Evaluation of rapeseed cake as a protein substitute in the feed of edible crickets: A case study using Gryllus assimilis

This paper aimed to investigate the optimization of Gryllus assimilis farming production by examining the effects of replacing soybean meal with rapeseed cake (25-100%) and supplementing it with rapeseed oil. The results reveal no adverse effects of soybean meal replacement on the feed conversion ratio and weight of the harvested crickets. However, incorporating larger quantities of rapeseed cake into the diet increased crude protein and decreased fat content. Moreover, the composition of fatty acids varied significantly, with increased levels of oleic acid and decreased levels of palmitic acid, while a high rapeseed cake content led to a decrease in the atherogenic and thrombogenic index values. The amino acid composition remained unaffected. In conclusion, the study demonstrates that rapeseed cake can serve as a viable substitute for soybean meal in the diet of Gryllus assimilis.

Effect of Conventional Preservatives and Essential Oils on the Survival and Growth of Escherichia coli in Vegetable Sauces: A Comparative Study

Essential oils have gained attention as natural alternatives to chemical preservatives in food preservation. However, more information is needed regarding consumer acceptance of essential oils in actual food products. This study aimed to compare the effects of conventional preservatives, heat treatment, and essential oils derived from thyme, oregano, and lemongrass on the survival and growth of pathogenic Escherichia coli in vegetable sauces. The results demonstrated a gradual decrease in pathogen numbers over time, even in untreated samples. On the fifth day of storage, heat treatment, sodium chloride, and acidification using citric acid (pH 3.2) exhibited reductions of 4.4 to 5.3 log CFU/g compared to the untreated control. Among the essential oils tested, lemongrass essential oil at a concentration of 512 mg/kg demonstrated the most remarkable effectiveness, resulting in a reduction of 1.9 log CFU/g compared to the control. Fifteen days after treatment, the control samples exhibited a contamination rate of 6.2 log CFU/g, while E. coli numbers in treated samples with heat, sodium chloride, citric acid (pH 3.2), and lemongrass essential oil (512 mg/kg) were below the detection limits. Additionally, sensory evaluation was conducted to assess the acceptability of the treated samples. The findings provide valuable insights into the potential utilisation of essential oils as natural preservatives in vegetable sauces and their impact on consumer acceptance.

ELECTROPHORETIC DETERMINATION OF CHITIN IN INSECTS

An electrophoretic method (on-line coupled capillary isotachophoresis with capillary zone electrophoresis with conductometric detection (cITP-CZE-COND)) for the determination of chitin in insects based on the analysis of glucosamine after acidic hydrolysis of the sample is described. Chitin is deacetylated and hydrolyzed to glucosamine by acidic hydrolysis (6 M sulfuric acid, 110 °C, 6 h). Under optimized electrophoresis conditions, glucosamine (GlcN) is separated from other sample components in cationic mode and detected with a conductometer within 15 min. The performance method characteristics of the GlcN assay, i.e., linearity (0.2-20 μmol), accuracy (103 ± 5%), repeatability (1.9%), reproducibility (3.4%), limits of detection (0.06 μmol/L) and quantification (0.2 μmol/L), were evaluated. On a series of 28 insect samples, it was proven that cITP-CZE-COND provides results of chitin content in insects comparable to the literature data. The important features of the developed cITP-CZE-COND method are easy sample treatment, high sensitivity and selectivity, and low running costs. It is clear from the above that the cITP-CZE-COND method is suitable for analysis of insect samples for chitin content.

Assessment of the Nutritional Quality of Plant Lipids Using Atherogenicity and Thrombogenicity Indices

Dietary lipids derived from plants have different compositions of individual fatty acids (FA), providing different physical and chemical properties with positive or adverse health effects on humans. To evaluate the nutritional value and assess the FA composition of various plants, the atherogenicity (AI) and thrombogenicity (TI) indices were calculated and reviewed for nine different categories of fats and oils. This included common oils, unconventional oils, nut oils originating from temperate regions, Amazonian and tropical fats and oils, chia seed oil, traditional nuts originating from temperate regions, unconventional nuts, seeds, and fruits, and their products. The main factors influencing fatty acid composition in plants are growth location, genotype, and environmental variation, particularly temperature after flowering, humidity, and frequency of rainfall (exceeding cultivar variation). The lowest AI was calculated for rapeseed oil (0.05), whereas the highest value was obtained for tucuman seeds (16.29). Chia seed oil had the lowest TI (0.04), and murumuru butter had the highest (6.69). The differences in FA composition and subsequent changes in the lipid health indices of the investigated fats and oils indicate their importance in the human diet.

