Volume 14 (2016)
  Special Issue II

Journal Full Text: Vol14S2

Contents


Pages

1249–1260 V. Alle, U. Kondratovics, A. Osvalde and M. Vikmane
Differences in cadmium accumulation and induced changes in root anatomical structures in plants used for food
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Differences in cadmium accumulation and induced changes in root anatomical structures in plants used for food

V. Alle¹*, U. Kondratovics¹, A. Osvalde² and M. Vikmane¹

¹University of Latvia, Faculty of Biology, Department of Plant Physiology, St. Jelgavas 1, LV-1004 Riga, Latvia
²University of Latvia, Institute of Biology, Laboratory of Plant Mineral Nutrition, St. Miera 3, LV-2169 Salaspils, Latvia
*Correspondence: vita.alle@lu.lv

Abstract:

 A rapid urbanization passes all over the world thus the effect of chemicals, including heavy metals, increases on plants. Heavy metal pollution poses a serious hazard to humans’ health, and it uptake into plants is the primary way through which it can enter the food chain. The goal of this study was to investigate the impact of cadmium (Cd) contamination on plant growth responces, Cd uptake, and changes in the root anatomical structures as species-specific reaction to Cd stress. The vegetation experiment was carried out with monocotyledon Hordeum vulgare L. and dicotyledonous Lactuca sativa L. The plants were grown in quartz sand under controlled optimal growth conditions. Changes in the root structure and Cd accumulation were studied at five levels of Cd added as Cd(NO3)2 4 H2O solution in substrate. The level of Cd in the air-dry plant material was estimated by an atomic absorption spectrometer. To identify structural changes in the plant roots which were caused by Cd accumulation cross sections were cut using microtome and stained with Astra Blue/Safranin for observations using a light microscope. Barley and lettuce growth and development were significantly influenced by increasing the amount of Cd in substrate. There were differences in the ability to accumulate Cd in above-ground plant parts depending on a model object. Substrate contamination with Cd caused significant changes in the root anatomical structures. The obtained results confirmed significance of anatomical and physiological studies to reveal species-specific plant response to Cd stress to avoid heavy metal entrance in the food.

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1261–1270 K. Antoņenko, M. Duma, V. Kreicbergs and D. Kunkulberga
The influence of microelements selenium and copper on the rye malt amylase activity and flour technological properties
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The influence of microelements selenium and copper on the rye malt amylase activity and flour technological properties

K. Antoņenko¹*, M. Duma¹, V. Kreicbergs¹ and D. Kunkulberga²

¹Latvia University of Agriculture, Faculty of Food Technology, Department of Chemistry, St. Liela 2, LV-3001 Jelgava, Latvia
²Latvia University of Agriculture, Faculty of Food Technology, Department of Food Technology, St. Riga 22, LV-3002 Jelgava, Latvia
*antokrist@inbox.lv

Abstract:

 The positive effect of microelement selenium (Se) on the amylase activity and technological properties of malt is well known. Copper (Cu) is an essential microelement required for the normal functioning of living organisms, plants and most microorganisms. The aim of the current research was to investigate the interaction of two microelements – copper and selenium and its influence on the rye malt and flour properties. Rye grain of 96% viability were soaked and germinated at temperature +6 ± 2 °C for 3 days, using Se (VI) containing solution (Se concentration 8.5 mg L-1) or selenium with copper(II) containing solutions (Se concentration 8.5 mg L-1, Cu concentrations 3 mg L-1, 5 mg L-1, 10 mg L-1). After that sample were dried in the oven for 24 hours at temperature of + 73–108 °C. Control sample-germinating rye grain without microelements additives. Activity of amylase was determined in all experimental samples, because it characterizes the malt quality. Amylases are starch hydrolysing enzymes; more over there are known several amylases: α-amylases, β-amylases, isoamylases, etc. with different mechanisms of reaction. There different analytical methods were used for determination of α-amylase activity. The first was Ceralpha method (Megazyme test kits). The second method use complete reagents for quantitative determination of α-amylases (Phadebas Amylase Test). The third was iodometrical method. Different amounts of malt fortified with Se and Cu were added for investigation of rye flour technological properties. The falling number and the maximum viscosity were determined. The obtained results show that analysed additives of microelement copper decreases the enzyme activity. Analysed rye flour technological properties were better using malt only with selenium supplement.

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1271–1283 N.V. Barakova, N.N. Skvortsova and N.Y. Sharova
Extraction of biologically active compounds from fruit, berry and grain Grist using ViscoStar 150L enzyme complex
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Extraction of biologically active compounds from fruit, berry and grain Grist using ViscoStar 150L enzyme complex

N.V. Barakova¹*, N.N. Skvortsova¹ and N.Y. Sharova²

¹International Research Centre ‘Biotechnologies of the Third Millennium’, ITMO University, St. Lomonosova 9, RU 191002 Saint-Petersburg, Russian Federation
²Federal State-Funded Scientific Establishment ‘All-Russia Research Institute for Food Additives’ (FGBNU VNIIPD), Chair of Food Microingredients’ Processing, 55 Liteinii ave., RU 191014 Saint-Petersburg, Russian Federation
*Correspondence: n.barakova@mail.ru

Abstract:

 This work aimed to evaluate the efficiency of treating plant tissue with enzymatic agent ViscoStar 150L for the extraction of biologically active compounds. In the current study the screening of extraction methods from citrus fruit peels (grapefruit, lemon, orange) was performed. The samples treated with enzymatic agent ViscoStar 150L showed better extraction results than the traditional ethanol/water extraction method. Citrus peels’ extracts assayed for antioxidant activity (determined as ferric reducing antioxidant power – FRAP) decreased in the following order: grapefruit > orange > lemon. The enzymatic agent ViscoStar 150L proved to have a positive synergic effect on juice yield from cowberry previously treated with a complex pectolytic enzymatic agent. The enzymatic agent ViscoStar 150L proved to have a synergic effect on grain grist mashes previously treated with an amylolytic enzymatic agent, the inhibitor activity of the compounds produced by actinomycetic microorganisms grown on substrates based on these mashes being higher than that of previously known inhibitors.

