Volume 16 (2018)
  Special Issue 2

Full text of the journal: Volume 16 Special Issue 2

Contents


Pages

1301-1311 A. Aboltins, T. Rubina and J. Palabinskis
Shrinkage effect on diffusion coefficient during carrot drying
Abstract |
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Shrinkage effect on diffusion coefficient during carrot drying

A. Aboltins¹, T. Rubina²* and J. Palabinskis¹

¹Latvia University of Life Sciences and Technologies, Faculty of Engineering, Institute of Agricultural Machinery, J.Cakstes Blv 5, LV-3001 Jelgava, Latvia
²Latvia University of Life Sciences and Technologies, Faculty of Information Technologies, Department of Computer Systems, Liela 2, LV-3001 Jelgava, Latvia
*Correspondence: tatjana.rubina@llu.lv

Abstract:

Many studies have been previously carried out on the carrot drying and the undergoing processes. The developed mathematical models provide an opportunity to gain an understanding of this complex process and its dynamics. But they are simplified and based on a number of assumptions, including calculation of diffusion coefficient values. In one of the previous studies, the authors of this study determined that the diffusion coefficient is linearly dependent on the moisture concentration with the assumption that the sample’s geometric shape does not change. The aim of this study is to determine the dependence of the diffusion coefficient on the moisture concentration taking into account the change in sample thickness during the drying experiment. The experiments were carried out with carrot slices of three different thicknesses: 5 mm, 10 mm and 15 mm thickness on the film infrared dryer at temperature 40 °C. During the experiments, measurements of the weight and thickness of the slices were performed. Using the experimental data the average thickness and diffusion coefficient of slices was calculated depending on the moisture concentration. Obtained results show that thickness depends linearly on the moisture concentration. Using experimental data and obtained average values of samples thickness, the values of diffusion coefficient was calculated. The results indicate that diffusion coefficient value depend linearly on moisture concentration. Their values are close and tend to zero when the concentration decreases if the thickness changes are taken into account during the experiment.

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1312-1321 P. Adadi, E.G. Kovaleva, T.V. Glukhareva and N.V. Barakova
Production and investigations of antioxidant rich beverage: utilizing Monascus purpureus IHEM LY2014-0696 and various malts
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Production and investigations of antioxidant rich beverage: utilizing Monascus purpureus IHEM LY2014-0696 and various malts

P. Adadi¹*, E.G. Kovaleva², T.V. Glukhareva² and N.V. Barakova¹

¹Department of Food Biotechnology for Plant Origin Products, Faculty of Food Biotechnologies and Engineering, ITMO University, Lomonosova street 9, RU191002, St. Petersburg, Russia Federation
²Department of Technology for Organic Synthesis, Institute of Chemical Engineering, Ural Federal University, Mira street 19, RU620002 Yekaterinburg, Russia Federation
*Correspondence: pariseadadi@gmail.com

Abstract:

Antioxidant evokes numerous health benefits to the consumer as well as stabilisation of the beverages flavours. Therefore, this paper provides detailed information on the application of Monascus purpureus IHEM LY2014-0696 in combination with various malts in brewing antioxidant rich beverage (ARB). Starter culture Angkak was prepared by solid state bioprocessing (SSB). Single infusion method of mashing was used. Physicochemical parameters, volatile compounds, DPPH (2, 2-diphenyl-1-picrylhydrazyl) radical scavenging activity and fermentability of the wort were evaluated. Distillation procedure based on pycnometry technique was use to quantify the alcohol content (%ABV). Fermentability of the wort was found to be 97.6 ± 0.46% whilst %ABV was equal to 5.42 ± 0.03. It was observed that ARB showed a strong DPPH radical scavenging activity of 1.00 × 10–4 mol × equ (R2 = 0.91) whereas 3.43 × 10–5 mol × equ (R2 = 0.81) for wort. The strong antioxidant activity (AOA) is thought to be caused by pigments produced by M. purpureus IHEM LY2014-0696 and other compounds originated from the malts and hops utilised in brewing ARB. A total of 4 volatile compounds were identified in the present study. Incidence of microbial load ranged from 2.14 ± 0.04 × 107 and 0.8 ± 0.1 × 105 for M. purpureus IHEM LY2014-0696 and bacterial respectively was observed in the ARB. This study contradicts some previous ones, as the ARB brewed did not take the red pigment produced by the M. purpureus. Panellists generally expressed their acceptance for the ARB as they assessed it as a new product, moreover, taking account its health benefits.

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1322-1330 I. Augšpole, M. Dūma and B. Ozola
Bioactive compounds in herbal infusions
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Bioactive compounds in herbal infusions

I. Augšpole*, M. Dūma and B. Ozola

Latvia University of Life Sciences and Technologies, Faculty of Food Technology, Department of Chemistry, Liela iela 2, LV-3000, Jelgava, Latvia
*Correspondence: ingrida.augspole@llu.lv

Abstract:

Herbal teas are very popular and known as important source of biologically active compounds. Some of popular Latvian herbal teas: Calendula (Calendula officinalis L.), Matricaria chamomilla (Matricaria chamomilla), Lady’s-mantle (Alchemilla vulgaris L.), Jasmine (Jasminum officinale L.), Yarrow (Achillea millefolium L.) and Linden flowers (Tilia spp.) were selected for analysis. This study was carried out with the aim to investigate the effect of extraction time (10, 15, 20 min) on the content of total flavonoids and total phenols as well as antioxidant activity of herbal tea extracts. The infusions were prepared by usual domestic preparation technique using ground air-dried plant materials and boiling deionized water (0.055 μS cm-1) for extraction. Content of total flavonoids, total phenols and antioxidant activity was determined spectrophotometrically. Dry matter content was determined in lyophilized herbal infusions. The obtained results indicated that extraction time did not affected the content of biologically active compounds in the herbal infusions significantly (P > 0.05). The highest level of flavonoids was found in Jasmine and Lady’s-mantle infusions (average 104.98 ± 9.21 mg quercetin equivalent 100 g-1 and 115.28 ± 5.25 QE mg 100 g-1 respectivelly), while the lowest was determined in Matricaria chamomilla extract – (average 70.10 ± 4.68 QE mg 100 g-1). Lady’s-mantle tea contained the largest amount of total phenols (average 4126.62 ± 26.24 mg gallic acid equivalents 100g-1), the lowest – Calendula tea 1828.04 ± 10.37 mg GAE 100 g-1). Data analysis showed a close linear positive correlation between the content of total flavonoids and total phenols in herbal infusions (R2 = 0.872; r = 0.934) with the probability of 99%. In general, all samples tested in this study, demonstrated high level of antioxidant activity (from 75.04 to 91.54 mmol Trolox equivalents 100 g-1). Results of the present experiments demonstrated that content of dry matter in analysed herbal teas was significantly different (P < 0.05).

