Sunčica Kocić-Tanackov

Effects of Onion (Allium cepa L.) and Garlic (Allium sativum L.) Essential Oils on the Aspergillus versicolor Growth and Sterigmatocystin Production

In the present study the effects of individual and combined essential oils (EOs) extracted from onion (Allium cepa L.) bulb and garlic (Allium sativum L.) clove on the growth of Aspergillus versicolor and sterigmatocystin (STC) production were investigated. The EOs obtained by hydrodistillation were analyzed by GC/MS. Twenty one compounds were identified in onion EO. The major components were: dimethyl-trisulfide (16.64%), methyl-propyl-trisulfide (14.21%), dietil-1,2,4-tritiolan (3R,5S-, 3S,5S- and 3R,5R- isomers) (13.71%), methyl-(1-propenyl)-disulfide (13.14%), and methyl-(1-propenyl)-trisulfide (13.02%). The major components of garlic EO were diallyl-trisulfide (33.55%), and diallyl-disulfide (28.05%). The mycelial growth and the STC production were recorded after 7, 14, and 21 d of the A. versicolor growth in Yeast extract sucrose (YES) broth containing different EOs concentrations. Compared to the garlic EO, the onion EO showed a stronger inhibitory effect on the A. versicolor mycelial growth and STC production. After a 21-d incubation of fungi 0.05 and 0.11 μg/mL of onion EO and 0.11 μg/mL of garlic EO completely inhibited the A. versicolor mycelial growth and mycotoxins biosynthesis. The combination of EOs of onion (75%) and garlic (25%) had a synergistic effect on growth inhibition of A. versicolor and STC production.

Antifungal activities of basil ( Ocimum basilicum L.) extract on Fusarium species

The basil extract composition was determined by the GC-MS method and 38 different components were identified. The major components of the basil extract were estragol (86.72%), trans-α-bergamotene (2.91%), eucalyptol (2.67%), trans-ocimene (1.04%), linalool (0.72%), methyl-eugenol (0.71%), etc. The antifungal potential of the basil extract was tested against Fusarium oxysporum, F. proliferatum, F. subglutinans , and F. verticillioides isolated from cakes, using the agar plate method. Extract concentrations of 0.35 and 0.70% (v/v) significantly inhibited the growth of F. proliferatum (33.37 and 44.30%, respectively) and F. subglutinans (24.74 and 29.27%, respectively) whereas other investigated Fusarium species exhibited much lower sensitivity. The basil extract completely inhibited the growth of investigated Fusarium spp. at the concentration of 1.50% (v/v). Higher concentrations (0.35 and 0.70% (v/v)) reduced growth of aerial mycelium in all tested species. Strong medium pigmentation in the case of F. proliferatum and F. verticillioides was observed. The microscopic examination of the samples confirmed the presence of hyphae deformations with a frequent occurrence of fragmentations, thickenings and diminished sporulation. In addition to the basic, sensory, role the extract of basil has in the food product, it exerted significant antifungal properties, depending on its concentration. Key words : Basil (Ocimum basilicum L.) extract, components, antifungal activity, Fusarium spp.

Antifungal activity of oregano (Origanum vulgare L.) extract on the growth of Fusarium and Penicillium species isolated from food

The effect of the oregano extract (Origanum vulgare L.) on the growth of Fusarium and Penicillium species isolated from cakes and ready-for-use fresh salads from different kinds of vegetables was investigated. The contents of the active component of extract were identified by GC-MS and they include: carvacrol (34.2%), carvone (18.5%), p-cimene (8.05%), thymol (3.74%). The oregano extract showed the ability to reduce mould growth at all applied concentrations. Stronger inhibitory effect on the growth of Penicillium species, contrary to Fusarium, was determined. At extract concentration of 2.50 mL/100 mL, growth of P. aurantiogriseum, P. glabrum and P. brevicompactum was completely inhibited during 14 days of incubation. At the same concentration, growth of Fusarium proliferatum was inhibited by 81.71%, F. oxysporum by 85.84%, F. verticillioides by 86.50%, P. chrysogenum by 86.2% and F. subglutinans by 88.85%.