Folate contents in insects as promising food components quantified by stable isotope dilution

Concerning the increasing population, edible insects are of growing interest due to several advantages such as sustainable production and as a source of high-quality nutrients. One of the less studied nutrients are folates, in the context of insects is folates, which play an important role in human metabolism. In the article, we describe how six different insect species are reared and extracted for five common folate vitamers by high-performance liquid chromatography interfaced with tandem mass spectrometry (LC-MS/MS). For this purpose, house crickets (Acheta domesticus—adults), Jamaican field crickets (Gryllus assimilis—adults), discoid cockroaches (Blaberus discoidalis—nymphs), migratory locusts (Locusta migratoria—adults), mealworms (Tenebrio molitor), and lesser mealworms (Alphitobius diaperinus) were investigated. The total folate content differs between 59.1 ± 6.50 and 143 ± 11.1 μg/100 g. Also, the feed, which was adapted to the needs of the insects and differed for some species, was extracted for their total folate content. The four different feed compositions (rapeseed, chicken feed, bramble leaves, and a mix of chicken feed, wheat bran, and carrot/apples) showed a folate content of about 100 μg/100 g, except for hay, where the content was 300 μg/100 g. In general, the insect folate content is comparable to other food and seems to be a promising source of folates. However, the amount of consumption needed to meet the requirement must also be considered. Moreover, the effect of different influencing factors is not yet entirely clear and needs further investigation.

The Effect of Microwave Irradiation on the Representation and Growth of Moulds in Nuts and Almonds

Microwave (MW) irradiation is a non-destructive method that can be applied as an alternative method to inhibit the growth of microorganisms. The present study evaluated the effect of MW irradiation on the occurrence of moulds in nuts and almonds. Samples of unshelled natural almonds, pistachios, and in-shell peanuts were treated with different doses of MW irradiation (2400–4000 W). The effect of MW irradiation on mould counts was evaluated by cultivating immediately after irradiation and after 3 and 6 months of storage. The most represented genera in all analysed samples were Aspergillus (68%), Penicillium (21%), and a small amount of Cladosporium (3%). Mould numbers significantly decreased after MW treatment. The treatments with MW irradiations at 3000 and 4000 W significantly reduced the mould colony counts, and their effect persisted during storage; irradiation at 2400 W was partially effective. The strongest effect of MW irradiation was observed in in-shell peanuts. MW irradiation seems to be a promising method for maintaining the microbiological quality of nuts.

Basil – a comparison of the total phenolic content and antioxidant activity in selected cultivars

During the lifetime, the human body forms a considerable amount of free radicals damaging DNA, cell membranes, and their components. A wider application of basil (Ocimum basilicum), an aromatic plant and one of the common gastronomic commodities in the human diet could help to prevent the formation of free radicals and to remove them from the human body. Therefore, determination of antioxidant activity and total content of phenolic substances in selected cultivars of basil (Ohře, Sweet green, Salad leaf, Purple opal, Thai) in a fresh and frozen state and the mixture with another plant (garlic, mint, rocket, spinach) in the fresh and refrigerated state was performed. The total content of phenolic substances in basil was established by the spectrophotometric Folin-Ciocalteu method. DPPH spectrophotometric method was used to analyze the antioxidant activity. The results have shown statistically significant differences between basil cultivars under the same growing conditions. The values of antioxidant activity in frozen samples ranged from 5.1 ±0.4 mg.g-1 AA FW to 11.71 ±0.18 mg.g-1 AA FW and the total phenolic content varied between 2.77 ±0.16 mg.g-1 GAE FW in TH and 8.93 ±0.13 mg.g-1 GAE FW. A statistically significant difference between fresh and frozen samples was established only in the “Ohře” cultivar. After the storage in cold temperatures, all mixtures showed a reduction in the antioxidant activity and total content of phenolic substances. The mixture of basil and mint performed the highest values of antioxidant activity and total content of phenolic substances and significantly differed from the other mixtures most often. The addition of basil and its mixtures to food and beverages can substantially increase their biological value and subsequently also the quality of human nutrition.