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1331-1340 I. Beitane, G. Krumina–Zemture and M. Sabovics
Effect of germination and extrusion on the phenolic content and antioxidant activity of raw buckwheat (Fagopyrum esculentum Moench)
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Effect of germination and extrusion on the phenolic content and antioxidant activity of raw buckwheat (Fagopyrum esculentum Moench)

I. Beitane¹*, G. Krumina–Zemture¹ and M. Sabovics²

¹Latvia University of Agriculture, Faculty of Food Technology, Department of Nutrition, Riga Street 22, LV–3004 Jelgava, Latvia
²Latvia University of Agriculture, Faculty of Food Technology, Department of Food Technology, Riga street 22, LV–3004 Jelgava, Latvia
*Correspondence: ilze.beitane@llu.lv

Abstract:

The aim of the research was to determine the total phenolic content, antioxidant activity and phenolic compounds in raw and germinated common buckwheat grain and their extruded products in order to estimate the effect of germination and extrusion on the total phenolic content, antioxidant activity and phenolic compounds in buckwheat. A total of 10 buckwheat samples were analysed, where the raw buckwheat grain was the control sample, four samples were germinated and then extruded. The total phenolic content was determined using the Folin–Ciocalteu assay. The antioxidant activity was determined using a micro plate assay and phenolic compounds with Liquid Chromatography –Time of Flight Mass Spectrometer method.
The results showed that germination of buckwheat significantly affected the total phenolic content, antioxidant activity, radical scavenging activity and content of phenolic compounds. The decrease of the total phenolic content, antioxidant activity, radical scavenging activity and the content of some phenolic compounds depended on germination time – 48 h of germination provided greater concentrations at the end of a 24 h germination period, whereas the content of some phenolic compounds like rutin, quercetin and vitexin increased substantially after germination, besides, the increase of phenolic compounds depended on the germination time. In total 26 different phenolic compounds were detected in raw and germinated buckwheat samples and only one compound with an m/z value 385.1282 was unidentified. The data of extrusion revealed a significant decrease of total phenolic content, antioxidant activity, radical scavenging activity and phenolic compounds content in buckwheat samples (P < 0.05). In the extruded buckwheat samples novel phenolic compounds like 4–hydroxybenzoic acid, homovanillic acid, catechin, ferulic acid, and hyperoside were detected.

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1341-1350 L. Chladek, P. Vaculik and A. Vagova
The measurement of energy consumption during milling different cereals using the sieve analyses
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The measurement of energy consumption during milling different cereals using the sieve analyses

L. Chladek*, P. Vaculik and A. Vagova

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 21 Prague 6 - Suchdol, Czech Republic
*Correspondence: chladekl@tf.czu.cz

Abstract:

This paper deals with the measurement of energy consumption required for disintegration of different cereals depending on the desired fineness of obtained grist. The energy consumption necessary for milling was compared with the results of a sieve analysis before and after the disintegration process. The obtained results were compared with energy expended during the disintegration of cereals and were analysed to determine the coefficients of the ratio of fineness of milling/energy consumption. They was found to have good conformity. Special attention was paid to the RRSB distribution for determination of statistic average particle size and specific area of malt grist. Specific area of grist particles from different cereals was determined by calculation of the limited area and x axis in diagrams, this effort is necessary for optimisation of the disintegration process with impact on the quality of final food.

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1351-1359 B. Dalecka and L. Mezule
Study of potential PCR inhibitors in drinking water for Escherichia coli identification
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Study of potential PCR inhibitors in drinking water for Escherichia coli identification

B. Dalecka* and L. Mezule

Riga Technical University, Faculty of Civil Engineering, Water Research laboratory, Kipsalas 6A-263, LV-1048 Riga, Latvia
*Correspondence: brigita.dalecka_1@rtu.lv

Abstract:

In the last few decades, the polymerase chain reaction (PCR) has become one of the most powerful molecular biological tools. However, the PCR is an enzymatic reaction and therefore sensitive to inhibitors which may occur in drinking water samples. In this work, the possible inhibition effect of chlorine, humic acids, and iron for real-time PCR (qPCR) efficiency was studied and the environmental sample from drinking water treatment system before iron removal was selected and analysed. The results demonstrated that the highest concentrations of humic acids (5 mg L-1 and 1 mg L-1) and iron (4 mg L-1) inhibited the PCR reaction while no effect of chlorine was observed. The analysis of the environmental sample with spiked Escherichia coli cells demonstrated reduction efficiency of the average threshold cycle (Ct) values compared with control dilution series determining the possible inhibition for qPCR assay.

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1360-1372 N. Dubrovskaya, O. Savkina, L. Kuznetsova and O. Parakhina
The development of gluten-free sourdough bread technology with rowan powder
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The development of gluten-free sourdough bread technology with rowan powder

N. Dubrovskaya¹, O. Savkina²*, L. Kuznetsova² and O. Parakhina³

¹Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya street 29, RU195251 St. Petersburg, Russia
²St. Petersburg Branch, State Research Institute of the Baking Industry, Podbelskogo Highway 7, RU196608 St. Petersburg, Pushkin, Russia
³Institute of Refrigeration and Biotechnologies, ITMO University, Lomonosova street 9, RU191002 St. Petersburg, Russia
*Correspondence: 1103savkina@mail.ru

Abstract:

A new form of technology was developed which focused on gluten-free bread with gluten-free sourdough and rowan powder (from the botanical species Sorbus aucuparia). This new form of technology allows organoleptic characteristics to be improved, along with structure, texture, microbial spoilage resistance, and the shelf life of gluten-free bread. The gluten-free dry microbial composition with lactic acid bacteria was developed as a starter for sourdough. The lactic acid bacteria, L. brevis E38, was experimentally selected for dry microbial composition on the basis of its antagonistic activity against ropy bread disease pathogens (B. subtilis and B. licheniformis). The dependence was revealed of the accumulation of acetic acid and lactic acid in the sourdough on the microbial composition during fermentation. A gluten-free sourdough technology was developed which involved a new starter, rice, and soy flour at a ratio of 0.2:2:1. It was shown that the use of soy protein slows down the fermentation process in the sourdough. An increase – in acidity levels of between 7.5–9.5 times higher in the dough with sourdough and rowan powder when compared to dough without sourdough. Sourdough usage allowed compressibility of the crumb to be increased by between 1.8–2 times, with a specific volume of 19.0% and a porosity of 9.8% and 11.5%, and for the sensory characteristics to be improved as perceived by consumers. It was proved that microbial composition with a lactic acid bacteria, L. brevis E38, inhibits ropy disease and mould development in bread. The results of the present study showed that the addition of sourdough and rowan powder can be used to improve the quality of gluten-free bread.

