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Screening of Lactobacillus plantarum with broad-spectrum antifungal activity and its application in preservation of golden-red applesOriginal PaperKangning Li, Wenyi Zhang, Lai-Yu Kwok, Bilige MengheCzech J. Food Sci., 2020, 38(5):315-322 | DOI: 10.17221/175/2020-CJFS Fungal food spoilage is a common problem that leads to both great economic losses and serious health problems. This study screened the antifungal activity of 137 Lactobacillus plantarum isolates against six common food spoilage indicator fungi using an overlay method and indicator strains of the species Aspergillus flavus, Fusarium moniliforme, Penicillium expansum, Penicillium chrysogenum, Cladosporium cladosporioides, and Aspergillus niger. Among Lactobacillus plantarum isolates, strain IMAU80174 was selected as the most effective based on the results of mycelium growth inhibition by its cell-free supernatant (CFS) and tolerance to simulated gastrointestinal juices and bile. The CFS of Lactobacillus plantarum IMAU80174 showed heat and protease resistance, and it was active only in a low pH environment. The application of the CFS to golden-red apples could slow down spoilage caused by inoculation of Penicillium expansum. |
New food compositions to increase the content of phenolic compounds in extrudatesReviewEvžen Šárka, Marcela Sluková, Petra SmrčkováCzech J. Food Sci., 2020, 38(6):347-358 | DOI: 10.17221/223/2020-CJFS Phenolic compounds are linked to a number of health benefits, including antioxidant, antibacterial, antiglycaemic, antiviral, anticarcinogenic, anti-inflammatory and vasodilatory properties. To improve a great loss of phenolics during extrusion, researchers have investigated incorporating functional ingredients into the extrusion input mixture. Other reasons for the addition of active ingredients are the re-use of by-products from food technology, decreasing the calorie content of extruded food, inhibition of starch digestion, and the colour change of the gluten-free products. The paper presents 28 examples of new designs for extrusion based on rice, corn, cassava, sorghum, and lentil flours and on other crops, together with the analyses of phenolics. The present results show the highest total phenolic content in sorghum among cereals, and lentil flour and orange peel powder among mixtures for extrusion to prepare extrudates. The highest content of total flavonols was found in the mixture containing corn and freeze-dried red and purple potatoes. |
Relationship between the fat and oil composition and their initial oxidation rate during storageOriginal PaperMonika Sabolová, Václav Zeman, Gabriela Lebedová, Marek Doležal, Josef Soukup, Zuzana RéblováCzech J. Food Sci., 2020, 38(6):404-409 | DOI: 10.17221/207/2020-CJFS Until now, the relationship between the fat and oil composition and their oxidation stability has been studied only at elevated temperatures (typically above 100 °C). Therefore, the initial oxidation rates of 19 edible fats and oils were determined as an increase in the peroxide value during storage in the dark at 35 °C with free access to air (oxygen). The initial oxidation rates of fats and oils were compared with parameters characterising these fats and oils (peroxide value, acid value, fatty acid composition, antioxidant capacity, and tocochromanol content). Using a simple correlation analysis, the initial oxidation rate correlated the most strongly with the peroxide value of the analysed fats and oils (P < 0.01). A highly reliable model (P < 0.0001) was obtained by multivariate statistical analysis. According to this model, the initial oxidation rate is affected mainly by the peroxide value and then by total trans fatty acid content, and antioxidant capacity. |
Rye - the nutritional and technological evaluation in Czech cereal technology - A review: Grain and floursReviewMarcela Sluková, Lucie Jurkaninová, Ivan Švec, Pavel SkřivanCzech J. Food Sci., 2021, 39(1):3-8 | DOI: 10.17221/203/2020-CJFS Rye is a later cereal compared to wheat and barley. The main use of rye in human nutrition consists in the processing of grain to flour (dark and wholemeal) and in the baking industries in sourdough and bread making. During the last fifty years, there has been a decline in the consumption of rye in the Czech Republic. Rye is a nutritionally interesting cereal due to its high fibre content. The part of the review presents the development of consumption of rye and rye products, nutritional significance of rye products, changes in the properties and content of rye grain components during processing with a focus on the evaluation of the effect of milling on components and microstructure of rye flour. |
