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Gastric survival of lactic acid bacteria in probiotic-labelled products from the Turkish market: An in vitro studyOriginal Paper

Gizem Özlük, Gabriela Krausová

Czech J. Food Sci., 2025, 43(5):344-351 | DOI: 10.17221/36/2025-CJFS

The resilience of lactic acid bacteria (LAB) in commercial probiotic products remains a critical area of investigation, particularly regarding their capacity to survive the harsh gastric environment. Scientific guidelines indicate that at least 6 log CFU·g–1 of viable probiotics must reach the intestines to achieve therapeutic benefits, which often requires an initial concentration of 8–9 log CFU·g–1 in the product. However, national regulations may specify lower thresholds; for example, Turkish Food Legislation requires 6 log CFU·g–1 for probiotic products and 7 log CFU·g–1 for kefir products. This study evaluates the in vitro gastric survival of LAB in 20 probiotic-labelled foods and 5 supplements available in the Turkish market using a simulated gastric model. Results reveal that 75% of the marketed probiotic-labelled foods comply with their label claims. Additionally, 55% of the samples demonstrate LAB strains fully resistant to gastric acidity. Dairy-based products exhibit significantly better survival rates under simulated gastric conditions compared to supplements, highlighting their potential for enhanced therapeutic efficacy.

Enhancing rheological properties of dough and quality of potato fibre-enriched breadOriginal Paper

Omar Saleh, Hossam S. El-Beltagi, Abdelrahman R. Ahmed, Hefnawy Taha, Haiam O. Elkatary, Abdalla El‐Hadary, Hoda A.S. Farag, Mahmoud Sitohy, Ahmed Mahmoud Ismail, Ali Osman

Czech J. Food Sci., 2025, 43(6):462-469 | DOI: 10.17221/29/2025-CJFS

This study investigates the effect of varying concentrations of potato fibre (PF) (1, 2, and 3%) on wheat flour (WF) dough rheological properties and the resultant pan bread quality. Chemical analysis, physical characteristics (weight, loaf volume, and specific volume), and colour attributes were estimated to assess bread quality. The impact of PF on bread sensory evaluation was estimated. The addition of PF significantly affected the properties of the dough. Moreover, the data indicated a substantial increase in water absorption (P ≤ 0.05) from 57.2% for the control to 65.5, 73.3, and 77.6% with the addition of 1, 2, and 3% PF to WF, respectively. Protein, crude fibre, and ash levels significantly increased (P ≤ 0.05) with higher PF ratios. Moisture and carbohydrate contents were markedly reduced (P ≤ 0.05). The specific volume considerably decreased from 3.15 cm3·g–1 in the control to 2.9, 2.74, and 2.53 cm3·g–1 with the addition of 1, 2, and 3% PF to WF, respectively. All replacement samples exhibited no significant alterations (P ≤ 0.05) in L* values and substantially (P ≤ 0.05) increased values of yellowness (b*) in all fortified samples relative to the control. Sensory assessments revealed that PF can be incorporated into WF at concentrations of 1% and 2% without compromising the overall acceptability of bread compared to the control.

Current nutritional guidelines in terms of the effect on gut microbiota and human health considering the WHO and FAO recommendationsReview

Barbora Rù¾ièková, Pavel Kohout

Czech J. Food Sci., 2023, 41(1):1-7 | DOI: 10.17221/186/2022-CJFS

The purpose of this paper is to evaluate current nutritional guidelines of modern diets based on medical and nutrition facts and their effect on gut microbiota and health, considering current recommendations of world authorities such as FAO and WHO. For this purpose, the first part is devoted to the impact of microbiota on human health, and special attention is committed to the effect of fibre on gut microbiota. The second part is dedicated to the fundamental division of diets and the evaluation of concrete nutritional guidelines of modern diets into microbiota and health, followed by the recommendations of global authorities. Modern diets include diets from the point of view of medical science (e.g. Mediterranean), promoted by nutritionists and authorities (e.g. Nordic) and by social trends (e.g. vegan). The evaluation summarises that high-fibre diets have tremendous benefits on human health. Diets with fresh, local and naturally fermented food positively impact the gut microbiota, hence human health (agrarian diets). The results of the review show that the nutritional guidelines associated with the lowest mortality are the Mediterranean with the Atlantic or Nordic diet, which is in line with the recommendation of the world authorities (FAO, WHO, UN). The low-fibre western diet with highly processed foods with no or very low levels of live bacteria appears to be high-risk in terms of preventing civilisation diseases with a negative impact on gut microbiota, which is in line with current FAO and WHO guidelines.

Effect of onion waste powder on the rheological characteristics, sensory attributes, and antioxidant properties of mayonnaiseOriginal Paper

Tsvetko Prokopov, Kremena Nikovska, Milena Nikolova, Pavel Merdzhanov, Mina Dzhivoderova-Zarcheva

Czech J. Food Sci., 2023, 41(3):182-188 | DOI: 10.17221/19/2023-CJFS


The recovery and utilization of onion processing waste would contribute to the solution of environmental problems. This research presents the way of successful supplementation of onion processing waste in mayonnaise. Different levels (0, 1, 2, and 3%) of onion waste powder (OWP) were used as an additive to mayonnaise, based on sunflower oil. The final mayonnaise formulations were evaluated for sensory properties, rheological behaviour, oxidative stability, total phenolic content, total flavonoids, and antioxidant activity. The results indicated that OWP could be used as a potential health-promoting functional ingredient in amounts of 2% to produce mayonnaise enriched with total phenolic compounds and flavonoids, having high antioxidant activity, acceptable quality, and overall consumer preference.