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1284–1298 T. Evstigneeva, N. Skvortsova and R. Yakovleva
The application of green tea Extract as a source of antioxidants in the processing of dairy products
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The application of green tea Extract as a source of antioxidants in the processing of dairy products

T. Evstigneeva*, N. Skvortsova and R. Yakovleva

International Research Centre Biotechnologies of the Third Millennium ITMO University, St. Lomonosov 9, 191002, Saint-Petersburg, Russian Federation
*Correspondence: romihka@mail.ru

Abstract:

 Regular consumption of foods containing antioxidants reduces the bodily content of free oxygen radicals, which can cause pathological changes and premature organism aging. The aim of this work was the development of the formulations and determination of the parameters for the production of cottage cheese products with polyphenol fraction of green tea extract as a source of plant antioxidants. Parameters to obtain extracts with the high content of extracted substances and high antioxidant activity were determined. Optimal performance was achieved by brewing dry green tea leaves with (70 ± 2) °C water, followed by steeping at the same temperature for 10 minutes with continuous mechanical stirring. Optimal dry tea leaves to water ratio used for tea extracts’ preparation was identified. The level of tea extract in cottage cheese products’ recipes was determined. The flavour fillers which combine the best with green tea extract and taste were identified. The positive effect of tea extract component on shelf life of cottage cheese product was shown.

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1299–1305 D. Herak
Image analysis of the shapes and dimensions of Teff seeds (Eragrostis tef)
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Image analysis of the shapes and dimensions of Teff seeds (Eragrostis tef)

D. Herak

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Mechanical Engineering, Kamycka 129, CZ 16521 Prague, Czech Republic e-mail: herak@tf.czu.cz

Abstract:

 With aid of the image analysis using trio ocular microscope the dimensions, circumferences and areas in two perpendicular planes of Teff seeds were measured and based on this information the new ellipsoid model of the seed’s shape was derived and compared with measured values. From statistical analysis implies that this model on probability 0.95 is significantly identical with measured values of the Teff seeds. Determined model can help more accurately set up and developed accurate mathematical model for describing mechanical behaviour of individual seeds as well as bulk seeds.

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1306–1314 I. Jansons, V. Strazdina, R. Anenkova, D. Pule, I. Skadule and L. Melece
Development of new pig carcasses classification formulas and changes in the lean meat content in Latvian pig population
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Development of new pig carcasses classification formulas and changes in the lean meat content in Latvian pig population

I. Jansons¹*, V. Strazdina¹, R. Anenkova¹, D. Pule¹, I. Skadule² and L. Melece³

¹Institute of Food Safety, Animal Health and Environment ‘BIOR’, St: Lejupes 3, Riga LV-1076, Latvia
²Food and Veterinary Service, St. Peldu 30, LV-1050 Riga, Latvia
³Institute of Agricultural Resources and Economics, St. Struktoru 14, Riga, LV-1039, Latvia
*Correspondence: imantsjansons@inbox.lv

Abstract:

 Pig classification is based on objective estimation of the lean meat content of the carcasses. The European Union established a common framework for the classification of pig carcasses. Carcass classification serves as a quality development tool to encourage the breeding of animals, from which it is possible to get high quality carcasses for processors and consumers. It is a common practice to recalculate pig carcasses classification formulas and update existing classification methods (or develop new methods) after every five years.
The representative samples of 145 pig carcasses from all regions of Latvia were used for the dissection trial. The precisely dissected carcasses with the warm carcass weight 60–110 kg were selected according to fat thickness and gender of pigs (the sex ratio were 50% females and 50% castrated males). From the experimental data were developed new formulas for the four methods Intrascope (Optical Probe); Manual method (ZP); Pork Grader (PG200); Optigrade MCP. During sampling the average warm carcass weight was 89.31 kg. New coefficient was detected and formula was developed for calculation of carcass standard presentation in all cases if some of the carcass parts are missing; for the missing head 8.345, for the missing tail 0.072, for the missing forefeet 0.764, for the missing hind feet 1.558. The comparison between the currently used and new experimentally obtained formulas showed difference up to 1.86% in lean meat content. The results suggest high accuracy of new regression formulas, which fully meets requirements of EU legislation.

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1315–1327 S. Kampuse, L. Tomsone, Z. Krūma, M. Šabovics and I. Skrabule
Effect of lovage phenolics to formation of acrylamide in French fries
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Effect of lovage phenolics to formation of acrylamide in French fries

S. Kampuse¹*, L. Tomsone¹, Z. Krūma¹, M. Šabovics¹ and I. Skrabule²

¹Latvia University of Agriculture, Department of Food Technology, St. Rigas 22, LV-3004 Jelgava, Latvia
²Institute of Agricultural Resources and Economics, St. Zinatnes 2, LV-4126 Priekuli, Latvia
*Correspondence: skampuse@inbox.lv

Abstract:

 One of the novel methods for reduction of acrylamide in food is application of plant phenolics in technological process of Latvian plants as lovage contain significant amounts of plant phenolics and other natural antioxidants. The aim of current research was to determine the effect of lovage extracts to the formation of acrylamide in French fries. Variety ’Lenora’ potatoes were used. Potatoes were sliced and blanched in hot water (85 ± 2 °C 8 min). After blanching samples were treated with lovage water and ethanol extracts and four samples were obtained: control (without additional treatment); SW – sprayed with water extract, IMW – immersed in water extract, SE sprayed with ethanol extract. After treatment all samples were fried in oil (180 ± 2 °C) for 7 minutes. Total phenolic (TPC), vitamin C content and antioxidant activity (DPPH and ABTS) were determined for all samples before and after frying. For fried potatoes acrylamide and breaking force with texture analyser were determined. TPC of samples during frying decreased significantly but comparing fried samples the highest TPC in SE sample was determined. The highest DPPH radical scavenging activity was observed in samples treated with water extract but during frying the DPPH activity for all treated samples was lower than to control sample. The most significant changes in ABTS radical scavenging activity were observed and also the highest activity of sample SE was observed. Vitamin C content decreased significantly during frying, the highest vitamin C content in SE sample was determined. The highest maximal breaking force of fried potatoes was detected for sample IMW, but the lowest for sample SE. The lowest acrylamide content was found in sample, which was sprayed with lovage-water extract.

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1328–1346 L. Klavins, J. Kviesis, I. Steinberga, L. Klavina and M. Klavins
Gas chromatography–mass spectrometry study of lipids in northern berries
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Gas chromatography–mass spectrometry study of lipids in northern berries

L. Klavins, J. Kviesis, I. Steinberga, L. Klavina and M. Klavins*

University of Latvia, Raina blvd. 19, Riga, LV-1586, Latvia
*Correspondence: maris.klavins@lu.lv

Abstract:

 Wild berries from forests and bogs of Northern Europe are an excellent source of natural antioxidants, vitamins and fatty acids, all of which are substances with high biological activity. This study investigates lipids extracted from fresh and powdered berries, using low-polarity solvents (chloroform, diethyl ether and others) and a mixture of chloroform and methanol. Berry lipids were analysed by gas chromatography–mass spectrometry. The following berries were analysed: blueberry (Vaccinium myrtillus L.), bilberry (Vaccinium uliginosum L.), two cultivars of highbush blueberry (Vaccinium corymbosum L.), lingonberry (Vaccinium vitis-idaea L.), cloudberry (Rubus chamaemorus L.), black crowberry (Empetrum nigrum L.), cranberry (Vaccinium oxycoccos L.) and rowanberry (Sorbus aucuparia L.). One hundred and elevencompounds were identified and quantified in the 9 species of analysed berries. The lipid fraction contained compound classes like fatty acids, sterols, triterpenoids, alkanes, phenolic and carboxylic acids and carotenoids. All fresh berries contained high amounts of C18 unsaturated fatty acids (for example, up to 102 μg g-1 of blueberries) and phytosterols (86 μg of β-sitosterol g-1 of blueberries), and high amounts of benzoic acid were found in lingonberries (164 μg g-1). The analysed berry lipid profiles were compared using the principal component analysis and hierarchical cluster analysis. The two analyses showed that the lipid profiles of the studied berries reflect their taxonomy.

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1347–1360 A. Kovalcuks and M. Duma
Egg yolk oil as a source of bioactive compounds for infant nutrition
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Egg yolk oil as a source of bioactive compounds for infant nutrition

A. Kovalcuks* and M. Duma

Latvia University of Agriculture, Faculty of Food Technology, Department of Chemistry, St. Liela 2, LV3001 Jelgava, Latvia; *Correspondence: 0011103@llu.lv

Abstract:

 Egg yolk oil is a natural source of bioactive compounds such as DHA, fat–soluble vitamins, lutein, phospholipids and cholesterol. These important compounds are also found in breast milk: DHA for infant brain development, lutein for eye health, vitamins A and E to support developing cells. Egg yolk oil naturally contains vitamin D which is required for a normal bone development. Fatty acid profile of egg lipids is also close to human milk. The aim of this study was to evaluate the conformity of egg yolk oil for infant nutrition. In this study egg yolk oil extracted from liquid egg yolk using two-stage solvent extraction with polar and non-polar solvents was used. Extracted egg yolk oil was analyzed for fatty acids, fat-soluble vitamins, lutein, phospholipids and cholesterol using GC and HPLC methods. Results were compared with the chemical composition of human breast milk and nutritional recommendations for infant feeding. Fatty acid profile of egg yolk oil was similar to breast milk in terms of palmitic, stearic, linoleic and α-inolenic acids. Egg yolk oil used in this study was high in DHA, but low in ARA. Vitamin A, D and E content was sufficient for infant biological needs. Lutein and phospholipid content in egg yolk oil was lower than their content in breast milk fats, but cholesterol in opposite was in much higher concentration than available in breast milk. Chemical composition of egg yolk oil still makes it an excellent source of bioactive compounds for infant nutrition.

