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    Adhesion of bacteria Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and yeast Pichia membranifaciens to wooden surfaces
    (European Declaration on Food, Technology and Nutrition Network, Ljubljana, 2022, 2022-09-27) Tomičić, Ružica; Tomičić, Zorica; Thaler, Nejc; Humar, Miha; Raspor, Peter
    Microbial adhesion and biofilm formation on wooden surfaces is present in many different environments. In the food industry, biofilms can be a source of contaminations, causing food spoilage and reducing quality of products. Therefore, the aim of this study was to evaluate the potential of bacteria Escherichia coli ATCC 35218, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923 and yeast Pichia membranifaciens ZIM 2417 to adhere to wooden surfaces such as poplar (Populus sp.), Norway spruce (Picea abies), European beech (Fagus sylvatica) as well as European beech coated with commercial Belinka oil food contact and disinfectant P3-oxonia active 150. In order to better define the factors that could influence the adhesion of bacteria and yeast to European beech surfaces, temperature (10°C, 20°C, 27°C/37°C) and relative humidity (RH; 65%, 75%, 85%, 98%) were also examined. Adhesion was determined by the number of colony-forming units per mm2 of sample (CFU/mm2). The results showed that gram-negative bacteria E. coli and P. aeruginosa exhibited a much better ability for adherence to wooden surfaces than gram-positive bacteria S. aureus and yeast P. membranifaciens. It was evident that adhesion of S. aureus and P. membranifaciens was lower on spruce compared to poplar and beech, indicating that this wooden species possesses substantially better hygienic characteristics. In addition, noteworthy is the fact that a drastic decrease in the number of adhered cells for E. coli, S. aureus and P. membranifaciens became apparent when the beech wood surfaces were coated with oil and disinfectant, while in the case of P. aeruginosa adhesion was significantly stimulated. Our data also indicated that the lowest relative humidity and temperature had a repressive effects on the adherence of all tested bacteria and yeast, suggesting that these findings offers a great potential applicability in food-processing industry for the purpose of controlling the possibility of biofilm formation.
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    Advantages of Using Natural Deep Eutectic Solvents (NADES) for Obtaining Functional Additives for Food Production
    (German Jordanian University, 2022-06) Kljakić Cvetanović, Aleksandra; Pavlić, Branimir; Teslić, Nemanja; Stupar, Alena; Pojić, Milica; Mandić, Anamarija; Mišan, Aleksandra
    In recent decades, there has been a growing public interest in natural sources of biologically active molecules, and an increasing number of people are showing a tendency to use natural products in treatment as well as nutrition. Natural bioactive compounds in food preparations can play a multiple role, above all they can be powerful antioxidants with the ability to protect the body from free radical attacks, have a beneficial effect on strengthening the immune system, prevent many diseases and protect the body from premature aging. In addition to these effects on the body, the incorporation of bioactive compounds, such as polyphenols, has a beneficial effect on the quality of food. This is closely related to their antimicrobial potential, which affects the sustainability and durability of the product. Plants are a significant source of polyphenols and are obtained in significant quantities by extraction from plant material. However, bearing in mind that food products require high standards in its production and extracts with specific caractersistics, the extraction technique for this pupose should be choosen carefully. Withal, the food industry faces the challenges of sustainable production that will affect all aspects of life (economic, social and environmental) by the creation of food solutions to meet the socio-economic needs and interests of citizens, while eliminating or significantly reducing harmful impacts on the environment and natural resources. NADES solvents are the latest generation of green solvents. They can be formulated exclusively from natural ingredients such as sugars, amino acids, organic acids, etc. Which makes them edible, biodegradable and completely safe to use. Moreover, they offer „ready-to-use“ extracts, which means that they can be directly incorporated in food withought purification. In the frame of this work, extraction of polyphenols from Sambucus ebulus L. was done by three different NADES solvents prepared in the following manner: (N1) glycerol: betaine (2:1), (N2) betaine:glucose (1:1), (N3) glycerol:fructose (4:1). The ingreadiants were mixed with usig magnetic stirrer until a transparent stable liquid was obtained. Obtained liquid NADES solvents were used for the extraction and obtained extract were characterized in terms of their chemical composition as well as biological potential, in the first place antioxidant and antiradical ability. In the same time, extraction was performed using conventional (referent) technique and the obtained results were compared. The obtained results clearly showed an advantage of NADES extracts in terms of biological and chemical characteristics, but also in the stability, which justifies their further use in functional food production.