Fatty acids profile, atherogenic and thrombogenic indices in freshwater fish common carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss) from market chain

OBJECTIVE

The study examined the fatty acids composition and main nutrients composition in two freshwater fish species in the Czech Republic during one year.

METHODS

Samples of common carp and rainbow trout were taken from a market chain during a year. All samples were homogenized and analyzed for lipid, protein, water, and ash contents. Energy value (E), sum of polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFA) and saturated fatty acids (SFA), atherogenic index (AI) and thrombogenic index (TI) were then calculated.

RESULTS

The freshwater fish on the Czech market chain have beneficial average value content of unsaturated fatty acids, Σ MUFA+PUFA in carp is 69.46% of all fatty acids, similar average value of Σ MUFA+PUFA - 70.83% is in rainbow trout. The calculated average value of AI in carp is 0.52 (SD = 0.06), AI in rainbow trout is 0.63 (SD = 0.07), the average TI in carp is 0.63 (SD = 0.09), TI in rainbow trout is 0.49 (SD = 0.05).

CONCLUSION

Freshwater fish in the Czech market chain have beneficial value of PUFA, so AI and TI indices are low in both species of analysed fish. Regular consumption of fish meat is important in the prevention of cardiovascular diseases.

Vitamin C and nitrates contents in fruit and vegetables from farmers' markets and supermarkets

Fruits and vegetables are the best food sources of vitamin C. However, fruits and vegetables can be also sources of potentially harmful substances to the human body, nitrates being one of these. The aim of this study was to compare vitamin C and nitrates contents in selected fruits and vegetables from supermarkets and local farmers' markets. Samples of plums, strawberries, apples, spinach, red peppers and tomatoes were chosen for analysis. Content of vitamin C and nitrates was analyzed by HPLC/DAD. The hypothesis was that local market fruits and vegetables contain more vitamin C and fewer nitrates than samples bought in supermarkets. Laboratory analyses showed that there were differences in vitamin C in the case of strawberries, tomatoes and red peppers. The highest level of ascorbic acid was in red pepper samples (141 mg.100g-1). In the case of fruit, the highest content was in strawberries (70 mg.100g-1). As far as nitrates content is concerned, in three cases out of six, the fruit and vegetables we tested from farmers' markets contained lower concentrations of nitrates than those purchased at supermarkets and the hypothesis was accepted in these cases. There was no significant difference between the nitrate content of the local market and supermarket strawberries and red peppers. Tomatoes had significantly higher nitrate content when purchased at farmers' markets than at supermarkets. Leafy vegetables are considered to be the major source of nitrates, and this was confirmed by this study. The highest content of nitrates was in the spinach sample (2969 mg.kg-1). Among all fruit samples, strawberries had the highest nitrates levels (maximum 131 mg.kg-1). The results of this work showed that the content of ascorbic acid and nitrates differs significantly depending on the type of fruit or vegetables.

Sensory evaluation and acceptance of food made of edible insects

This paper discusses the sensory analysis of food enriched with selected edible insect species which are labelled as a novel food – house cricket (Acheta domesticus) and mealworm (Tenebrio molitor). Energy bars of two different compositions with the addition of cricket flour and puff pastry bars sprinkled with the whole roasted mealworm larvae were evaluated by consumer tests performed via a questionnaire survey. Respondents represented both men and women in equal numbers and included consumers with the experience of the sensory analysis and edible insects to ensure accurate results. Sensory analyses revealed that respondents associated their tastes with already known flavors (salty, sweet, bitter, fish, French fries, chicken, and mushrooms). The most common answer from respondents was a salty taste, followed by a sweet taste. There were also unusual comparisons such as pine seeds. Consumers’ positive attitude to these energy bars has been registered which shows that the Czech consumer accepts edible insects in a suitable form as a novel food and possible part of the food basket.