Cadmium in liver and kidneys of domestic Balkan and Alpine dairy goat breeds from Montenegro and Serbia

ABSTRACT Concentrations of cadmium (Cd) were determined in the samples of 144 animals around 1 and of 144 animals around 4 years old. Cd was analysed by inductively coupled plasma-optical emission spectrometry (ICP-OES), after microwave digestion. Cd concentrations were higher (p < 0.05) in kidney than in liver and higher (p < 0.05) in older animals than in young ones. In domestic Balkan goat which was raised in a free-ranged system Cd accumulation was lower (p < 0.05) than in Alpine goat raised in an intensive production system. Geographic region did influence Cd accumulation only in older animals. Higher Cd levels (p < 0.05) were determined in goats from Serbia. The highest obtained Cd concentrations in both tissues were lower than maximum levels set by European and national legislation for ruminants (cattle and sheep).

Antifungal activity of the basil (Ocimmum basilicum L.) extract on Penicillium aurantiogriseum, P. glabrum, P. chrysogenum, and P. brevicompactum

This study was aimed at investigating the antifungal potential of basil (Ocimmum basilicum L.) extract against toxin-producing Penicillium spp. (P. aurantiogriseum, P. glabrum, P. chrysogenum, and P. brevicompactum) isolated from food. The basil extract composition was determined by the GC-MS method. The major component identified in the extract was estragole (86.72%). The determination of the antifungal activity of basil extract on Penicillium spp. was performed using the agar plate method. Basil extract reduced the growth of Penicillium spp. at all applied concentration levels (0.16, 0.35, 0.70, and 1.50 mL/100mL) with the colony growth inhibition from 3.6 (for P. glabrum) to 100% (for P. chrysogenum). The highest sensitivity showed P. chrysogenum, where the growth was completely inhibited at the basil extract concentration of 1.50 mL/100mL. The growth of other Penicillium spp. was partially inhibited with the colony growth inhibition of 63.4 % (P. brevicompactum), 67.5% (P. aurantiogriseum), and 71.7% (P. glabrum). Higher concentrations (0.70 and 1.50 mL/100mL) reduced the growth of the aerial mycelium of all tested Penicillium species. In addition, at the same extract concentrations, the examination of microscopic preparation showed the deformation of hyphae with the frequent occurrence of fragmentations and thickenings, occurrence of irregular vesicle, frequently without metulae and phialides, enlarged metulae. The results obtained in this investigation point to the possibility of using basil extract for the antifungal food protection.

Fungi and mycotoxins: Food contaminants

The growth of fungi on food causes physical and chemical changes which, further affect negatively the sensory and nutritive quality of food. Species from genera: Aspergillus, Penicillium, Fusarium, Alternariа, Cladosporium, Mucor, Rhizopus, Eurotium and Emericella are usually found. Some of them are potentially dangerous for humans and animals, due to possible synthesis and excretion of toxic secondary metabolites - mycotoxins into the food. Their toxic syndroms in animals and humans are known as mycotoxicoses. The pathologic changes can be observed in parenhimatic organs, and in bones and central nervous system also. Specific conditions are necessary for mycotoxin producing fungi to synthetize sufficient quantities of these compounds for demonstration of biologic effects. The main biochemical paths in the formation of mycotoxins include the polyketide (aflatoxins, sterigmatocystin, zearalenone, citrinine, patulin), terpenic (trichothecenes), aminoacid (glicotoxins, ergotamines, sporidesmin, malformin C), and carbonic acids path (rubratoxins). Aflatoxins are the most toxigenic metabolites of fungi, produced mostly by Aspergillus flavus and A. parasiticus species. Aflatoxins appear more frequently in food in the tropic and subtropic regions, while the food in Europe is more exposed to also very toxic ochratoxin A producing fungi (A. ochraceus and some Penicillium species). The agricultural products can be contaminated by fungi both before and after the harvest. The primary mycotoxicoses in humans are the result of direct intake of vegetable products contaminated by mycotoxins, while the secondary mycotoxicoses are caused by products of animal origin. The risk of the presence of fungi and mycotoxin in food is increasing, having in mind that some of them are highly thermoresistent, and the temperatures of usual food sterilization is not sufficient for their termination. The paper presents the review of most important mycotoxins, their biologic effects, the condition of their synthesis, occurence in food, permitted tolerant intake, as well as the possibility of their degradation. [Projekat Ministarstva nauke Republike Srbije, br. TR 31017]

Markovian ants in a queuing system

The synthesis of memoryless Markovian systems and Ant based concept with memory characteristics of deposit pheromone is the basis for the presented artificial intelligence hybrid Only the initial elements of the system are specified in this paper by illustrating the routes of two ants The pheromone capacity was first modelled as an exponential-type random variable The Ant Queueing System was formed The pheromone capacity was then used to form two independent exponential random variables The convolution of these variables induces significant quality and quantity changes, mainly the decrease in entropy The study also provides a possible method for dealing with stationary queueing systems when we are familiar with the state probability and the arrival rate and service rate are unknown.