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    AFLATOXINS IN MAIZE FROM SERBIA: A TEN-YEAR REPORT
    (Matica Srpska, Novi Sad, Serbia, 2022-06-02) Kos, Jovana; Radić, Bojana; Janić Hajnal, Elizabet; Radović, Radmila; Mandić, Anamarija; Đekić, Sanja
    Aflatoxins (AFS) are carcinogenic and highly toxic compounds produced by Aspergillus species. Food and feed contaminated with AFS pose a high risk to human and animal health. In terms of the Republic of Serbia, the main concern is related to the prevalence of AFS in maize. Serbia represents a leader in maize production and exports in Europe, and it is among the top 10 exporters in the world. In the recent years maize yield as well as quality and safety are strongly affected by weather conditions. This report aimed to present AFS occurrence in harvested maize samples from Serbia in the ten years (2012-2021). Maize samples were collected from maize growing seasons which were characterized by extreme drought (2012), hot and dry conditions (2013, 2015, 2017, 2021), extreme precipitation (2014), and weather conditions usual for a moderate-continental climate (2016, 2018, 2020). The highest AFS concentrations, as well as contamination frequency of AFS were detected in maize samples originating from the 2012 maize growing season, followed by 2015, 2021, 2013, and 2017. On the other hand, in samples originating from 2014, 2016, 2018, 2019, and 2020, there were no AFS detected. The obtained results indicate that changes in weather conditions, recorded in the period of ten years, had a significant influence on the presence or absence of AFS in maize. They were detected in samples from five among ten investigated years, and in all contaminated samples, from each year, aflatoxin B1 was the most dominant. In the period of ten investigated years, Serbia was faced with climate changes which had a great overall impact on the prevalence of AFS in maize. The findings of this report as well as climate change prediction for South-East Europe indicate that maize from Serbia may become susceptible to problems concerning AFS and therefore there is a need for Serbia to enhance the control strategy of maize as well as maize management practices which would greatly contribute to improving the quality and safety of food and feed.
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    Aflatoxins in the food and feed chain: from maize to milk
    (2023-09) Radić, Bojana; Šarić, Bojana; Šarić, Ljubiša; Jovanov, Pavle; Đermanović, Branislava; Marić, Aleksandar; Kos, Jovana
    Contamination of the food chain and animal feed with mycotoxins in Serbia is causing increasing concern due to previous, current, and predicted climate change. More and more often recorded drought conditions represent the greatest challenge, in the first place for the aflatoxins occurrence. In Serbia, during the previous decade, frequent occurrences of aflatoxins were recorded, first of all in maize and maize products, and then in milk and dairy products. All of the above affected: the quality, safety and yield of maize; large economic losses; mismatches between Serbian and European Union regulations for maximum levels of aflatoxins; confusion among consumers, etc. Analysis of maize, milk, and dairy products in the period from October 2022 to May 2023 indicates that Serbia again faced a significant problem related to aflatoxins occurrence. The frequent presence of aflatoxins in maize and milk is of great concern for contamination of the whole food and feed chain since maize represents the basic food for dairy animals, while milk and dairy products represent the main foodstuffs in human nutrition, especially for children. Since the aflatoxins problem in Serbia has lasted for more than a decade, there is a need to implement the necessary measures to improve resistance to the effects of climate change.
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    Amino acid profiles of cereals
    (University PIM, Banja Luka, Republic of Srpska, B&H, 2023-06-15) Tomičić, Zorica; Spasevski, Nedeljka; Lazarević, Jasmina; Čabarkapa, Ivana; Tomičić, Ružica
    Cereals play a key role to satisfy the global food demand of a growing population, especially in developing countries where cereal-based food production is the only predominant source of protein and energy. The quality of protein of cereals is based on their amino acid composition, especially on the content and availability of essential amino acids. The aim of this study was to analyze the chemical composition and amino acid profiles of different cereals, such as barley, maize, oat, rice, rye and wheat, that are important for nutritional purposes in human diet. The content of protein, moisture and crude fat in cereals varied significantly from 7.83 to 13.22 %, 11.45 to 13.80 %, and from 1.67 to 6.35 %, respectively. The obtained results showed that oat had the highest contents of crude protein (13.22 %), crude fat (6.35 %) and crude cellulose (9.42 %) compared to other cereals. Significant (p < 0.05) variation existed in the content of essential and nonessential amino acids among samples with the highest level in oat and wheat. Essential amino acids accounted for one-third of the total amino acids in the tested cereals. Glutamic acid was found to be the most abundant amino acid. Although lysine is the limiting amino acid for all cereals, the amount varies among species, being highest in oat and lowest in maize and rice. It could be concluded that the amino acid composition of oat is the most favorable among cereals due to its high protein content and the content of lysine which can be found in limited amounts in most of the cereals.