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1361–1371 Z. Kruma, L. Tomsone, R. Galoburda, E. Straumite, A. Kronberga and M. Åssveen
Total phenols and antioxidant capacity of hull-less barley and hull-less oats
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Total phenols and antioxidant capacity of hull-less barley and hull-less oats

Z. Kruma¹*, L. Tomsone¹, R. Galoburda¹, E. Straumite¹, A. Kronberga² and M. Åssveen³

¹Latvia University of Agriculture, Department of Food Technology, Rigas iela 22, LV-3004 Jelgava, Latvia
²Institute of Agricultural Resources and Economics, Zinatnes iela 2, LV-4126 Priekuli, Latvia
³Norwegian Institute of Bioeconomy Research, Fredrik A. St. Dahls 20, 1432 Ås, Norway
*Correspondence: zanda.kruma@llu.lv

Abstract:

 Grain products are the main source of carbohydrates but they also contain other bioactive substances such as phenolic compounds. Content of phenolic compounds differ among cereal types, varieties, and farming methods. The aim of the current study was to assess total phenolic content and radical scavenging activity in different oats and barley varieties compared to hulled ones. In the experiment hull-less varieties / lines were analysed: three barley (line ‘GN 03386’, from Norway and ‘Kornelija’, ‘Irbe’ from Latvia) and three oats varieties (‘Bikini’, ‘Nudist’, from Norway and ‘Stendes Emilija,’ from Latvia). One hulled variety of barley and oats from each country was included in the experiment for comparison. For the isolation of phenolic compounds ultrasound assisted extraction was used. For all extracts the total phenol content and DPPH, ABTS+ radical scavenging activity were determined spectrophotometrically. Overall, the highest content of total phenols was detected in hull-less barley samples. The barley variety with the highest content was line ‘GN 03386,’ followed by varieties ‘Kornelija’, ‘Irbe,’ and hulled Norwegian barley variety ‘Tyra’. High DPPH and ABTS+ radical scavenging activity was recorded in barley line ‘GN 03386’. Generally, there was strong correlation between total phenol content and ABTS˙+radical scavenging activity and moderate correlation between total phenol content and DPPH radical scavenging activity. In conclusion, the barley varieties had generally higher content of bioactive substances than oats and the barley line ‘GN 03386’ seems to be one of the best.

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1372–1383 Z. Kruma, L. Tomsone, T. Ķince, R. Galoburda, S. Senhofa, M. Sabovics, E. Straumite and I. Sturite
Effects of germination on total phenolic compounds and radical scavenging activity in hull-less spring cereals and triticale
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Effects of germination on total phenolic compounds and radical scavenging activity in hull-less spring cereals and triticale

Z. Kruma¹, L. Tomsone¹, T. Ķince¹*, R. Galoburda¹, S. Senhofa¹, M. Sabovics¹, E. Straumite¹ and I. Sturite²

¹Latvia University of Agriculture, Faculty of Food Technology, Department of Food Technology, St. Rigas 22, LV-3004 Jelgava, Latvia
²Norwegian Institute of Bioeconomy Research, St. Fredrik A. Dahls 20, Ås, Akershus, NO 1432, Norway
*Correspondence: tatjana.kince@llu.lv

Abstract:

 The aim of the current research was to evaluate changes in the content of total phenolic compounds and radical scavenging activity at different germination stages of triticale, hull-less barley, hull-less oats, wheat, and rye. Grain germination was performed for 12, 24, 36 and 48 h at controlled conditions. Ultrasound assisted extraction was used for isolation of total phenolic compounds. For all extracts the total phenolic compounds content, DPPH radical and ABTS+ radical scavenging activity were determined spectrophotometrically. The results of the experiments demonstrated that the highest content of total phenolic compounds and the highest antiradical activity was determined in hull-less barley samples. In all studied grains the content of phenolic compounds increased significantly during soaking and germination process. DPPH radical scavenging activity during germination increased. ABTS+ radical scavenging activity also increased after soaking process and dynamics were cereal type dependent. Pearson’s coefficients between the phenolic compound levels and antioxidant activity taking into account all obtained results were high. Very strong positive correlations between the content of phenolic compounds and antioxidant activity were determined for triticale during germination. Also antioxidant activity determined by both tests correlated with the highest results for barley and oats. The highest content of total phenolic compounds determines the optimum duration of germination to be 24 hours, except rye samples where the highest value was reached only after 48 hours of germination. Shorter time was required to reach the highest values of DPPH radical activity – for wheat rye, and triticale, namely 12 hours.

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1384–1395 P. Lääniste, V. Eremeev, E. Mäeorg and J. Jõudu
Effect of sowing date on oil, protein and glucosinolate concentration of winter oilseed rape (Brassica napus L.)
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Effect of sowing date on oil, protein and glucosinolate concentration of winter oilseed rape (Brassica napus L.)

P. Lääniste, V. Eremeev*, E. Mäeorg and J. Jõudu

Estonian University of Life Sciences, Kreutzwaldi 1, EE 51014 Tartu, Estonia *Correspondence: vyacheslav.eremeev@emu.ee

Abstract:

 The effect of time of sowing on oil and meal quality of winter oilseed rape (Brassica napus L. cv. Express) was investigated at the Institute of Agricultural and Environmental Sciences of the Estonian University of Life Sciences in the period of 2001–2005. The rape seeds were sown at weekly intervals on four different dates: 8th, 15th, 22nd and 29th of August. The study shows that sowing date and environmental conditions affect the seed quality of winter oilseed rape. Early sown oilseed rape plants were more adapted to stressful conditions associated with high or low temperatures. The seeds of such plants had higher oil concentration (up to 50.2%) and a lower protein concentration (approximately 19%). Plants sown in late August were less tolerant to stressful conditions and their seed oil concentration was lower (47–48% DM). Oil and protein yield were higher in the early sown crops because the seed yield was higher. Also the glucosinolate (GSL) concentration of the seeds was affected by the time of sowing and weather conditions. Shortage of rainfall before harvest increased the GSL concentration in the seeds. Plants sown in late August did not tolerate the extreme environmental conditions and their seed glucosinolate concentration appeared to increase.