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1373-1382 A. Hejtmánková, J. Táborský, V. Kudelová and K. Kratochvílová
Contents of tocols in different types of dry shell fruits
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Contents of tocols in different types of dry shell fruits

A. Hejtmánková*, J. Táborský, V. Kudelová and K. Kratochvílová

Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamýcká 129, CZ165 00, Prague, Czech Republic
*Correspondence: hejtmankova@af.czu.cz

Abstract:

The aim of this study was to identify all forms of vitamin E in different kinds of dry shell fruits (generally called ‘nuts’) obtained from different sources and to perform their mutual comparison. All tocols were determined by reversed phase HPLC using isocratic elution with fluorescence detection. Almonds were evaluated as the most important source of α-tocopherol (average value 1,132 mg kg-1), β-tocopherol was present in all samples as a minor component, its maximum content was found in hazelnuts (9.6 mg kg-1). γ-Tocopherol was found in all kinds of nuts and the highest content was found in pistachios (584 mg kg-1), very high amount of δ-tocopherol was contained in Brazil nuts (2,298 mg kg-1). Tocotrienols were found in a smaller number of nut kinds than tocopherols. α-Tocotrienol was found only in three kinds of nuts – Brazil nuts, which contained the highest amount (399 mg kg-1), pine nuts and hazelnuts grown in the Czech Republic, which were analyzed soon after harvest. Similarly, γ-tocotrienol was determined only in four kinds of nuts (pistachios, macadamias, cashew and walnuts grown in the Czech Republic), which were analyzed soon after harvest; the most significant amount was found in pistachios (34.8 mg kg-1), β- and γ-tocotrienols were below the detection limit. In the Czech Republic, walnuts and hazelnuts are the most widely cultivated and consumed nuts. While in walnuts the most important form is γ-tocopherol (459 ± 40 mg kg-1), in hazelnuts it is α-tocopherol (863 ± 10 mg kg-1).

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1383-1387 D. Herak, C. Mizera, P. Hrabe and A. Kabutey
3D image analysis of the shapes and dimensions of several tropical fruits
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3D image analysis of the shapes and dimensions of several tropical fruits

D. Herak¹*, C. Mizera¹, P. Hrabe² and A. Kabutey¹

¹Czech University of Life Science Prague, Faculty of Engineering, Department of Mechanical Engineering, Kamycka 129, CZ16521 Prague, Czech Republic
²Czech University of Life Science Prague, Faculty of Engineering, Department of Mechanical Engineering, Kamycka 129, CZ16521 Prague, Czech Republic
*Correspondence: herak@tf.czu.cz

Abstract:

Three dimension virtual models of Avocado (Persea americana), Salak (Salacca zalacca), Dragon fruit (Hylocereus undatus), Mango (Mangifera indica), Coconut (Cocos nucifera) using 3D scanner Intel RealSense were determined. Calculated models based on arithmetic and geometric diameter were also determined. From statistically analysis implies that virtual models on significance level 0.05 are significantly different with calculated values based on arithmetic or geometric diameter.

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1388-1395 T. Kince, E. Straumite, D. Klava, Z. Kruma, K. Abelniece and A. Balgalve
Effects of processing conditions on physical parameters of triticale flakes
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Effects of processing conditions on physical parameters of triticale flakes

T. Kince¹, E. Straumite¹*, D. Klava¹, Z. Kruma¹, K. Abelniece² and A. Balgalve²

¹Latvia University of Life Sciences and Technologies, Faculty of Food Technology, Department of Food Technology, Rigas iela 22, LV-3004 Jelgava, Latvia
²Ltd Felici, Rigas gatve 8, LV-2164 Adazi, Adazu novads, Latvia
*Correspondence: evita.straumite@llu.lv

Abstract:

Consumer interest in breakfast cereal flakes has increased during the last few years. Various technologies, used to produce flakes, significantly influence their quality parameters and shelf-life stability. The main purpose of the present research was to investigate how different processing methods affect the physical parameters of triticale flakes. For obtaining the flakes, cleaned whole triticale grains were treated using the following technologies: dry processing (hot air), steam processing and soaking with subsequent steaming. For preparing the flakes different kilning methods and traditional flaking rolls were used. Traditionally made rolled and dried whole grain triticale flakes were analysed as a control sample. Using standard methods, the flakes’ moisture content, water activity, microstructure, swelling capacity and colour changes were analysed. The gap settings of flake rollers do not influence significantly (P < 0.05) changes of starch during processing. However, the starch granules were fully transformed into sugars in the flake samples with greater thickness. Non-significant (P < 0.05) steaming and hot air drying (toasting) conditions’ effects were observed on the changes of the starch granules during processing. Strong correlation was determined during the analysis of water activity and moisture content. The moisture content of the ready- to-eat flakes varied from 2.54% to 10.66%, and the water activity value was from 0.108 to 0.494. Compared with traditionally processed flakes (control sample) the colour of the flakes prepared using other technologies changed significantly, the ΔE values varied from 9.587 to 18.554. The colour of the soaked-steamed-rolled-hot air dried samples was similar but those significantly differed from the colour of soaked-dried-rolled-hot air dried flake samples. The soaked-dried-rolled-hot air dried flakes were darker compared with other analysed flake samples.