Biologically active compounds contained in grape pomace

A healthy lifestyle and gastronomic trends based on traditional and local foods accompanied by waste-free technologies are currently in the primary focus. One of the raw materials with properties in alignment with such requirements is grape pomace. This paper evaluates the antioxidant activity of grape pomace (which is homogenized into a brown powder) and selected commonly available commercial flours – wheat bread, rye plain, and rye whole grain flour – using DPPH (2,2‑diphenyl-1-picryl-hydrazyl-hydrate) and total polyphenol content method, where was used Folin-Ciocalteaure agent and then it was determined by spectrophotometric method (the measure of absorbance). The total amount of polyphenols in grape pomace was measured of 47.94 mg GAE.g-1, but the value 0.27 mg GAE.g-1 was measured in wheat bread flour. Grape pomace performed the antioxidant activity of 57.45 mg AAE.g-1, whereas wheat bread flour of only 0.21 mg AAE.g‑1 Compared to selected commercial flours, the total amount of polyphenols in grape pomace was up to 150 times higher and the ratio of antioxidant activity between grape pomace and wheat bread flour was even more than 280 times higher. This makes it possible to fortify commercial, commonly available flours with different amount of grape pomace so that products with a higher amount of biologically active substances can be prepared. Another benefit could be a reduction in health risks and a contribution to improving consumer health.

The effect of fatty acid profile on the stability of non-traditional and traditional plant oils

The effect of fatty acid composition on the autoxidation of selected plant oils (rapeseed (canola) oil, corn oil, frying oil, grapeseed oil, pomace olive oil, rice bran oil, sunflower oil and high oleic sunflower oil) during their storage was studied. Oils were purchased in retail food stores. Oxidative stability of plant oils was monitored during the storage under the Schaal test conditions at 60 °C in 100 mL beakers and the dark for 40 days. The weight changes, the peroxide and acid values were analysed during the storage. Changes in the composition of fatty acids were analyzed by the gas chromatography-mass spectrometry. The results obtained by monitoring the weight changes of oils correlated with their peroxide values. The induction period in case of grapeseed and sunflower oils was 27 and 28 days respectively. The induction period for frying and rapeseed oils were around 35 days. The remaining four oils had induction periods over 40 days. The acid values at the end of experiment correspond to both the relative weight gain and the the peroxide values. The stability of oils depended mainly on the degree of fatty acids unsaturation. A strong negative correlation between oleic acid content and oil stability expressed as the peroxide value was found. The significant positive correlation was found in case of linoleic acid. The relative content of polyunsaturated fatty acids decreased during the storage while the content of saturated and monounsaturated fatty acids increased. The highest relative increase in oleic acid was found at the least stable oils, grapeseed and sunflower oils, by 37.5% and 25.3% respectively. The initial content of free fatty acids monitored by the acid value did not affect the oxidation rate. With consideration to all monitored parameters the grapeseed and the sunflower oils were the least stable. The most stable ones were olive pomace and high oleic sunflower oils.

The Effect of Barley and Lysine Supplementation of Pasture-Based Diet on Growth, Carcass Composition and Physical Quality Attributes of Meat from Farmed Fallow Deer (Dama dama)

Fallow deer (Dama dama) are important meat producing species providing venison and other products to an international market. The present study investigated the effects of different feed rations on the growth, carcass characteristics and physical attributes of the longissimus lumborum (LL) and semitendinosus (SET) muscles of 45 farm-raised male fallow deer. The animals were divided into three separate groups: 15 pasture-fed (P), 15 pasture-fed and supplemented with barley (B), and 15 pasture-fed and supplemented with barley and lysine (BL). The animals were slaughtered at an average age of 17 months at three time points: after 155, 169 and 183 days on feed. The addition of barley to the feed ration significantly increased weight gain and had positive effects on slaughter and carcass weights, dressing-out proportion, carcass composition, the weight of LL muscle, and increased the redness, yellowness and chroma values of LL muscle. The supplementation with lysine reduced the amounts of carcass and internal fats without compromising other economically important traits.