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    Antifungal and antibiofilm activity of plant extracts against yeast Candida albicans, Candida glabrata and Pichia membranifacien
    (Matica Srpska, Novi Sad, Serbia, 2022-06-02) Tomičić, Ružica; Tomičić, Zorica; Kocić Tanackov, Sunčica; Raspor, Peter
    Yeast biofilms pose health risks in clinical environments and food industry. Despite years of effort, new antifungal approaches are needed since it is known that biofilms show much greater resistance to the antifungal agents than their free-living counterparts. Hence, we investigated antifungal activity of plant extracts such as Humulus lupulus, Alpinia katsumadai and Evodia rutaecarpa against Candida albicans ATCC 10261, Candida glabrata ZIM 2369 and Pichia membranifaciens ZIM 2417. The aim of this study was to investigate whether these plant extracts can interfere with biofilm formation as well as acting on preformed biofilms. The minimal inhibitory concentrations (MICs) of plant extracts were determined using the CLSI M27-A2 broth microdilution method. The method used to assess antibiofilm activity was crystal violet staining. According to the MIC values in this study, all plant extracts were effective in the inhibition of yeast strains. On the other hand, A. katsumadai, E. rutaecarpa and H. lupulus extracts exhibited the highest antibiofilm activity against C. albicans to the stainless steel surface at both tested concentrations (1/2 × MIC and 1 × MIC). A. katsumadai was also effective in the initial phase of biofilm formation of C. glabrata at 1/2 × MIC and 1 × MIC, while the inhibition of preformed biofilm was more difficult to achieve. Our results clearly demonstrate that biofilms of C. glabrata are more resistance to the extracts as compared to C. albicans. Regarding P. membranifaciens, extracts of A. katsumadai and E. rutaecarpa were promoted the growth and development of a preformed biofilm.
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    Antimicrobial activity essential oil of Origanum heracleoticun against Prototheca bovis
    (2022-06) Čabarkapa, Ivana; Varga, Ana; Plavšić, Dragana; Šarić, Ljubiša; Tomičić, Zorica; Todorić, Olja
    Prototheca is a unicellular, achlorophyllous yeast-like microalga. The most important animal disease caused by Prototheca is bovine mastitis. The outbreaks of bovine mastitis caused by Prototheca bovis (formerly P. zopfii gen. 2) have been reported in several countries including Serbia. Bovine protothecosis is a serious therapeutic problem given that Prototheca has proven highly resistant to common drugs used for the treatment of mastitis. Therefore, an outbreak of protothecosis in dairy cows may lead to very significant economic losses. The objective of this study was to determine the antimicrobial activity of O. heracleoticum essential oil against five mastitis-associated strains of P. bovis. In addition, this study determined antimycotic and antibiotic susceptibility patterns of P. bovis. The following antibiotics and antifungal agents were tested: ampicillin (AMP10), gentamicin (GEN10), streptomycin, (STR10), clindamycin (DA2), fluconazole (FLU25), econazole (ECN10), clotrimazole (CLO50), miconazole (MCL10), itraconazole (ITC50), ketoconazole (KCA10), voriconasole (VO10), nystatin (NY100IU), and amphotericin B (AMB20). Essential oil of O. heracleoticum inhibited the activity of P. bovis strains, with minimal inhibition concentration (MIC) of 0.156 µL/mL and with minimal cidal concentration (MCC) of 0.625 µL/mL. Strains of P. bovis were found to be highly resistant to most of the recommended antimicrobials used against bacteria and fungi. From a total of 12 antimicrobials only nystatin, amphotericin B, gentamicin, and streptomycin were found to be effective against all P. bovis strains. Obtained results revealed that the tested EO of O. heracleoticum possesses remarkable antimicrobial activities and could be used in the development of pharmaceutical formulation as an alternative to conventional antibioticantimycotic therapy. Key words: Prototheca bovis, antimicrobial activity, essential oil, mastitis
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    ANTIMICROBIAL ACTIVITY OF ESSENTIAL OILS FROM MEDICAL PLANTS GROWN IN LIGHT MODIFIED ENVIRONMENT
    (Univerza v Ljubljani, Biotehniška fakulteta, Ljubljana, Slovenija, 2022-06-15) Milenković, Lidija; Šunić, Ljubomir; Mastilović, Jasna; Kevrešan, Žarko; Kovač, Renata; Cvetković, Dragan; Stanojević, Ljiljana; Danilović, Bojana; Stanojević, Jelena; Ilić, Zoran S.
    Thyme, marjoram, lemon balm, mint, and sweet basil were used to determine whether light modification (plants grown under pearl nets with 50% shaded index or un-shaded - open field conditions) could improve the antimicrobial activity of essential oils (EOs). Obtained results were discussed concerning previously determined yield and composition of EOs from five medicinal plants. Seven microorganisms were selected to determine the antimicrobial activity of medicinal plants essential oils. The inhibition zone is dependent primarily on the plant species and the influence of shading is much less expressed. The results revealed that EOs from Thymus vulgaris L., proved most active against all isolates with inhibitory zone range from 24 mm (B. subtilis) to 56 mm (C. albicans). From all species of the plants, only marjoram exhibits inhibition (18-20 mm) in the case of P. aeruginosa. EOs from shaded thyme and marjoram expressed higher inhibition effects in comparison to other shaded or unshaded plants against all tested microorganisms. EOs from all shaded plants, except basil, showed higher anti-candida activity than EOs from unshaded plants. The results of this study suggest that the natural products derived from Lamiaceae plantsmay have potential use in the food and/or pharmaceutical industries as antimicrobial agents.