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1396-1404 O. Krasulya, I. Potoroko, L. Tsirulnichenko, S. Khmelev, V. Bogush and S. Anandan
Sonochemical effects on food emulsions
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Sonochemical effects on food emulsions

O. Krasulya¹, I. Potoroko², L. Tsirulnichenko²*, S. Khmelev³, V. Bogush¹ and S. Anandan⁴

¹Moscow State University of Technologies and Management named after K.G. Razumovskiy, Department of Regulation of roar of food products and examination of goods, 73, Zemlyanoy Val., RU109004 Moscow, Russia
²South Ural State University, Higher School of Medicine and Biology, Department of Food and Biotechnology, 85 Lenin Avenue, RU454080 Chelyabinsk, Russia
³Altai Technical University, Lenin Avenue, 46, RU656038 Biysk, Russia
⁴Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Tiruchirappalli, IN620 015, India
*Correspondence: linchikz@mail.ru

Abstract:

Acoustic cavitation of food emulsions is widely applied as the main processing method to improve the quality of a finished product and its organoleptic characteristics, as well as to increase production performance. To identify the optimal modes of ultrasonic emulsification, we propose a model of emulsion droplet breakup in an acoustic cavitation field, which allows us to determine the dependence of emulsion droplets’ diameter on exposure time and intensity of action. The developed models enabled us to pioneer complex research of the dependence of emulsion droplets’ diameter on time given the maximum radius of cavitation bubbles and physical properties of liquid phases in the emulsion composition. We carried out the first complex theoretical and practical research of how shapes and positions of absolutely fixed boundaries influence the propagation of oscillations in a activating liquid medium (food emulsion). To verify the adequacy of the obtained theoretical models, we studied the dependence of emulsion droplets’ breakup rate (by the example of a model water/oil emulsion) on the exposure time and the intensity of ultrasonic action. The calculation results revealed that the results of a series of experiments and the results obtained with the use of the developed mathematical model are consistent. Based on the theoretical data obtained, we designed an industrial flow- type acoustic cavitation device aimed at acting on food emulsions; it differs from analogous devices in that it has within it a cylindrical wave acting through solid walls of the tunnel for transmitting processed liquid.

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1405-1416 Z. Kruma, R. Galoburda, L. Tomsone, I. Gramatina, S. Senhofa, E. Straumite, D. Klava, T. Kince, I. Cinkmanis, J. Zagorska and D. Kunkulberga
Changes in the nutritional value of breakfast cereals containing germinated spring grain flakes during storage
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Changes in the nutritional value of breakfast cereals containing germinated spring grain flakes during storage

Z. Kruma*, R. Galoburda, L. Tomsone, I. Gramatina, S. Senhofa, E. Straumite, D. Klava, T. Kince, I. Cinkmanis, J. Zagorska and D. Kunkulberga

Latvia University of Life Sciences and Technologies, Faculty of Food Technology, Department of Food Technology, Rigas iela 22, LV-3004 Jelgava, Latvia
*Correspondence: zanda.kruma@llu.lv

Abstract:

The aim of current research was to assess the nutritional value of breakfast cereals containing germinated spring grain flakes and its changes after 6 month storage. Three types of breakfast cereals were prepared and packaged in two types of Standup pouches – Pap50g/Alu7/Pe60 (AL), Pap40g/PELD20/PE40 (PE). For the accelerated shelf life test the samples were stored at 35 ± 2 °C and dietary fibre, protein, fat, B-group vitamins, sugars, total phenol content and DPPH, ABTS+ radical scavenging activity were determined. Developed breakfast cereals have high nutritional value and all are high in fibre and thiamine. Additionally, sample S2 is source of protein, riboflavin, niacin, and S3 – is source of riboflavin and high in niacin. Comparing total phenolic content and antioxidant capacity of tested samples S3 showed the highest values. Storage and selected packaging influenced stability of nutrients, and for S1 and S2 AL showed better results whereas for S3 – PE.

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1417-1424 Z. Kruma, E. Straumite, T. Kince, D. Klava, K. Abelniece and A. Balgalve
Influence of Technological Parameters on Chemical Composition of Triticale Flakes
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Influence of Technological Parameters on Chemical Composition of Triticale Flakes

Z. Kruma¹*, E. Straumite¹, T. Kince¹, D. Klava¹, K. Abelniece² and A. Balgalve²

¹University of Life Sciences and Technologies, Faculty of Food Technology, Department of Food Technology, Rigas iela 22, LV-3001, Jelgava, Latvia
²Ltd Felici, Rigas gatve 8, LV-2164, Adazi, Adazu novads, Latvia
*Correspondence: zanda.kruma@llu.lv

Abstract:

Triticale is hybrid crop developed by crossing wheat (Triticum) and rye (Secale) and in last years it become more popular for food applications, including flake production. Different approaches are developed to improve flakes technology by applying different cooking, rolling, toasting parameters resulting in high quality products. All these technologies influence also nutrition quality of product due to the different stability of these compounds during mechanical and thermal treatment. The aim of current experiment was to investigate the influence of technological parameters on chemical composition of triticale flakes. In current experiment triticale grains and triticale flakes obtained by different technologies was tested. For evaluation of the influence of technological parameters, different flaking and rolling parameters were tested. For all samples were determined composition of basic nutrients (fats, proteins, fibres, sugars, ash), minerals (Ca, Mg, K, Zn, P), vitamins, total phenolics and antioxidant activity. Triticale has high nutritional quality, containing significant amounts of protein, fibres, vitamins and minerals. Technological processes significantly influence cereals composition, but it depends on parameters tested. Control sample showed lower results and hierarchical cluster analyses showed that samples 1/3/1, 2/1/2/1, 2/1/3/1, 2/1/4/1 are similar in composition of bioactive compounds. Results showed that for selection of the best method for flaking physical and/or sensory properties should be taken in account.

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1425-1434 G. Krumina–Zemture, I. Beitane and I. Cinkmanis
Flavonoids and total phenolic content in extruded buckwheat products with sweet and salty taste
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Flavonoids and total phenolic content in extruded buckwheat products with sweet and salty taste

G. Krumina–Zemture¹*, I. Beitane¹ and I. Cinkmanis²

¹Latvia University of Agriculture, Faculty of Food Technology, Department of Nutrition, Riga street 22, LV–3004, Jelgava, Latvia
²Latvia University of Agriculture, Faculty of Food Technology, Department of Chemistry, Liela street 2, LV–3001, Jelgava, Latvia
*Correspondence: gita.krumina@llu.lv

Abstract:

The aim of research was to evaluate the effect of added ingredients used for taste improvement on flavonoids and total phenolic content in extruded buckwheat products. The added ingredients were – sugar, vanilla sugar, stevia, agave syrup, cinnamon, caraway, garlic powder, sweet pepper powder and salt. Six extruded buckwheat products were analysed, where an extruded buckwheat product without added ingredients was a control sample, two extruded buckwheat products were with sweet taste and three products with salty taste. Total phenolic content was determined using the modified Folin–Ciocalteu method but flavonoid content according to LC-TOF-MS method.
The highest total phenolic content (p < 0.05) was determined in extruded buckwheat product with vanilla sugar + stevia (91.17 ± 0.67 GAE mg 100g-1DW). It was almost three times higher than in the control sample. The significant differences were observed in extruded buckwheat products with caraway + salt + agave syrup (41.5 ± 0.12 GAE mg 100g-1DW) and sweet pepper powder + salt + agave syrup (42.39 ± 0.80 GAE mg 100g-1DW) comparing to other extruded products (p < 0.05). The highest content of rutin and quercetin (p < 0.05) was established in extruded buckwheat product with garlic powder + salt + agave syrup, whereas the highest content of catechin and epicatechin – in extruded buckwheat product with vanilla sugar + stevia. The extruded buckwheat product with caraway + salt + agave syrup in addition contained luteolin, kaempferol and isoquercitrin. The results of research showed that some added ingredients used for taste improvement can significantly influence the total phenolic content and flavonoid content.

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1435-1443 M.V. Lugova and T.P. Arseneva
Development of the composition and technology of the frozen dessert without sugar, using sesame flour
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Development of the composition and technology of the frozen dessert without sugar, using sesame flour

M.V. Lugova and T.P. Arseneva*

Saint-Petersburg National Research University of Information Technologies, Mechanics and Optics, Department of Applied Biotechnology, 9, Lomonosova street, RU191002 St. Petersburg, Russian Federation
*Correspondence: tamara-arseneva@mail.ru

Abstract:

The article presents the results of the analysis of the entry dose of stevioside, topinambur syrup, sesame flour and the type of stabilizer added to the milk ice cream formula, theoretically calculated, using solids according to GOST 31457-2012 for development of a functionally oriented dessert with low content of fat and without sugar. It has been established that the entry dose of the stevioside and the topinambur syrup in an amount of 0.03 and 5% respectively to the mixture mass of the frozen dessert allows us to get the product with pleasant flavor and scent. The use of the PGX-1 stabilizer (Germany) with an entry dose of 0.4 to the mixture mass allows us to get the product with the best indicators for whipping, thawing resistance, density and uniformity of consistency. It has been determined that the entry dose of sesame flour added to the mixture mass varies from 1.5 to 2%. It is expedient to put it into the normalize mixture after the process of homogenization before milling, pre-brewing with water in the ratio of 1:10 for 15–20 minutes to humidity (80 ± 1) %. It has been found that the expiration date of the frozen dessert without sugar with the use of sesame flour is 6 months at a temperature of – 18 °C.

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1444-1456 L. Nilova and S. Malyutenkova
The possibility of using powdered sea-buckthorn in the development of bakery products with antioxidant properties
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The possibility of using powdered sea-buckthorn in the development of bakery products with antioxidant properties

L. Nilova* and S. Malyutenkova

Peter the Great St. Petersburg Polytechnic University, Institute of Industrial Management, Economics, and Trade, Graduate School of Commodity and Service, Novorossiyskaya street 50, U194021 St. Petersburg, Russia
*Correspondence: nilova_l_p@mai.ru

Abstract:

The article examines ways of increasing the antioxidant capacity of bakery products (referred to here as BP) by adding powdered peel, powdered seeds, and powdered marc produced from sea-buckthorn berries. Three different versions of BP were developed with the maximum addition of the following powders: from the peel (3%), from the marc (5%) with a sugar content of 14.5%; and from seeds (5%) with a sugar content of 5%, and with a potato flake content of 5%. BPs with the addition of sea-buckthorn powders were baked at two temperature regimes: 200°C and 220 °C. The content of phenolic compounds, flavonoids, and ascorbic acid were determined for the sea-buckthorn powder, for the crust of BP, and in BP crumbs. The antioxidant activity of BP was determined by the use of two methods: by chemiluminescence, and by their reaction to the DPPH-radical. Cyclic amides (lactams) were determined in BP crusts and crumbs with the use of the IR spectroscopy method. The AOA of powdered sea buckthorn depended upon the volume of phenolic compounds and ascorbic acid in them: peel > marc > seeds. The antioxidant properties of BPs decreased in the following order and were aligned the following way: BP with marc > BP with peel > BP with seeds. They displayed higher AOA levels than was calculated in theoretical tests, depending upon the volume of powders in the recipe. An increase of the baking temperature led to a loss of phenolic compounds and vitamin C, as well as to the formation of poly lactams. BP baked at the temperature regime of 200 °C displayed the greatest AOA levels.

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1457-1465 D. Nsengumuremyi, N.V. Barakova, V.A. Romanov, A.S. Mityukov and A.V. Guzeva
The effect of sapropel extracts on microflora and physicochemical parameters of Dried Distillers’ Grain
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The effect of sapropel extracts on microflora and physicochemical parameters of Dried Distillers’ Grain

D. Nsengumuremyi¹*, N.V. Barakova¹, V.A. Romanov¹, A.S. Mityukov² and A.V. Guzeva²

¹Saint Petersburg National Research University of Information Technology, Mechanics, and Optics, Department of Food Biotechnology (Vegetable stock), Lomonosova street 9, RU191002 St. Petersburg, Russia
²Federal State-funded Scientific Establishment, ‘Russian Academy of Sciences (RAS) Limnology Institute’ (INOZ RAN), Syevasťyanova street 9, RU196105 St. Petersburg, Russia
*Correspondence: nsedanco@yahoo.fr

Abstract:

This article is devoted to the effect of ultradispersed humate sapropel extracts, obtained from air-dry samples of sapropel, from Seryodka deposit (Pskov region, Russia) by alkaline extraction under the action of ultrasonic radiation, on microbial and physicochemical parameters of Distillers’ grain (DG) during storage. At the end of the distillation, wet DG was divided and treated with sapropel extract. The untreated sample served as a control. Both (treated and untreated) were then dried to 10% moisture content. Microbial and physicochemical parameters (moisture content, pH, titrable acidity (TA), acid value (AV) of fats) were assessed before storage of dried DG. A similar experiment was repeated after one week of storage but on microbial load. The microbial counts ranged from 2.3 × 104 CFU g-1 (untreated) to 1.77 × 104 CFU g-1 (treated) before storage while 2.5 × 104 CFU g-1to 2.18 × 104 CFU g-1 accounted for after a week of storage. The pH had increased from 4.5 ± 0.1 to 6.1 ± 0.1 before and after treatment respectively. TA likewise decreased from 3.2 ± 0.4 to 2.03 ± 0.06%. The results showed that sapropel extracts had effects on microflora and physicochemical parameters of DDG.