Effect of sex on the nutritional value of house cricket, Acheta domestica L

Since January 2018, insects have been recognised as novel foods in the EU, but their nutritional value varies, and factors affecting their nutritional composition have been debated. We investigated the effect of sex on the nutritional value and chemical composition of the house cricket (Acheta domestica L.). Both sexes were rich in protein and lipids. The proximate composition was partly influenced by sex; females contained a significantly higher amount of lipids (18.3-21.7 vs 12.9-16.1 g/100 g dry matter, p = 0.0001) and fewer proteins than males (61.2-64.9 vs 66.3-69.6 g/100 g dry matter, p = 0.0001). Males contained more chitin (p = 0.0015) and nitrogen chains (p = 0.0003) than females. Only the ash (p = 0.4314) and nitrogen-free extract (p = 0.4871) were uninfluenced by sex. Furthermore, nutrient quality expressed as essential amino acid (72.3-77.1), thrombogenicity (1.22-1.45), and atherogenicity indices (0.53-0.58) did not differ between sexes (p > 0.05).

Ensuring Food Integrity by Metrology and FAIR Data Principles

Food integrity is a general term for sound, nutritive, healthy, tasty, safe, authentic, traceable, as well as ethically, safely, environment-friendly, and sustainably produced foods. In order to verify these properties, analytical methods with a higher degree of accuracy, sensitivity, standardization and harmonization and a harmonized system for their application in analytical laboratories are required. In this view, metrology offers the opportunity to achieve these goals. In this perspective article the current global challenges in food analysis and the principles of metrology to fill these gaps are presented. Therefore, the pan-European project METROFOOD-RI within the framework of the European Strategy Forum on Research Infrastructures (ESFRI) was developed to establish a strategy to allow reliable and comparable analytical measurements in foods along the whole process line starting from primary producers until consumers and to make all data findable, accessible, interoperable, and re-usable according to the FAIR data principles. The initiative currently consists of 48 partners from 18 European Countries and concluded its "Early Phase" as research infrastructure by organizing its future structure and presenting a proof of concept by preparing, distributing and comprehensively analyzing three candidate Reference Materials (rice grain, rice flour, and oyster tissue) and establishing a system how to compile, process, and store the generated data and how to exchange, compare them and make them accessible in data bases.

Comparing the quality of honey from beekeepers and honey from the market chain

Honey is a valuable food for its beneficial nutritional and dietetic effects. The quality of honey fluctuates considerably according to various criteria, the adulteration of honey with cheaper substitutes is not negligible. The quality of honey in the market chain with honey taken from beekeepers was compared in this study. A total of 10 samples from each group were tested for basic qualitative markers and compared with legislative criteria. The samples were analysed for fructose and glucose content, water content, titratable acidity and two tests for illegal sugar additions. The results revealed the addition of 25% of the technical syrup in one sample of honey from the market chain, one sample had the sum of fructose and glucose 56,3%, it is below the required limit 60% (differed by 6,3%). In other parameters the samples complied with the valid legislation. All tested parameters in honey from beekeepers met the criteria of the legislation, only 1 sample of blossom honey had the sum of fructose and glucose just below the required limit. The sum of fructose and glucose in this sample was 58.3 %, it differed by 2.9% from the required content of 60%. Sensory analysis was used to assess four samples of honey from beekeepers collected by different techniques. Results have not shown significant difference in sensory properties between manually pressed honey and honey obtained after whirling. The responses characterizing the favourable sensory properties of the examined honey samples were prevailing. The difference between the perception of honey after whirling and honey harvested by press manually was not demonstrated in sensory properties.

Formation of oxysterols during thermal processing and frozen storage of cooked minced meat

BACKGROUND

Cholesterol is susceptible to oxidation and the formation of oxysterols, which could have a negative health effect. The formation and distribution of oxysterols was investigated in meatloaves prepared under different baking regimes with an increased temperature or prolonged time. The effect of frozen storage and marjoram addition on the level of oxysterols was also investigated.

RESULTS

The effect of baking regime on the content and distribution of oxysterols was determined. Temperature was the most important factor affecting 7-ketocholesterol formation in baked meatloaf. Its content was significantly higher after baking at 250 °C compared to at 180 °C. The content of 7-ketocholesterol increased from the centre (87 µg kg^-1 ) to the surface (122 µg kg^-1 ) of baked meatloaves prepared under standard conditions. The level of α-tocopherol and its distribution was also affected by the baking regime. A higher level of 7-ketocholesterol was found in baked meatloaves after their frozen storage. The addition of marjoram did not change this level.