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    Antioxidative and antibacterial properties of honey from Serbia, Kosovo and Bosnia and Herzegovina
    (2022-04) Sakač, Marijana; Jovanov, Pavle; Marić, Aleksandar; Novaković, Aleksandra; Plavšić, Dragana; Škrobot, Dubravka
    Honey is a natural sweetener produced by honeybees using nectar. It has been used not only for food, but also for therapeutic purposes. Carbohydrates, primarily glucose and fructose (85-95%), dominate in honey composition. In addition to sugars, honey contains about 200 substances present in small amounts, including minerals, proteins, enzymes, amino acids, organic acids, vitamins, polyphenols and other phytochemicals. The type of honey is determined by the type of pollen, i.e. nectar, insect secretions, as well as climatic conditions and soil composition. The health benefits of honey, used for centuries for therapeutic purposes, derive from its antioxidant nature, antimicrobial and antiproliferative activity. The antioxidant capacity of honey primarily depends on the phenolic profile of honey, which is conditioned by botanical and geographical variations. The antibacterial activity of honey results from the high osmolarity and acidity of honey, as well as the presence of hydrogen peroxide and phenolic compounds. With the aim to assess the antioxidant capacity and antibacterial activity of different types of honey characteristic for the region, nineteen samples (acacia, linden, heather, sunflower, phacelia, basil, anise, sage, chestnut, hawthorn, buckwheat, lavender and meadow) were collected from different locations in the Republic of Serbia, Kosovo and Bosnia and Herzegovina and examined. Honey samples were also tested for physicochemical parameters (moisture, pH value, electrical conductivity, free acidity and HMF) to ensure that they meet the requirements for honey quality. Based on the obtained results of honey physicochemical profile, it was concluded that all tested samples were in accordance with the regulations of national and EU regulations. The antioxidant potential of honey samples was assessed by determining the total phenol content (TPC) and evaluating the antiradical activity on diphenylpicrylhydrazyl radicals (DPPH·). The highest phenol content was found in basil honey (101 ± 2.72 mg GAE/100 g), while the lowest was registered in rapeseed honey (11.5 ± 0.70 mg GAE /100 g). Samples of heather, anise, phacelia, sage, chestnut and lavender honey were also rich in TP (80–100 mg GAE/100 g). Scavenging activity on DPPH· varied among samples and was highest for lavender honey (IC50 = 88.2 ± 2.11 mg/mL) and lowest for rapeseed honey (IC50 = 646 ± 8.72 mg/mL). Antibacterial activity was estimated in vitro using agar diffusion tests and measuring minimal inhibitory concentration (MIC). Among investigated bacterial strains following resistant potencies were determined: E. coli > E. coli ATCC 8739 > E. faecalis > Proteus mirabilis > S. aureus > S. epidermidis. The linden honey from Fruška Gora (MIC values of 3.12% and 6.25% against S. aureus and S. epidermidis, respectively) and phacelia honey (MIC values of 6.25% and 3.12% against S. aureus and S. epidermidis, respectively) showed the strongest antibacterial activity.
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    Antioxidative properties of gluten-free crackers based on chickpea flour and pumpkin seed oil processing by-products
    (University of Novi Sad, Faculty of Technology Novi Sad, 2022) Maravić, Nikola; Tomić, Jelena; Škrobot, Dubravka; Popović, Ljiljana; Rakita, Slađana
    During the digestion process antioxidant compounds could be released from food matrix, as well as transformed into other compounds with lower bioaccessibility due to interaction with other constituents such as fibers, proteins, and polysaccharides. To produce beneficial effects bioactive compounds should be available for absorption once the whole digestive process has occurred. Since the utilization of chickpea flour and pumpkin seed oil byproducts results with high protein and fiber products, this examination was conducted to determine antioxidant activity and potential benefit effects to human health. Five different formulations were produced where Control sample contained 100% chickpea flour, while in other formulations pumpkin seed press-cake flour (virgin (VF) and cold pressed (CF)) were used at two substitution levels(20 and 35%, w/w). After preparation of gluten-free crackers, in vitro digestion was carried out (cephalic, gastric, and intestinal phase simulated with enzymes, temperature and pH control). Before and after digestion protein content, electrophoresis, antioxidative tests and total phenolic content was determined. Obtained results showed that antioxidant activity, as well as total phenolic content increased after conducted in vitro digestion in all samples. Compared to Control sample, higher values of mentioned parameters are noticed. Furthermore, electrophoresis and protein examination show the breakdown of proteins into smaller molecular weights. From obtained results it could be concluded that in vitro digestion of prepared cookies resulted with higher antioxidant activity, which implies on potential benefits of consuming this type of product.
