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

The effect of drying on antioxidant activity of selected lamiaceae herbs

Antioxidant activity and total phenolics content of selected fresh and dried herbs from the Lamiaceae family were compared. The analysed herbs included Thymus vulgaris, Origanum vulgare, Satureja hortensis, Origanum majorana, and Origanum heracleoticum from the 1st and the 2nd harvests. The antioxidant activity was determined using DPPH method and the total content of phenols was analysed using the Folin-Ciocalteu reagent. Ascorbic and gallic acids were used as reference standards. All the analysed herbs had the reasonable potential to reduce the DPPH radical. The dried herbs from the 2nd harvest had the highest antioxidant activity. Oregano exhibited the highest antioxidant activity from the analyzed samples of both harvests together. The descending order of the samples was oregano ˃ Greek oregano ˃ marjoram ˃ summer savory ˃ thyme. Marjoram from the 2nd harvest had the highest antioxidant activity from the fresh samples. The lowest activity was observed in thyme from the 2nd harvest. In case of dried samples, the highest antioxidant activity was measured in sample of Greek oregano from the 2nd harwest. The lowest activity was observed in thyme from the 1st and 2nd harvest again. The descending order of total phenolics content for both harvests together was oregano ˃ Greek oregano ˃ marjoram ˃ summer savory ˃ thyme. In case of fresh herbs the highest total phenolics content was measured in oregano from the 1st harvest, the lowest content was measured in summer savory from the 2nd harvest. Greek oregano from the 2nd harvest had the highest values from dried herbs. Dried thyme from the second harvest had the lowest total phenolics content. The correlation between the DPPH values and the total content of phenols was determined (for fresh herbs: 0.4917; for dried herbs: 0.8698). According to the total content of phenols a statistically significant difference between the fresh and dried herbs from the 2nd harvest (p = 0.0185) was found

Comparison of antioxidant activity, content of polyphenols and flavonoids in liturgical and common wines

This article deals with the comparison of biologically active substances (antioxidant capacity, content of polyphenols and flavonoids) in samples of common and liturgical wines. For determination were chosen these varieties Pinot Noir, Red Traminer and Chardonnay. The total content of polyphenols and flavonoids were found by visible diode array spectrophotometer. For determination of total antioxidant capacity was used the DPPH test. Results of this paper did not prove a general difference between liturgical and common wines, although between individual samples a statistically significant difference was found. Furthermore, the results show considerably higher values of biologically active substances in red wines Pinot Noir against white wine Red Traminer and Chardonnay - the total antioxidant capacity was considerably in excess of values up to 30 times, the total content of polyphenols up to 50 times and the total content of flavonoids up to 50 times. From the content of biologically active substances point of view, the red wine is recommended for human health. © 2019 Potravinarstvo Slovak Journal of Food Sciences

Nutritional values of edible Coleoptera (Tenebrio molitor, Zophobas morio and Alphitobius diaperinus) reared in the Czech Republic

Edible insects have gained the status of highly nutritious food with high protein and fat content. However, nutritional value of insects is not constant. It could be affected by species, developmental stage, rearing technology, nutrition or sex. This study's goal is to determine the protein and fat contents of three edible beetle species (giant mealworm - larvae of Zophobas morio, mealworm - larvae of Tenebrio molitor and, lesser mealworm - larvae of Alphitobius diaperinus) bred in the Czech Republic. Based on the obtained results, all investigated species could be considered as a reasonable source of lipids and two of them (mealworm and lesser mealworm) are also an excellent source of protein. Crude protein content of mealworm (630 g. kg-1 DM) was found to be higher than in other studies. The investigated species of lesser mealworm contained 600 g of crude protein/kg DM, which was equal to the results of other authors. Most authors report a higher content of nitrogen in the giant mealworm than were the values measured by this experiment (390 g.kg-1 DM). The lipid content in the tested samples was found in a range of 170 - 390 g.kg-1 DM. The highest lipid content was found in the larvae of giant mealworm and the lowest lipid content was found in the larvae of mealworm. The determined fat content of lesser mealworms was 290 g.kg-1. The fatty acid profiles of all samples were also determined. © 2016 Potravinarstvo. All rights reserved

The importance of higher alcohols and esters for sensory evaluation of Rheinriesling and Chardonnay wine varieties

For a consumer, one of the first characters for evaluation of wine is its scent. A pleasant aroma of wine associated with the subsequent taste experience can be remembered by the consumer for a long time and appreciated appropriately. For this reason, the aromatic properties of wine are very important to both consumers and producers. The question, however, is to assess the evaluation of wine sensory evaluation based on a rapidly developing chemical analysis without the use of a panel of evaluators. This study has dealt with the problem of the correlation of sensory evaluation of wine with the total content of higher alcohols and esters in wine prepared from the same wine varieties (Rheinriesling and Chardonnay) on the same vineyard under the same climatic conditions and processed using the same production technology in the years 2008 - 2012. The total content of higher alcohols and esters was determined by gas chromatography with a mass spectrometer (GC/MS). The correlation between the sensory evaluation and the total content of higher alcohols has not been established. However, the direct effect of the total content of the esters on the level of the sensory analysis of the two varieties studied was demonstrated. This can be an important economic indicator for a manufacturer who can estimate the sensory quality of the wine only on the basis of chemical analysis and thus estimate the success of the wine on the consumer market. © 2018 Potravinarstvo Slovak Journal of Food Sciences