Effects of cultivation media and NaCl concentration on the growth kinetics and biogenic amine production of Lactobacillus reuteriOriginal PaperPatrik Body, Gabriel Greif, Gabriela Greifová, Margaréta Sliacká, Mária GreifováCzech J. Food Sci., 2021, 39(1):9-16 | DOI: 10.17221/190/2020-CJFS We analysed and compared the ability of four strains of Lactobacillus reuteri of sheep origin ranked as NSLAB (non-starter lactic acid bacteria) to grow and produce biogenic amines (BA) under cultivation conditions varying in cultivation media and salt content. The production of biogenic amines was primarily dependent on the growth rate of L. reuteri under particular cultivation conditions. From among produced BA, tyramine appeared as the dominant one while L. reuteri CCM 3644 possessed the most potent aminogenic ability. The influence of NaCl on the growth and production of BA was dependent on their concentration. Higher salt concentration (≥ 3% w/v) significantly inhibited the production of BA. On the contrary, the addition of 1-2% of NaCl w/v significantly improved the production of BA by three tested strains of L. reuteri (CCM 3642, 3644, and 3645). Finally, to better describe the production of BA over time, the relations between selected variables were calculated using linear regression. The appropriate fitting and the corresponding equations suggested the polynomial (degree 2) or exponential relations between the increasing concentration of NaCl and the concentration or calculated specific production rates of produced BA. |
Antioxidant potential of tea assessed by optical absorption spectroscopy in DNA-encased carbon nanotubesOriginal PaperLijun Wang, Shusuke Oura, Yongbo WuCzech J. Food Sci., 2021, 39(1):23-28 | DOI: 10.17221/135/2020-CJFS It is essential to develop a simple method to assess food quality quantitatively. Available methods primarily rely on nanotechnology and offer high selectivity and sensitivity. In this study, we aimed to develop a sensitive nanoprobe, and, to this end, a double-stranded DNA-encased HiPco carbon nanotube (dsDNA-HiPco) hybrid was prepared and used to evaluate the antioxidant potential of a Chinese tea against hydrogen peroxide (H2O2) with a range of irradiation wavelengths. The morphology and dispersion of the hybrids were analysed using atomic force microscopy, which showed that dsDNA wrapped on the SWCNT surface well and homogeneous dispersion of the rod-shaped tubes while the concentration of dsDNA was 1 mg mL-1. The antioxidant effect of Chinese tea was evaluated by using near-infrared absorption and photoluminescence of the hybrid. Experimental results revealed that the tea exerted excellent antioxidant effects when the hybrid was pre-treated with 0.03% wt H2O2. Catechin present in the Chinese tea played a pivotal role in exerting the antioxidant effects. Therefore, a simple detection method proposed herein can be successfully applied in various fields, including biology, medicine, and the food industry. |
Properties of Indonesian plantain cultivars during ripening and recommendation for flour ingredientsOriginal PaperRima Kumalasari, Luki Vanadiani, Riyanti Ekafitri, Ina Siti Nurminabari, Dewi Desnilasari, Nur Kartika Indah Mayasti, Diki Nanang SurahmanCzech J. Food Sci., 2021, 39(1):35-41 | DOI: 10.17221/94/2020-CJFS This research aims to examine the physicochemical changes in five Indonesian cultivars of plantain during the normal ripening and determine the optimal ripeness stage for flour. Cultivars 'Kapas', 'Tanduk', 'Raja Bulu', 'Siam', and 'Kepok Kuning' were selected for the research. The cultivars were stored at room temperature of 24.8-31.7 °C and relative humidity of 59.5%-99.9%. Peel colour, weight loss, pulp to peel ratio, firmness, pH, TSS, moisture content, starch, reducing sugars, and titratable acidity were evaluated. The results showed that the best unripe flour based on the starch content for 'Kapas', 'Raja Bulu', 'Tanduk', and 'Siam' cultivars was at stages 1-3 and 'Kepok Kuning' cultivar at ripening stages 1-2. On the other hand, in ripe banana flour, the best stage for 'Kepok Kuning', 'Tanduk', and 'Siam' cultivars was stage 4, for 'Raja Bulu' cultivar stages 4-5 and for 'Kapas' cultivar stages 4-7. |
Modelling the inactivation of Staphylococcus aureus at moderate heating temperaturesOriginal PaperVeronika Lehotová, Karla Miháliková, Alžbeta Medveďová, Ľubomír ValíkCzech J. Food Sci., 2021, 39(1):42-48 | DOI: 10.17221/201/2020-CJFS The survival of bacterial contaminants at moderate processing temperatures is of interest to many food producers, especially in terms of the safety and quality of the final products. That is why the heat resistance of Staphylococcus aureus 2064, an isolate from artisanal Slovakian cheese, was studied in the moderate temperature range (57-61 °C) by the capillary method. The fourth decimal reduction time t4D- and z-values were estimated in two steps by traditional log-linear Bigelow and non-linear Weibull models. In addition, a one-step fitting procedure using the Weibull model was also applied. All the approaches provided comparable t4D-values resulting in the following z-values of 11.8 °C, 12.3 °C and 11.3 °C, respectively. Moreover, the one-step approach takes all the primary data into z-value calculation at once, thus providing a more representative output at the reasonable high coefficient of determination R2 = 0.961 |