Investigation of multimycotoxins by LC-MS/MS in maise semolina chipsOriginal Paper

Oktay Samadzade, Karlo Muratoğlu, Serkan Kemal Büyükünal

Czech J. Food Sci., 2023, 41(3):212-220 | DOI: 10.17221/241/2022-CJFS


Chips made from maize semolina are rarely mycotoxin analysed because they are classified as low-risk foods in routine legal control plans. It is essential to foresee the health risks these snack foods may pose in the medium and long term, whose consumption frequency and quantity have increased with the changing consumer behaviours during the pandemic. The most outstanding development in mycotoxin analysis in recent years has been the use of high-pressure liquid chromatography together with mass spectrometry (LC-MS/MS) as a detector. For aflatoxin (AF) B1, B2, G1, G2, ochratoxin A (OTA), zearalenone (ZEN), deoxynivalenol (DON), fumonisin B1 (FB1), fumonisin B2 (FB2), citrinin (CIT), HT-2 toxin, and T-2 toxin determination in our samples, the LC-MS/MS analysis method with electrospray ionisation interfaces was utilised. Aflatoxin B1 levels in 22.7% of the samples (2.01–17.49 μg·kg–1) and total aflatoxins (TAF) in 26.7% of the samples (6.71–24.67 μg·kg–1) were determined to exceed the limits defined in the Turkish Food Codex Contaminants Regulation. CIT could not be detected in any of the samples. ZEN + DON + OTA was found in 21.3% of the samples, DON + TAF + total fumonisins (FUM) in 19.3%, and TAF + ZEN + FUM in 18.7%.


Effect of gamma irradiation, high sugar content and antimicrobials on survival of Escherichia coli: A reviewReview

Viktória Dobó, Renáta Homlok, Csilla Mohácsi-Farkas, Ágnes Belák

Czech J. Food Sci., 2023, 41(4):231-247 | DOI: 10.17221/235/2022-CJFS


Dried fruits are popular ready-to-eat snacks. However, due to cross-contamination or contact with infected persons, Escherichia coli could be present, of which some strains are pathogenic, thus, the consumption of contaminated dried fruits could pose a public health risk. Microbial cells subjected to stress factors such as osmotic shock, radiation and antimicrobials could induce complex stress response systems and adaptation. Radiation and antimicrobials have been shown to cause an SOS response in E. coli, which affects cellular metabolism, such as the enhanced ability to repair DNA and mutagenesis. Studies have shown that glucose plays a critical role in the down- or upregulation of locus for enterocyte effacement (LEE)-encoded virulence of E. coli. Gamma radiation could also cause the formation of viable but nonculturable (VBNC) cells. If these cells are present in a sample, the number of viable cells will be underestimated by the plate count method leading to the false conclusion that the product is germ-free. We have reviewed in this article how stressors such as high sugar content, gamma radiation, and antimicrobials affect the survival of E. coli in dried fruits.

Endocrine disruptors in foods: Overlooked factors contributing to the prevalence of obesityReview

Wenli Wu, Yang Yang, Bee KangTan, Shaoling Lin, Yaping Chen, Jiamiao Hu

Czech J. Food Sci., 2023, 41(6):393-405 | DOI: 10.17221/80/2023-CJFS


Endocrine disruptors, also known as endocrine-disrupting chemicals, could mimic or interfere with the body's hormones. Indeed, naturally occurring endocrine disruptors have been widely identified in daily foods. Moreover, industrialisation has resulted in increasing synthetic endocrine disruptors being produced and used as food additives or in food package materials, which makes exposure to endocrine disruptors become more common. Although the safety of synthetic chemicals has been extensively evaluated before entering into the food industry, increasing evidence has also highlighted that long-lasting exposure might influence long-term metabolic outcomes and be associated with the prevalence of obesity. Therefore, this review summarised the sources, detection methods, obesogenic effects and possible mechanisms of endocrine disruptors commonly found in foods, as well as discussed possible underlying mechanisms by which endocrine disruptors contribute to the increased risk of obesity. In conclusion, the review may provide useful information for understanding the association between endocrine disruptors and obesity, which could provide a new angle of view for preventing obesity prevalence.

Investigate the mystery of Baijiu production region – Environmental factors for Luzhou (Sichuan, China)Review

Guo Qingyan, Tang Yurun, Zhao Fan, Liu Ying, Tian Lei, He Zongjun, Guan Tongwei

Czech J. Food Sci., 2023, 41(5):323-339 | DOI: 10.17221/72/2023-CJFS


With a long tradition of brewing history, Chinese strong-flavour Baijiu (SFB) developed prosperously in the southwest, especially in Luzhou, and has existed for more than 300 years building craftwork and brewing techniques. As a product of the distillation of fermented grains, its production involves many microbial communities. During this time, microbial communities within production have burgeoned and evolved throughout the development history, enhancing unique texture and flavour. Meanwhile, environmental factors are critical constituents in the production, which provide the optimal conditions for processing procedures and various microorganisms, including externally controlled macro-environment and micro-environment of fermentation. By studying the correlation with environmental factors from macro and micro perspectives, we illustrated the bond with environmental symbiotic and holistic patterns of the intrinsic microbial community and fermentation characteristics. This review is essential to study and control the whole ecological conditions of the Baijiu fermentation process, aiming to gain insight into the dynamics of the microorganisms and ensure a traditional fermentation environment for quality control.