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1466-1474 А.А. Sabirov, N.V. Barakova and Е.А. Samodelkin
Effect of impact-activating-disintegration treatment on grain protein fraction of autumn rye
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Effect of impact-activating-disintegration treatment on grain protein fraction of autumn rye

А.А. Sabirov¹*, N.V. Barakova¹ and Е.А. Samodelkin²

¹Saint Petersburg National Research University of Information Technologies, Mechanics and Optics (ITMO University), Lomonosov street 9, RU191002, St. Petersburg, Russia
²Research Institution Research Center 'Kurchatov Institute'- Central Research Institute for Engineering Materials ̒Prometheus̕, Shpalernaya street 49, RU191015 St. Petersburg, Russia
*Correspondence: alfirsabirov@gmail.com

Abstract:

This paper studies the distribution of rye protein fractions according to their mass and amino acid composition while milling by machines with different work tools. The research was conducted on the autumn rye of harvest year 2017 with kernel moisture content of 8%. Cereals were milled in the machine of an impact-activating-disintegrating type DEZI-15 with three-row and five-row rotors which rotate at 120 s-1, and in the laboratory mill with a knife-rotor work tool. The milling grain size was determined by a diffraction-type grain analyser Malvern Mastersizer 2000. The average grain size obtained from three-row disintegrating rotor was 167 μm, from the five-row rotor 158.1 μm, and from the laboratory knife-rotor mill 384 μm, respectively. The free amino acids composition in flour samples was investigated using the size exclusion chromatography method (SEC-method). The polypeptide composition of total grain protein has been determined by One-dimensional SDS-acrylamide gel electrophoresis. According to the electropherogram results obtained from all the the content of high-protein fraction of 200 kDa. The glutelin fraction with molecular weight of 116.25 kDa is definitely observed in the sample obtained from the three-row disintegrating rotor. Whereby the lowest glutelin content has been detected in the flour sample obtained from the five-row disintegrating rotor. Fractions with molecular weight of 60–75 kDa – globulin fractions – come up frequently in the sample obtained from the three-row disintegrating rotor. Prolamine fractions of 45–47 kDa are clearly observed in the flour sample obtained from the laboratory knife-rotor mill. The albumin fraction with molecular weight of 17–28 kDa are mostly observed in the samples obtained by three-row and five-row disintegrating rotors. Few LMW fractions (from 6.5 to 15 kDa) are found in samples obtained using the impact-activating-disintegrating technique, mostly in the sample milled in the laboratory knife-rotor mill. Based on the data of free amino acid content in sample investigated it can be concluded that the impact-activating-disintegrating techniques does not cause reduction in protein biological value. The albumin rich flour milled in the disintegrator can be used for production of functional food. Due to the low content of glutelin protein fraction the flour obtained from the five-row disintegrating rotor offers the greatest promise for production of gluten-free foods.

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1475-1485 I. Sepelevs and G.A. Reineccius
Encapsulation of Gallic acid in solid lipid core surrounded with maltodextrin shell
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Encapsulation of Gallic acid in solid lipid core surrounded with maltodextrin shell

I. Sepelevs¹* and G.A. Reineccius²

¹Latvia University of Life Sciences and Technologies, Faculty of Food Technology, Rigas street 22, LV-3004 Jelgava, Latvia
²University of Minnesota, Department of Food Science and Nutrition, 1334 Eckles Ave, MN 55108, St. Paul, USA
*Correspondence: igor_shepelev@inbox.lv

Abstract:

Multiple phase capsules had been prepared in a single spray drying process. The main goal of the present study was to investigate whether the conversion of a portion of the modified starch (wall material used in spray drying) to resistant starch (RS) would offer added protection of encapsulated material. To achieve this, dry gallic acid (GA; a model water soluble phenol compound used in the present study) was initially dispersed in palm oil and stabilized with Polyglycerol Polyricinoleate (PGPR 4175) as an emulsifier. This dispersion was homogenized with a modified starch (MS, dextrose equivalent of 15) solution, that was previously treated with high pressure and increased temperature to achieve starch retrogradation, and then spray dried. It was possible to produce only small amounts of RS from modified starch, varying from 0.1 to 0.2% of total carbohydrate content. GA content in the lipid phase of the capsule was determined by lipid droplet size in the O/W emulsion (the feeding solution), as smaller droplets results in the significantly bigger surface area, and more intensive GA diffusion from O to W phase. Maltodextrin shell wall was able to prevent leaking of the melted palm oil form the capsule core to the surface during seating tests, preventing agglomeration of capsules. This could be very important for the storage/transportation of capsules in the uncontrolled temperature conditions.

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1486-1492 A. Smejtkova and P. Vaculik
Comparison of power consumption of a two-roll mill and a disc mill
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Comparison of power consumption of a two-roll mill and a disc mill

A. Smejtkova* and P. Vaculik

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 21 Prague 6 – Suchdol, Czech Republic
*Correspondence: smejtkova@tf.czu.cz

Abstract:

Grinding or milling is often used process, for example in the production of feed, grinding of malt in beer production, grinding of cereals on flour, etc. In order to optimize the energy intensity of the whole production process, it is necessary to know the energy consumption of individual processes. The grinding of malt influences the mashing process, the drawing-off and the boiling yield. Correct grain grinding makes the endosperm available for enzyme and physicochemical reactions during wort production. Husks affect the drawing-off process. Two-, four- or six-roll mills, in some cases a hammer mill or disc mill, are most commonly used for grinding of malt. Power consumption was monitored when light, Munich, caramel and coloring malt were grinding. A two-roll mill and a disc mill with engine speeds of 1,500 rpm and 2,800 rpm were used for grinding. The gap between the mill rollers and the mill disks was set to 0.4 mm. The fineness of the grinding was evaluated for all types of malt on all used equipment. The energy intensity of the grinding was correlated on 1.0 kg of malt and then compared.

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1493-1508 K. Spalvins, K. Ivanovs and D. Blumberga
Single cell protein production from waste biomass: review of various agricultural by-products
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Single cell protein production from waste biomass: review of various agricultural by-products

K. Spalvins*, K. Ivanovs and D. Blumberga

Riga Technical University, Institute of Energy Systems and Environment, Azenes street 12/1, LV 1048, Riga, Latvia
*Correspondence: kriss.spalvins@rtu.lv

Abstract:

Agricultural waste constitutes for most of the manmade waste streams. Processing of biodegradable waste materials ensures the treatment of harmful substances and allows to reduce environmental pollution. In addition, conversion of these waste materials in value-added products makes these recycling methods more economically viable. Single-cell protein is one of the value-added products that can be produced by microbial fermentation of waste materials. In this review various biodegradable agricultural by-products as substrates for production of SCP are categorized and compared.