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    Antiproliferative properties of honey from Serbia, Kosovo and Bosnia and Herzegovina
    (2022-06) Sakač, Marijana; Jovanov, Pavle; Marić, Aleksandar; Četojević-Simin, Dragana; Novaković, Aleksandra; Plavšić, Dragana; Škrobot, Dubravka
    Honey is a natural sweetener produced by honeybees using nectar. The type of honey is determined by the type of pollen, i.e. nectar, insect secretions, as well as climatic conditions and soil composition. The health benefits of honey, used for centuries for therapeutic purposes, derive from its antioxidant nature, antimicrobial and antiproliferative activity. With the aim to assess the antiproliferative activity of different types of honey characteristic for the region, nineteen samples (acacia, linden, heather, sunflower, phacelia, basil, anise, sage, chestnut, hawthorn, buckwheat, lavender and meadow) were collected from different locations in the Republic of Serbia, Kosovo and Bosnia and Herzegovina and examined. Honey samples were also tested for physicochemical parameters (moisture, pH value, electrical conductivity, free acidity and HMF) to ensure that they meet the requirements for honey quality. Based on the obtained results of honey physicochemical profile, it was concluded that all tested samples were in accordance with the regulations of national and EU regulations. The antiproliferative potential of honey samples was assessed by in vitro tests using tumor cell lines: HeLa (cervcal carcinoma), MCF7 (breast epithelial adenocarcinoma), HT-29 (colon adenocarcinoma) and MRC-5 (normal fetal lung fibroblasts). The highest antiproliferative activity was obtained by linden honey sample 1 (IC50 MCF7 = 7.46 ± 1.18 mg/mL and IC50 HeLa =12.4 ± 2.00 mg/mL) and meadow sample 2 (IC50 MCF7 = 12.0 ± 0.57 mg/mL, IC50 HeLa = 16.9 ± 1.54 mg/mL and IC50 HT-29 = 23.7 ± 1.33 mg/mL) towards breast (MCF7), cervix (HeLa) and colon (HT-29) cancer cells. Active components other than sugars contributed to cell growth activity. Probably, antiproliferative activity was achieved by polyphenols.
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    Antiproliferative properties of honey types from the Western Balkans
    (2023-04) Sakač, Marijana; Jovanov, Pavle; Četojević-Simin, Dragana; Marić, Aleksandar; Maravić, Nikola; Kovač, Renata
    Honey is a natural sweetener used not only for food, but also for therapeutic purposes. It contains carbohydrates, primarily glucose and fructose (85–95%) but also contains about 200 substances present in small amounts (minerals, proteins, enzymes, amino acids, organic acids, vitamins, polyphenols and others). The type of honey is characterized by the type of pollen, insect secretions, as well as climatic conditions and soil composition. The health benefits of honey results from its antioxidant nature, antimicrobial and antiproliferative activity. Several studies demonstrate the anticancer activity of honey, namely honey shows a chemopreventive effect against various cancer cell lines and tissues in in vitro and in vivo studies. This activity can be explained by different mechanisms including cell cycle arrest, induction of apoptosis, modulation of oxidative stress and immuno-modulation. Therefore, honey can be applied in alternative medical treatment of human tumors. With the aim to assess the antiproliferative properties of different types of honey characteristic for The Western Balkans, nineteen samples (acacia, linden, heather, sunflower, phacelia, basil, anise, sage, chestnut, hawthorn, buckwheat, lavender and meadow) were collected from different locations in the mentioned region and examined. The quality of honey samples was also tested to ensure that they meet the requirements defined by the national and international legislation. All tested honey samples were in accordance with the regulations of national and EU regulations. The antiproliferative activity of honey samples was evaluated using human tumor cell lines HeLa (cervcal carcinoma), MCF7 (breast epithelial adenocarcinoma), HT-29 (colon adenocarcinoma) and MRC-5 (normal fetal lung fibroblasts). The most active samples were linden honey sample from Fruška gora (IC50MCF7 = 7.46 ± 1.18 mg/mL and IC50HeLa = 12.4 ± 2.00 mg/mL) and meadow sample 2 (IC50 MCF7 = 12.0 ± 0.57 mg/mL, IC50 HeLa = 16.9 ± 1.54 mg/mL and IC50 HT-29 = 23.7 ± 1.33 mg/mL) towards breast (MCF7), cervix (HeLa), and colon (HT-29) cancer cells. The most active samples, linden and meadow 2 also affected the growth of MRC-5 cells derived from healthy lung tissue with IC50MRC-5 = 9.93 ± 0.68 mg/mL and IC50MRC−5 = 12.9 ± 0.34 mg/mL, respectively. Colon carcinoma cell line HT-29 was the least sensitive to the evaluated samples. Standard (glucose) had lower and uniform cell growth effect with IC50 values ranging from 33–40 mg/mL towards all evaluated cell lines, indicating that active components in samples other than sugars contributed to cell growth activity. These compounds are probably polyphenols. Polyphenolic profile investigation will be needed to correlate antiproliferative activities and polyphenol contents for evidences of the mechanisms of their action.