Comparison of physicochemical properties, phenolic profiles and antioxidant capacity of hawthorn berries stored at different temperatures and timeOriginal Paper

Xueyan Wei, Yanjing Yin, Kang Xu, Tao Wang, Chuanhe Zhu, Wen Liu, Mengmeng Guo

Czech J. Food Sci., 2023, 41(6):419-427 | DOI: 10.17221/112/2023-CJFS

This research investigated the effect of different storage temperatures on the compositional changes, physicochemical characteristics, and functional properties of hawthorn berries. Storage at 25 °C resulted in the gradual decrease of the moisture, hardness, sugar, titratable acid, and colour of hawthorn berries. These changes decreased with decreasing storage temperature, and the minimal changes happened at frozen storage (–18 °C). Similarly, the decreasing rate of ascorbic acid, extractable polyphenol (EPP), and flavonoids during storage also decreased with reducing storage temperature (25 °C > 4 °C > –18 °C). Hydrolysable polyphenol (HPP) was relatively stable during the hawthorn storage, and non-extractable proanthocyanidins (NEPA) increased with decreasing temperature. Ferric reducing antioxidant power (FRAP) of EPP and HPP decreased at 25 °C, while polyphenolic oxidase (PPO) and peroxidase (POD) activities decreased. Decreasing the storage temperature can improve the stability of the nutritional properties, antioxidant capacity, and enzyme activity of hawthorn. The specific storage temperature depends on the final processing conditions and the purposes of the hawthorn berries.

Utilisation of chicken eggshell nanopowder on physicochemical quality, microstructure, and amino acid profile of beef pattiesOriginal Paper

Herly Evanuarini, Agus Susilo, Uun Yanuhar, Adelya Desi Kurniawati

Czech J. Food Sci., 2023, 41(6):428-435 | DOI: 10.17221/156/2023-CJFS

Chicken eggshells are a source of calcium and protein that can be added to restructured meat products, including patties. This study aimed to improve the chemical quality of beef patties with the addition of chicken eggshell nanopowder, including pH, protein content, ash content, fat content, antioxidant activity, calcium, microstructural quality, and identification of amino acid profiles. The method used in this study was a laboratory experiment arranged in a completely randomised design with five treatments: without the addition of chicken eggshell nanopowder as a control, the addition of chicken eggshell nanopowder 0.1, 0.3, 0.5, and 0.7% (w/w) with five replications. Data were analysed using the analysis of variance. It was followed by Duncan's multi-range test when the differences were significant or very significant. The research results show that the addition of chicken eggshell nanopowder to beef patties had a very significant effect (P < 0.01%) on pH, protein content, ash content, fat content, antioxidant activity, calcium, microstructural quality through scanning electron microscopy, and several amino acids. The addition of 0.7% chicken eggshell nanopowder could improve the chemical quality of the beef patties. The patty matrix was uniform and compact, and the air voids were getting tighter with the addition of chicken eggshell nanopowder, which was increasing based on scanning electron microscopy observations. Moreover, beef patties had various types of amino acids to achieve the best treatment.

Nutritional habits comparison of the baby boomer, X, Y, and Z generations located at a private college in Muğla, TürkiyeOriginal Paper

Halime Zülal Zeren, Elif Burcu Bali, Hülya Demir

Czech J. Food Sci., 2023, 41(6):436-445 | DOI: 10.17221/105/2023-CJFS

The present study aimed to reveal intergenerational differences in the nutritional habits of the baby boomer, X, Y, and Z generations at a private college in Muğla, Türkiye. The study population included the students of the TED Bodrum College in Muğla province in the 2021–2022 academic year, including 311 participants: baby boomers (74), X (66), Y (43), and Z (128) generations. An online questionnaire was used to compare the eating habits among the generations. The data were evaluated using SPSS software. Most of the generations believed in healthy eating. Physical image and social media mainly influence the healthy eating habits of the Z generation. The baby boomers and X generations mostly skipped lunch, while the Y and Z generations skipped breakfast. Baby boomers, X, and Y generations mostly prefer healthy foods; however, the Z generation attaches importance to tasty foods. Z generation's interest in nutrition mostly concerns their physical appearance, not their health. Nutritional knowledge must be strengthened, particularly among young generations, and nutrition education programs need to be better supported by the government and educational sectors.

