Albert Ivanov Krastanov

University Of Food Technology - Plovdiv | UFTP · Faculty of Biotechnology

Stable symbiotic starter cultures were created using selected strains of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus with antimicrobial activity against pathogens and necessary antibiotic sensitivity, growth kinetic parameters, and metabolic profiles. The volatile compound profiles of the obtained st...

Research on food-derived bioactive peptides is expanding and the need for a convenient online platform that combines a foolproof and intuitive user interface with a reliable database and tools for prediction and analysis is rising. In this regard, this paper presents an open-access web-based platform PepLab (Peptides Laboratory), available at www.p...

Higher basidiomycetes are recognized as functional foods due to their bioactive compound content, which exerts various beneficial effects on human health, and which have been used as sources for the development of natural medicines and nutraceuticals for centuries. The aim of this study was to evaluate and compare the biological potential of basidi...

Today there is an increasing amount of scientific evidence of the effects of probiotic bacteria as components of the gut microbiota on human health. Among their numerous health benefits are their antioxidant (AO) properties attracting more and more attention. Lactobacilli and bifidobacteria are the most important part of the human gut microbiome. M...

The concept of functional foods is gaining more importance due to its role in maintaining a healthy status and preventing some metabolic diseases. The control of diabetes, in particular type-2 (T2DM), could be considered a big challenge since it involves other factors such as eating habits. From the pharmacological point of view, inhibiting digesti...

Macrolepiota procera (MP) is an edible mushroom used in the treatment of diabetes, hypertension and inflammation. However, the structure and biological effects of its polysaccharides (PSs) are unclear. This study investigates the structural features of a PS complex from MP (MP-PSC), its immunomodulatory activities and effects on probiotic and patho...

In this study, we developed and optimized a growth medium using various nitrogen sources for the cultivation of Lactobacillus delbrueckii ssp. bulgaricus, a probiotic and essential dairy starter culture. The composition of de Man, Rogosa, and Sharpe (MRS) culture medium was modified, and the nitrogen content was replaced by alternative nitrogen sou...

The aim of this study is to characterize the bioactivity of mycelial biomass and crude exopolysaccharides (EPS) produced by Trametes versicolor NBIMCC 8939 and to reveal its nutraceutical potential. The EPS (1.58 g/L) were isolated from a culture broth. The macrofungal biomass was rich in protein, insoluble dietary fibers and glucans. The amino aci...

In this study, we developed and optimized a growth media by evaluating various nitrogen sources for the cultivation of Lactobacillus bulgaricus, a probiotic and an important dairy starter culture. We modified the composition of deMan, Rogosa and Sharpe (MRS) culture media and substituted the nitrogen content with alternative nitrogen sources X-Seed...

Lactic acid bacteria (LAB) are essential dairy starter cultures that are significantly employed for the manufacture of fermented dairy products such as yogurt and cheese. LAB predominantly produce lactic acid as a major end product of fermentation, and they synthesize important metabolites that impart the organoleptic characteristics of fermented f...

Ethnopharmacological relevance Geranium sanguineum L. is used for treatment of inflammations, anemia, malignant diseases of the blood-forming organs, diarrhea, respiratory infections, etc. Only flavonoids in root extracts have been elucidated as immunostimulating and anti-inflammatory compounds, and polysaccharides in the herb have not been examine...

The harshest conditions of the human gastrointestinal tract were simulated in order to study probiotic bacteria in their intended environment. Eight Lactobacillus strains were cultivated in MRS broth with added bile in different concentrations and their growth was monitored as optical density. The gathered data was used to determine the MIC of bile...

The objective of this study was to investigate the effect of sublethal concentrations of 5 antibiotics (tetracycline, erythromycin, penicillin G, lincomycin, ciprofloxacin) and 2 preservatives (benzoic and sorbic acid) on the growth and development of 8 probiotic Lactobacillus strains. All lactobacilli were subjected to a large range of concentrati...

In this study, for the first time, the potential of rose flowers and lavender straw waste biomass was studied as feeding lignocellulose substrates for the cultivation of newly isolated in Bulgaria Ganoderma resinaceum GA1M with the objective of obtaining mycelium-based bio-composites. The chemical characterization and Fourier Transform Infrared (FT...