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1509-1516 J. Táborský, A. Hejtmánková, E. Hlavatá and L. Chládek
A study of dynamics of bitter acids and xanthohumol in hop pellets during storage
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A study of dynamics of bitter acids and xanthohumol in hop pellets during storage

J. Táborský¹*, A. Hejtmánková¹, E. Hlavatá¹ and L. Chládek²

¹Czech University of Life Sciences, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamýcká 129, CZ165 00 Prague 6, Czech Republic
²Czech University of Life Sciences, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 00 Prague 6, Czech Republic
*Correspondence: taborsky@af.czu.cz

Abstract:

Eight varieties of hop pellets were analyzed for the contents of α-acids, ß-acids and xanthohumol according to the EBC 7.7 analytical method. The pellets were extracted with acidified mixture methanol – diethylether and analyzed using HPLC with a diode-array detector and a Nova-Pak column C18. Four series of analyses were performed: immediately after the unpacking of the pellets and then after five, seven and nine months of storage at 4 °C. According to the first series of analyses, the contents were assayed as following (α-acids, ß-acids, xanthohumol resp., all in weight % in pellets): Galaxy (13.4, 8.0, 0.74), Citra (11.1, 3.0, 0.48), Tradition (8.2, 8.0, 0.58), Cascade (4.5, 5.2, 0.25), Northern Brewer (4.0, 2.9, 0.37), Sládek (3.5, 4.0, 0.48), Saaz (2.0, 3.4, 0.24), and Triskel (1.7, 3.6, 0.18). According to these results, variety Galaxy was found as the richest in all three parameters. After nine months of storage at 4 °C, the weight loss of α-acids ranged from 4.1% (Citra and Triskel) to 66.4% (Galaxy). The losses of β-acids and xanthohumol were less distinctive (from zero to 31.3% and 25.7%, resp.) and indicated good long storage possibilities of these compounds at convenient conditions (darkness, low temperature, elimination of direct influence of oxygen).

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1517-1526 S. Vasiljeva, G. Smirnova, N. Basova and D. Babarykin
Cadmium-induced oxidative damage and protective action of fractioned red beet (Beta vulgaris) root juice in chickens
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Cadmium-induced oxidative damage and protective action of fractioned red beet (Beta vulgaris) root juice in chickens

S. Vasiljeva¹*, G. Smirnova¹², N. Basova¹ and D. Babarykin²

¹University of Latvia, Institute of Biology, 3 Miera Str., LV-2169 Salaspils, Latvia
²Institute of Innovative Biomedical Technology Ltd, 2 Inchukalna Str., LV-1014 Riga, Latvia
*Correspondence: svetlana.vasiljeva@lu.lv

Abstract:

Cadmium (Cd) is one of the most dangerous environmental bioaccumulative pollutants that affects many organs in humans and animals. Present investigation was conducted to evaluate the protective effect of fractioned red beetroot juice on Cd-induced oxidative stress in chickens. The named red beetroot juice fraction (BJF) was received by juice ultrafiltration. Per oral administration of BJF for 10 days followed by dietary Cd exposure (50 mg kg-1 of diet) was evaluated in the in vivo experiments in chickens. The prominent increase of Cd concentration in blood plasma, liver and kidney provoked the rise of oxidative processes activity in organs. BJF treatment attenuated the Cd-induced oxidative stress. The changes of oxidative stress markers – the reduction of hepatic and kidney malondialdehyde amount, the increase of glutathionperoxidase level in liver and blood catalase activity indicated the possible antioxidative influence of BJF. Chickens exposed to Cd showed no evidence of clinical toxicity, but exhibited some features of adverse action of this heavy metal. The increase of uric acid concentration in blood serum is associated with protein catabolic processes intensified by Cd affect. Suppressive effect of Cd on the immune response in chickens manifested in alteration of cell and humoral immunity parameters. The data of the most investigated oxidative stress markers, biochemical and immunological indices in Cd-exposed chickens were almost back to the values, when received BJF per os during 10 days. Administration of fractioned red beetroot juice to Cd-treated chickens prevented the oxidative impact of this heavy metal and provided immunomodulating effect.

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1527-1533 J. Vecvagars, D. Bārzdiņa and D. Kairiša
Meat chemical composition of pasture pure lambs and crossbreeds
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Meat chemical composition of pasture pure lambs and crossbreeds

J. Vecvagars, D. Bārzdiņa and D. Kairiša*

Latvia University of Life Sciences and Technologies, Faculty of Agriculture, Institute of Agrobiotechnology, Liela street 2, LV – 3001 Jelgava, Latvia
*Correspondence: daina.kairisa@llu.lv

Abstract:

Increased customer interest of safe, healthy and environmentally friendly food consumption promote development of sheep farming industry in Latvia. Aim of the paper – explain of different pasture-fattened sheep breed and their crosses lamb meat composition traits. A study of pasture fattened lamb meat chemical composition was carried out from year 2013 to 2017. Fattening lambs were kept in breeding rams control station ‘Klimpas’ (57°50’58.8’’N 25°19’39.6’’E) pasture array. Lambs were slaughtered in a certified slaughterhouse, but analysis of meat chemical composition were conducted in laboratory of Institute of Food Safety, Animal Health and Environment (BIOR). For the analysis of the meat chemical composition were used up to 1 kg heavy Quadriceps femoris muscle samples. In meat were analysed following elements of its chemical composition: dry matter, protein, fat, minerals, pH, cholesterol and unsaturated fatty acids. Data analysis shows that the lambs before slaughter ranged in age from 5 to 8 months. Lamb meat obtained from the study groups had a significantly different total amount of dry matter and fat. The lowest total fat, but the highest ash content was obtained in the lamb meat of the extensive breed group. The lowest total fat and the highest ash content were obtained in the lamb meat from the extensive breed group. In meat obtained a small (in individual samples < 0.10%) cis-10-pentadecenoic acid, cis-11-eicosenoic acid and myristoleic acid content. Of unsaturated fatty acids in lamb meat were represented higher amount of oleic acid, linoleic acid and elaidic acid.