Characteristics of cases with foodborne diarrheagenic Escherichia coli infection in Huzhou, ChinaOriginal Paper

Deshun Xu, Lei Ji, Wei Yan, Yuehua Shen

Czech J. Food Sci., 2023, 41(6):446-454 | DOI: 10.17221/151/2023-CJFS


Diarrheagenic Escherichia coli (DEC) is a common pathogen around the world that can cause disease with symptoms of diarrhoea. We collected all clinical DEC isolates from diarrhoea samples in three sentinel hospitals for active surveillance of foodborne diseases in Huzhou, China, between 2020 and 2022. The isolates were characterised according to demographic characteristics, time distribution, distribution of suspected culprit foods, antimicrobial results of susceptibility testing, analysis of virulence genes, and pulsed-field gel electrophoresis (PFGE) typing. The positive detection rate was 7.28%, the highest for enteroaggregative E. coli (EAEC) strains, followed by enterotoxic E. coli (ETEC) strains. The predominant virulence genes were astA/pic in EAEC (57.25%) and estIa/estIb in ETEC (17.94%) strains. The proportion of cases was relatively high in children aged 6 years old (15.27%), and the peak of incidence was between June and September. The rates of drug resistance in DEC were high in Huzhou, and the spectrum of drug resistance was wide. The highest rate of drug resistance was for AMP (63.51%), and multiple drug resistance was common. The household was the leading site of DEC infection, and meat and meat products were the main suspected culprit foods (18.15%). EAEC strains showed 52.4–100.00% sequence identity, and ETEC strains showed 52.2–100.00% sequence identity. All cases of DEC infection in Huzhou were sporadic between 2020 and 2022. Strengthening continuous surveillance will be useful in the risk assessment of foodborne diseases caused by DEC.

Determination of some heavy metals in different wheat flour brands in Sulaimani, Kurdistan Region – IraqOriginal Paper

Muhammad Faruq Wahab, Dara Muhamed Jamil

Czech J. Food Sci., 2023, 41(6):455-461 | DOI: 10.17221/85/2023-CJFS

Wheat flour is one of the most important sources of nutrients, and it is widely consumed worldwide as a raw ingredient in bread and other pastries. High heavy metal concentrations in the consumed wheat products could induce higher health risks. This study evaluated the heavy metal concentrations in the most available foreign and domestic wheat flour in Sulaimani, Kurdistan Iraq. The wheat flour samples were collected from different locations, and the heavy metal concentration was measured by inductively coupled plasma optical emission spectrometry (ICP-OES). The mean values in wheat flour samples were roughly within the permissible limit set by Iraqi standard (IQS), GCC Standardization Organization (GSO) (GCC – Gulf Cooperation Council), Codex, and FAO/WHO. Heavy metals were detected in the descending order copper (Cu) > lead (Pb) > arsenic (As) > chromium (Cr) > nickel (Ni) > cadmium (Cd) > cobalt (Co). The results showed that wheat flour samples from the Sulaimani markets were slightly contaminated with Ni, and one domestic wheat flour sample with Pb was probably linked to fertiliser and soil contamination. It is concluded that wheat flour could be a source of chronic exposure to toxic heavy metals such as nickel and lead, resulting in adverse health issues later. Consequently, regular monitoring of soil contamination, water quality, and use of recommended levels of fertilisers and pesticides in the agricultural areas of Sulaimani are recommended.

Nutritional composition analysis and quality evaluation of cattle in different regions of Guizhou Province (China)Original Paper

HaoXiang Xu, WenJu Luo, Lu Lei, JiuLing Long, Bo Yu, YuanFeng Zhao, Rong Ai, Jiang Lingling, Jiang Ran, JingRui Zhou (email: 296655827@qq.co

Czech J. Food Sci., 2023, 41(6):455-472 | DOI: 10.17221/133/2023-CJFS

This study aimed to investigate the variations in nutritional composition among different breeds of cattle in Guizhou. Specifically, this study selected Guanling, Weining, Sinan, Wuchuan, and Simmental cattle as experimental subjects. Assessing the nutritional quality of the longissimus dorsi muscle involves evaluating various parameters, including ultimate pH (pHu), meat colour, water-holding capacity, shear force, protein and fat content, levels of organic acids and amino acid composition. The study's findings indicated notable variations among the muscles of different cattle breeds tested. Guanling, Wuchuan, and Simmental cattle exhibited the highest water-holding capacity, while Wuchuan cattle displayed the highest shear forces. Guanling cattle and Simmental cattle had the highest levels of protein and fat. Weining cattle and Simmental cattle demonstrated the highest concentrations of lactic acid and oxalic acid. Guanling cattle exhibited the highest total amino acid and essential amino acid content. Moreover, Guanling cattle and Weining cattle showed the highest lightness (L*) and yellowness (b*) values, indicating lighter meat colour, while Weining cattle had the highest redness (a*) value, indicating redder meat colour. No significant differences among the five cattle breeds were observed in pHu and propionic acid content. These results provide a theoretical basis and serve as a data reference for assessing the suitability of different beef varieties for various processing purposes.