Phloridzin as a marker for evaluation of fruit products authenticityOriginal PaperMagdaléna Hrubá, Josef Baxant, Helena Čížková, Veronika Smutná, František Kovařík, Rudolf Ševčík, Kristýna Hanušová, Aleš RajchlCzech J. Food Sci., 2021, 39(1):49-57 | DOI: 10.17221/239/2020-CJFS Abstract: Phloridzin (phloretin-2'-O-glucoside) is a phenolic compound characteristic of the genus Malus. This study aimed to evaluate phloridzin as a marker of undeclared addition of apples in fruit products. To test this proposal, the heat and oxidation stability of phloridzin was firstly confirmed. Then the distribution and variability of phloridzin in apples were studied, showing no difference between the tested apple varieties (Golden Delicious, Granny Smith, Rubin and Champion) but a significant difference in phloridzin content in seeds (2 380 ± 755 mg kg-1) compared to peel, flesh and core, which contained less than 70 mg kg-1. The effects of different stages of apple purée production at an industrial scale were also investigated. The kinetics of phloridzin diffusion from seeds to apple homogenate played an important role in the final phloridzin content in 16 analysed apple purées (26-39 mg kg-1). Finally, the survey of phloridzin content in 31 fruit products in the market was carried out. Phloridzin was also measured in eight jams and fillings which did not declare the presence of apples on their labels; findings from 2 to 6 mg kg-1 indicate the addition of apples from 5% to 20%. It was confirmed that phloridzin appears to be a suitable marker for detecting the undeclared presence of apples, which are a cheap substitute for the declared fruit types. |
Rye - nutritional and technological evaluation in Czech cereal technology - A review: Sourdoughs and breadReviewMarcela Sluková, Lucie Jurkaninová, Simona Gillarová, Šárka Horáčková, Pavel SkřivanCzech J. Food Sci., 2021, 39(2):65-70 | DOI: 10.17221/204/2020-CJFS Rye is a nutritionally and healthy valuable cereal. It is a significant substrate for biotechnological processing. This review presents the basic procedures for rye sourdough refreshing, the characteristics of used LAB and yeast, the types of sourdough use in the Czech Republic and in global perspective. The fermentation process leads to the activation and accessibility of a number of healthy bioactive components of rye flour. Compounds with antifungal activity formed during fermentation can effectively enhance the microbial stability of bread. Rye sourdoughs as a part of the bread recipe cause not only the leavening of dough but also desired texture and sensory properties of bread. |
Dragon fruit: A review of health benefits and nutrients and its sustainable development under climate changes in VietnamReviewThi-Thuy-Hai Luu, Truc-Linh Le, Nga Huynh, Pablo Quintela-AlonsoCzech J. Food Sci., 2021, 39(2):71-94 | DOI: 10.17221/139/2020-CJFS Dragon fruit or pitaya is an exotic tropical plant that brings multiple benefits to human health thanks to its high nutritional value and bioactive compounds, including powerful natural antioxidants. Extracts from stems, flowers, peels, pulps of dragon fruit own a range of beneficial biological activities against pathogenic microbes including bacteria, fungi and viruses, and diseases like diabetes, obesity, hyperlipidaemia, and cancer. Moreover, dragon fruit extracts have cardiovascular and hepatoprotective properties, as well as prebiotic potential. Vietnam is a tropical country with favourable climate conditions for the development of pitaya plantations, which have great adaptability and tolerance to a wide range of environmental conditions (e.g. salinity adaptation, favour light intensity, drought resistance, etc.). The dragon fruit, thanks to its nutritional properties, biological activities, and commercial value has become a cost-effective product for the Vietnamese economy, particularly in the poorest areas of the Mekong Delta region, and a driving force in the sustainable development of Vietnam under the challenges posed by the global climate change such as saline intrusion and drought. |
Mycotoxins in apples coming from organic production and integrated pest managementOriginal PaperPavla Sehonová, Michaela Němečková, Lucie Plhalová, Petr Maršálek, Veronika Doubková, Petr Chloupek, Jana Čaloudová, Zdeňka Svobodová, Jana BlahováCzech J. Food Sci., 2021, 39(2):100-105 | DOI: 10.17221/246/2020-CJFS The aim of this study was to compare the occurrence of important mycotoxins often contaminating fruits, in particular aflatoxin B1, ochratoxin A, patulin, and an indicator of fungal metabolism - kojic acid, in dried apples from organic production and integrated pest management with origin in the Czech Republic. Regardless of the production management, both aflatoxin B1 and patulin concentrations were below the limit of quantification. Ochratoxin A was present in all samples examined in our study with concentrations ranging from 4.22 to 15.99 µg kg-1. Kojic acid concentrations ranged from 3.57 to 9.44 mg kg-1. However, no significant difference in ochratoxin A and kojic acid concentrations was found between samples coming from integrated pest management and samples coming from organic agriculture. The results of this study show that apples originating in organic production or integrated pest management have, under the same independent conditions, an equal probability of containing (or omitting) similar levels of the investigated mycotoxins. Moreover, these results, while demonstrating safe levels of some mycotoxins in different agricultural practices also highlight gaps in knowledge and legislation that may have direct and crucial effects on human health. |