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Since rapeseed and sunflower meals are two of the most representative oilseed crops in the world, this study was focused on ethanol-wash solutes (EWS) obtained as wastes from the protein isolation process of rapeseed and sunflower meals. These meals have been previously valorised; however, the use of the EWS is unexplored. The present study is aime...

The species Trametes versicolor refers to medicinal mushroom well known in traditional Asian medicine for over 2000 years. Due to the long time required for basidiocarp formation, attention has recently been given to the submerged cultivation method for the production of mycelial biomass and various bioactive components. Exopolysaccharides (EPS) pr...

The aim of this review was to present various topics related to lactose intolerance with special attention given to the role of fermented foods and probiotics in alleviating gastrointestinal symptoms. Lactose intolerance is a common digestive problem in which the human body is unable to digest lactose, known as milk sugar. Lactose intolerance can e...

The agricultural waste with lignocellulose origin is considered to be one of the major environmental pollutants which, because of their high nutritional value, represent an extremely rich resource with significant potential for the production of value added bio-products. This review discusses the applications of higher fungi to upcycle abundant agr...

The inhibition of certain digestive enzymes by target food matrices represents a new approach in the treatment of socially significant diseases. Proving the ability of fruits to inhibit such enzymes can support the inclusion of specific varieties in the daily diets of patients with diabetes, obesity, Alzheimer’s disease, etc., providing them with m...

In the current study the phytochemical composition of extract from Ziziphus jujubа Mill (Rhamnaceae) fruits obtained by pressurized liquid extraction (PLE) was investigated. The phytochemical analysis showed the presence of triterpenes, flavo�noids and phenolic acids. The fruit extract had a total phenolic content of 21 ±2.01 mg gallic acid equiva...

The biological and organoleptic properties of Bulgarian yogurt are largely determined by the metabolic activity of the selected strains of Lactobacillus delbrueckii ssp. bulgaricus. The HS-SPME-GC-MS technique was used to analyze the volatile compounds produced by the following strains: Lactobacillus delbrueckii ssp. bulgaricus MG1, MG2, MG3 MG4, M...

Edible flowers are considered as a valuable source of bioactive compounds and are used as food and medicine with growing interest. Microwave extraction technique was employed as a green approach to obtain water extracts from seven edible flowers including Viola tricolor L., Cucurbita pepo L., Sambucus nigra L., Calendula officinalis L., Hibiscus ro...

Inulinase was immobilised by entrapment method in polyacrylamide/polyethylene glycol composite and evaluated for its efficiency for short-chain fructooligosaccharides (3–6 degrees of polymerisation) production in batch hydrolysis system. Aqueous two-phase polymerisation technique was used to synthesise the composite, where aqueous polyethylene glyc...

Nowadays, a modern trend of the animal husbandry is to increase the reproductive potential of livestock and poultry. There is a large interest worldwide in discovering new and safe non-hormonal biologically active substances obtained from natural sources, which could substitute the synthetic hormones. The positive influence on reproduction in lives...

Research on lactic acid bacteria has confirmed how specific strains possess probiotic properties and impart unique sensory characteristics to food products. The use of probiotic lactic acid bacteria (LAB) in many food products, thus confers various health benefits to humans when they are frequently consumed in adequate amounts. The advent of functi...

Background and objectives Hypertension is associated with the overproduction of free radicals, generating oxidative stress, which could contribute to the lipid peroxidation, altering the blood lipid levels, and to the development of diseases such as diabetes. The aim of this work was to evaluate the bioactivity of cooked red and black quinoa over b...

Date fruit is an excellent source of nutritional and health benefits. The chemical composition of dates includes carbohydrates, dietary fiber, proteins, fats, minerals and vitamins, enzymes, phenolic acid, and carotenoids, all of which are directly linked to nutritional and health benefits for consumers. A number of studies have also confirmed the...

The present research work was carried out to evaluate the antioxidant potential of several grains and seeds, such as chia, common oat, proso millet, amaranth, quinoa, buckwheat, flax seed, and einkorn. The antioxidant and radical scavenging activity was determined by using different in vitro assays. The phytochemical screening revealed that the stu...

Recently, there has been a considerable interest in finding natural antioxidants from plant materials to replace the synthetic ones. The edible flowers represent a valuable alternative source of bioactive compounds and have been used as food and herbs with increasing interest. The antioxidant properties of 7 edible flowers of the South Bulgaria, in...