Formulation optimisation for pilot-scale honey powder production: A response surface methodology and central composite design approachOriginal Paper

Angelina Risky Maharani, Lilik Eka Radiati, Agus Susilo, Firman Jaya, Anang Lastriyanto, Dewi Masyithoh

Czech J. Food Sci., 2024, 42(1):45-54 | DOI: 10.17221/215/2023-CJFS


This research aimed to optimise a pilot-scale formulation for seamless scale-up, considering critical variables such as the honey-to-maltodextrin ratio, temperature, and drying time. Employing response surface methodology with a central composite design approach, the investigation systematically assessed the impact of four key factors within predetermined upper and lower limits: honey volume (90–900 g % dry basis), maltodextrin (60–600 g), drying temperature (60–70 °C), and drying time (180–300 min). Subsequently, these factors were randomised and optimised using the Design Expert software system. The analysis of variance revealed the significant impact of each drying factor, their interactions, and squared squares on the honey-to-maltodextrin ratio, as well as the effects of drying temperature and time. Validation results underscored the model reliability, exhibiting narrow standard deviations ranging from 0.001% to 1.3%. These outcomes emphasise the efficacy of Response Surface Methodology (RSM) and Central Composite Design (CCD) in refining formulations, offering valuable insights into appropriate product development and a seamless scale-up process.

Modelling of desorption isotherms for dried meat: New approach and newly applied modelOriginal Paper

Pøemysl Richtr, Josef Bauer, Svatopluk Henke, Rudolf ©evèík

Czech J. Food Sci., 2024, 42(1):55-63 | DOI: 10.17221/170/2023-CJFS


In this paper, desorption isotherms of two jerky products were studied (whole-muscle jerky – sample 1 and minced jerky – sample 2). The work focused on the comparison of the Dynamic Dewpoint Isotherm (DDI) method and the Saturated Salt Slurry (SSS) method and testing the newly applied model for modelling desorption isotherms for dried meat. Data were statistically processed using 8 models [Guggenheim-Anderson-de Boer (GAB), Double Log Polynomial (DLP), Henderson, Chin, Smith, Oswin, Hasley, and newly applied model] and statistically evaluated using coefficient of determination (R2), root mean squared error (RMSE) and mean relative percentage deviation (P-value). The DLP model (25 °C) reached R2 ≥ 0.999, P-value ≤ 1.84 for DDI, and R2 ≥ 0.998, P-value ≤ 4.37 for SSS method. The GAB model reached R2 ≥ 0.997, P-value ≤ 2.58 for DDI, and for SSS method the GAB model reached R2 ≥ 0.998, P-value ≤ 5.47. The new model reached P-value ≤ 5.73 for DDI and P-value ≤ 3.48 for SSS method. All models reached the P-value < 10% except for Smith and Chin models. The DDI method and newly applied model prove to be a suitable and precise approach to the evaluation of isotherms of dried meat products.

Study of substitution of beef and tapioca flour with tuna meat and purslane flour on meatball qualityOriginal Paper

Nafly Comilo Tiven, Tienni Mariana Simanjorang

Czech J. Food Sci., 2024, 42(1):64-70 | DOI: 10.17221/196/2023-CJFS


Tuna meat (Thunnus atlanticus – blackfin tuna) and purslane flour (Portulaca oleracea L.), which contain high protein and polyunsaturated fatty acids but are low fat and cholesterol, are used to substitute beef and tapioca flour to produce quality meatballs. This study aims to determine the effect of substituting beef and tapioca flour with tuna meat and purslane flour on meatballs' chemical, physical, and sensory quality. The beef was substituted with 40% tuna meat, and tapioca flour was substituted with 0, 10, and 20% purslane flour. The data obtained were analysed using a complete randomised design, with three treatments and five replications, respectively, and further tested with the Duncan test. The results showed that increasing the level of purslane flour can increase (P < 0.01) the chemical quality (water, protein, fat, ash, and omega-3) but decrease (< 0.01) the cholesterol of the meatballs. Physical quality (water holding capacity and sensory quality (colour) of meatballs were increased (P < 0.01), but taste and acceptability were decreased (< 0.01). It can be concluded that substituting beef and tapioca flour with tuna meat and purslane flour can increase the chemical and physical quality.

Cup viscometer – A practical analytical toolShort Communication

Milan Hou¹ka

Czech J. Food Sci., 2024, 42(1):71-76 | DOI: 10.17221/159/2023-CJFS


This paper focuses on helping smaller companies in the manufacturing industry who need to know the viscosity of their products or raw materials and do not have the funds to invest in expensive rotary rheometers. We developed a calibrated simple cup. It has replaceable nozzles designed so that dripping liquids cannot distort discharge times. The calibration of the cup is based on the relationship between kinematic viscosity and outflow time, which is valid for the laminar flow regimes. Here we described calibration and measurement procedures and methods for detecting non-Newtonian flow behaviour and the viscoelasticity of measured liquids. The maximum measurement error of 3% is defined for cases where all distractions are removed.