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    Applicability of different kinetic models on biosorption of molassigenic metal ions in closed-loop fixed-bed column system
    (2022-10) Peić Tukuljac, Lidija; Krulj, Jelena; Pezo, Lato; Kojić, Jovana; Maravić, Nikola
    Valorization of by-products from the food industry is a generally accepted trend with an increasing tendency of its application in everyday life. One of the most difficult sustainability challenges is to overcome problems with an enormous amount of accumulated sugar beet pulp. Annually, around 15 million tons of sugar beet has been processed only in the EU. Novel findings have been directed towards the reutilization of the sugar beet pulp as an effective cation-exchange biomaterial. Sugar beet pulp was used as a biosorbent for molassigenic metal ions removal from the alkalized juice. Alkalized juice represents an intermediate product of the sugar juice processing stage. Dry matter (DM) of the alkalized juice represents only sucrose and macroelements (minerals). Sodium (Na) and potassium (K) are present in an alkalized juice in the amount of 9500 mg/ kg DM, whereas calcium (Ca) is present in the lower amount (700 mg/kg DM). Since all of the processes in the sugar industry are continual, biosorption was conducted in the closed-loop fixed-bed column system under the temperature 70oC, pH=12.5 and a biosorbent dose of 2.5 g/L. Metal ions content in the alkalized juice after 15, 30, 45, 60, 90, 105, 120, 180 and 240 minutes was detected according to ISO 6869:2000 using the Varian, SpectrAA—10 Atomic Absorption Spectrometer. Three non-linear kinetic models including pseudo-first, pseudo-second, and Elovich were applied to the obtained results in order to get insight into the biosorption mechanism. Equilibrium regarding all three monitored molassigenic metal ions was reached after 15 minutes. Ca ions were removed from the alkalized juice in the highest amount (51.6%). Whereas monovalent Na (14.6%) and K (7.8%) ions were less successfully removed. According to the one-dimensional correlation coefficient (R2) the most adequate kinetic models for closed loop biosorption are pseudo-first (R2≥0.98) and pseudo-second (R2≥0.98). Therefore, the biosorption process is controlled by chemisorption and ion-exchange. Under the established conditions molassigenic metal ions removal process has rapid dynamics. Successful application of the closed-loop system potentially enables scale-up of the whole system.
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    Application of temporal dominance of sensations in sensory profiling of sourdough starter odour
    (National Society of Processing and Energy in Agriculture, 2022) Škrobot, Dubravka; Tomić, Jelena; Dapčević-Hadnađev, Tamara; Maravić, Nikola; Jovanov, Pavle; Hadnađev, Miroslav
    Sourdough is one of the oldest examples of natural starters, obtained from the mixture of cereal flour and water, fermented with naturally occurring or selected lactic acid bacteria (LAB) and yeasts. Fermentation process depends on naturally occurring microbiota, type of flour, flour composition, additional ingredients, tap water, and temperature. During fermentation, acidification, proteolysis and activation of a number of enzymes, as well as the synthesis of microbial metabolites, influence not only the nutritional/functional quality of baked goods but also contribute to development of odour and flavour of starter and final product. In order to describe the evolution of the sourdough odour during starter activation, the method of temporal dominance of sensations is performed. Temporal Dominance of Sensations (TDS) is method used in sensory analysis which enables characterization of an entire profile of complex food in a short time. This approach is aimed at repeatedly recording the dominant sensations perceived during the tasting period. For the presented study experienced sensory panellists (n = 12, eight female and four male, 25 – 45 years old), used to participate in sensory profiling, were recruited. Whole grain wheat sourdough starter samples were collected and evaluated for each 1 h within six hours from the start of the sourdough activation. Samples were delivered to the panellists in a glass jars with a lid. The panellists were instructed that once they remove the lid, they have to click on the “START” button on the screen to begin the evaluation and to activate software. During an evaluation, the panellists had to select dominant odour sensation from ten simultaneously presented odour attributes (brans, flour, dough, yeast, acetic acid, lactic acid, sour milk, yoghurt, cheese, and fruity). When panellists noticed that one dominant odour perception changed, they had to score new dominant sensation. If none attribute was perceived as dominant sensation, panellists had to click the “End” button. TDS was performed for all samples within three replicate sessions by all panellists. TDS data was collected by Excel, while with XLSTAT software collected data was calculated and presented by curves showing dominance rate (Axis Y) for each 0.2 s step during the 1 min period (Axis X). TDS curves clearly showed changes in odour profile during period of sourdough starter activation. At the beginning of the activation process, flour-like, brans-like and dough-like attributes were dominant odour characteristics. However, during the time, these odour characteristics had little contribution to the overall odour profile since they became masked with more sharp odour notes reminiscent of sour milk, cheese, yoghurt and acetic acid. Over time, odour profile became more complex indicating complexity of biochemical processes.