Effect of ultraviolet-C light and mild thermal treatment on the storage life of orange juiceOriginal PaperPaola Hernández-Carranza, Arely Peralta-Pérez, Raúl Avila-Sosa, Irving Israel Ruiz-López, Alfredo César Benitez-Rojas, Carlos Enrique Ochoa-VelascoCzech J. Food Sci., 2021, 39(2):106-112 | DOI: 10.17221/21/2020-CJFS This study aimed to evaluate the effect of low-dosage treatment with ultraviolet-C light (19.75 J L-1 for 5 min), mild thermal treatment (40 °C for 5 min), or their combination on the native microflora (mesophiles and moulds plus yeast) and consumer acceptance of orange juice at the beginning and after storage (5 or 22 °C). Results indicated that UV-C light and mild thermal treatments reduce 0.19 ± 0.03 and 0.25 ± 0.02 log cycles (both kinds of microorganisms), respectively. The combination of treatments displays an additive effect against mesophiles (0.47 ± 0.01 log) and moulds plus yeasts (0.42 ± 0.02 log). After 9 days of storage at 5 °C, combined treatment did not present any microbial increases (P > 0.05), while consumer acceptance was similar (P > 0.05) to the fresh orange juice. Although several studies about the use of hurdle technology using UV-C light in orange juice have to be conducted, the results obtained in this study are promising, and they can be used for further studies. |
Dissemination and characteristics of Klebsiella spp. at the processed cheese plantOriginal PaperTereza Gelbíčová, Kristýna Kořená, Lucie Pospíšilová-Hlucháňová, Nicol Straková, Renáta KarpíškováCzech J. Food Sci., 2021, 39(2):113-121 | DOI: 10.17221/232/2020-CJFS The genus Klebsiella is not generally considered as a major foodborne pathogen and with regard to food production it represents also a hygiene indicator. This study was focused on the monitoring of Klebsiella spp. dissemination at the processed cheese plant and determination of virulence determinants and antibiotic resistance of obtained strains. Klebsiella spp. were detected in 43% (37/87) of samples: swabs from the cheese processing environment (34/69), personnel (2/3) and raw material (milk powder) from an opened packaging (1/7). All tested samples of final processed cheeses were negative for the presence of Klebsiella spp. Obtained strains were identified as K. oxytoca (n = 32) and K. pneumoniae (n = 23). Typing results enabled to reveal the presence of two predominant PFGE clusters of K. pneumoniae and K. oxytoca suggesting the occurrence of suspect persistent strains, and spread of Klebsiella spp. between the production environment and the personnel. The melting process of processed cheese production was able to eliminate Klebsiella spp. in the final products, although some K. oxytoca and K. pneumoniae strains carried genes of the locus of heat resistance 1 (LHR1), which may lead to their increased heat resistance. K. pneumoniae and K. oxytoca isolated from the processed cheese plant did not represent any hypervirulent or multidrug-resistant strains which could be a potential threat to public health. |
Simultaneous quantifications of four purine derivatives biomarkers in cow milk by SPE HPLC-DADOriginal PaperMihaela Vlassa, Filip Miuța, Cătălin DragomirCzech J. Food Sci., 2021, 39(2):122-130 | DOI: 10.17221/297/2020-CJFS In this study, simultaneous quantification of allantoin, uric acid, xanthine, and hypoxanthine in cow milk by solid phase extraction (SPE) and high performance liquid chromatography-diode array detection (HPLC-DAD) method was perform. Five different SPE cartridges were tested in order to evaluate the isolation of purine derivatives (PD) from cow milk. Chromatography was carried out on ODS-2 Hypersil column and 0.05 M (NH4)2HPO4 buffer solution (pH = 7.76) as mobile phase. The HPLC-DAD validated method showed a linearity with regression coefficients higher than 0.999 and the limits of detection and quantification with values in the range 0.09-0.74 µg mL-1 and 0.27-2.24 µg mL-1, respectively. The method showed good precision with a relative standard deviation (RSD) below 4.48%, while the accuracy ranged from 95.34 to 104.47% for all analytes. The best recovery degree of PD by SPE were obtained on Strata SCX cartridge for xanthine (87.79%) and hypoxanthine (89.02%); on Strata NH2 for allantoin (35.09%) and on Strata C8 for uric acid (101.08%). Finally, the HPLC-DAD method with SPE on SCX cartridges was applied to quantify the PD in a batch of thirty cow milk samples. |
Mycotoxins in oat flakes - changes during production and occurrence on the Czech marketOriginal PaperTomas Dropa, Zbynek Dzuman, Petra JonatovaCzech J. Food Sci., 2021, 39(2):131-139 | DOI: 10.17221/247/2020-CJFS Raw oats are frequently contaminated by fungi producing mycotoxins, and as such, they can pose a health risk to humans regularly consuming oat products. To reveal the effect of particular processing steps on contamination levels in final oat products, two series of samples obtained from an oat flake manufacturer were analysed. Among oat fractions treated, the most significant mycotoxin decrease was demonstrated in cleaning and dehulling steps, where the observed mycotoxin reduction was in the range of 13-75% for monitored mycotoxins, enniatin B, enniatin B1, HT-2 toxin, T-2 toxin, beauvericin and tentoxin. The overall mycotoxin reduction found in final oat flakes was in the range of 65-100%. Furthermore, 20 commercially available oat flakes from the Czech market were analysed. We detected 16 mycotoxins, mainly trichothecenes and emerging enniatins with levels in the interval of 1-156 μg kg-1. With regard to the current EU legislation, two analysed oat flake products exceeded the maximum limit for ochratoxin A. |