Molecular hydrogen content of different dietary supplementsShort Communication

Sergej Ostojic, Milan Vranes

Czech J. Food Sci., 2024, 42(2):136-140 | DOI: 10.17221/16/2024-CJFS


The main goal of this study was to evaluate the concentration and release dynamics of molecular hydrogen (H2, dihydrogen) in dietary evaluate supplements and identify products that provide a biologically significant amount of dihydrogen suitable for human consumption. We examined ten commercial supplements marketed for their dihydrogen content, including slow-release capsules and tablets (4 products), effervescent powders and tablets (5 products), and canned ready-to-drink beverage (1 product). These products were acquired either through online purchases, from retail stores, or obtained free of charge directly from the manufacturers upon request. Dihydrogen concentration was measured using a highly sensitive Clark-type hydrogen microsensor with a detection limit 0.05 µmol·L–1. Out of the ten products examined, only three (30.0%) exhibited dihydrogen levels surpassing the levels marketed as biologically relevant (500 µmol·L–1), and one of these products (a canned ready-to-drink beverage) approached this level with a concentration of 439.2 µmol·L–1. Interestingly, all slow-release capsules yielded negligible amounts of hydrogen (< 2 µmol·L–1), while a slow-release tablet delivered 43.6 µmol·L–1 of dihydrogen per single dose. The substantial variance in dihydrogen content among the assessed supplements holds significant implications for the general public, as high-potency products have the potential to provide up to 7 000 times more dihydrogen per single dosage compared to their low-potency counterparts.

Influence of the storage duration on the health promoting tyrosine, tryptophan, and total phenolics in potato tubersOriginal Paper

Rita Asakaviciute, Zita Maknickiene

Czech J. Food Sci., 2024, 42(2):93-99 | DOI: 10.17221/161/2023-CJFS

This research investigated the influence of the storage duration on the health promoting tyrosine, tryptophan and total phenolics in potato tubers. In the course of storage, the total amount of accumulated compounds in the dry mass of organically grown potato tubers increases. This is determined by individual properties of potato variety, storage time, and interaction of these two factors (P < 0.05). Organic potato tubers show increased total phenolic compounds in their dry matter during storage. This is due to a variety of characteristics, storage time and the interaction of these two factors (P < 0.05). A more pronounced increase in total phenolic compounds during storage was observed in 2022 than in 2021.

Chokeberry (Aronia melanocarpa) as natural antioxidant for the meat industryOriginal Paper

Andrea Mesáro¹ová, Marek Bobko, Luká¹ Jurèaga, Alica Bobková, Katarína Poláková, Al¾beta Demianová, Judita Lidiková, Ondøej Buèko, Andrea Mendelová, Tomá¹ Tóth

Czech J. Food Sci., 2024, 42(3):184-191 | DOI: 10.17221/38/2024-CJFS

Aronia melanocarpa is one of the many fruit types rich in polyphenolic compounds. Therefore, we used this fruit in our research as a possible natural antioxidant, which was added to pork sausages. Four groups were prepared: control group, a group with ascorbic acid, and groups with 3 and 5 mL·kg–1 of chokeberry extract. During storage, we monitored changes in pH, colour, texture and oxidative stability of pork sausages and sensory evaluation. We did not observe any negative effects of the extract on the quality of pork sausages during storage. Regarding oxidative stability, the lowest increase in malondialdehyde (MDA) was observed in the group with 5 mL·kg–1 of chokeberry extract, which was comparable to the group with ascorbic acid.

Enriching wheat flour with grape pomace powder impacts a snack's chemical, nutritional, and sensory characteristicsOriginal Paper

Amal Hassan Alshawi

Czech J. Food Sci., 2024, 42(4):243-250 | DOI: 10.17221/103/2024-CJFS


Because grape pomace powder (GPP) contains abundant phenolic chemicals and fibres, GPPs can serve as a filler in developing novel food products. This study examined how the GPP amounts affected a composite flour's physicochemical properties and bakery snacks' chemical, technical, and sensory properties. The experimental procedure involved replacing wheat flour (WF) with GPP at 5–20% while maintaining 100% WF as the control. The addition of GPP resulted in a significant decrease in the oil absorption capacity (P ≤ 0.05), while the rehydration index and water absorption capacity increased (P ≤ 0.05). The peak length (5.44–5.90 min), pasting temperature (70.20–80.92 °C), peak viscosity (124.72–172.80 RVU; RVU – relative value unit), trough viscosity (60.76–82.04 RVU), breakdown viscosity (69.56–93.74 RVU), final viscosity (162.70–222.30 RVU), and setback viscosity were measured. The addition of GPP to the composite flour and snacks decreased the lightness (L*) and increased the redness (a*) and yellowness (b*). The items' higher dietary fibre (DF) allowed them to claim 'high fibre content' when the maximum GPP was added. The GPP also increased the snacks' total solids, protein, ash, fibre, total phenolics content (TPC), and antioxidant capacity. The sensory acceptability of the snacks made with 5–10% GPP instead of WF was higher.

Nanocellulose as a fat substitute to improve the quality of emulsified sausages: Effects of morphology and contentOriginal Paper

Hongzhen Guo, Xiaolan Shang, Yunping Cheng, Qiuling Li

Czech J. Food Sci., 2024, 42(5):364-371 | DOI: 10.17221/114/2024-CJFS

Two different morphologies of nanocellulose – cellulose nanofibres (CNFs) and cellulose nanocrystals (CNCs) with different contents were added to emulsified sausages to replace pork back fat in different proportions (10%, 30%, and 50%), and the colour, emulsion stability, texture characteristics and dynamic rheological behaviour of emulsified sausages were analysed. The results indicate substituting fat with nanocellulose led the L* (lightness) and a* (redness) values increased and the b* (yellowness) values decreased of the emulsified sausages. Increasing nanocellulose concentration improved the emulsion stability of the sausages. In terms of emulsion stability, the use of CNFs outperformed CNCs, especially for samples substituted with 50% fat. In terms of texture, emulsified sausages where CNCs replaced fat showed lower hardness, viscosity, and chewiness compared to those with CNFs. The dynamic rheological results indicated that when the fat replacement levels were 10% and 30%, samples using CNFs as fat substitute had slightly higher storage modulus (G') values than those using CNCs. However, for 50% fat replacement, samples using CNFs as fat substitute had significantly higher G' values than those using CNCs, which demonstrates that higher CNFs concentrations are more conducive to the formation of a three-dimensional network structure.