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    Applying different infrared spectrophotometry methods for determining
    (University of Novi Sad, Faculty of Technology Novi Sad, 2022-10) Hromiš, Nevena; Popović, Senka; Šuput, Danijela; Ugarković, Jovana; Čabarkapa, Ivana
    Chitin, the most abundant biopolymer after cellulose, is a linear, highly crystalline polysaccharide, built from acetylglucosamine monomer units connected by β-1,4 glucosidic bonds. High degree of acetylation (DA) and the crystallinity of chitin molecules make it insoluble in common commercial solvents. Chitosan is the name for chitin substitutes with a low degree of acetylation. The degree of deacetylation in chitin usually ranges from 5% to 15%, and in chitosan from 70% to 95%. This contributes to the solubility of chitosan in aqueous solutions of acids and enables the use of chitosan and its bioactivity. When chitosan biopolymer film properties are considered, DA is an important input, due to the proven influence of DA on chitosan film´s mechanical, physico-chemical and bioactive properties. Developed methods for chitosan DA determination are based on different approaches: infrared spectroscopy, UVspectrophotometry, nuclear magnetic resonance, colloidal titration, and potentiometric titration. Various procedures using infrared spectroscopy technique have been developed to determine DA of chitosan. In this article, these methods were tested for application on chitosan isolated from blue crab shell (Callinectes sapidus). Two different approaches were assessed: 1) determination of the absorption ratio of a probe band and of a reference band and estimation of DA of unknown samples by comparison with samples with known DA and 2) evaluation of several proposed absolute methods that are used in the literature for the DA determination. Results showed that applied absolute methods gave results that varied between the methods applied, but were consistent among different samples within the framework of a particular method. Use of different probes and reference bands for calculation of ratios that would be compared to the reference samples of a known DA was more appropriate method. Selected ratios were A1655/A3450 and A1320/A1420. IR techniques for chitosan DA determination without reference to samples of known DA or calibration curve could be used for qualitative evaluation of DA, while quantitative determination should include mentioned references. Use of absolute methods for determination of DA by IR spectroscopy was shown not to be appropriate in this work
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    Assessment of honey quality from the area of Rtanj mountains
    (2022-04) Marić, Aleksandar; Jovanov, Pavle; Sakač, Marijana; Novaković, Aleksandra; Maravić, Nikola; Radović, Radmila; Ikonić, Predrag
    Honey is a natural product that contains more than 200 different compounds and consists mainly of sugar, water, and other components such as organic acids, proteins (enzymes), vitamins, minerals, and phenolic compounds. As honey is food consumed all over the planet, certain standards and norms are needed that guarantee its identity and quality to be safely consumed by consumers. The limited availability and relatively high price of this natural product are good reasons to counterfeit honey. Therefore, determining the parameters of honey quality is extremely important from identifying markers that confirm its authenticity. The quality of honey is determined based on its physical and chemical characteristics, the most important of which are water content, pH value, acidity, electrical conductivity, ash content, sucrose content, reducing sugars, and HMF content. The aim of this work was to determine the quality parameters (water content, pH, total acidity, and electrical conductivity) of meadow honey samples from the mountain Rtanj, collected in 2019. Based on the obtained results of certain parameters of honey quality, which ranged from: water content (13.6 – 18.6%), pH value (3.4 – 5.3), total acidity (23.2 – 47.7 mmol/kg), and electrical conductivity (0.2 – 1.3 mS/cm), it can be concluded that all samples were in accordance with the prescribed national and EU regulations, except in the case of electrical conductivity, where four samples of honey observed value greater than 0.8 mS/cm prescribed by regulations. The increased electrical conductivity value can be explained by the fact that samples were collected at different localities and that nectar honey was mixed with honeydew, which is characteristic of the forest area.
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    Assessment of mineral composition of blue crab (Callinectes sapidus) shell from Tivat Bay and Ulcinj coastal waters
    (Institute of Marine Biology University of Montenegro Kotor, Montenegro, 2022) Rakita, Slađana; Čabarkapa, Ivana; Spasevski, Nedeljka; Lazarević, Jasmina; Joksimović, Aleksandar; Joksimović, Danijela; Drakulović, Dragana
    The blue crab (Callinectes sapidus) has been considered an invasive species distributed in the Adriatic and other parts of the Mediterranean Sea, and represents a significant threat to the global marine ecosystems, because it may cause native species extinction and transformation of entire ecosystem functioning. Valorization of the blue crab waste (i.e. shell) into new products has been sought as a promising solution to reduce its negative effects. Therefore, the evaluation of chemical composition with a focus on the mineral composition of the blue crab shell was carried out within this research. For that purpose, blue crabs were caught in two different sites of the coastal part of the Adriatic Sea (Tivat Bay and Ulcinj). The samples of the blue crab were cooked by steaming for 10 min and then, shell from crab claws, head and legs (sample I) were separated from the shell of the rest of the body (cephalothorax) (sample II). The obtained results showed that both samples from Tivat Bay and Ulcinj were rich in calcium and magnesium. Calcium in the crab shell is in the form of calcium carbonate. Samples I and II from Tivat Bay and Ulcinj were also characterized with higher content of sodium and potassium. Regarding microelements, the samples had lower amounts of iron, manganese, zinc and copper. When evaluated the safety, it was determined that the concentrations of cadmium, arsenic and mercury in the samples were low or under detection limits, whereas the concentration of lead ranged between 1.32 and 1.75 mg/kg, indicating that crab shells accumulated lead. Based on the findings, it can be concluded that due to high calcium content blue crab shells from Tivat Bay and Ulcinj coastal waters have metal removal capacities and hence have a great potential as an adsorbent for the remediation of metal-bearing solutions. This potential, combined with the low cost of crab shells, could result in a cost-effective effluent treatment system.