Cadmium and lead in female cattle livers and kidneys from Vojvodina, northern Serbia

ABSTRACT Concentrations of cadmium (Cd) and lead (Pb) were determined in livers (n = 52) and kidneys (n = 52) of female cattle (345–2717 days old) from dairy farms in the region Vojvodina. Cd and Pb were analysed by inductively coupled plasma-optical emission spectrometry, after microwave digestion. Cd and Pb concentrations did not exceed the Serbian and European maximum set limits in any sample. The Cd concentrations in the livers and kidneys ranged from 0.033 to 0.151 mg kg−1 wet weight and from 0.055 to 0.510 mg kg−1 wet weight, respectively. The corresponding Pb concentrations were 0.015-0.159 mg kg−1 wet weight and 0.021-0.196 mg kg−1 wet weight, respectively. Mean Cd and Pb concentrations were significantly lower (p < 0.001) in the liver (0.072 and 0.053 mg kg−1 wet weight) than in the kidney (0.190 and 0.075 mg kg−1 wet weight). There were good correlations between Cd in liver and Cd in kidney, Pb in liver and Pb in kidney, Cd level and age and Pb level and age in both tissues.

Effect of yeast storage temperature and flour composition on fermentative activities of Baker's yeast.

Bakers yeast is a set of living cells of Saccharomyces cerevisiae. It contains around 70-72% of water, 42-45% of proteins, around 40% of carbohydrates, around 7.5% of lipids (based on dry matter), and vitamin B-complex. On the basis of yeast cell analysis it can be concluded that yeast is a complex biological system which changes in time. The intensity of the changes depends on temperature. Yeast sample was stored at 4°C i 24°C for 12 days. During storage at 4°C, the content of total carbohydrates decreased from 48.81% to 37.50% (dry matter), whereas carbohydrate loss ranged from 40.81% to 29.28% at 24°C. The content of trehalose was 12.33% in the yeast sample stored at 4°C and 0.24% at 24°C. Loss of fermentative activity was 81.76% in the sample stored at 24°C for 12 days. The composition of five samples of 1st category flour was investigated. It was found that flours containing more reducing sugars and maltose enable higher fermentation activities. The flours with higher ash content (in the range 0.5-0.94%) had higher contents of phytic acid. Higher ash and phytic contents in flour increased the yeast fermentative efficiency. In bakery industry, a range of ingredients has been applied to improve the products quality such as surface active substances (emulsifiers), enzymes, sugars and fats. In the paper, the effect of some ingredients added to dough (margarine, saccharose, sodium chloride and malted barley) on the yeast fermentative activity was studied. The mentioned ingredients were added to dough at different doses: 0.5, 1.0, 1.5 and 2.0%, flour basis. It was found that the investigated ingredients affected the fermentative activity of yeast and improved the bread quality.

Possibility of L-(+)-lactic acid fermentation using malting, brewing, and oil production by-products

Industrial by-products such as brewers spent grain (BSG) hydrolysate, malt rootlets extract (MRE) and soybean meal extract (SME) were used for L-(+) lactic acid (LA) production by a pure L. rhamnosus ATCC 7469 strain. The effect of the addition of MRE (10-50%) or SME (10-50%) in BSG hydrolysate on batch and fed-batch LA fermentation was evaluated. The addition of MRE and SME increased the concentration of free amino nitrogen (FAN) and essential minerals (Fe, Mg, Mn, and Zn), which had a positive effect on the fermentation. Also, the MRE addition significantly lowered C/N ration to a more favorable level for the efficient LA fermentation. In batch fermentation, the highest LA concentration (25.73 g/L), yield (86.31%), and volumetric productivity (0.95 g/L h-1), were obtained with the addition of 50% MRE. Further increase in LA concentration to 58.01 g/L, yield to 88.54%, and volumetric productivity to 1.19 g/L h-1 was achieved in fed-batch fermentation with addition of 50% MRE. A high optical purity of LA with 99.7% of L-(+)-isomer was obtained on the substrate based on industrial by-products. In addition, solid remains after BSG hydrolysis and MRE and SME preparation, together with the biomass of L. rhamnosus separated after the fermentation could be a good base for feed preparation.