Factors influencing consumer behaviour in the beer market in the Czech RepublicOriginal Paper

Veronika Svato¹ová, Petra Kosová, Zuzana Svobodová

Czech J. Food Sci., 2021, 39(4):319-328 | DOI: 10.17221/153/2020-CJFS

The aim of the paper is to identify the factors influencing consumers when beer consumption and when choosing restaurants for beer consumption in the Czech Republic (CR). A partial goal was to compare preferences and factors influencing beer consumers from the Vysoèina Region and the South-Moravian Region. The survey included a questionnaire survey, which 408 respondents took part in. The results showed that the most influential factors in the selection of beer for consumers are taste, a high-quality brand, and Czech production. Surprisingly, price was not found to be an influential factor in beer selection but is rather neutral. Factors that influence consumers most when choosing a restaurant for beer consumption were also identified. Consumers are most influenced by the quality of the beer on offer and the environment in which it is consumed.

Assessment of chemical contaminants in fresh and packaged tender coconut (Cocos nucifera) waterShort Communication

Padmaja Rambabu Jonnalagadda, Srujana Medithi, Summaiya Lari, Kalyan Chinthanuri, Yogeswar Dayal Kasa, Raju Nagaraju, Janardhan Vanka, Venkaiah Kodali

Czech J. Food Sci., 2022, 40(2):154-162 | DOI: 10.17221/200/2021-CJFS

Pesticide residues and heavy metals were analysed in both fresh tender coconut water (FTCW) (n = 161) and packaged tender coconut water (PTCW) (n = 126) samples collected from three southern states of India [Andhra Pradesh (AP), Kerala (KL), and Tamil Nadu (TN)]. A method validated in the laboratory using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used for pesticide residues, while heavy metals were analysed using a validated method of inductively coupled plasma-optical emission spectrometry (ICP-OES). Significant differences in heavy metal concentrations were assessed using analysis of variance (ANOVA) and post hoc test (between different varieties collected 'within' and 'among' states). FTCW samples [n = 9 (6%)] collected from TN showed Monocrotophos and Malathion residues in the range of 1.0 µg L-1 to 51.6 µg L-1 and 0.5 µg L-1 to 0.6 µg L-1, respectively, while they were detected in n = 5 (4%) of the PTCW samples at a range of 0.90 µg L-1 and 0.82 µg L-1 to 1.56 µg L-1. Heavy metals such as cadmium (Cd), chromium (Cr), lead (Pb), and stannum (Sn) were detected in different varieties collected from all three states. Some of the PTCW samples also contained traces of Cd, Cr, cobalt (Co), and Pb. Arsenic (As) was found in one sample from KL, while none of the samples was contaminated with mercury (Hg). The present study accentuates the need for fixing standards for the pesticide residues in coconut water.

Classification of hazelnuts according to their quality using deep learning algorithmsOriginal Paper

Nizamettin Erbaº, Gökalp Çinarer, Kazim Kiliç

Czech J. Food Sci., 2022, 40(3):240-248 | DOI: 10.17221/21/2022-CJFS

Hazelnut is a product with high nutritional and economic value. In maintaining the quality value of hazelnut, the classification process is of great importance. In the present day, the quality classification of hazelnuts and other crops is performed in general manually, and so it is difficult and costly. Performing this classification with modern agricultural techniques is much more important in terms of quality. This study was based on a model intended to detect hazelnut quality. The model is about the establishment of an artificial intelligence-based classification system that can detect the hidden defects of hazelnuts. In the developed model, the visuals used in the dataset are divided into training and test groups. In the model, hazelnuts are divided into 5 classes according to their quality using AlexNet architecture and modern deep learning (DL) techniques instead of traditional hazelnut classification methods. In this model developed based on artificial intelligence, a very good approach was presented with the accurate classification of 99%. Moreover, the values regarding precision and recall were also determined at 98.7% and 99.6%, respectively. This study is important in terms of becoming widespread information technology use and computer-assisted applications in the agricultural economics field such as product classification, quality, and control.