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1534-1545 R. Zarins, Z. Kruma and I. Skrabule
Optimisation of biologically active compounds ultrasound assisted extraction from potatoes using response surface methodology
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Optimisation of biologically active compounds ultrasound assisted extraction from potatoes using response surface methodology

R. Zarins¹*, Z. Kruma¹ and I. Skrabule²

¹Latvia University of Life Sciences and Technologies, Faculty of Food Technology, Department of Food Technology, Rigas iela 22, LV-3004 Jelgava, Latvia
²Institute of Agricultural Resources and Economics, Zinātne iela 2, Priekuli, Priekuli municipality, LV-4126 Latvia
*Correspondence: reinis-zarins@inbox.lv

Abstract:

Potato (Solanum tuberosum L.) is source of phenolic compounds and from plant matrixes can be extracted by several methods. In recent years ultrasound assisted extraction has become more popular due to its efficiency for recovery of phenolic compounds and antioxidants and response surface methodology is an effective tool for optimisation of extraction procedure by evaluating different variables and their interaction. The aim of the current research was to optimize ultrasound assisted extraction of biologically active compounds from potatoes by response surface methodology. For experiment purple-flesh potato variety ‘Blue Congo’ was selected. Control sample was extracted by stirring for 1 hour. Box-Behnken design was used for optimization of extraction conditions from fresh potatoes and as variables were selected: ethanol concentration (% v/v), hydrochloric acid concentration (molarity) and time (min). For extracts as responses total phenolic, total flavonoid, total anthocyanin content and antioxidant activity (DPPH, ABTS+ scavenging activity) were determined using a spectrophotometric methods. Significant models were obtained for antocyanins, total phenols and DPPH radical scavenging activity. Optimisation of extraction showed that for maximising all responses optimal HCl concentration is 2.5M, ethanol concentration 79.4% and extraction time 60 minutes, resulting in following responses: 57.41 mg 100 g-1 of anthocyanins, 238.52 mg 100 g-1 of TPC, 24.58 mM TE 100 g-1 of DPPH scavenging activity and 12.99 mM TE 100 g-1 of ABTS scavenging activity. Conventional extraction method showed significantly lower results. It could be concluded that ultrasound assisted extraction is effective method for recovery of phenolic compounds and solvents and extraction time is significant parameter influencing efficiency.

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1546-1554 R. Zarins, Z. Kruma, L. Tomsone, S. Kampuse, I. Skrabule and I.H. Konosonoka
Comparison of phenolic compounds and antioxidant activity of fresh and freeze-dried potatoes
Abstract |
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Comparison of phenolic compounds and antioxidant activity of fresh and freeze-dried potatoes

R. Zarins¹, Z. Kruma¹*, L. Tomsone¹, S. Kampuse¹, I. Skrabule² and I.H. Konosonoka²

¹Latvia University of Agriculture, Faculty of Food Technology, Department of Food Technology, Rigas iela 22, LV-3004 Jelgava, Latvia
²Institute of Agricultural Resources and Economics, Zinātne iela 2, Priekuli, Priekuli municipality, LV-4126 Latvia
*Correspondence: zanda.kruma@llu.lv

Abstract:

Potatoes (Solanum tuberosum L.) contain a wide range of compounds with health benefits, and different techniques have been developed for the determination of these compounds. Freeze-drying is a common method for the preservation and preparation of samples for the analyses of bioactive compounds, but it is well known that drying influences the composition of food products. The aim of the current study was to compare phenolic compounds and antioxidant activity of fresh and freeze-dried potatoes. In the experiment 11 cultivar potatoes grown in experimental fields of the Institute of Agricultural Resources and Economics in 2016 were analysed. Potatoes were freeze-dried. Homogenized fresh and freeze-dried samples were extracted with an ethanol/water (80/20 w/w) solution. Total phenolic content (TPC) was determined using the Folin-Ciocalteu method, and the antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH˙) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays. The highest TPC and radical scavenging activity were determined in cultivars ‘Peru Purple’ and ‘Blue Congo’ potatoes. Freeze-drying influenced all the tested parameters but more significantly the TPC, and for certain cultivars a reduction of more than 30% was observed. A strong correlation between TPC, DPPH and ABTS in fresh and freeze-dried samples was observed, r = 0.81, r=0.93, r = 0.92, respectively. It could be concluded that the effect of freeze-drying on TPC and antioxidant activity is cultivar dependent.

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1555-1562 K. Žolnere, I. Ciproviča, A. Ķirse and I. Cinkmanis
A study of commercial β-galactosidase stability under simulated in vitro gastric conditions
Abstract |

A study of commercial β-galactosidase stability under simulated in vitro gastric conditions

K. Žolnere¹*, I. Ciproviča¹, A. Ķirse¹ and I. Cinkmanis²

¹Latvia University of Life Sciences and Technologies, Faculty of Food Technology, Department of Food Technology, Rīgas iela 22, LV–3004 Jelgava, Latvia
²Latvia University of Life Sciences and Technologies, Faculty of Food Technology, Department of Chemistry, Lielā iela 2, LV–3001 Jelgava, Latvia
*Correspondence: k.zolnere@gmail.com

Abstract:

β-Galactosidase activity in milk may be affected by several factors, such as temperature, pH, milk composition, and metal ions. It is important to note that digestive proteases and gastrointestinal pH can affect enzyme activity during transit through the gastrointestinal tract. For the investigation of commercial β-galactosidase stability in human and animal gastric tracts, human gastrointestinal tract (GIT) models were employed, enabling prediction of enzyme activity under in vivo conditions. The aim of this study was to analyse and compare commercial β-galactosidase stability under simulated in vitro gastric conditions. Commercial enzymes (Ha Lactase 5200 produced by Kluyveromyces lactis and NOLA™Fit5500 produced by Bifidobacterium bifidum expressed in Bacillus licheniformis, Chr. Hansen, Hørsholm, Denmark; GODO-YNL2 produced by Kluyveromyces lactis, Danisco, Copenhagen, Denmark) were used for this study. Commercial enzymes were added to GIT models at 1 and 5 mL L–1. The enzyme activity was assessed as the percentage of lactose hydrolysis by the enzymes from Kluyveromyces lactis and Bacillus licheniformis using HPLC after digestion. β-Galactosidase extracted from yeast (Kluyveromyces lactis) and bacteria (Bacillus licheniformis) was found to be effective as a strategy for improving lactose tolerance.

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