Food chemistry, microbiology,biotechnology and safety

Section „Food Chemistry and Food Microbiology”

Stimulation of vital activity of lactic acid bacteria in the preparation of a liquid acid-forming ferments in bakery products
Стимулиране на жизнената дейност на млечните бактерии при приготвянето на течни формиращи полуфабрикат в производството на хлебопекарном
The influence of the new flour nutrient substrates with the introduction of phyto raw materials on the viability and activity of lactic acid bacteria cultured in liquid acid-forming ferments, which are used for making bread from rye flour and mixture of rye and wheat flour, are established. It was established that the phyto raw materials lead to the stimulation of lactic acid bacteria. The highest stimulating ability is Echinaceae purpurea herba, and then Salviae Folia, Artemisia absinthium herba and Cortex Quercus
Автори: Samuylenko Tatyana

Study on the properties of the oils obtained from waste plant biomass
Изследване свойствата на масла от отпадни растителни продукти
Study on the properties of the oils obtained from waste plant biomass Silvia Georgieva1*, Jose Coelho2, Roumiana Stateva1, Stanislava Boyadzhieva1 , George Angelov1 1 Insitute of Chemical enginereenig, Bulgarian Academy of Sciences,Sofia,Bulgaria 2 Instituto Superior de Engenharia de Lisboa, Lisbon, Portugal Corresponding author: The overproduction of free radical and oxidative stress are involved in the progression of degenerative disease. Natural antioxidant substances play a key role in interfering with the oxidation process by inhibiting free radicals. Antioxidants in vegetable oils with ω-3 or ω-6 fatty acids have been much concern. Spent coffee and grape seeds are waste by products from daily coffee consumption and wine production. Lipids are among the most important components of coffee beans. Coffee oil contains wax, triglycerides and unsaponifiable matter, saturated and unsaturated acids with high sun protection factor. Grape seed contains 8%–20% of oil and is used as a functional food product because of its high levels of hydrophilic constituents, such as phenolic compounds, and lipophilic constituents (vitamin E, unsaturated fatty acids and phytosterols). Regarding the fatty acid composition, linoleic acid is the most abundant fatty acid in the grape seed oils, The purpose of this work is to study the antioxidant activity of the oils obtained from waste spent coffee ground and grape seeds and study of the rheological properties of model cosmetic emulsions. Oils was obtained by conventional extraction with different solvents and supercritical extraction with CO2 and Ethanol as co-solvent. Utilization of these by-products will reduce environmental wastes, enhance their economic value and provides valuable substances for use in the food and cosmetics industry. Keywords: coffee oil, grape seed oil, antioxidants, rheology
Автори: Silvia Georgieva*, Jose Coelho, Roumiana Stateva, Stanislava Boyadzhieva, George Angelov

Section „Food Biotechnology and Nanotechnology”

Antifungal properties of SiO2/hydroxypropyl cellulose hybrid materials doped with zinc ions against Candida albicans 74
Антигъбични свойства на SiO2/хидроксипропил целулозни хибридни материали с включени цинкови йони срещу Candida albicans 74
The fungi resistance to many conventional medicines cause a serious problem for people. To overcome this challenge, it is important to explore novel antifungal agents. A variety of manufactured metal oxide nanoparticles are being developed and incorporated into products where their catalytic capacity make them attractive for a broad range of applications. This study presents an investigation of antifungal properties of hybrid materials based on silica, hydroxypropyl cellulose and ZnSO4.7H2O. They were synthesized by sol-gel technique and as a source of silica was used tetraethylortho silicate (TEOS). The quantity of organic substance was 5 wt. % and the zinc concentration varied from 0,5 to 5 wt. %. The strain that was used for determination of potential antifungal activity of materials was Candida albicans 74. The first experiment was focused on counting the survived cells after contact of fungi and materials with different zinc concentrations. The results show that the zinc amount and the cultivation time influence the number of colonies. The second method was based on measuring the free zone of growth formed around well with materials. It was examined that the zone size depends on the amount of zinc ions. The investigated materials reveal good antibacterial and antimicrobial effect but further experiments are needed to confirm their non-toxicity activity against mammalian cells and they could be a promising candidate for future biomedical application.
Автори: Цветелина Ангелова, Надежда Рангелова, Нели Георгиева

