Potravinarstvo Slovak Journal of Food Sciences
Not a member yet
1254 research outputs found
Sort by
Morphological and antiradical characteristics of Rugosa rose (Rosa rugosa Thunb.) fruits canned in different kind of honeys and in beverages prepared from honey
Get PDFThe aim of the work was to determined the basic morphological and morphometric traits of rugosa rose (Rosa rugosa Thunb.) and antiradical activity of fruit pulp canned in different kind of honeys and in beverages prepared from honey. In experiments there were used 4 genotypes of roses originated from arboretum Mlyňany (Slovakia). The evaluation of 11 morphometric traits of fruit showed that the average weight of the fresh fruit without pedicle reached up 5.14 - 5.46 g, the weight of pedicle was 0.05 - 0.08 g, weight of pulp and seeds 4.80 - 5.13 g, weight of calyx 0.25 - 0.31 g, length and width of fruit (16.10 - 18.13 mm, 21.38 - 22.46 mm), the number of seeds in fruit 48.45 - 71.05, thickness of pulp 2.63 - 2.97 mm. Separated fruit pulp was canned at 40 °C and 80 °C and premixed in robinia honey and honeydew honey. Beverages were prepared by mixture of fruit pulp in honey (15 g) with cold water (150 mL). Antiradical activity was determined by DPPH method in fruit pulp (in methyl alcohol and water extracts), in honeys (black locust honey and honeydew honey) and beverages. There had been confirmed statistically significant differences in morphological traits, especially in colour and shape of fruit. Antiradical activity of fresh fruit pulp in methyl alcohol extract was determined 94.59%, in water extract 89.71%. Antiradical activity of black locust honey was 7.63%, honeydew honey 6.54%. Antiradical activity was determined also adding honeydew honey and black locust honey to fresh pulp of fruit prepared at 80 °C (33.55% and 77.58%). In beverages prepared from fresh pulp, honey and water it was investigated the higher values of antiradical activity in samples with addition of honeydew honey (81.81 - 83.86%) in comparison with robinia honey (75.57 - 79.96%)
Recombinant metalloprotease as a perspective enzyme for meat tenderization
Get PDFeptidase family M9 (MEROPS database) is true collagenases and contains bacterial collagenases from Vibrio and Clostridium. One of the producers of M9A subfamily peptidase is Aeromonas salmonicida (locus - ASA_3723). The aim of the study was production of recombinant metallopeptidase Aeromonas salmonicida by transformation Pichia pastoris for further meat tenderization. Laboratory amounts of recombinant peptidase were obtained and test evaluation of enzyme activity was performed. Recombinant peptidase broke the peptide bond «Pro-Leu-Gly-Met-Trp-Ser-Arg» (one of the collagen chains, (Mw = 846.06)). The concentration of the substrate (peptide) after 180 min was 2 – fold decrease as compared with control. The maximum shear force of heat-treated samples had a 1.27 – fold decrease as compared with the control. As a result of histological studies of beef shank samples, the specific effect of the supernatant on the structure of connective tissue was established. Muscle fibers have not changed. The recombinant enzyme could be used for the meat tenderization
Unusual aspects of the fat content of mealworm larvae as a novel food
Get PDFThe work focuses on some aspects of content and properties of the fat in mealworm as a novel food. The total fat content of this species is a markedly variable nutritional value that is significantly dependent on the breeding conditions. In this work, the fat content of a mealworm from various Czech suppliers ranged from 202 g.kg-1 to 282 g.kg-1 dry matter, determined using the Soxhlet extraction method. The total average value from all suppliers was 235.8 ±40.8 g.kg-1. This is a range that can be expected by the customer when buying mealworm larvae from a random Czech supplier. Furthermore, the work graphically compares the values of the total fat content with other comparable commodities of animal origin, e.g. chicken or fish. Finally, the aim was to obtain initial information about the comparison of the sensory properties of the mealworm fat with other fats of animal origin using a simple electronic nose. There was a difference between the fat obtained from insect larvae and the conventional unprocessed fats. This work brings a wider view of fat as a taste carrier in a new food - a mealworm
Use of some biostimulants to improve the growth and chemical constituents of sweet pepper
Get PDFThe experiment was conducted during two successive seasons 2016 and 2017 on sweet pepper plants to study the effect of foliar application of some natural extracts (fulvic acid at 2, 4 and 6% or algae at 1, 2 and 4 g.L-1) were applied three times along each season (after 2, 4 and 6 weeks of planting). The influence was evaluated through the response of vegetative growth, and some physical and chemical characteristics of sweet pepper fruits. The results obtained showed that the algae extract at 1 g.L-1 in most cases was better than the other spray treatments investigated to improve most fruit characteristics (length, diameter and yield of fruits), vegetative growth, and chemical properties followed by 6% fulvic acid. With regard to organic acids, malic and citric acids are the main organic acids found in sweet pepper. Malic, succinic and glutaric acids were higher in 1 g.L-1 algae extract treatment, but the concentration of citric acid was higher in 6% fulvic acid treatment. Therefore, algae extract and fulvic acid could be safely recommended as a natural biostimulants application for improving most desirable characteristics of sweet pepper grown under the same experimental condition