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1396–1406 T. Michlová, H. Dragounová, R. Seydlová and A. Hejtmánková
The hygienic and nutritional quality of milk from Saanen goats bred in the Moravian-Silesian region
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The hygienic and nutritional quality of milk from Saanen goats bred in the Moravian-Silesian region

T. Michlová¹*, H. Dragounová², R. Seydlová² and A. Hejtmánková¹

¹Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamýcká 129, CZ165 21, Prague, Czech Republic
²Dairy Research Institute Ltd, Ke dvoru 791/12A, CZ160 00, Prague, Czech Republic
*Correspondence: michlova@af.czu.cz

Abstract:

 The aim of the study was to monitor milk yield and the hygienic and nutritional quality of milk of Saanen goats in the Moravian-Silesian region in Czech Republic. Milk samples were collected once a month during the lactation period. The average milk yield in the standardized lactation was 1,100 liters. The somatic cell count in pool samples ranged from 470 x 103 to 696 x 103. The total microorganism count ranged from 3.6 x 103 to 1.4 x 105. The pathogen Staphylococcus aureus was proven no more than in 6.3%. The highest values of all main components of milk were achieved within a relatively short time after kidding (April 2015). The average content of fat was 3.64  0.52 g 100 ml-1, 3.17  0.16 g 100 ml-1 of protein, 2.60  0.06 g 100 ml-1 of casein, 4.56  0.24 g 100 ml-1 of lactose, and 12.02  0.80 g 100 ml-1 of solids. Average content of vitamin A was 0.27  0.14 mg kg-1 and average content of vitamin E was 0.60  0.34 mg kg-1. Content of vitamin E increased almost continuously during the lactation, and the content of vitamin A was significantly higher at the end of lactation. In lyophilized milk powder the average trace metal contents were 7.76  0.92 g kg-1 Ca, 1.62  0.26 g kg-1 Mg, 15.3  1.43 g kg-1 K, 789  111 mg kg-1 Na, 23.2  2.73 mg kg-1 Zn, and 0.85  0.55 mg kg-1 Cu. Contents of minerals varied during the lactation period, but no significant trends were observed.

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1407–1418 T. Michlová, A. Hejtmánková, H. Dragounová and Š. Horníčková
The content of minerals in milk of small ruminants
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The content of minerals in milk of small ruminants

T. Michlová¹*, A. Hejtmánková¹, H. Dragounová² and Š. Horníčková¹

¹Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamýcká 129, CZ 165 21 Prague, Czech Republic
²Dairy Research Institute Ltd, Ke dvoru 791/12A, CZ 160 00 Prague, Czech Republic
*Correspondence: michlova@af.czu.cz

Abstract:

 The aim of this study was to determine and compare the content of sodium, potassium, calcium, magnesium, zinc, copper, lead, and cadmium in sheep and goat milk of different breeds from 9 farms in the Czech Republic (herds of 18–330 goat´s heads and 30–380 sheep heads). Pool samples of milk were collected once a month (April – September) during lactation in the years 2011–2013. The content of minerals was determined using atomic absorption spectroscopy. Most of the analyses of the contents of Cd and Pb were below the limit of detection. Other determined values of these two contaminants were lower than maximal tolerable amount according to previously valid regulation No. 298/1997 Sb of the Ministry of Health of the Czech Republic given for cow's milk. The contents of each element in the whole of the reference period were in a relatively wide range. Determined levels of Ca, Mg, K, Na, Zn and Cu in goat milk related to the weight of lyophilized milk powder varied from 1.40–8.08 g kg-1, 0.16–1.42 g kg-1, 8.16–31.10 g kg-1, 0.72–5.43 g kg-1, 7.59–44.10 mg kg-1, and 0.21–1.46 mg kg-1 respectively. Determined levels of Ca, Mg, K, Na, Zn and Cu in sheep milk varied from 1.69–9.13 g kg-1, 0.21–1.36 g kg-1, 3.53–11.90 g kg-1, 0.65–5.05 g kg-1, 13.70–34.30 mg kg-1, and 0.15–2.10 mg kg-1 respectively. Statistically higher (P < 0.05) content of potassium was determined in goat milk in comparison with sheep milk. The contents of all followed minerals in milk samples from each farm collected during the lactation period were very variable, but it is not possible to find any direct relationship between the content of studied elements and the date of sampling. It was found that the year has statistically significant influence especially on the content of Ca and Mg in milk of small ruminants.

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1419–1426 A.C. Olcay, G. Bilir, Ö. Taş, M. Deniz and D. Ekinci
Partial Purification of β–glucosidase enzyme from soybean (Glycine max) and determination of inhibitory effects two quercetin derivatives on enzyme activity
Abstract |
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Partial Purification of β–glucosidase enzyme from soybean (Glycine max) and determination of inhibitory effects two quercetin derivatives on enzyme activity

A.C. Olcay, G. Bilir, Ö. Taş, M. Deniz and D. Ekinci*

Ondokuz Mayıs University, Faculty of Agriculture, Department of Agricultural Biotechnology, TR 55139 Samsun, Turkey; e-mail: deniz.ekinci@omu.edu.tr

Abstract:

 Glucosidases are enzymes that catalyze the hydrolysis of the glycosidic linkage of glycosides, leading to the formation of a sugar hemiacetal or hemiketal and the corresponding free aglycon. Activity of glucosidases is crucial for several biochemical processes. Thus, discovery of new glucosidase inhibitors is crucially important owing to potential therapeutic applications of this enzyme in the treatment of diabetes, human immunodeficiency virus infection, metastatic cancer, lysosomal storage disease etc. In the current study, inhibitory potential of ‘quercetin’ and its isomeric form ’morin hydrate’ on the activity of β-glucosidase enzyme, present in the extract of soybean (Glycine max L.) seeds, were investigated. The compounds exhibited moderate inhibitory action in low milimolar concentrations. I50 values were calculated as 0.188 and 0.138 mM for quercetin and morin hydrate, respectively. The results have confirmed that these compounds can be used as leads for designations of novel glucosidase inhibitors which would be used in medicinal biotechnology and food science and technology.