Phenotypic characterisation of lactobacilli using Biolog system
Фенотипна характеристика на лактобацили чрез използване на система Biolog
In recent years, scientific community has focused its attention on the microflora of home-made dairy products as a source of new candidate-probiotic strains. In a prospective 3-year study a collection of 78 Lactobacillus ssp. was established. One of the main steps for their further application requires their precise and accurate identification, according to modern polyphasic taxonomy. The phenotypic characterization is an important step for every new isolate. For this purpose, six of the isolates were subjected to identification with Biolog system. A phenotypic fingerprint for each of the strains was obtained, resulting in identification to species level with high accuracy: Lactobacillus hamsteri (2 strains), Lactobacillus fermentum (2 strains), Lactobacillus delbrueckii ssp. lactis (1 strain), Lactobacillus salivarius ssp. salicinus (1 strain). Due to the similar nutritional and growth requirements of LAB, further verification of the obtained results is needed with high discriminative molecular methods.
Автори: Вероника Немска, Петя Логар, Таня Рашева, Здравка Шолева, Светла Данова, Нели Георгиева

The edible films, applied to the surface of a product, possess barrier properties and decrease the speed of water evaporation from the product. That prolongs the storage period of the goods and preserves their water-soluble components. The water vapor permeability of edible films, made from different polymers – pectin and hydroxypropyl methylcellulose has been analyzed in the current research. The results show the suitability of the use of these edible films as barriers for water evaporation. That can determine the possible use of the edible coatings with certain goods.
Автори: Радослав Радев, Георги Димитров

Mechanisms of extraction of organic acids by means of molecular extractants and ionic liquids
Механизми на екстракция на органични киселини с молекулни екстрагенти и йонни течности
Carboxylic acids are a large group of compounds widespread in nature with a variety of applications in various areas, such as the food, chemical, biochemical and pharmaceutical industries. They are often present in fermentation media and industrial waste water, from where they must be removed and used. One way of removing organic acids from aqueous solutions is through liquid-liquid extraction. Conventional molecular extractants in this process are usually not used on their own. In most cases they are diluted with various toxic, inflammable and explosive organic diluents. In the last decade aqueous two-phase systems (ATPS) based on ionic liquids (IL) have been successfully applied in various extraction and separation processes. The interest in them is based on the fact that they can be used both as extractants and as alternative substitutes for volatile diluents, for which reason they have been named “green” solvents. The present work shows the mechanisms of the extraction process of natural organic acids as well as the extractants which are primarily used for this purpose. These are conventional molecular extractants and ionic liquids. IL have the advantage of removing the acid in greater measure than conventional extractants, which makes them more effective. This determines the new methods as a solid basis for developing “green” strategies with a significantly reduced impact on the environment.
Автори: Светлана Живкова, Милен Богданов

Effect of Interaction with Food Constituents on Plant Extracts Antibacterial Activity
Effect of Interaction with Food Constituents on Plant Extracts Antibacterial Activity
Many plant extracts show a lower antibacterial activity in foods than in vitro. Gaillac red wine powder and Cinnamon cassia essential oil were selected for their in vitro antibacterial activity against Staphylococcus aureus and Listeria innocua, respectively. In order to assess their potential application to the preservation of raw meat or dairy products, respectively, their antibacterial activity was tested in Mueller Hinton broth (MHB) supplemented with 20% beef meat proteins to mimick meat protein content and in TSB, skimmed, semi-skimmed and whole milk, respectively. Supplementation of MHB with beef extract proteins annihilated the antibacterial activity of Gaillac red wine powder as well as of resveratrol, a polyphenol present in red wine. The comparison of the anti-Listeria innocua activity of C. cassia essential oil in TSB 1% (w/w), skimmed, semi-skimmed and whole milk led to the conclusion that its antibacterial activity was significantly reduced in the presence of milk fat globules. These diffrences are likely due to interactions of plant antimicrobial molecules with food components at the expense of their interaction with target unwanted bacteria.
Автори: Lynda Bouarab-Chibane, Nadia Oulahal, Emilie Dumas, Nga Trinh Thi Thanh, Jalloul Bouajila, Jean-Pierre Souchard, Pascal Degraeve