In this study, we modified reinforced clostridial medium (RCM) to selectively enumerate and isolate Lactobacillus delbrueckii ssp. bulgaricus, a probiotic and important starter culture in the dairy industry. The disparity in the reported carbohydrate fermentation pattern of L. delbrueckii ssp. bulgaricus was used to develop a growth medium not only...

The study reported in this research communication evaluates the chemical (solvents) and mechanical (sonication, bead-beater) extraction methods to determine the maximum recovery of β-galactosidase from L. bulgaricus spp. Among all extraction techniques, sonication-assisted extraction yielded the highest amounts of enzyme activity (between 1892–2156...

This review aims to familiarize the reader with research efforts on the cultivation media of lactic acid bacteria (LAB). We have also included a brief discussion on standard ingredients used in LAB media and chemically defined media as related to bacterial growth requirements. Recent research has focused on modifying standard media for the enumerat...

The antimicrobial activity of strains Lactobacillus delbrueckii ssp. bulgaricus MG1, Lactobacillus delbrueckii ssp. bulgaricus MG2, Lactobacillus delbrueckii ssp. bulgaricus MG3 and Lactobacillus delbrueckii ssp. bulgaricus MG4 has been investigated against pathogenic microorganisms Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 8739, List...

This paper describes the development of a simple method for mixed non‐covalent and covalent bonding of partially purified inulinase on functionalized multiwall carbon nanotubes (f‐MWCNTs) with polypyrrole (PPy). The pyrrole was polymerized on MWCNTs electrochemically in order to fabricate MWCNTs/PPy nanocomposite. Two multiple forms of enzyme were...

This study reveals the selection of a yeast strain, possessing inulinase activity and finding the optimal conditions of cultivation. Intra- and extracellular activity assay was performed after cultivation on media, containing inulin as a sole source of carbon. Optimization of the cultivation conditions was carried out for establishing the favorable...

This study reveals the selection of a yeast strain, possessing inulinase activity and finding the optimal conditions of cultivation. Intra- and extracellular activity assay was performed after cultivation on media, containing inulin as a sole source of carbon. Optimization of the cultivation conditions was carried out for establishing the favorable...

The ability of the fungus Fusarium moniliforme to degrade phenol, catechol, 2,4-dichlorophenol and their mixtures was investigated in the present study. The biodegradation studies were performed in a liquid medium with the phenolic compounds as a sole carbon and energy source. It was fbund that temperature of 25 oC was optimal for 100% degradation...

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...

Inulinase from Bacillus sp 11/3 was purified with aqueous two phase systems (ATP) and two multiple forms of the enzyme were recovered from the polyethylene glycol (PEG) upper phase. The main subject of this research was to immobilize the enzymes on chitosan beads without the purification step from the PEG phase. In addition, the performance of the...

Modern life is characterized by physical inactivity and poor food choices, which is often a prerequisite for unhealthy weight gain and overweight/obesity. These factors unlock the emergence of a number of diseases including diabetes, cardiovascular problems, different types of cancer, etc. The pursuit of scientists to seek strategies to prevent, r...

Bacteriocins are biologically active compounds produced by a large number of bacteria, including lactic acid bacteria (LAB), which exhibit antimicrobial activity against various saprophytic and pathogenic microorganisms. In recent decades, bacteriocins are increasingly becoming more important in different branches of the industry due to their broad...

In this study, extracellular inulinase from Bacillus sp. 11/3 was partially purified and concentrated using aqueous two-phase system (ATPS). Two different phase forming salts and four types of polyethylene glycol (PEG) were used. Binodal curves and tie-length lines (TLLs) for eight ATPS were developed. For inulinase purification, concentrations of...

Lipase production during submerged cultivation of Aspergillus carbonarius NRRL369 was studied. In order to increase lipase activity an optimal composite design was applied. Optimal concentrations of the nutrient medium components were found to be (g/l): rapeseed oil 20.0, Tween 80 20.0, meat extract 5.6, MgSO 4 1.0, and KH 2 PO 4 4.0. The result wa...

Biodegradation of mixed substrates phenol and catechol and phenol and 2,4-dichlorophenol at high inhibitory initial concentrations (2 g/dm3) by Trametes versicolor 1 in a “fed-batch” process is studied. It is established that Trametes versicolor 1 (biomass 50 g/dm3) biodegrades total 6.14 g mixture of phenol and catechol for 14 d at 2 feedings and...