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    Assessment of rheological properties of carp feed mixtures with different protein sources using Mixolab
    (2024) Ilić, Petar; Banjac, Vojislav; Hadnađev, Miroslav; Pojić, Milica; Vidosavljević, Strahinja; Stojkov, Viktor; Tiwari, Brijesh
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    Auto-ML GC/MS fingerprinting strategy for cereal flour authentication
    (2022) Pastor, Kristian; Ilić, Nebojša; Kojić, Jovana; Nastić, Nataša; Krulj, Jelena; Ačanski, Marijana
    Despite food authentication being a global challenge since decades, not much work has been done in developing authentication methodologies of cereal flours and bakery products. This research represents an innovative and rapid method for classifying types of non-gluten and gluten-containing cereal flours: 10 corn, 5 wheat, and 5 barley samples. To achieve this aim, a gas chromatography – mass spectrometry (GC/MS) instrument was coupled to an automated machine learning algorithm (AutoML). Grains were sampled from the experimental fields of the Institute of Field and Vegetable Crops in Novi Sad, Serbia. Cereals were milled into flour, after which liposoluble matter was extracted with n-hexane, and derivatized into corresponding volatile compounds using a 0.2 M trimethylsulfonium hydroxide solution. Total ion current chromatograms consisting of 1666 datapoints/scans were used as raw signals, each of them representing a unique fingerprint of a cereal class. However, the aim of this work was to apply the Weka open-source software in automated mode, as a single, highly parametric machine learning framework for classifying types of flour into classes defined by botanical origin and gluten content. This was achieved using an Auto-Weka package with a state-of-the-art Bayesian optimization method, thus solving the combined algorithm selection and hyperparameter optimization (CASH) problem. The Weka’s learning algorithm took into account all classifiers provided by the software: 27 base learners, 10 meta-methods, and 2 ensemble methods. Both 60 and 120 min time-budgets were carried out by the computer unattended. In each case, a Support Vector classifier (SMO) using normalized polynomial kernel was recommended as the most optimal, using a 10-fold cross-validation to exploit the performance gains on a given dataset. Cereal flour samples were adequately classified in 3 groups: non-gluten corn, and gluten wheat and barley. The presented approach directly supports the application of artificial intelligence on processing chemical information, in order to develop methods for food authentication.
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    Bactericidal effectiveness of active chlorine solution with essential oils
    (University of East Sarajevo, Faculty of Technology, 2023-03-20) Tomičić, Zorica; Čabarkapa, Ivana; Šarić, Ljubiša; Ikonić, Predrag; Todorić, Olja; Džomba, Marina; Tomičić, Ružica
    Insufficient hygiene of food contact surfaces often leads to food contamination with bacteria that cause foodborne diseases in humans, which is a growing public health problem and causes large economic losses, despite modern improvements in food production and preservation techniques. The use of natural substances with antimicrobial activity, such as essential oils, is an environmentally friendly and effective way to control the presence of potentially pathogenic bacteria. These agents are increasingly used in combination with conventional antimicrobial agents. Therefore, the aim of this study was to examine the antimicrobial activity of essential oils namely Lavandula officinalis (lavender), Melaleuca alternifolia (tea tree), Menthae piperitae (mint) and Rosmarinus officinalis (rosemary), and active chlorine solution (0.1%) (Aqualor H1000, Sigma d.o.o., Crvenka) against two gram-positive bacteria Bacillus cereus ATCC 11778 and Staphylococcus epidermidis ATCC 12228, and two gram-negative bacteria Pseudomonas aeruginosa ATCC 10145 and Salmonella Typhimurium ATCC 14028, as well as to evaluate the antimicrobial activity of essential oils and active chlorine solution (0.1%) mixed in different combination (FIC) in order to detect synergistic or antagonistic effects and discuss these effects (FICI, FIC index) on the basis of an improved checkerboard technique. The results showed a synergistic and additive effect for most combinations of active chlorine solution and essential oils. While with the reference strain P. aeruginosa ATCC 10145, an indifferent effect was observed in the combination of active chlorine solution with essential oils of mint and rosemary. The effectiveness of the solution of active chlorine with essential oils was determined using the quantitative suspension test according to the DGHM method. The results indicated that the maximum germicidal effect of the solution was achieved after exposure for 5 minutes for all tested bacteria. The lowest degree of reduction was recorded against B. cereus ATCC 11778 and S. Typhimurium ATCC 14028 at the shortest exposure time of 1 minute, while a stronger effect was recorded against S. epidermidis ATCC 12228 and P. aeruginosa ATCC 10145. Taking into account that there has been an increased interest in the use of natural antimicrobial agents in recent years, the application of a combination of active chlorine with essential oils represents a significant strategy in the control of pathogenic bacteria.