Chemical composition and technological characteristics of wines from red grape varieties, selected in Bulgaria

V. Haygarov1, T. Yoncheva1, Z. Nakov2, M. Ivanov2, D. Dimitrov1*

1Department of Enology and Chemistry, Institute of Viticulture and Enology, 1 Kala Tepe str., 5800 Pleven, Bulgaria 2Department of Cultivars and Cultivar Maintenance, Institute of Viticulture and Enology, 1 Kala Tepe str., 5800 Pleven, Bulgaria

(Manuscript received 20 May 2016; accepted for publication 5 February 2017)

Abstract. Chemical analysis of grapes and technological characterization of wines from red varieties Storgoziya, Kaylashky rubin, Trapezitza, Rubin and Bouquet, created by the method of intraspecific and interspecific hybridization at the Institute of Viticulture and Enology – Pleven, Bulgaria were made. The technological maturity of the grapes as raw material for producing quality red wines was determined. Rubin variety was with the highest sugar content – 23.10±0.73 %, titratable acids – 6.18±0.34 g/dm3 and pH 3.40±0.71. The other varieties were with optimal condition for the production of red wines in terms of sugars and titratable acids. The chemical composition and organoleptic characteristics of the experimental wine samples were established. The ethyl alcohol content in the produced wines was in the range from 12.33±0.23 vol. % (Bouquet) to 13.31±0.34 vol. % (Kaylashky rubin). The content of titratable acids was in the range of 5.33±0.43 g/dm3 (Trapezitza) up to 6.88±0.21 g/dm3 (Kaylashky rubin). There were no significant differences in the analyzed indicators and taste evaluation between experimental wines and wine of Vitis vinifera – Pinot noir grape variety used as control sample.

Accumulation of astaxanthin and canthaxanthin in muscle tissues of Rainbow trout (Oncorhynchus mykiss W.) fed with xanthophyll supplemented feed

M. Tzanova*

Deparment of Biochemistry, Microbiology and Physics, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria (Manuscript received 17 November 2016; accepted for publication 13 February 2017)

Abstract. In this study the rate of accumulation of both main pigments in Salmonidae – astaxanthin (AX) and canthaxanthin (CX) in different muscle tissues of Rainbowtrout(OncorhynchusmykissW.)andtheirdistributioninfleshandheartwasresearched. Experimentalfishwerereared100daysintwotanksastwo parallel experimental groups and fed with market feed, containing 40 AX and 25 CX. The diet was according to the manufacturer’s recommendations, which are consistent with fish size and water temperature. The accumulated pigment quantities in the muscle tissues, were measured everytwentydaysbyhighperformanceliquidchromatographywithphotodiodearraydetectionafterselectivexanthophyllextraction. ThehighestratesofAX and CX deposition were recorded on the 60th and 80th day. The average contents of AX and CX were at the end of the trial 1.943 ± 0.167 and 0.807 ± 0.021 in skeletal muscle and 0.683 ±0.055 and 0.280 ±0.017 in cardio muscle, respectively.

Fish production and some traits of meat quality in rainbow trout (Oncorhynchus mykiss) farmed in different production systems

St. Stoyanova*, Y.Staykov, G. Zelqzkov, I. Sirakov, G.Nikolov

Department of Biology and Aquaculture, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria (Manuscript received 26 October 2016; accepted for publication 22 November 2016)

Abstract. The rainbow trout (Oncorhynchus mykiss), an important species in Bulgarian aquaculture, is farmed in different production systems as raceways, net cages etc. The aim of the present study was to evaluate the effect of two different rearing systems on fish production, survival rate, meat chemical, mineral composition and farming economic efficiency of culticated rainbow trout (Oncorhynchus mykiss). The information from a survey on fish production and economic efficiency traits was collected from two national rainbow trout farms using the two commonest fish farming systems: in raceways, Happy Fish Ltd fish farmandinnetcages,ForestGroupLtdfishfarm.Theaverageindividualweightgain(g),totalweightgain(kg), feedconversionratio,productioncostsof1kg fish and the economic efficiency coefficients were determined for the two studied fish farms. The final live weight of rainbow trout in net cages was 0.30 kg vs 0.35 kg in raceways. The average individual weight gain was higher in raceways farming system (0.30 kg) than in net cages farm (0.26 kg). The mortality rate of fish in raceways was considerably lower: only 1% as compared to that in net cages (4%). The feed conversion ratio at the end of the experiment showed identical values for trout in both farms 1.01. The meat water content of fish reared in raceways and net cages was 77.46±0.65% and 74.52±0.52% respectively (P≤0.01).The protein content of fish meat was higher in fish farmed in net cages 18.84±0.29% as compared to fish cultivated in raceways 17.60±0.49% (P≤ 0.05). Meat fat content of rainbow trout, reared in the net cage system was also considerably higher (5.26±0.30%) than the respective parameter in fish farmed in ponds(3.60±0.15%)(P≤0.001).The content of Ca and P washig her in rainbow trout sreared in race ways(138.96±± 1) compared with the values of these parameters of fish in net cages (134.46±1.96 and 2690.31±42.81 (P≤ 0.05). The K and Na content exhibited the opposite tendency with substantially higher values in trouts farmed in net cages (2658.26±48.75 and 671.31±16.16 than in fish in raceways (2552.90±39.93 and 569.32±13.75≤0.05, P≤0.001). The production costs of 1 kg rainbow trout were by 17.27% lower in the Forest Group farm than in the Happy Fish farm. The coefficient of economic efficiency in the net cage farm was by 23.44%higher than that of the race ways production system.