Biodegradation of phenol, catechol and 2,4-dichlorophenol, at higher initial inhibitory concentrations, by Trametes versicolor 1 in a “fed-batch” process is investigated. The strain (2.5 g biomass) biodegrades total 7.45 g phenol for 20 days at initial phenol concentration of 1.0 g/dm³ and 6 feedings with concentration 1 g/dm³. At initial concentra...

Nowadays a quick and inexpensive method, which allows rapid, in vivo comprehensive probiotic bacteria identification, is needed. To elucidate a new concept to evaluate probiotic bacteria, near infrared spectroscopy with aquaphotomics were applied to monitor the growth of eight Lactobacillus bulgaricus and one Lactobacillus gasseri bacteria strains....

Microbial inulinases have great potential for industrial use in producing fructooligosaccharides (FOS) from inulin. The aim of this study is the evaluation of the inulinase activity (intra- and extracellular) of newly isolated species from the following genera: Penicillium, Kluyveromyces, Lactobacillus and Bacillus. Microorganisms that possess intr...

The Lemon balm (Melissa officinalis L.) is an important aromatic and medicinal plant from Lamiaceae family. Its leaves and essentials oils are used in folk medicine for the treatment of fevers and colds, hyperthyroidism, headaches and toothaches. Melissa officinalis is a rich source of volatile oil, flavonoid glycosides and derivatives of caffeic a...

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 Publisher regrets that some author corrections made during the proof stage of this article were not added during the production process. Abbreviations: CR3, omplement receptor 3 to be CR3, complement receptor 3. Results: p. 952, 18th row, left side: content to be contents. Table 1: bww% to be bw/w%. Table 3: R in italics to be R in normal style...

The previous few decades have seen the development of biosensors and their use in monitoring of pesticides in food and environmental samples. Although inhibition based biosensors have been subject of several recent research works, their performance characteristics greatly depend on the type of immobilization, and the presence of interfering compoun...

Two pectic (chPS-L1, chPS-L2) and one polyphenolic (chPP-L) fractions were obtained from lavender flowers after boiling water extraction, exhaustive removing of alcohol-soluble molecules and SEC. chPS-L1 (52.4 kDa) contains mainly low-acetylated and high-methoxylated homogalacturonans (HG), and smaller rhamnogalacturonan (RG) I backbone fragments r...

Silver linden flowers contain different pectins (PSI-PSIII) with immunomodulating properties. PSI is a low-esterified pectic polysaccharide with predominant homogalacturonan region, followed by rhamnogalacturonan I (RGI) with arabinogalactan II and RGII (traces) domains. PSII and PSIII are unusual glucuronidated RGI polymers. PSIII is a unique high...

Laccase (benzendiol:oxygen oxidoreductase; E.C.1.10.3.2) is a copper – containing enzyme, part of the group of so-called blue oxidases. The enzyme catalyzes the oxidation of many phenolic compounds and aromatic amines using molecular oxygen as a terminal electron acceptor. Laccases are widely distributed in higher plants, bacteria and fungi. Tramet...

In the current study the phytochemical profile of 70% ethanol extract of Ziziphus jujubа (Rhamnaceae), cultivated in Bulgaria has been investigated. The fruit extract contained numerous phytochemicals, such as triterpenes, phenolic acids and flavonoids. Five triterpenes, 11 phenolic acids and 5 flavonoids have been identified. The fruit extract had...

Biodegradation of high concentration of phenol (1g/l), catechol (2 g/l) and 2,4-dichlorophenol (2g/l) by Trametes versicolor is studied. Modified kinetic model of Verhulst/Aiba/Andrews is fitted to describe the specific growth rate at inhibitory growth type. When catechol is used as carbon source the microbial culture shows highest specific growth...

Laccases are a part of the group of multicooper-containing oxidases, which in the last decades are object of intensive study due to their broad substrate specificity. Polycyclic aromatic hydrocarbons (PAHs) are a class of hazardous organic compounds which are abundant in the environment. Fluorene is a PAH, which is very toxic to aquatic organisms,...

Polysaccharide inulin was isolated by different methods comprised conventional, accelerate solvent extraction (ASE), ultrasound – assisted extraction (UAE), and microwave extraction (MWE) from Helianthus tuberosus L. tubers. The resulting carbohydrate presented tasteless, white, dry powder. The isolated inulin was characterized in terms of yield, d...