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1427–1433 A. Pastukhov
The influence of heat transfer coefficient on moisture evaporation rate during the cooling of fresh baked white pan bread
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The influence of heat transfer coefficient on moisture evaporation rate during the cooling of fresh baked white pan bread

A. Pastukhov

ITMO University, Institute of Refrigeration and Biotechnologies, Department of Technological Machines and Equipment, St. Lomonosova 9, RU 191002 St. Petersburg, Russia; e-mail: artem.pastukhov1984@gmail.com

Abstract:

 Cooling rate is a very critical parameter. Low cooling rates can limit production capacity in a bakery, while higher cooling rates can lead to a higher moisture evaporation rate and result in the greater weight loss of the product. The principal objective of this work is to study the effect of heat transfer coefficients on heat and mass transfer processes, which take place in freshly baked white pan bread during its cooling.
The model of bread cooling process is built based on experimental results, Fourier’s second law for heat transfer and Fick’s second law for mass transfer. The new model allows studying what influence the heat transfer coefficient has on the cooling rate. Several dependencies are revealed and discussed in this article. Several pieces of advice for developing an air distribution system are also provided.

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1434–1441 A. Põldvere, A. Tänavots, R. Saar, S. Sild and L. Lepasalu
Effect of heat treatment at constant 120 °C temperature on the rheological and technological properties of pork
Abstract |
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Effect of heat treatment at constant 120 °C temperature on the rheological and technological properties of pork

A. Põldvere¹⋅²⋅*, A. Tänavots², R. Saar¹, S. Sild¹ and L. Lepasalu¹

¹Estonian University of Life Sciences, Institute of Veterinary Medicine and Animal
Sciences, Department of Food Science and Technology, F.R reutzwaldi 56/5,
EE51014 Tartu, Estonia
²Estonian University of Life Sciences, Institute of Veterinary Medicine and Animal
Sciences, Department of Animal Genetics and Breeding, F.R. Kreutzwaldi 62,
EE51014 Tartu, Estonia
³Estonian Pig Breeding Association, Aretuse 2, EE61411 Märja, Tartumaa, Estonia
*Correspondence: aarne.poldvere@emu.ee

Abstract:

The aim of the study was to evaluate the influence of low-temperature heat treatment on the physical and technological properties of pork. The Longissimus thoracis muscles from four pigs were used to determine the quality indicators of pork at 24 hours after slaughtering. Meat samples were cooked at constant 120 °C in a cooking bag until the internal temperatures of 62, 67, 72, 77 and 82 °C. Raw meat was the darkest and differed considerably (P < 0.05) from the heat-treated meat. The colour values of the heat-treated meat differed slightly among internal temperature phases. The ultimate pH value of raw meat also differed significantly (P < 0.05) from that of cooked meat. The pH value of cooked meat varied only within the range of 0.05 units. The electrical conductivity of muscle decreased gradually as the temperature increased. In case of heat-treated meat, the cooking loss increased considerably (from 18.88% to 31.73%) along with the increase in the internal temperature. The Warner-Bratzler shear force value was the highest (38.50 N) in the meat cooked until 77 °C, and the lowest (28.51 N) in that cooked until 67 °C. Strong negative correlation (P < 0.001) between electrical conductivity and cooking loss was observed during the heating procedure. Heat treatment can significantly decrease the electrical conductivity and increase the cooking loss of meat. Meat was the toughest when the internal temperature was 77 °C. However, the best rheological properties were observed in the meat cooked until the internal temperature of 72 °C.

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1442–1450 I. Shepelev, R. Galoburda and T. Rakcejeva
Changes in the total phenol content in the industrial potato peel wastes during the storage
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Changes in the total phenol content in the industrial potato peel wastes during the storage

I. Shepelev*, R. Galoburda and T. Rakcejeva

Latvia University of Agriculture, Faculty of Food Technology, St. Liela 2, LV-3001 Jelgava, Latvia
*Correspondence: igor_shepelev@inbox.lv

Abstract:

 As a zero value by-product from the economic point of view, potato (Solanum tuberosum L.) peel is a good source of phenols. As a manufacturing waste, potato peels are stored at the uncontrolled conditions and are exposed to the fermentative, oxidative, and microbial degradation. The aim of the present study was to determine the phenol degradation dynamics in the stored peels so the maximum storage time could be defined to achieve the efficient phenol extraction. Three different types of samples were prepared by abrasion peeling method and stored at room temperature, in open air, up to six days. Phenol extracts were obtained using ethanol-based solvent. Total phenol content was expressed as a gallic acid equivalent; antiradical activity was measured using the 2,2-diphenyl-1-picrylhydrazylradical. Results revealed that total phenols during the storage are more stable in the larger peel samples that can be stored up to two days without significant changes in the total polyphenol content and antiradical activity. Finely shredded peel demonstrated significant decrease in the total phenol amount and in the antiradical activity already on the second day of the storage. This fact indicated that in the finely shredded peel samples phenols are easily accessible to the oxidative and fermentative processes. It is possible, that after peeling there were big amounts of chlorogenic acid in the samples. When total amount of polyphenols decreased, chlorogenic acid degraded and caffeic acid was released in sufficient amount to hold antiradical activity of the extract on the high level.