A study of combined minced meat from hydrobionts for snacksOriginal PaperDementieva Natalia Valerievna, Boitsova Tatiana Maryanovna, Bogdanov Valeryi DmitrievichCzech J. Food Sci., 2021, 39(2):140-148 | DOI: 10.17221/264/2020-CJFS This paper considers the developments whose application is promising for the fishing industry under the production of dried snack products. Fish chips are non-traditional dried products. The goal of this research was to study the functional and technological properties of minced systems consisting of fish and seafood. Minced systems were pre-treated with special food additives to improve their rheological properties and organoleptic indicators. The objects of research were stuffed meat products which included 65% to 75% of pollock, 15% of Pacific herring, and 10% to 20% of seafood. A study of technochemical indicators showed that minced systems were high-protein. They contained 30.0-34.8% of protein, 2.2-3.7% of lipids, and 0.8-2.5% of carbohydrates. Minced systems made of hydrobionts are characterised by the high water-holding capacity of 74.52-90.3%, which indicates good lyophilic properties of raw materials. When studying the rheological parameters of minced systems from hydrobionts, it was found that the maximum shift tension was 6.0-8.1 kPa. The stickiness index was 2 400-3 200 Pa, the dynamic viscosity was within the range of 650-850 Pa s (pascal seconds). The effective viscosity index for fish mince with good mouldability is 600-900 Pa s. The organoleptic evaluation showed that minced systems from hydrobionts pre-treated with food additives had high sensory characteristics. |
Selected aspects of edible insect rearing and consumption - A reviewReviewJiří Mlček, Anna Adámková, Martin Adámek, Marie Borkovcová, Martina Bednářová, Lenka Kouřimská, Veronika HlobilováCzech J. Food Sci., 2021, 39(3):149-159 | DOI: 10.17221/288/2020-CJFS The presented work brings a comprehensive study of edible insect farming with an impact on the environment and human health. The review focuses not only on commonly monitored parameters such as carbon footprint or feed conversion but also on waste management. It also highlights the positive and negative aspects of eating edible insect regarding human health. Compared to other livestock, the rearing of edible insect brings less environmental burden and higher environmental protection. This review aimed to summarise current knowledge and broaden the complex view of the issue. |
Enzymatic degradation of polysaccharides in Chinese vinegar residue to produce alcohol and xyloseOriginal PaperKunyi Liu, Shulai Zhou, Qi Wang, Bin Jiang, Liran Yang, Bing Lu, Huawei YuanCzech J. Food Sci., 2021, 39(3):160-168 | DOI: 10.17221/326/2019-CJFS Vinegar residue is a key secondary waste in the brewing industry that is often disposed irresponsibly, due to its large quantity and lack of reasonably effective use, causing environmental pollution issues. NaOH was used to pretreat Chinese vinegar residue, and the reaction products were consumed by the enzyme complex and Saccharomyces cerevisiae 1300 during the stage of simultaneous saccharification and fermentation (SSF). The results show that the optimal pretreatment conditions for Chinese vinegar residue were solid-to-liquid ratio of 1 : 11, NaOH concentration of 2.2%, pretreatment temperature of 63 °C, pretreatment time of 80 min, and amount of 4.9 IU g-1 xylanase. While these optimal conditions allowed more effective enzymatic degradation of the dried vinegar residue and resulted in the total sugar yield of 66.1%. Subsequently, dried vinegar residue and enzyme complex were added into the SSF process four times, and SSF reacted in a shaker at 120 r min-1 and 37 °C for 120 h, the yields of ethanol and xylose were 31.4% and 18.5%, respectively. Therefore, the method of Chinese vinegar residue for alcohol and xylose production by SSF was proved. |
Isoflavones of the red and Hungarian clover and possible impact on animal dietOriginal PaperMirjana Petrović, Dejan Sokolović, Snežana Babić, Tomáš Vymyslický, Jordan Marković, Vladimir Zornić, Zora Dajić-StevanovićCzech J. Food Sci., 2021, 39(3):169-175 | DOI: 10.17221/27/2020-CJFS The content of daidzein, genistein, formononetin, and biochanin A isoflavones was studied in natural populations of red and Hungarian clover, to estimate their impact on fodder quality and to determine directions in possible breeding programs. The study included 6 red clover (Trifolium pratense) and 6 Hungarian clover (Trifolium pannonicum) populations, collected in the central Balkans. The differences between the species and among the populations were analysed. The average content of total isoflavones was 1.393 mg g-1 and 0.487 mg g-1 of air dry matter in Hungarian clover, respectively. While the most prevailed isoflavone in red clover was biochanin A (46%), the Hungarian clover populations were rich in genistein (43%). The red clover leaves accumulated the highest content of isoflavones. The Hungarian clover flowers and leaves had an equal amount of isoflavones. The obtained values of the total isoflavones could not affect the overall nutrient quality and therefore, researched natural populations of two clover species could be considered for further breeding programs. |