The effect of the type electrodes on the energy and ecological efficiency of microbial fuel cells
Ефектът на типа електроди върху енергийната и екологичната ефективност на микробните горивни клетки
The traditional methods for waste water treatment are connected with high energy consumption. This is why that biological treatment of water is nowadays on the agenda. In our previous investigation it has been proposed, the pollutants oxidation and reduction to be carried out in a microbial fuel cell, designed from our laboratory, in which it simultaneously cleared the wastewater from sulphide and nitrate ions and generated electricity. The experiments were carried out with two types of electrodes, graphite and pyrolyzed wadding. We have compared under the same conditions usual chemical fuel element to such with biological denitrification in the anode section. The results demonstrate advantage of microbial fuel cell.
Автори: Ts. Parvanova-Mancheva*, E. Razkazova-Velkova, M. Martinov, S. Stefanov, Venko Beschkov

Section „Analysis and Control of Foodstuffs”

Amperometric sensing of hydrogen peroxide using glassy carbon electrode modified with rhodium
Амперометрично определяне на водороден пероксид с използване на модифициран с родий стъклографитов електрод
Following our previous studies on the catalytic activity of electrochemically deposited on glassy carbon Rh electrocatalyst towards the reduction of hydrogen peroxide (H2O2) electroreduction, the electrochemical performances of the modified electrode were studied by means of cyclic voltammetry and chronoamperometry at pH-values from 5.0 to 9.0. Electrode exhibited a rapid, sensitive and reproducible response for the quantitative determination of H2O2 at low applied potentials (-0.1 V and 0 V vs. Ag/AgCl, 3M KCl). Amperometry carried out at constant potential of 0 V at pH 6.0 (25 oC) gave the following operational parameters: detection limit of 4 μM, linear dynamic range up to 5.5 mM and sensitivity of 0.43 μA μM−1 cm−2 .
Автори: Янна Лазарова - УХТ Пловдив, Тотка Додевска - УХТ Пловдив

Broad-band fluorescent all-fiber sources compatible with conventional and microstructured optical fibers
Широкоспектърни изцяло влакнесто-оптични флуоресцентни източници съвместими с конвенционални и микроструктурни оптични влакна
In this article an overview of our recent research in the area of miniature broadband light sources compatible with optical fibers is presented. In the examined works the dependency of fluorescent spectrum of the excitation source characteristics on the length of microcapillaries filled with a solution of a fluorescent dye was studied. As microcapillary structures a fiber-optic glass ferrule with two parallel openings with diameters of 125 μm and a glass capillary with inner diameter of 100 μm were used. The fluorescent medium used was the organic fluorescent dye Rhodamine 6G dissolved in glycerine. The presented microcapillary structures were all-fiber and compatibility was demonstrated both with conventional and microstructured optical fibers. Two types of microstructured optical fibers were used: a photonic-crystal fiber and a hollow-core fiber. Due to their unique properties, these fibers were studied intensively in the past ten years which shows the topicality of the studies presented. Fiber-optic micro-optics was used both in the pumping and the receiving system of the construction which is an advantage over previous works related to this topic.
Автори: Веселин П. Владев