Some results of evaluation of new-introduced apricot cultivars under conditions of Plovdiv region

V. Bozhkova*, M. Nesheva

Fruit Growing Institute, 4004 Plovdiv, Bulgaria
(Manuscript received 15 May 2016; accepted for publication 24 August 2016)

Abstract.ApricotisnottypicalspeciesforSouthCentralRegionofBulgaria,wherethePlovdivregionoccupiesalargepart oftheterritory,butlast5yearsthe area and production remain stable. In this study, are presented the first results of investigation on seven new introduced apricot cultivars ‘Bergecot’, ‘Flavor cot’, ‘Jenny cot’, ‘Lady cot’, ‘Perle cot’, ‘Sweet cot’ and ‘Tom cot’, carried out at the Fruit Growing Institute in Plovdiv. The investigation included phelogical data, fruit dimensions, chemical composition and sensory evaluation of the fruits. The studied cultivars more often entered the stage of flowering after second part of March and the differences between them were insignificant – one or two days. Among the investigated cultivars four of them ripened in the third decade of June, ‘Lady cot’ ripened in the beginning of July, ‘Bergecot’ in the end of July and ‘Jenny cot’ in the first half of August. The largest fruits had cultivar ‘Lady cot’ – 57.86 g, andthesmallestone’Flavorcot’–37.64g.Thetotalsolublesolids(TSS)contentinthepresentstudyvariedfrom13.4°Brixin’Perlecot’to23.3°Brix in’Jeny cot’ cultivar. The highest vitamin C content was found in ‘Bergecot’ – 29.40 mg/100 g and it is statistically proved. According to the final evaluation the cultivars ‘Bergecot’ and ‘Sweet cot’ have exellent sensory characteristics and the other 5 cultivars are classified in the group of first class. According to the obtained data, all evaluated cultivars in this study are suitable for growing under the conditions of Plovdiv region. The most attractive and quality fruits have cultivars ‘Lady cot’, ‘Perle cot’, ‘Bergecot’ and ‘Sweet cot’.


Amino acid composition of lamb meat from the North East Bulgarian fine fleece breed and its crossbreds with Australian merino and Ile de France from internal breeding

R. Slavov1*, G. Mihaylova1, St. Ribarski2, D. Panayotov1, D. Pamukova1, D. Dragnev1

1Department of Animal Science – Ruminants and Dairy Farming, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria 2Department of Morphology, Physiology and Nutrition, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 1 May 2016; accepted for publication 25 August 2016)

Abstract. A comparative analysis of amino acid composition of lamb meat from the North East Bulgarian fine fleece breed (I gr.) and its crossbreds from internal breeding with 25% heredity from the Australian merino (II gr.) and Ile de France (III gr.) breeds was conducted. Upon starting the experiment lambs were equal and during the experiment they were placed under similar conditions of feeding and rearing. To establish the amino acid composition of meat slaughter analyses were performed at 100 and 130 days of age. From the carcass of each slaughtered animal individual mean samples were taken. Studies were carried out in the Research Laboratory of the Faculty of Agriculture at Trakia University. As a result of the studies the following conclusions were made: 1⁄4 Ile de France crossbreds in a sophisticated crossing have the highest total amino acid content, including essential amino acids in the meat of 100- and 130-day-old lambs, 6.87% and 7.36%, respectively. The lysine/arginine ratio, relating to protein atherogenicity, varies within narrow ranges among groups and marks slight increase with age – from 1.31-1.37 at 100 days to 1.41-1.46 at 130 days. With the increase of age in crossbreds from internal breeding total protein amino acid content grows, that being most prominent in lambs from the III group – from 41.92 to 43.49%. The values of total protein indices increase compared to the reference protein (from 117.97% to 118.22% for II group and from 116.44% to 120.80% for III group) and the whole egg protein (from 89.39% to 91.92% for II group and from 90.53% to 93.93 for III group). It has been found that internal breeding of crossbreds with 25% heredity from the Ile de France breed has positive effect concerning the total amino acid content of lamb meat at 100 and 130 days of age, essential amino acid content in it and the levels of total amino acid indices. Internal breeding of crossbreds with 25% heredity from the Australian merino breed does not have an adverse effect on the levels of the studied traits.