Dynamic high pressure microfluidization (DHPM): Physicochemical properties, nutritional constituents and microorganisms of yam juiceOriginal PaperMengpei Liu, Rong Wang, Jia Li, Lihua Zhang, Jiajia Zhang, Wei Zong, Wenjuan MoCzech J. Food Sci., 2021, 39(3):217-225 | DOI: 10.17221/284/2020-CJFS Dynamic high pressure microfluidization (DHPM) is considered an emerging and promising technique for the continuous production of fluid foods. This study measured the effect of DHPM on yam juice. After DHPM processing, the content of total soluble solids (TSS), turbidity, flavonoid and non-enzymatic browning was significantly decreased, with the biggest drops being 35.5, 86.2, 20.7, and 66.7%, respectively. Moreover, the average particle size was decreased from 1 944 nm to 358 nm, which showed a strong positive correlation with turbidity. The reduction coefficients and electric conductivity of Escherichia coli, Saccharomyces cerevisiae and Lactobacillus plantarum were increased significantly after DHPM processing. Combined with morphological analysis, DHPM processing had good bactericidal effects on E. coli and S. cerevisiae. These results provided reference values for the application of DHPM technology in the development of yam juice. |
Utilisation of triticale (X Triticosecale Wittmack) and residual oat flour in breadmakingOriginal PaperAnna Fraś, Kinga Gołębiewska, Damian Gołębiewski, Magdalena Wiśniewska, Marlena Gzowska, Dariusz R. MańkowskiCzech J. Food Sci., 2021, 39(3):226-233 | DOI: 10.17221/249/2020-CJFS During the last few years, non-bread cereals, as a rich source of bioactive components, play an increasingly important role in the production of new healthier food. A large number of diet-related diseases in society requires developing and regular consumption of high-quality food. In this study, triticale flour was supplemented with residual oat flour (ROF), which is a by-product in the production of oat fibre concentrate, to obtain triticale-oat bread with improved chemical composition and quality. The flours obtained from 3 winter triticale cultivars were enriched with 10%, 15%, and 20% of ROF. An increasing level of ROF resulted in higher protein and lipids content and a two-fold increase in β-glucan content (from 0.3% for control breads to 0.6% for 20% ROF) what improved the quality of dietary fibre in breads (DF). The bread parameters, especially bread volume (BV), the shape of loaves, crust colour and crumb texture, decreased with the addition of ROF. The triticale-oat breads with the best quality were obtained from 10% addition of ROF. Results confirmed the possibility of utilisation triticale and ROF for the production of bread with a unique chemical composition constituting a simultaneously rich source of DF. |
Wheat rheological and Mixolab quality in relation to cropping systems and plant nutrition sourcesOriginal PaperMagdaléna Lacko-Bartošová, Lucia Lacko-Bartošová, Petr KonvalinaCzech J. Food Sci., 2021, 39(4):265-272 | DOI: 10.17221/189/2020-CJFS The objective of this study was to evaluate the effect of cropping systems [integrated (INT) vs. organic (ORG)] and plant nutrition sources (synthetic in INT vs. approved organic in ORG) on analytical and rheological quality traits of winter wheat and its productivity. The results after 16 years of field experiments were evaluated. Pre-crop for winter wheat was N-fixing crop. Grain yield of winter wheat (6.8 t ha-1 in INT, 6.5 t ha-1 in ORG) did not differ significantly, while plant nutrition sources had an equal and positive effect on the yield. Crude protein quantity was higher in INT system by about 0.2%. The farinograph dough development time and dough stability were the longest for ORG and fertilised treatments. Mixolab quality indicators showed a clear distinction between ORG and INT systems and fertilisation in the protein and starch characteristics of the grain. The ORG reported longer Mixolab stability of the dough, mainly on fertilised treatment (8.8 min). Starch characteristics - torque C4 (amylolytic activity) and torque C5 (starch retrogradation) were higher for ORG system. Torque C2, protein weakening, was not affected by the cropping system. ORG system has the potential to achieve consistent, high-quality yields with significantly lower reliance on external inputs. |