CONCLUSION

Inadequate culinary conditions used for preparation of baked meat can contribute to an increased oxysterol intake in the diet. Frozen storage did not stop oxysterol formation. The inhibition effect of marjoram on sterols oxidation was not confirmed. © 2017 Society of Chemical Industry.

Effect of humates in diet of dairy cows on the raw milk main components

The effect of supplemental humic substances (HS) on the main milk components was investigated. A total of 10 dairy cows (Czech pied cattle, crossbred Czech pied cattle ´ Ayrshire and crossbred Czech pied cattle ´ Red Holstein) were tested. Animals were randomly divided into 2 groups, control (C) and experimental (E). Animals fed the same feed mixture and group E was additionally supplemented with HS (200 mg.kg-1 of product Humafit prepared from the Sakhalin Leonardite). The experimental period took 3 months. Cows were milked twice a day. The milk composition (lactose, fat, crude protein, pure protein and casein) of every cow was monitored on days 0, 14, 28, 42, 56, 70 and 84 of the experiment. Pure protein content was determined by Kjeldahl method, other components were analysed using an infrared analyserMilkoScan FT 120. It was found that the crude protein, pure protein and casein content in milk of group E significantly (p <0.05) increased from the 56th day of the experimental period. Differences of the protein fraction contents in group C and of the dry matter, non-fat dry matter, lactose and fat content in both groups were non-significant (p <0.05).Higher protein and especially casein content in milk could be very important for the cheesemaking as it could increase the cheese yield.

Electronic nose in edible insects area

Edible insect is appraised by many cultures as delicious and nutritionally beneficial food. In western countries this commodity is not fully appreciated, and the worries about edible insect food safety prevail. Electronic noses can become a simple and cheap way of securing the health safety of food, and they can also become a tool for evaluating the quality of certain commodities. This research is a pilot project of using an electronic nose in edible insect culinary treatment, and this manuscript describes the phases of edible insect culinary treatment and methods of distinguishing mealworm (Tenebrio molitor) and giant mealworm (Zophobas morio) using simple electronic nose. These species were measured in the live stage, after killing with boiling water, after drying and after inserting into the chocolate.The sensing device was based on the Arduino Mega platform with the ability to store the recorded data on the SD memory card, and with the possibility to communicate via internet. Data analysis shows that even a simple, cheap and portable electronic nose can distinguish between the different steps of culinary treatment (native samples, dried samples, samples enriched with chocolate for cooking) and selected species. Another benefit of the electronic nose could be its future introduction into the control mechanisms of food security systems (e.g. HACCP).

The effect of oregano essential oil on microbial load and sensory attributes of dried meat

BACKGROUND

Microbial load can be controlled using either synthetic or natural preservatives. Particular interest has been focused on the potential application of plant essential oils as safer additives for meat. However, there is no published research on the use of essential oils during the meat drying process. This study was focused on enhancing the meat drying process by using oregano essential oil (OEO) to inhibit the growth of bacteria and thus obtain a value-added dried meat product. The sensory response from assessors is presented.

RESULTS

It was found that the application of OEO in meat was effective in inhibiting Salmonella enteritidis and Escherichia coli. After 6 h of drying at 55 °C, 2 mL (0.038 mL L^-1 air) and 1.5 mL (0.028 mL L^-1 air) of OEO were considered as the minimal inhibitory concentrations (MICs) against S. enteritidis and E. coli respectively. Samples treated with 0.75 mL of OEO were more attractive for consumption compared with the control; at a higher concentration of OEO, the sensory quality of the food was affected.

CONCLUSION

A value-added dried meat product obtained by using OEO to enhance food safety received an acceptable sensory response from consumers. © 2016 Society of Chemical Industry.