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1451–1459 L. Skarkova, A. Smejtkova, D. Satrudinov and P. Vaculik
Influence of the packaging material on the quality parameters of tobacco during ageing
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Influence of the packaging material on the quality parameters of tobacco during ageing

L. Skarkova¹*, A. Smejtkova¹, D. Satrudinov² and P. Vaculik¹

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ 165 21 Prague 6-Suchdol, Czech Republic
²Novosibirsk State Agrarian University, Dobroljubova 160, RU 630039 Novosibirsk, Russian Federation *Correspondence: skarkova@tf.czu.cz

Abstract:

 Tobacco is one of the most extensively studied plant materials in the history. During its production tobacco leaf goes through many different operations from curing (drying) to ageing. Among all of them storage and ageing are very important operations. Properly stored tobacco develops its full flavour, becomes more aromatic and is ready to be sent to a customer for cigarette production. In this work changes in the quality of dried tobacco leafs during ageing (12 and 24 months) in different packaging materials are evaluated. Four samples of the FCV tobacco (Flue-Cured Virginia) grown in Northern Light Soils (NLS) region (India) were analysed. Two different liners inside of C-48 cartons – polyliner and kraft paper – were used for tobacco packaging. Quality evaluation of tobacco samples was done on the basis of analysis of chemical compo-nents (total alkaloids, reducing sugars, volatiles) and colour changing during the ageing process. Organoleptic analyses were performed as a final assessment of tobacco flavour and quality.

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1460–1466 I. Skudra and A. Ruza
Winter wheat grain baking quality depending on environmental conditions and fertilizer
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Winter wheat grain baking quality depending on environmental conditions and fertilizer

I. Skudra¹²* and A. Ruza¹

¹Latvia University of Agriculture, Faculty of Agriculture, Institute of Agrobiotechnology, St. Liela 2, LV3001 Jelgava, Latvia
²Latvian Rural Advisory and Training centre, St. Rigas 34, LV3018 Ozolnieki region, Ozolnieki parish, Ozolnieki, Latvia
*Correspondence: ilze.skudra@llkc.lv

Abstract:

Yield and quality of wheat grain depends on many factors such as environmental conditions, soil quality, genetic parameters and fertilization, especially nitrogen fertilizer which is one of the most important factor influencing quality parameters of winter wheat. Field experiments were done at the Research and Training Farm Vecauce of the Latvia University of Agriculture during 2013 till 2015. The aim of our study was to determine effect of nitrogen fertilization and environmental conditions on winter wheat (Triticum aestivum L.) variety ‘Kranich’ grain quality parameters. The investigated factors were six different nitrogen application norms (0 – control, 85, 153, 175+S21, 187 N kg ha-1) and differential nitrogen norm according to chlorophylmeter (Konica Minolta Ltd.) data 180 N kg ha-1 in 2013, 150 N kg ha-1 in 2014 and 205 N kg ha-1 in 2015. One more variant was added – 175 N kg ha-1 in 2015. During the study years the meteorological conditions were significantly different. Our trials results showed that protein content suitable for bread making was obtained in variants N175+S21, 180 and 187 in year 2013, in all N application forms in 2014, but in 2015 – in all applications except N0, N175+S21, N85. The meteorological conditions had factor influence (2) 46% on protein content, but fertilizer application – 35%. Strong significant relationship at the 0.01 probability level between protein content and gluten content (r = 0.99), sedimentation value (r = 0.97) and falling number (r = 0.74) was found.

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1467–1474 L. Strauta, S. Muižniece-Brasava and I. Gedrovica
Physical and Chemical Properties of Extruded Pea Product
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Physical and Chemical Properties of Extruded Pea Product

L. Strauta*, S. Muižniece-Brasava and I. Gedrovica

Latvia University of Agriculture, Faculty of Food technology, St. Liela 2, LV-3002 Jelgava, Latvia; *Correspondence: strauta.liene@gmail.com

Abstract:

 Peas (Pisum sativum L.) are a good source of protein, dietary fibre, and certain minerals, thus making them valuable nutrients in human diet. Unfortunately, peas are not commonly used in human diet due to their long cooking time. New products should be manufactured to increase the presence of peas in human diet. In order to make the grey peas easier for people to consume, extrusion cooking was used. Due to varying recipes, different products were obtained. Peas of the variety ‘Bruno’ with and without the addition of wheat and oat flour and egg powder were used in the experiments. Protein, fat and starch content of these products was analysed chemically but their pH, size, hardness, and volume mass was measured using physical methods. The average pH for all the samples was 7.3 ± 0.5, size differences ranged from 5.4 ± 0.4 mm to 10.3 ± 0.5 mm in length and 6.4 ± 0.2 to 11.7 ± 0.8 mm in width. More fat was found in the sample with onion flavour – up to 9.5 ± 0.5 g 100 g-1 – but the least amount of fat was found in the sample without any seasoning – 0.6 ± 0.05 g 100 g-1 on average. The average starch content was 23 ± 2 g 100 g-1, while the highest protein content was discovered in the sample where grains and egg powder had not been added – 26.9 ± 0.2 g 100 g-1, and the lowest – 18.6 ± 0.5g 100 g-1 – in the sample with the largest grain proportion. The samples with the highest volume mass were the ones with added egg powder – 43 ± 2 N and 387 ± 2 g L-1. The obtained results show that the largest and crispiest sample was acquired using only pea flour, and pea and wheat flour mixed in the proportion 1:1.