Isolation and identification of lactic acid bacteria from fermented meat products and evaluation of their antimicrobial effectOriginal PaperSevim Feyza Erdogmuş, Ugur Cengiz Erişmiş, Cevdet UguzCzech J. Food Sci., 2021, 39(4):289-296 | DOI: 10.17221/222/2020-CJFS In this study, 30 lactic acid bacteria (LAB) were isolated from 20 different fermented meat products obtained from the Afyonkarahisar province (Turkey). Molecular identification of these isolates was performed by amplification of the 16S rDNA gene using the polymerase chain reaction (PCR) method. LAB isolated from 'sucuk' (spicy and fermented sausage) samples were identified as Enterococcus faecalis (2 isolates), Enterococcus durans (1 isolate), Lactobacillus sakei (3 isolates), Lactobacillus curvatus (2 isolates), Weissella viridescens (3 isolates), Weissella cibaria (2 isolates) and Weissella hellenica (1 isolate). LAB, isolated from salami samples, were identified as W. viridescens (1 isolate), E. durans (3 isolates), Leuconostoc mesenteroides (4 isolates), Carnobacterium maltaromaticum (1 isolate), Macrococcus caseolyticus (1 isolate). Also, LAB, isolated from sausages samples, were identified as E. faecalis (1 isolate), E. durans (4 isolates), Lactobacillus plantarum (1 isolate). Both agar spot and agar well diffusion assay methods were used to determine the antimicrobial activity of the LAB isolates. Isolates of LAB showed higher antimicrobial activity against Listeria monocytogenes ATCC 19115, Staphylococcus aureus ATCC 25923, Klebsiella pneumoniae NRRL B 4420, Pseudomonas aeruginosa ATCC 11778, Streptococcus faecalis NRRL B 14617 than against Escherichia coli ATCC 35218 and Bacillus subtilis NRS 744. Results showed that the LAB isolates produced antimicrobial substances that have a potential for different industrial and biotechnological uses. |
Isolation of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus from nature: Technological characterisation and antibiotic resistanceOriginal PaperHakan Tavsanli, Tülay Elal Mus, Figen Cetinkaya, Ergün Ayanoglu, Recep CibikCzech J. Food Sci., 2021, 39(4):305-311 | DOI: 10.17221/296/2020-CJFS Yoghurt fermenting bacteria were isolated from natural sources including plants, dew, and rain samples (total of 300 samples) by the same methods nomadic peoples used for several centuries in Turkey. Inoculation into the reconstituted skim milk followed by planting on specific media and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) analysis allowed for the identification of 18 Lactobacillus delbrueckii subsp. and 26 Streptococcus thermophilus. A multiplex polymerase chain reaction (PCR) assay applied to lactobacilli enabled the identification of 5 isolates as L. delbrueckii subsp. bulgaricus. The isolates showed a varying range of acidification rates and proteolytic activity in reconstituted skimmed milk (RSM). S. thermophilus isolates showed a broader range of resistance and the most frequent resistance was observed for streptomycin (69.2%), gentamycin (65.3%), clindamycin (61.5%), ampicillin (61.5%), kanamycin (53.8%), and erythromycin (50%). For L. delbrueckii subsp. the highest resistance was determined for vancomycin (38.8%), ciprofloxacin (33.3%), and penicillin (27.8%). The frequency of multiple resistance was tested on 14 different antimicrobials determining that 19 S. thermophilus (73%) and 3 L. delbrueckii subsp. (16.7%) demonstrated resistance to more than three different antibiotics. In contrast to this wide-ranging resistance, five isolates from each genus were found to be susceptible to all tested antibiotics. The present study indicates that lactic acid bacteria (LAB) isolated from nature may have broad-range of resistance to antibiotics and could be a source for the transfer of resistance. |
Food allergies and intolerances - A reviewReviewRenata Winterová, Marie Pokorná Bartošková, Zdeněk Kejík, Jana Rysová, Ivana Laknerová, Marian Urban, Zuzana ŠmídováCzech J. Food Sci., 2021, 39(5):329-339 | DOI: 10.17221/151/2020-CJFS In recent years, food allergies and intolerances have had a growing presence in the population. This may be due to either genetic predisposition or allergy that develops later in life. In addition, an increase in the recorded cases can also be caused by improved diagnostic and detection methods and discovering new allergens. The article provides an overview of the most common food allergies and intolerances and their symptoms. |
Methods for suppressing Fusarium infection during malting and their effect on malt qualityReviewCarlo Antonio Ng, Michaela Poštulková, Dagmar Matoulková, Vratislav Psota, Ivo Hartman, Tomas BranyikCzech J. Food Sci., 2021, 39(5):340-359 | DOI: 10.17221/221/2020-CJFS The incidence of Fusarium head blight (FHB) in cereal grains such as barley and wheat is of growing concern due to climate change threatening food safety. Further processing of cereals by malting provides an ideal environment for the growth of Fusarium, leading to food safety concerns due to the production of mycotoxins, production challenges with the negative effects to malt and beer qualities, and economic loss owing to the field yield reduction. To improve food safety and product quality, different methods of fungal control have been investigated and reported in the literature. Traditional methods to control fungal growth and mycotoxin production have included chemical and physical methods, but these treatments led to worsened malt properties, limiting their applicability to the brewing industry. Biological control methods have, therefore, attracted wide interest as alternative treatments due to their ability to limit Fusarium growth and mycotoxin production in malting cereals without toxic by-products, thus exhibiting promise for improving food safety. Various biological agents have been investigated and applied in malting and have shown the potential to suppress Fusarium spp. growth and mycotoxin production. These agents include several lactic acid bacterial (LAB) species and Geotrichum candidum. Another promising biocontrol agent for malting control is Pythium oligandrum, which has successfully limited Fusarium infection in other agricultural crops. The review outlines the Fusarium-control methods reported referenced for the brewing industry and the present prospects in biological control applications on the promise of P. oligandrum as a novel agent for malting. |