Formation of sensory active substances during ripening of Dutch-type cheese with reduced salt contentOriginal Paper

Irena Nìmeèková, ©árka Tre¹lová, Helena Èí¾ková, Tereza Rambousková, Jan Forejt, Zdenìk ©vandrlík, Vojtìch Kru¾ík, Dana Gabrovská

Czech J. Food Sci., 2023, 41(2):103-110 | DOI: 10.17221/239/2022-CJFS

The reduction of NaCl content in cheeses is nutritionally desirable but quite challenging due to NaCl's key role during cheese production and ripening. We focused on reformulated Dutch-type cheeses ripened for 120 days and their microbiological and sensory characteristics, including of determining organic acids (electrophoresis) and volatile substances (SPME-GC-MS analysis). Experimental batches contained 0.64, 0.90, and 1.19% NaCl or 0.77% NaCl together with 0.33% KCl. The influence of salts on lactose and citrate metabolism (the formation of lactic, acetic, and formic acid, ethanol, diacetyl, acetoin and 2,3-butanediol), proteolysis (the formation of glutamic acid), lipolysis and β-oxidation of fatty acids (the formation of 2-butanone, 2-butanol, hexanal, hexanoic and octanoic acid) was undetected. Contrarily, brining conditions affected the contamination of cheese surfaces with yeasts and halotolerant microorganisms and cheese consistency. While a typical consistency was formed only in the cheeses with 1.19% NaCl acceptable saltiness was declared in the cheeses with the content of salts 0.90% or higher. The partial replacement of NaCl with KCl caused metallic off-taste in the cheeses that ripened longer than Consistent acceptance seems to be the most limiting factor for the tested reformulation appears.

Listeria monocytogenes clones circulating in the natural environment of the Czech Republic and SlovakiaOriginal Paper

Zuzana Tomá¹tíková, Lucie Hlucháòová, Tereza Gelbíèová, Renáta Karpí¹ková

Czech J. Food Sci., 2023, 41(2):127-136 | DOI: 10.17221/234/2022-CJFS

Listeria monocytogenes is not only a pathogen causing a serious food-borne disease in humans but can also occur as a saprophyte in the natural environment. This study aimed to evaluate the occurrence of L. monocytogenes obtained from the natural environment of the Czech Republic (hereinafter Czechia) and Slovakia in 2016–2018 and to compare the clonal relationship of strains circulating in the environment with the strains originating from the food chain and humans. Altogether, 217 samples of mud, surface water, vegetation and soil were collected in 61 locations. Samples were processed according to the modified EN ISO 11290-1 standard. The obtained L. monocytogenes isolates were characterised using serotyping, macrorestriction analysis, followed by pulsed-field gel electrophoresis, whole genome sequencing (WGS), and antimicrobial susceptibility testing. L. monocytogenes were detected in 8.8% of the examined samples and were isolated in 15 locations, mainly from the mud from the banks of the surface water sources. Altogether, 25 L. monocytogenes strains were obtained from 19 positive samples. Serotypes 1/2a, 4b, and 1/2b were detected among the strains. Twenty combined AscI/ApaI pulsotypes were obtained by macrorestriction analysis. Altogether, 12 sequence types (STs) were detected using Multi-locus sequence typing (MLST) by WGS, with ST451 being the most frequent. The core genome MLST analysis revealed a heterogeneous population of environmental strains. No phenotype resistance was detected by antimicrobial susceptibility testing. Screening of antimicrobial-resistance genes using the platform ResFinder revealed the genes fosX in 24 isolates and blaTEM-116 in one isolate. The occurrence of L. monocytogenes in various samples from natural environments within wide altitude range during different seasons of the year may highlight this bacterium's remarkable adaptability and exceptional tolerance to external factors. Serotype distribution of the strains circulating in the natural environment of Czechia and Slovakia seems to reflect distribution in the human population more than in the food chain.

Technological approaches applied in the design of gluten-free bakery productsReview

Rodica Siminiuc*, Dinu Țurcanu

Czech J. Food Sci., 2023, 41(3):155-172 | DOI: 10.17221/180/2022-CJFS


Gluten-free (GF) bakery products differ significantly from standard wheat flour products, usually with inferior characteristics. To reproduce the visco-elastic properties of wheat flour dough, GF bread is balanced by complex formulations based on gluten-free flour and starches, including hydrocolloids. They must ensure maximum similarity with conventional products to reduce the resistance of final consumers to GF products. Identifying formulations or technologies that would help mimic the gluten matrix has been and remains the focus of research in GF product design. Most research focuses on ingredients. This study provides an overview of the various technological strategies in designing GF bakery products: technologies applied to cereals, flours, dough, and final products. The study could broaden the boundaries regarding developing, selecting, and using technologies to design GF products. It would also serve as a support for further research into the development of GF products, perhaps by leveraging local products and ingredients and adapting efficient, low-cost, environmentally friendly (including combined) technologies in such a way as to obtain products with high nutritional, rheological and organoleptic value.

The use of modern fermentation techniques in the production of traditional wheat breadOriginal Paper

Pavel Skøivan, Marcela Sluková, Ivan ©vec, Helena Èí¾ková, Iveta Horsáková, Eli¹ka Rezková

Czech J. Food Sci., 2023, 41(3):173-181 | DOI: 10.17221/39/2023-CJFS

A traditional Czech bakery white bread product is commonly made with directly mixed dough with the addition of yeast. In order to be able to reduce the salt content of the final product without compromising its acceptability to consumers, the dough was prepared with the addition of pre-ferments and wheat sourdoughs. The aim was to deepen the flavour background of the product and thus have a positive effect on its sensory properties. Wheat sourdoughs were prepared and tested using starter cultures and matured under different conditions. The resulting products were tested both sensorially and by means of precise physical methods.

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