Quality traits of eggs from autosexing Easter eggers

H. Lukanov1*, A. Genchev1, A. Pavlov2, I. Penchev1

1Department Animal Science – monogastric and other animals, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
2Department of Pharmacology, Physiology of animals and Physiological chemistry, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 5 July 2016; accepted for publication 31 August 2016)

Abstract. The main egg quality traits were investigated in two autosexing F1 Easter egger crosses. Partridge Araucana roosters were used as carriers of the eggshell biliverdin pigmentation gene. Maternal forms used for obtaining the two experimental crosses were high-producing layer hens carrying the sex-linked S and B genes. Experimental groups comprised F1 crosses of partridge Araucana roosters with white mutational Rhode Island hens or hens with barred colour mutation. The aim of the study was to investigated the quality traits of blue-green eggs produced by autosexing hens. The egg quality was evaluated at 38 weeks of age. Studied traits comprised egg weight (g), shape index, albumen index (AI), Haugh units (HU), yolk index (YI), yolk colour (Roche scale), percentages of albumen, yolk and eggshell (%), eggshell surface (cm2), eggshell density (mg/cm2), average eggshell thickness (μm) and eggshell colour. The group W was outlined with the highest egg weight – 61.03±0.47 g, and group A – with the lowest (50.91±0.32 g). The albumen and yolk quality was the best in group A, where albumen index was 0.075±0.002, Haugh units – 76.53±0.8 and yolk index – 0.491±0.009. The analysis of eggshell colour showed that eggs of group A were with the highest lightness (L*) value (73.60±0.77), whereas eggs of groups W and AW had egg lightness of 60.45±0.53 and 61.11±0.55 (p<0.001) respectively. The shell colour index (SCI) demonstrated a certain overlap of values in eggs with protoporphyrin and biliverdin taints. After introduction of a correction coefficient and recalculation of SCI*, the values of green eggs assumed a negative sign and could be distinguished from brown eggs.


Estimation of differences in trace element composition of Bulgarian summer fruits using ICP-MS

G. Toncheva1, K. Nikolova2, D. Georgieva3, G. Antova4, V. Kuneva5

1Department of General and Inorganic Chemistry with Methodology of Chemistry Education, Faculty of Chemistry University of Plovdiv Paisii Hilendarski,
4000 Plovdiv, Bulgaria
2Department of Mathematics and Physics, Faculty of Economics University of Food Technologies, 4000 Plovdiv, Bulgaria
3Department of Analytical Chemistry and Computer Chemistry, Faculty of Chemistry, University of Plovdiv Paissii Hilendarski, 4000 Plovdiv, Bulgaria
4Department of Chemical Technology, Faculty of Chemistry, University of Plovdiv Paissii Hilendarski, 4000 Plovdiv, Bulgaria
5Department of Mathematics, Physics and Informatics, Faculty of Economics, Agricultural University, 4000 Plovdiv, Bulgaria
(Manuscript received 14 May 2016; accepted for publication 20 June 2016)

Abstract. The content of potentially essential and toxic elements: chromium, manganese, iron, copper, nickel, cadmium and arsenic in Bulgarian fruits such as aronia, morello, cherry, raspberry, nectarine peach, apple type „akane” and pear type „early gold” were investigated. By using the ICP-MS we found that raspberry has the highest content of iron (4635.9 ± 53.2 μg kg-1), manganese (5690.9 ± 31.7 μg kg-1) and chromium (150.2 ± 2.5 μg kg-1), while the richest in copper is the nectarine (887.5 ± 31.19 μg kg-1). The content of toxic elements (nickel, cadmium and arsenic) is in amount significantly below the permissible standards. Single ANOVA and subsequent Dunkan’s test were used to define the fruit and to estimate the significance of chemical elements. The test for multidirectional comparisons indicated that for five of the investigated seven elements: iron, copper, nickel, cadmium, and arsenic the fruits are statistically distinguishable. According to hierarchical cluster analysis the fruits are into one cluster.