Investigation of pork meat in chicken- and beef-based commercial products by ELISA and real-time PCR sold at retail in KosovoOriginal PaperRreze M Gecaj, Skender Muji, Flutura C Ajazi, Bajram Berisha, Alltane Kryeziu, Muharem IsmailiCzech J. Food Sci., 2021, 39(5):368-375 | DOI: 10.17221/164/2020-CJFS Food adulteration and fraudulent practices are widely observed in the food industry worldwide and are of great concern for Balkan countries. This study aims at investigating the level of undeclared pork meat in commercial beef and chicken meat products sold in Kosovo by implying one commercial enzyme-linked immunosorbent assay (ELISA) and two confirmatory real-time polymerase chain reaction (PCR) approaches [ready-to-use real-time PCR and real-time PCR with primers specific for pork mitochondrial deoxyribonucleic acid (DNA)]. In supermarkets in the capital city, Prishtina, 62 meat products were randomly sampled, and the three methods were applied. Additionally, these three approaches were evaluated for their practicability, reproducibility, and cost. The results showed that pork was present in 32% of beef- and 8% chicken-based products. ELISA and real-time PCR with pork specific primers showed 100% of reproducibility for beef- and chicken-based products. In contrast, the ready-to-use real-time PCR kit showed 100% reproducibility in chicken-, but only 75% in beef-based samples. ELISA was more rapid than both real-time PCR approaches, but it was more challenging when large numbers of samples were processed. The real-time PCR approach with pork specific primers was the cheapest, while the ready-to-use real-time PCR was the most practical method. Commercial ELISA, in combination with real-time PCR with pork specific primers, provides a reliable and affordable testing methodology that can be implemented for rapid detection and monitoring of pork adulteration in diverse commercial foods. |
Extrusion rheometry of collagen doughOriginal PaperJan Štípek, Jan Skočilas, Jaroslav Štancl, Rudolf ŽitnýCzech J. Food Sci., 2021, 39(5):384-392 | DOI: 10.17221/265/2020-CJFS Although collagen is widely used (for example, in the food industry, in the pharmaceutical industry and in biomedicine), the rheological properties of the material are not well known for high concentrations (8% collagen, 90% water). Rheological properties were measured using a capillary-slit rheometer (an extrusion process), where the tested sample of collagen matter was pushed by a hydraulically driven piston through a narrow rectangular slit at very high shear rates of 50-6 000 s-1. The Herschel-Bulkley (HB) constitutive equation and a new correlation taking into account the finite gap width was used to evaluate the rheological properties (n = 0.2, K = 879 Pa sn, τ0 = 2 380 Pa). Use was made of a new yield stress measurement method evaluating τ0 'post mortem' after extrusion stops. The effects of wall slip and of air bubbles, which caused apparent compressibility of the 'silly putty' collagen material, were also studied. Corrections of the wall slip effect were implemented using sliding layer thickness δ. |
Phenolic composition of Croatian olive leaves and their infusions obtained by hot and cold preparationOriginal PaperValerija Majetić Germek, Paula Žurga, Olivera Koprivnjak, Kristina Grozić, Iva Previšić, Šime Marcelić, Smiljana Goreta Ban, Igor PaskovićCzech J. Food Sci., 2021, 39(5):393-401 | DOI: 10.17221/185/2020-CJFS Leaves and infusions of six Croatian olive cultivars grown in an organic orchard under the same agronomic conditions were characterised by high-performance liquid chromatography-ultraviolet/visible spectrophotometry (HPLC-UV/VIS). The total identified phenols in leaves ranged from 3 818 mg 100 g-1 [cultivar Istarska crnica (IC)] to 10 572 mg 100 g-1 of dry mass [cultivar Oblica (OB)]. The canonical discriminant analysis (CDA) provided a distinct separation of cultivars based on leaves' phenolic profiles. Hot- and cold-water infusions (200 mL) were prepared from 1 g of dry leaves. The average transfer rate of the total phenols in the cold-water infusions was 40% (25 °C/30 min), while in the hot-water infusions was 63% (75 °C/3 min) and 76% (100 °C/3 min). Although the cold-water infusions had the lowest transfer rate, they contained important levels of hydroxytyrosol derivatives ranging from 16.6 mg 200 mL-1 to 36.5 mg 200 mL-1 depending on the cultivar. Therefore, both hot and cold preparations are effective in obtaining antioxidant-rich natural beverages. |