Ivermectin, doramectin, abamectin and moxidectin are macrocyclic lactones, used in veterinary medicine for treatment and control of parasitic infections. Under the Regulation of the European Union (№37/2010) lactone application is strictly controlled in the case of treatment of animals producing milk for human consumption. Concerning the determination of residues of macrocyclic lactones in milk matrix by High Performance Liquid Chromatography with fluorescent detector (HPLC-FLD), fast, sensitive and selective method is developed. The preparation of instrumental analysis samples includes extraction with acetonitrile, as well as solid phase extraction with C18 cartridge. Prior to injection into a HPLC system, the samples are derivatized with trifluoroacetic anhydride and 1-methylimidazole to obtain the fluorescent analytes derivatives. Chromatographic conditions are: reverse phase (column Agilent Eclipse XDB-C18), gradient elution with methanol and water and fluorescent detection (excitation and emission wavelengths: 365 nm and 475 nm, respectively). The analytic method corresponds to the requirements of the current legislation on the control of animal origin food, intended for human consumption.
Автори: М. Пейчева, М. Камбуров

Section „Food Safety”

Оксидативен стрес и растителни антиоксиданти
Antioxidant activity is strongly influenced by the amount of total phenolics, natural habitat and the specific growing conditions (climate, soil minerals, humidity external contaminants), flowering period and other factors. Oxidative stress plays an important role in the development of chronic and degenerative diseases as cancer, autoimmune diseases, rheumatoid arthritis, cataracts, aging, cardiovascular and neurodegenerative diseases. The human body has several mechanisms to counteract oxidative stress, by producing natural antioxidants or by submitting them to the outside through food and/or supplements. Once the antioxidant enters the body, it does not necessarily pass unchanged through the gastro-intestinal tract. It must therefore be considered bioavailability and bioactivity. The bioavailability of phenolic and polyphenolic compounds was studied in detail over the past two decades, whether by examining the kinetic models of polyphenol absorption in body fluids of healthy volunt
Автори: Aneta Popova

A survey of seasonal variations of aflatoxin M1 in raw milk in Polog and Pelagonia region
A survey of seasonal variations of aflatoxin M1 in raw milk in Polog and Pelagonia region
In this paper the incidence of contamination of aflatoxin M1 (AFM1) in raw milk samples collected in Polog and Pelagonia region was investigated. Aflatoxin M1 (AFM1) analysis was carried out by using the competitive enzyme-linked immunosorbent assay (ELISA) technique. For that purpose raw milk samples were collected from the bulk tank in the period of three year. The highest incidence of samples exceeding the maximum residual limit (MRL) were observed during winter in both regions (0,135 µg/kg; 1,03 µg/kg respectively). Considering seasonal variability, this study showed that AFM1 incidence and levels in raw milk samples obtained in winter were significantly higher (p< 0.05) than those obtained in summer also there is a statistical significant difference between the samples obtained in spring than those obtained in summer (p< 0.05).
Автори: Biljana Trajkovska, Liljana Kuzmanovska, Ljupche Kochoski, Kujtim Elmazi, Borche Makarijoski, Vesna K.Hristova

Effect of the use of mycotoxin-adsorbing agents in cow’s food, on the reduction of Aflatoxin M in milk
Effect of the use of mycotoxin-adsorbing agents in cow’s food, on the reduction of Aflatoxin M in milk
Aflatoxins are a major threat to human health because it causes mutations in DNA and weakens the immune response. The body is inserted through the food of animal origin (milk and dairy products) and plant origin and inhalation of contaminated air. There are 4 types of aflatoxins (B-1, B-2, G-1, G-2), of which the most dangerous is B-1, which is metabolized in the liver to the carcinogen metabolite M-1. Aflatoxins are heat stable and are not eliminated by pasteurization. Because of these characteristics, regular checkups are necessary in order to prevent contamination of raw materials and food. The specific objective of the analysis was to confirm the usefulness of the mycotoxin absorbing agents, as food supplements in dairy cows, in minimization of aflatoxin levels in raw milk. For that purpose, all bulk tank milk from different lines in Pelagonia region were tested using ELISA method. When the first test showed data suggesting the presence of contamination with aflatoxins, the second check for individual farmers was done and with the proven contamination, the addition of Mycosorb, as a mycotoxin absorbing agents, to the feed was recommended to reduce the amount of aflatoxins. The data were collected for 3 consecutive years, from Pelagonia region. The contamination of the bulk tank milk during the years was distributed unequally, with the greater predominance of the autumn and winter, when more corn silage was used as an animal feed. The maximum contamination was observed during 2013 (November) of 1,03 μg/kg, and for the rest of the time, the highest contamination level for specific sectors was around 0,6 μg/kg. After the use of Mycosorb, the level of Aflatoxin M in the milk was reduced below the acceptable limit of 0,05 μg/kg. According to the results obtained during this study, we can conclude that the use of Mycosorb can significantly help in regulation of the level of aflatoxin M1 in raw milk without impairing the quality and safety of milk as a raw materi
Автори: Ljupche Kochoski1*, Liljana Kuzmanovska2, Biljana Trajkovska1, Gordana Dimitrovska1, Dimche Kitanovski1, Borche Makarijovski1

