suillus luteus) grown in the Batak mountain, Bulgaria. Phosphatidic acids were the main components in lipids from Suillus luteus (34.2 %). The content...
Sucrose octaacetate (octa-O-acetylsucrose) has been synthesized by esterification of sucrose with acetic anhydride using ultrasound-assisted irradiation. This sucrose ester is a white, water-insoluble substance with a bitter taste. The FT-IR and NMR spectra confirmed acetylation and revealed the hydrophobic incorporation in sucrose molecule. Furthe...
The aims of the current research were to evaluate and to compare the antioxidant activity and the content of total phenolic, flavonoids and fructan content in infusions and microwave-assisted extracts from eight herbs: rosehip (Rosa canina L.), peppermint (Mentha piperita L.), thyme (Thymus vulgaris L.), coltsfoot (Tussilago farfara L.), dandelion...
The aim of the current study was synthesis and characterization of CMC and further evaluation of its emulsion stabilizing properties for preparation of pharmaceutical and cosmetic emulsions. Carboxymethyl chitosan (CMC) with high degree of substitution (50 %) has been synthesized and further characterization of resulting product by FTIR, NMR spectr...
Inulin acetates with three different degrees of polymerization (DP) were designed and their structure was proven by infrared spectroscopy and nuclear magnetic resonance. For the first time the influence of the length of the carbohydrate chain and the acetyl residues on the growth of different microorganisms were evaluated. Inulin acetates in concen...
The aim of this study was to evaluate the adsorption capacity of the Schiff base chitosan-cinnamaldehyde for its application in dairy wastewater pre-treatment. Chemical oxygen demand (COD) reduction was used to evaluate the adsorption efficiency. The maximum COD percentage reduction of 33.5% was obtained at 40.0 C, pH 9.0, adsorbent dose 20 g L-1 ,...
Hydrocolloids, especially polysaccharides from traditional plant sources and their derivatives possessed significant emulsifying properties. Pectin
was isolated from celery tubers by accelerated “green” method for extraction based on ultrasonic irradiation. Further chemical modification of celery pectin was
performed with 4 mol/L NH The amidated ce...
Plasticizers used in the treatment of polyvinyl chloride (PVC), which in most cases are esters of carboxylic acids with linear or branched aliphatic alcohols (phthalates, octanoates, etc.), possess excellent functional properties. However, they prove to be somewhat toxic. Therefore, they should be replaced with safer and more effective substances l...
Jerusalem artichoke (Helianthus tuberosus L.) tubers are industrial crop considered as promising source for inulin production. Green method was performed for accelerated extraction of inulin from Helianthus tuberosus L. tubers by application of microwave irradiation. Further pretreatment of extract with acetone and ethanol yielded inulin (10 %), wi...
The growing interest in the modification of chitosan with improved solubility has been introduced new applications to enhance chitosan biological properties. The aim of the current study was to obtain carboxymethyl chitosan (CMC) and to apply it as stabilizer for preparation of cosmetic gels. For this purpose, initially, chitosan was reacted with m...
The aim of the current study was to develop and validate a rapid, sensitive and accurate method for simultaneous determination of sugars (glucose, fructose, sucrose and lactose) and polyols (erythritol, mannitol, sorbitol, isomalt and xylitol) in low-calorie and no-sugar added desserts by high pressure liquid chromatography coupled with refractive...
The Schiff basis of chitosan was synthesized under high-intensity ultrasound by the reaction with carbonyl compounds-citral and cinnamaldehyde at the following conditions: a temperature of 30 and 50 ºC, molar ratio of chitosan to aldehyde of 1 : 3 and 1 : 6 and reaction time of 5 and 10 hours, respectively. The structures of derivatives have been c...
: The quality and healthy status of food products for human nutrition present high priority in modern lifestyle. The objective of the current study was to evaluate the polyphenolic content and in vitro antioxidant activity of different green tea brands available in the Bulgarian market. To the best of our knowledge, no studies have been conducted t...
Commercial pectin is mainly derived from citrus peels or apple pomace, after juice production. The present study was focused on investigation the influence of extraction condition on the physicochemical characteristics of pectin polysaccharide obtained from orange peels. Effect of extraction with citric acid, oxalic acid, HCl and ammonium oxalate o...