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1475–1487 D. Tomruk, E. Devseren, M. Koç, Ö.Ö. Ocak, H. Karataş and F. Kaymak-Ertekin
Developing a household vacuum cooking equipment, testing its performance on strawberry jam production and its comparison with atmospheric cooking
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Developing a household vacuum cooking equipment, testing its performance on strawberry jam production and its comparison with atmospheric cooking

D. Tomruk¹, E. Devseren¹, M. Koç², Ö.Ö. Ocak¹, H. Karataş³ and F. Kaymak-Ertekin¹*

¹Ege University, Faculty of Engineering, Food Engineering Department, TR 35100 Bornova-İzmir, Turkey
²Adnan Menderes University, Faculty of Engineering, Food Engineering Department, TR 09010 Aydın, Turkey
³Arçelik A. Ş., R&D Center, TR 34940 İstanbul, Turkey
*Correspondence: figen.ertekin@ege.edu.tr

Abstract:

 In this research, the performance of a kitchen appliance cooking equipment prototype, which can operate either under vacuum or at atmospheric pressure, is aimed to be developed and tested on strawberry jam production. Vacuum cooking applications were carried out at two different conditions as 17.5 and 25 minutes at 75 °C. Strawberry jam was also cooked at atmospheric pressure for 5, 10, 15 and 20 min. The effect of cooking conditions under vacuum and atmospheric pressure was determined by the following analysis; brix, color (L*, a*, b*) values, chroma (C*), hue (h°), pH value, titratable acidity, reducing and total sugar content (%), hydroxymethylfurfural content (HMF) and sensorial analysis. When the strawberry jam that is produced at atmospheric pressure is compared to the ones that are produced under vacuum, atmospheric cooked jam got higher Brix and was more viscous depending on the applied elevated temperature. HMF content of jam produced at atmospheric pressure was also found to be excessively high compared to the jam produced under vacuum. As it has been foreseen in the beginning of the study, vacuum cooking has been effective in reducing the HMF content of the strawberry jam due to the low temperature application. Sensorial quality of the vacuum-processed strawberry jam was superior in terms of color, appearance, consistency, taste and overall acceptance comparing to the atmosphere processed jams. This data could be utilized to contribute to the development of a household vacuum cooking equipment and the opportunity to produce with less harmful ingredients in home environment.

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1488–1497 P. Vaculik, L. Chladek, M. Prikryl, A. Smejtkova and P. Brany
The temperature changes of barley malt during its disintegration on a two roller mill
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The temperature changes of barley malt during its disintegration on a two roller mill

P. Vaculik*, L. Chladek, M. Prikryl, A. Smejtkova and P. Brany

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ 165 21 Prague 6-Suchdol, Czech Republic; *Correspondence: vaculik@tf.czu.cz

Abstract:

This article discusses the change of temperature during disintegration on two roller mill. The production of barley and its treatment to malt is first step of beer brewing. The malt is the produced in malt plants. Crushing the malt is realized in only the brewery and is a core activity of brewing technology. This operation is performed both in craft breweries and in industrial brewery. This article therefore is focused on the theory of crashing solid phase with a respect of development of heat. Grinding barley malt is realised using mills of various designs or disintegrators. They are widely used mills with 2, 4, 5, 6 grinding cylinders. These roller mills are used in many other applications, not only in industrial food or drink production. For next treatment solid phase should be broken into smaller pieces (comminuted). The greater the extent of comminution, the large the surface area for impact on next treatment. The amount of mechanical energy converted to heat energy depends on the principle of the process disintegration and other parameters, i.e. distance of grinding gap, capacity, mechanical properties of crashing material etc. For these reasons, it is important to pay attention to the temperature change of barley malt during its disintegration on a mill.

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1498–1508 K.K. Vursavus and Z. Kesilmis
Modeling of impact parameters for nondestructive evaluation of firmness of greenhouse tomatoes
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Modeling of impact parameters for nondestructive evaluation of firmness of greenhouse tomatoes

K.K. Vursavus¹* and Z. Kesilmis²

¹University of Çukurova, Faculty of Agriculture, Department of Agricultural Machinery and Technologies Engineering, 01330 Adana, Turkey
²University of Osmaniye Korkut Ata, Faculty of Engineering, Department of Electrical and Electronics Engineering, Karacaoglan Campus, Fakiusagi, Osmaniye-Turkey
*Correspondence: kuvursa@cu.edu.tr

Abstract:

In this research, the potential of a nondestructive method for predicting firmness using impact parameters taken by a low-mass lateral impact device was explored. The tests were carried out on Bandita F1 greenhouse tomato variety at different maturity stages. In the nondestructive impact measurements, impact acceleration and contact time were sensed by an accelerometer attached on impact head, and main impact parameters such as maximum impact acceleration (A), time required to reach maximum acceleration (t) and contact time (tc) were extracted from the impact acceleration-contact time curves. Other impact parameters were derived through the theory of elasticity. These nondestructive impact parameters were compared with destructive reference parameters for predicting firmness of tomatoes. Force-deformation ratio at rupture point was used in the measurements of destructive reference parameter and this was expressed to be tomato firmness. A total of 10 (𝐴,𝑡,𝑡𝑐, 𝐴/𝑡, 𝐴/𝑡𝑐, 𝐴/𝑡2, 𝐴/𝑡𝑐2, (1/𝑡)2.5, (𝐴/𝑡)1.25, 𝐴2.5) measured and derived impact parameters were analyzed with the destructive reference test. A correlation matrix, stepwise regression and multiple linear regression were used for statistically evaluation. The effect of maturity stages on firmness and impact parameters was investigated by ANOVA test. Statistical analysis showed that the correlations between destructive reference and nondestructive impact parameter test results were significant at 1% level except t and (1/𝑡)2.5. The number of parameters being processed was reduced with stepwise regression analysis. The best model using MLR on variables /𝑡, 𝐴/𝑡𝑐2, and 𝐴2.5 was selected for predicting tomato firmness. As a result, low-mass impact device tested in the laboratory conditions gave high prediction of firmness for greenhouse tomato.

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