The estimated possibilities of process monitoring in milk production by the simple thermodynamic sensors

The characterization and monitoring of thermal processes in thermodynamic systems can be performed using the thermodynamic sensors (TDS). The basic idea of thermodynamic sensor is possible to use in many various applications (eq. monitoring of frictional heat, thermal radiation, pollution of cleaning fluid, etc.). One of application areas, where the thermodynamic sensor can find the new area for a using, is a production of milk products - cheese, yogurt, kefir, etc. This paper describes the estimated possibilities, advantages and disadvantages of the use of thermodynamic sensors in diary productions and simple experiments for characterization and monitoring of basic operations in milk production process by thermodynamic sensors. The milk products are often realized by fermenting or renneting process. Final stages of fermentation and renneting processes are often determined on the base of sensory evaluation, pH measurement or by analytical method. The exact time of the fermentation process completion is dependent on various parameters and is often the company know-how. The fast, clean and simple non-analytical non-contact method for monitoring and for the determination of process final stages does not exist in this time. Tests of fermentation process, renneting process and yoghurt process by thermodynamic sensors were characterized and measured in this work. Measurement of activity yeasts was tested in first series of experiments. In second series of experiments, measurement of processes in milk production was tested. First results of simple experiments show that the thermodynamic sensors might be used for determination of time behaviour of these processes. Therefore, the milk products (cheese, yogurt, kefir, etc.) is opened as a one of new application areas, where the thermodynamic sensor can be used.

Antifungal effect of essential oil components against Aspergillus niger when loaded into silica mesoporous supports

BACKGROUND

Essential oil components (EOCs) are known for their antifungal properties; however, their high volatility limits their application as antimicrobial agents. Strategies used for controlling the volatility of EOCs include encapsulation or loading into porous materials. This study evaluated the in vitro antifungal activity of selected EOCs (carvacrol, cinnamaldehyde, eugenol and thymol) against the fungus Aspergillus niger when loaded into MCM-41 and β-cyclodextrin (β-CD).

RESULTS

Carvacrol and thymol in Mobil Composition of Matter No. 41 (MCM-41) displayed remarkable enhanced antifungal properties in comparison to the pure or β-CD-encapsulated EOCs. In fact, carvacrol and thymol were able to maintain antifungal activity and inhibit fungal growth for 30 days, suggesting better applicability of these EOCs as natural preservatives.

CONCLUSIONS

The sustained antifungal effect of EOCs encapsulated into silica mesoporous supports was described.

The effect of food with different glycaemic index on the blood glucose level

Blood glucose levels are affected by many factors including the type of foods consumed, processing technology and cooking method. Hormone insulin lowers blood glucose to its constant level, while glucagon, growth hormone, adrenalin and glucocorticoids have the opposite effect. High steepness of the blood glucose level rise after meals may be unfavourable for the organism. Sugars are transferred into the blood at different speeds according to the type of food. Therefore the aim of this study was to confirm experimentally the effect of food on blood glucose levels in men and women of different ages. Two types of low, medium and high-glycaemic index (GI) foods were given to 4 men and 4 women of different age (from 35 to 65 years). All volunteers were healthy, slightly overweight, and without any regular sporting activity. None of them had any idea about their daily carbohydrates consumption and what the term glycaemic index meant. The volunteers came to the GI determination fasted in the morning. Their rise in blood glucose level was monitored by glucometer before the meal and after 1 and 2 hours of the consumption of baked potatoes (GI 85), white bread bun (GI 70), boiled potatoes (GI 64), rye bread (GI 62), potato dumplings (GI 52) and white cooked spaghetti (GI 41). Fasting blood sugar levels of volunteers highly depended on their age (p <0.0001) and gender (p <0.0001). The blood glucose values increased with age and were higher in men than in women. Significant influence of food GI on blood glucose levels in both men and women in all the age categories was observed (p <0.0001). An interaction between age and gender was also statistically highly significant (p <0.0001). One hour after consuming food the blood glucose values were significantly different from the values of fasting (p = 0.0035). The differences of these values did not depend on the age (p = 0.0574) and sex (p = 0.8256) of volunteers, but there was a significant difference on the GI value of food (p <0.0001). Significant interactions were also found in case of sex*age (p = 0.0002), age*GI (p <0.0001) and age*sex*GI (p <0.0001). Medium correlation was found between the GI values of food and the rise of blood glucose levels after 1 h (r = 0.6468). After the consumption of high-GI foods the values of glycaemia did not returned to their fasting levels even after 2 hours. There was still significant difference (p = 0.0032), but the values after 2 h were also statistically different from those after 1 hour (p <0.0001). The response to a particular type of consumed food depended on age (p = 0.0018) and especially the GI of foods.