Section „Ecology and Toxicology of Food and Biotech Industry”

Biogas Production from Animal Protein Waste, an Environmental Protection Technology Coupled With Energy Production
Производство на биогаз от отпадъци от животински протеини, технология за опазване на околната среда, съчетана с производство на енергия
Anaerobic fermentation (digestion) of animal proteins was the technology applied for biogas production. This technology rose from the need for environmental protection, the direct incineration of such wastes being more expensive. A pilot plant with two-stage digestion was built, which allowed for a biogas with a competitive energy-efficient calorific value to be used. The paper presents the possibility of energy use of the biogas produced this way.
Автори: Gheorghe Lazaroiu, Viorel Berbece, Lucian Mihaescu, Gabriel-Paul Negreanu

Biodegradation of 1,2-Dibromoethane by Bradyrhizobium japonicum cells immobilized onto a granulated activated carbon and onto granulated polymeric support
Биоразграждане на 1,2-Диброметан от клетки на щама Bradyrhizobium japonicum имобилизирани върху активен въглен и върху гранулирани полимерни носители
For a better understanding of the fate and persistence of 1,2-Dibromoethane in the environment and for development of bioremediation techniques for the cleanup of polluted locations, it is important to study the physiology and ecology of bacteria that degrade this toxic compound. Bradyrhizobium japonicum 273 produces haloalkane dehalogenase, which degrades halogenated aliphatic pollutants. The inhibitory effect of substrate was reduced by immobilization. This study compares biodegradation with free and immobilized cells onto a granulated activated carbon and onto granulated polymeric support. Processes of dehalogenation were carried out in flasks and in laboratory fermentor. Effect of electric field was investigated also. Complete biodegradation was received when concentration of bromide ions in the medium reaches its stoihiometric values.
Автори: Evgenia Vasileva, Tsvetomila Parvanova-Mancheva, Venko Beschkov

Biomethanization of acid hydrolysates from lignocellulosic materials
Биометанизация на киселинни хидролизати от лигноцелулозни материали
Lignocellulosic biomass is a natural renewable resource for second-generation bioenergy products. Its accumulation in large quantities is an environmental problem that leads not only to environmental pollution but also to the loss of valuable materials. The biotechnological conversion of lignocellulosic biomass into various industrial products is a cost-effective and environmentally sustainable process. This paper explores the energy potential of lignocellulosic hydrolyzate produced by acid hydrolysis of bleached cellulose. The main characteristics of the hydrolyzate as a substrate for biomethanation (COD 29 gO2 l-1, free protein 1.11 mg ml-1, furfural 0.133 mg ml-1, pentoses and hexoses- glucose 0.319 mg ml-1, xylose 1.121 mg ml-1, mannose 0.128 mg ml-1 and other) were determined. The biochemical methane potential of the acid hydrolyzate was determined - 0.855 lCH4 gCOD-1. It has been found that the studied substrate has a good potential for a possible raw material to produce biofuels and valuable organic chemicals. Key words: biochemical methane potential, acid hydrolyzate, bioenergy Acknowledgments: The present work is financially supported by scientific project № 11696 to Scientific research sector, UCTM- Sofia.
Автори: Polina Velichkova, Ivo Lalov, Ivo Valchev