Composition of meat in La Belle and White Plymouth Rock chickens, slaughtered at different age

Т. Popova*, E. Petkov, M. Ignatova

Institute of Animal Science, 2232 Kostinbrod, Bulgaria
(Manuscript received 16 May 2015; accepted for publication 8 June 2016)

Abstract. An experiment with two lines of chickens – synthetic line La Belle and White Plymouth Rock was carried out in the Institute of Animal Science, Kostinbrod to assess the meat quality in regards to chemical composition and the fatty acid profile at the age of 9 and 18 weeks. The age affected the lipid content which decreased significantly in breast (p<0.05) and thighs (p<0.01) in the older chickens of both lines. The content of protein and moisture in breast differed between the lines (p<0.05), showing higher protein and lower moisture in White Plymouth Rock chickens, while in the thigh muscles the line and age significantly interacted (P<0.001) in regards to these traits. Interactions between the two factors (p<0.01) was observed for the ash content in the breast, whereas in the thighs it tended to decrease with the age in both lines. The fatty acid composition of the meat was influenced mainly by the age of the chickens. The total content of the saturated fatty acids was increased in the thighs of the older birds (p<0.01), while the proportion of the monounsaturated fatty acids was decreased in the breast (p<0.01) and thighs (p<0.001) with advancing age of the chickens. The opposite was observed for the content of the polyunsaturated fatty acids in the breast, which increased at higher age of slaughter (p<0.001). In thigh meat, the changes of the polyunsaturated fatty acids induced by age followed the same pattern, however significant interaction with the line was observed (p<0.05). The cholesterol content in the breast differed significantly between the two lines (p<0.05) and reduced with age (p<0.001). In the thighs considerable decrease (p<0.001) of the cholesterol was observed in La Belle birds.


Heavy metal content in the meat of common carp (Cyprinus carpio L.) and rainbow trout (Oncorhynchus mykiss W.), cultivated under different technologies

St. Stoyanova*, I. Sirakov, K. Velichkova, Y. Staykov

Department of Biology and Aquaculture, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria (Manuscript received 15 October 2015; accepted for publication 19 February 2016)

Abstract. Water pollution from industrial production and developing agriculture is a serious problem in aquaculture. The aim of this study was to determine the content of heavy metals Zn (zink), Pb(lead), Ni (nickel) and Cd (cadmium) in the muscles of common carp (Cyprinus carpio L.) and rainbow trout (Oncorhynchus mykiss W.), grown under different technologies. In the current study were investigated common carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss), cultivated in net cages, earthen ponds and raceways. The concentration of heavy metals in the muscles of fish was determined by the methods of AAS in the Scientific laboratory of the Faculty of Agriculture. The influence of different production technologies on the bioaccumulation of Zn, Pb, Ni and Cd (in the flesh of common carp and rainbow trout) was found. The Ni content in muscles was 31.25% higher in common carp, cultured at earthen ponds, compared with its content in the flesh of the fish raised in net cages. The concentration of Pd and Ni in rainbow trout, raised in raceways was higher than that determinated for rainbow trout cultivated in net cages, by 25.0% and 7.14%, respectively. The concentration of Cd and Zn of these species, grown in raceways were lower by 33.33% and 2.14%, respectively, compared with their concentration in rainbow trout, cultivated in net cages.


Extraction and characterization of anthocyanin colorants from plant sources

S. Dyankova*, M. Doneva

Institute of Cryobiology and Food Technologies, 53 Cherni Vrah, 1407 Sofia, Bulgaria (Manuscript received 2 November 2015; accepted for publication 19 January 2016)

Abstract. Natural pigments (and especially those of anthocyanins) are a valuable source of bioactive compounds and may be used in the production of new functional food ingredients. Furthermore, their applications in the treatment and prevention of chronic disorders are becoming more and more widespread. In the last few years consumers have focused their attention on the natural biologically active compounds as functional food ingredients, and therefore, it may be assumed that natural colorants are an alternative source of synthetic additives. The aim of the study was to determine the quantitative content of monomeric anthocyanin pigments in extracts obtained from eight plants. The total content of monomeric anthocyanin pigments was measured by a pH-differential method. The TLC analysis of the pigment extracts from the different plants showed intensive rose, red and violet stripes corresponding to the anthocyanin content. The extracts from chicory and lavender petals were unstable and their color decreased in intensity in 1 month. The analysis of the experimental data shows that the yield of pigment substances depends on a few factors: the type of plant, the preliminary treatment of the plant and the solvent that is used. The largest quantity of extracted substances in the studied plants were isolated from chokeberry (2 195.9 cyd eq mg/l), followed by blackberry (1 466.2 cyd eq mg/l) and one variety of the grapes (1 199.3 cyd eq mg/l). In the case of chokeberry, the pigment content included a large number of anthocyanins and the combination of these components was the reason for the deep red/violet color of the extract. Fresh or frozen materials are the most suitable for extraction of anthocyanin pigments. On the whole, fruit pulp yielded a larger quantity of pigments than juice. Anthocyanins are water-soluble compounds and for that reason their isolation requires water and other polar solvents. Better stabilization of color is obtained by a slight acidification of the solvent with diluted hydrochloric acid. Due to the high content of organic acids in fruits, this effect is attained in a natural way.