Qualitative parameters of non-traditional types of vegetables

The main aim of this study was to determine selected quality indicators of non-traditional types of leafy vegetables. Mizuna (Brassica rapa japonica), Chinese mustard (Brassica juncea), edible chrysanthemum (Chrysanthemum coronarium) and arugula (Eruca sativa) belonged among the selected species of vegetables. During the one-year experiment, spring and autumn sowing was carried out for these species of vegetables. The measured quality parameters were the content of nitrates and ascorbic acid. Sampling was done in the morning and in the laboratory, the samples were further processed according to the type of determination. To determine the content of nitrates and ascorbic acid, leaves were removed from plants. The filtrate from the leaves was then prepared. Determination of nitrates and ascorbic acid was carried out using a special test strip and device Rqflex plus 10. The results of measurement of both sowing varieties were compared. Total nitrate content was higher up to 22% in plants sown in the autumn except edible chrysanthemum (Chrysanthemum coronarium). The highest content was recorded in arugula (Eruca sativa), which was recently implemented to the studies of the European Union and for which there were set the limits of nitrates. Overall, the nitrate content ranged from 221 to 334 ppm in spring varieties and from 249 to 384 mg/kg in autumn varieties. Ascorbic acid content was very high in Chinese mustard (Brassica juncea), edible chrysanthemum (Chrysanthemum coronarium) and arugula (Eruca sativa) in both spring and autumn varieties. Values of ascorbic acid ranged from 839 in autumn sowing up to 2909 mg/kg in spring sowing. These non-traditional types of leafy vegetables could be included among the other importants sources of vitamin C in the future.  

Comparison of the carbohydrate content in apples and carrots grown in organic and integrated farming systems

The aim of this study was to compare some quality parameters of apples and carrots from organic and integrated farming systems. In addition, the cultivars of carrots were grown in two plant densities (600 or 900 thousand plants per hectare). The fructose, glucose, saccharose and dry matter content of seven apple cultivars (Florina, Zvonkové, Topaz, Šampion, Ontario, Melrose and Idared) and two carrot cultivars (Afalon F1 and Cortina F1) were analysed by HPLC and gravimetric methods, respectively. Significant differences were found between organic and integrated apple samples. The interactions between cultivars and farming methods were also significant (p <0.0001). The dry matter and sugar level tendencies were not the same for all apple cultivars. Conversely, more consistent data were obtained for the two carrot cultivars. The bio carrots of both cultivars showed significantly lower dry matter content (p = 0.0004) and higher carbohydrate content (pfructose = 0.0303, pglucose = 0.0003, psucrose = 0.0083) than the samples from integrated production. Other factors like cultivar and plant density also played an important role in sugar content in carrots. Different densities of plants significantly affected the glucose content (p = 0.0373). Cultivar Aftalon F1 showed higher concentration of monosaccharides compared to Cortina F1 (pfructose = 0.0001 and pglucose <0.0001).

Quality of hemp seed oil depending on its obtaining

Hemp (Cannabis sativa L.) is probably one of the oldest field crops used in nutrition, but also for the production of fibres for clothes, ropes or canvas. Cannabis sativa is one of the most spread species of cannabis which belongs to family Cannabinaceae. The seeds are important part of cannabis sativa, which contains high part of lipids and proteins. It provides also valuable essential fatty acids, carbohydrates, fiber, vitamins and minerals. Due to low content of THC is possible to produce valuable oil from seeds, which is used in cosmetic and food industry. The aim of this work was to evaluate composition of hemp seeds from one harvest, observe and compare quality of parameters both cold pressed hemp seed oil and hemp seed oil by CO2 extraction.  Both oils are comparable in composition of fatty acids which follow from results of analyses. Also contents of sterols and moisture are similar in both oils. The saponification value is similar in both oils, conformable to as a iodine value. Also were found dissimilarities in colours, phospholipides, unsaponifiable matter, acid value and peroxide value. The cold pressed hemp seed oil contained lower values of unsaponifiable matter, colours and higher concentration of phospholipides and lower acid value. It is caused by influence of CO2. The oxidation stability of cold pressed hemp seed oil was four times higher than oil by CO2 extraction.