The aim of the current research was to perform two “green chemistry”
extractions (ultrasound and microwave irradiation) with methanol, 70% (v/v) ethanol and
water for extraction of biologically active substances from elecampane (Inula helenium
L.) roots and to compare their contents in all extracts. The presence of carbohydrates
(sugars, fructoolig...
Inulin esters were synthesized by transesterification reaction with methyl esters of three fatty acids (10-undecylenic, lauric and palmitic) under ultrasonic irradiation. The obtained esters were characterized by TLC and IR-FT spectroscopy. These inulin esters were examined for potential antimicrobial properties. The results from antibacterial assa...
The paper presents results obtained by experimental study of polyvinyl chloride (PVC) films containing sucrose
palmitate as bio-plasticizer. Influence of the plasticizer’s concentration on morphology and tensile properties of the polymer has been investigated in order to prove its plasticizing effect. It has been established a specific nonhomogeneo...
Tests under field conditions were conducted on the biofertilizer Kompovet and the biological pesticides Neem Oil and Neem Cake on the Gergana cucumber variety and Ismalia F1 zucchini variety. Trials were carried out in 2015-2016, in the village of Kostievo near Plovdiv. The treated variants accumulated more biomass, formed a greater number of femal...
Eco-friendly synthesis of methyl esters of two alginic acids with different ratio between M-block and G-blocks were performed by microwave irradiation. The alginates methyl esters have been characterized by degree of esterification (DE), HPLC-SEC, IR-FT and NMR spectroscopy and thermal analysis (TGA/DTA). The influence of reaction time on DE of alg...
Amidated derivatives of three previously esterified alginic acids with different ratio between manuuronic (M) and guluronic
(G) blocks have been synthesized in four different reaction media (methanol, ethanol, 1-propanol and 2-propanol). The
synthesized alginic acids products were characterized by anhydrouronic acid content (AUAC), the degree of es...
In the current research, pectic polysaccharide has been isolated from celery tubers (Apium graveolens var. rapaceum D. C.) by extraction with an aqueous ammonium oxalate. The obtained pectin has been characterized as low methoxylated (LM) with degree of esterification (DE) 36 % and anhydrouronic acid content (AUАC) 56 %, respectively. Additional mo...
The possibilities of using low-esterified amidated pectin isolated from Bulgarian plant cultures have been studied. The comparison
between pectin extracted from celery and commercial low-esterified amidated pectin showed that celery pectin can be used successfully
for preparation of functional fermented dairy products enriched with soluble dietary...
The purpose of this research was to evaluate the sugar and fructans content in stems
and leaves of different agave species Agave americana L., Agave americana L.
“Variegata”, Agave horrida Lem ex Jacobi, Agave victoriae-reginae T. Moore collected
from territory of Spain. The ultrasound-assisted extraction (frequency 36 kHz) at 65 °C
was performed w...
The aim of the current study was to evaluate the total phenolic content and radical scaveng-ing activity of water, 70 % ethanol and 95 % ethanol extracts obtained from both plant nettle (Urtica dioica) roots and edible artichoke flower heads (Cynara scolymus L.) by green chemistry extraction methods (ultra-sound and microwave irradiation). Cynara s...
Alginic acids are perspective biopolymers with significant application in food technologies and pharmaceuticals. The aim of the current research was to synthesized environment-friendly alginic acid derivatives (methylated and amidated alginic acids with the different ratio of M/G blocks in the polysaccharide backbone) by ultrasound irradiation. The...
The aim of the current research was to determine the ascorbic acid content, total tannins and total phenolic content in three extracts (water, 50 % v/v ethanol, 70 % (v/v) ethanol) obtained from dry wild growing rose hip fruits and to evaluate their antioxidant potential by four reliable methods: DPPH, ABTS, FRAP, CUPRAC. The highest ascorbic acid...
Chemical modification of alginic acid has been done by ultrasonic irradiation to obtain its methylated, ethylated and isopropylated derivatives. The influence of ultrasonic frequency and power on esterification process of alginic acid has been investigated. Alginate derivatives have been characterized by degree of esterification (DE) and IR-FT spec...
This article presents the results obtained by the ultrasound-assisted synthesis of sucrose and fructooligosaccharides (FOS) esters with fatty acids (palmitic and 10-undecylenic), the identification of the products and the study of their possible application as plasticizers in plastics processing. Fourier transform infrared spectroscopy (FTIR) and n...