Sensory and instrumental texture analysis of Bulgarian commercial pates

M. Tonchev1, T. Atanasov1, A. Todorova1, Ts. Atanasova1, N. Shtrankova1, M. Momchilova2 G. Zsivanovits2

1
University of Food Technologies (UFT), 4000 Plovdiv, Bulgaria

2
Food Research and Development Institute (FoodRDI), 4003 Plovdiv, Bulgaria

(Manuscript received 2 June 2017; accepted for publication 22 August 2017)

Abstract. The aim of this study was to characterize the textural differences between Bulgarian commercial pates with different ingredients and to adapt the used methods for later application in texture analysis of sterilized meat products. Texture parameters were studied by sensory and instrumental methods. The sensory panel was stated from students in similar age and was asked to fulfill a questionnaire about their likening the poultry pates bought from the commercial network. Nine points sensory scales were used, about appearance, colour, spreadability by knife to bread, flavor, consistency, taste, aftertaste and overall likening. The panelists were asked to rank the pates based on their colour, spreadability and consistency. Instrumental texture parameters – texture profile and spreadability work, were analyzed by Stable Micro Systems texture analyzer in Texture Profile Analysis (TPA) and compression methods. For further analysis of spreadability, the probes were scanned by flatbed scanner before and after compression and their area ratio was measured by image analysis method. The results of sensory analysis show that, the pate with duck meat received the highest liking based on the overall liking, followed by pate with turkey meat and pate from chicken meat and liver and the lowest liked was the pate with goose meat. Based on the sensory spreadability and consistency the hardest was the pate with goose meat followed by pate with turkey meat and pate from chicken meat and liver and the softest was the pate with duck meat. The results from instrumental spreadability and hardness showed positive correlations with the results of the sensory analysis.

Food emulsions with amidated pectin from celery (Apium graveolens var. rapaceum D.C.) tubers

Iv. Petrova1, N. Petkova2*, M. Ognyanov3, Ap. Simitchiev4, M. Todorova2, P. Denev2

1Department of Catering and Tourism, Faculty of Economic, University of Food Technologies, 4002 Plovdiv, Bulgaria
2Department of Organic Chemistry and Inorganic Chemistry, Technological Faculty, University of Food Technologies, 4002 Plovdiv, Bulgaria 3Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Laboratory of Biologically Active Substances, 4000 Plovdiv, Bulgaria
4Department of Machinery for Food Industry, Technical Faculty, University of Food Technologies, 4002 Plovdiv, Bulgaria

(Manuscript received 29 May 2017; accepted for publication 22 August 2017)

Abstract. Hydrocolloids, especially polysaccharides from traditional plant sources and their derivatives possessed significant emulsifying properties. Pectin was isolated from celery tubers by accelerated “green” method for extraction based on ultrasonic irradiation. Further chemical modification of celery pectin was performed with 4 mol/L NH3. The amidated celery pectin was obtained with the following characteristics: the degree of esterification (DE) 31%, the degree of amidation (DA) 16%, degree of acetylation (DAc) 2% and anhydrouronic acid content (AUAC) 68%. This modified pectin was incorporated in preparation of model30,40and50%oil-in-wateremulsions.Theeffectofamidationofcelerypectinonthestabilityofemulsionswasinvestigated. Theresultsshowedthat amidation increased the emulsifying properties of pectic polysaccharides. It affected also the rheological characteristics of model emulsion. The current study demonstrated preparation of emulsion with low-caloric amidated pectin as proper alternative to the traditional emulsifiers.

Carcass characteristics and technological properties of Musculus Longissimus Lumborum at lambs from the Bulgarian dairy synthetic population and its F1 crosses with meat breeds

N. Ivanov1*, T. Angelova1, S. Laleva1, S. Ribarski2, D. Miteva1, D. Yordanova1, V. Karabashev1, I. Penchev2

1Agricultural Institute, 6000 Stara Zagora, Bulgaria
2Department of Morphology, Physiology and Nutrition, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 28 March 2017; accepted for publication 26 May 2017)