Detection of selected heavy metals and micronutrients in edible insect and their dependency on the feed using XRF spectrometry

Edible insect can be a valuable source of nutrients, but also a potential source of heavy metals. Quick detection of over-limit heavy metals concentration could be a key to processing and quick distribution of edible insect products. The aim of this work was to evaluate the feed-dependent content of heavy metals in the mealworm and superworm using the X-ray fluorescence spectrometry as an easy, cheap and a timeless screening method for evaluating the content of heavy metals and microelements. Using a handheld analyser the content of Cd, Pb, Cu and Zn were detected. Both analysed species proved dependency of metal content on a feed. Detected level of Cu in mealworm was between 571 mg.kg-1 and 1768 mg.kg-1 and in superworm from 571 mg.kg-1 to 1768 mg.kg-1 based on the feed. The content of Zn was similar, between 725 mg.kg-1 and 1437 mg.kg-1 in mealworm and 555-1482 mg.kg-1 in superworm. The level of Pb was below the detection limit in all samples, thus from this point of view this food seems to be safe. On the contrary, the content of Cd in the dry matter samples was above the food limit - 147 mg.kg-1 to 230 mg.kg-1. From this point of view, the samples were evaluated as unsuitable for consuming. © 2017 Potravinarstvo Slovak Journal of Food Sciences, License

Fat from Tenebrionidae bugs – Sterols content, fatty acid profiles, and cardiovascular risk indexes

This work focused on analysing the content of selected sterols and profile of fatty acids of edible insect species – mealworm (Tenebrio molitor) and superworm (Zophobas morio), which are expected to increase their usability in human nutrition. Sterols content was determined using capillary gas chromatography method. Cholesterol content was determined at 1335 mg/kg in dry matter (DM) for the mealworm, which was less than for superworm (3224 mg/kg DM). Other sterols analysed were stigmasterol and β-sitosterol, which were once again higher in superworm (stigmasterol – 44 mg/kg DM and β-sitosterol – 414 mg/kg DM) than in mealworm (stigmasterol – 18 mg/kg DM and β-sitosterol – 171 mg/kg DM). From the nutritional point of view, the amount of cholecalciferol is also not negligible, which was 190 μg/kg DM in mealworm and 199 μg/kg DM in superworm. Atherogenic index (AI), thrombogenic index (TI), and cholesterol index (CSI) were calculated for both species and compared with the results of other authors. These indexes are often considered predictors of cardiovascular diseases. A potential benefit of both species could be the balanced proportion of sterols of animal and plant origin that could be nutritionally well-accessible and lower weight of dry matter necessary to consume to cover the daily dose of linoleic acid compared to dried beef. © Copyright by Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences.TBU in Zlin [IGA/FT/2019/004]; project BUT in Brno; FEKT [S-17-3934

The study of antioxidant components in grape seeds

The paper deals with the study of antioxidant properties of extracts from vine seeds (Vitis vinifera L.) using spectrometric and chromatographic techniques. Ten vine varieties (Cerason, Laurot, Kofranka, Gewürztraminer, Hibernal, Blaufrankisch, Zweigeltrebe, Erilon, Palava, and Welschriesling) obtained from the years 2015, 2016, and 2017 were selected for the study. The antioxidant activity was determined spectrophotometrically using four fundamentally different methods; the content of total polyphenolic compounds was determined using the Folin-Ciocalteu method. In 2015, the content of 14 antioxidants (gallic acid, caffeic acid, coumaric acid, coutaric acid, ferulic acid, fertaric acid, trans-piceid, trans-piceatannol, rutin, quercetin-3-β-d-glucoside, quercitrin, myricetin, catechin, and epicatechin) were studied. The results of the study show the high content of antioxidant components in grape seeds and the differences in content in individual varieties and in individual years.[IGA-ZF/2020-AP006]; [CZ.02.1.01/0.0/0.0/16_017/0002334

Nutritional potential of selected insect species reared on the island of Sumatra

Inhabitants of the Indonesian island of Sumatra are faced with the problem of insufficient food supplies and the consequent risk of undernourishment and health issues. Edible insects as a traditional and readily available food source could be part of the solution. The nutritional value of insects depends on many factors, e.g., species, developmental stage, sex, diet, and climatic conditions. However, edible insects bred in Sumatra for human consumption have never before been assessed with regard to their nutritional value. Our study involved analyses of crude protein, chitin, fat and selected fatty acid contents of giant mealworm larvae (Zophobas morio), larvae of the common mealworm (Tenebrio molitor) and nymphs of the field cricket (Gryllus assimilis). Crude protein content in the samples ranged from 46% to 56%. Highest (35%) and lowest (31%) amounts of fat were recorded in giant mealworm larvae and larvae of the common mealworm, respectively. Chitin amounts ranged from 6% to 13%. Based on these values, which are comparable to those known from other food insects reared in different regions of the world, the edible species bred in Sumatra could become food sources with a potential to help stave off hunger and undernourishment. © 2017 by the authors. Licensee MDPI, Basel, Switzerland

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). © 2017 Potravinarstvo Slovak Journal of Food Sciences