Abstract. The purpose of this study is to determine the effects of the breed on some of the carcass characteristics and the technological properties of Musculus Longissimus Lumborum in lambs from the Bulgarian Dairy Synthetic Population and its F1 crosses with Ile de France and Mutton Charollais breeds. The scientific study took place at the Agricultural Institute of Stara Zagora, Bulgaria. Object of the study were lambs from the Bulgarian Dairy Synthetic Population and its crosses with Ile de France and Mutton Charollais breeds. The internal organs weight of the animals from the three groups was measured after their slaughter. In order to determine the meat/bones ratio, the left carcass halves were deboned. The eye muscle area and analyzed samples of Musculus Longissimus Lumborum was determined. The results show a slight variation in the weight of the internal organs of the animals from the three groups. The Mutton Charollais crosses come first in terms of eye muscle area (11.34 cm2), followed by the Ile de France crosses (11.21 cm2), and the lambs from the reference group come last with only 8.64 cm2 (P ≤ 0.001). With regard to the meat/bones ratio, it was found out that in the Ile de France crosses it is the highest (2.90:1), followed by the Mutton Charollais crosses (2.68:1), and the lambs from the reference group (2.43:1) where it is the lowest (P >0.05). Ile de France crosses exhibited statistically significantly higher meat tenderness (P ≤ 0.001) and water-holding capacity (WHC) (P ≤ 0.01), while Mutton Charollais crosses – considerably higher cooking losses (P ≤ 0.001) than control animals.

Exopolysaccharide influence on acid gel formation

K. Yoanidu1, P. Boyanova2*, P. Panayotov2

1Department Industrial Microbiology, The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 26 Acad. G. Bonchev, 1113 Sofia,
Bulgaria

2Department of milk and milk products, Faculty of Technology, University of Food Technologies, 26 Maritza, 4000 Plovdiv, Bulgaria

(Manuscript received 12 February 2017; accepted for publication 16 April 2017)

Abstract. Turbidimetric monitoring of milk coagulation was conducted in situ. Milk gel was produced by acidification with the use of three strains of starter culture. These strains were characterized by various acidification rate and exopolysaccharides (EPS) production. The concentrations of EPS affect mostly the pH of gel formation (5.53 – low EPS – producing strain; 5.33 – medium EPS – producing strain; 5.46 – high EPS – producing strain) whereas the time of gel formation depends on the various rate of acidification of all three strains.

Concentration of sulfur-containing amino acids at turkey broilers during and after muscle dystrophy, fed with deficient feed supplemented with oxidised fat

K. Stoyanchev

Department of Internal Diseases and Clinical Toxicology, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 5 April 2016; accepted for publication 7 June 2017)

Abstract. The aim of the present study was to reproduce experimentally muscular dystrophy in 50 broiler turkeys, through early nutrition with a diet deficient in vitamin E, selenium and sulfur-containing amino acids, supplemented with oxidised fat and to study blood plasma sulfur containing amino acids (methionine and cysteine). The experiments were conducted with 1 day-old broiler turkeys. By the 3rd day of life, they were divided into 40 experimental (II group) and 10 control birds (I group); the latter were fed a standard compound feed, whereas the former group received a diet deficient in sulfur-containing amino acids methionine and cysteine (reduced up to 50%), vitamin E, and Se (from 0.2 mg/kg in standard feed to 0.01 mg/kg), further supplemented with oxidized fat containing peroxides and aldehydes with peroxide number of the food 8.0 meq O2/kg. The clinical signs of experimental muscle dystrophy in broiler turkeys 2
appeared first by the 25th day of feeding, when the mild clinical form (II A group) and the severe clinical form (II B group) werewas established. The results indicated clearly that in turkey broilers suffering from muscle dystrophy, the concentrations of sulfur-containing amino acids cysteine and methionine decreased. After the treatment of turkey broilers with muscle dystrophy, and supplementation with non-deficient forage with Se, vitamin E, but also with sulfurcontaining amino acids cysteine or methionine with Seled at a dosage 0.06 mg/kg, the plasma levels of sulfur-containing amino acids cysteine and methionine was normalized in the mild clinical form (II A group). The birds affected by the severe clinical form of disease (II B group), which were not treated with Seled® and whose deficient feed was not corrected, could not recover and levels of sulfur-containing amino acids cysteine and methionine did not normalize.

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 mg.kg-1 AX and 25 mg.kg-1 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 mg.kg-1 and 0.807 ± 0.021 mg.kg-1 in skeletal muscle and 0.683 ±0.055 mg.kg-1 and 0.280 ±0.017 mg.kg-1 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±1.12mg.kg-1and2844.32±39.31mg.kg- 1) compared with the values of these parameters of fish in net cages (134.46±1.96 mg.kg-1 and 2690.31±42.81 mg.kg-1) (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 mg.kg-1 and 671.31±16.16 mg.kg-1) than in fish in raceways (2552.90±39.93 mg.kg-1 and 569.32±13.75 mg.kg-1)(P≤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’.

odbutton6

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.

odbutton6