Physical factors relevant for efficient Hawthorn fruit extraction
Get PDFToday, the healthy nutrition market is one of the most promising market niches; modern consumers increasingly claim fortified products for their diets. One of the ways to increase the biological and physiological value of products is their enrichment with extracts of plant origin. The aim of the work was to study the influence of various factors on the process of hawthorn fruit extraction and determine the optimal parameters of the technological process. The study objects were hawthorn fruit extracts produced by the statistical method of maceration (with stirring). In the extracts obtained, there were determined the quantitative content of tannins and pectin substances, dietary fiber and vitamins. Currently, the global health and wellness food market is steadily growing due to changes in consumer behaviour patterns and developing of healthy self-consciousness. The studies conducted by the authors have shown that extracting of plant materials and the efficiency of biologically active substances extraction are influenced by the following factors: the extractant pH, grinding type and size of raw materials and process parameters. The optimal technological regimes have been established. They are the extraction temperature of 60 °C and extraction time of 30 minutes. The appropriate grinding size of dry hawthorn fruit has been determined to be up to 2.8 mm of a particle. In case of milk being an extractant, a high extraction dynamic of pectic substances and dietary fibers was observed. So, the hawthorn milk extract has been revealed to have higher organoleptic characteristics
The Studying the processing of food dye from beet juice
No full textThe manuscript describes a new method of red beet processing and the technology of manufacturing food colorant from the juice concentrate, which is natural, safe and useful analogue to existing expensive offers on the market of similar goods that have chemical origin not useful for regular consumption. Nowadays in order to give to food products a colour, close to natural coloring of fruits and vegetables, expensive synthetic dyes are used, which might have cancer-inducing effect when being accumulated by human organism. Therefore improving the technology for producing food grade dye from red beet juice is remarkably important task. Currently, there is a problem for vegetable processors - pectin substances complicate the process, like the illumination of juice and negatively affect its storage capacity. The article below reveals and substantiates the necessity of using a natural carbon-containing adsorbent shungite for the purification of beet juice from pectin substances. On the basis of the study, the authors suggest a more cost-effective way of producing a food dye from juice concentrate, which allows avoiding usage of expensive enzyme processing additives
Evaluation of the adaptogenic propertries of the Quark product enriched with probiotics, polyphenols and vitamins
Get PDFThe aim of the study is to evaluate protective properties of the quark product manufactured with transglutaminase and enriched with probiotics, oligomerous proanthocyanidines and vitamins; the biological experiment on the growing laboratory Wistar stock rats has been carried out. The rats of two from three groups subjected within 21 days to the effect of low-frequency weak variable magnetic field received in semi-synthetic diet composition extra experimental and control samples of the quark product. The index of feed intake and the rats’ body mass growth was registered within 32 days. At the end of the experiment blood serum biochemical index was evaluated. It was revealed that the animals consuming the experimental product substantially gained the mass before the effect (gain from the 1st up to 10th days made up 12%) as well as after effect (gain from 11th up to 32nd days – 10.3%); upon completion of the experiment the gains of these animals exceeded the gains of the rats consuming the control product by more than 28%. The experiment revealed the lipolipedemic and hypoglycemic effect of the experimental quark product that has been evidenced by the significant reduction of cholesterol (by more than 20%), glucose (up to 40%) in the rats’ blood serum. On administration of the experimental dairy product in the animals’ diet subjected to the impact of low-frequency weak magnetic field the effect of the broken balance recovery in antioxidant/pro-oxidant system was observed due to reduction of pro-oxidant load at the enzymatic as well as low molecular links of the antioxidant system. The identified antioxidant and adaptogenic effect of the developed dairy product promoting to reduce the intensity of free-radical oxidation at the impact of low-frequency electromagnetic field on the body make it possible recommend it in dietotherapy for correction of antioxidant/pro-oxidant status
Gender differences in consumer preferences when buying dairy products in Slovakia and Russia
Get PDFIn spite of geographical and culture differences between examined countries, there can be found similarities in consumer behavior of men and woman and also the similar tendencies on the dairy product market. In the last decade different fields of science concerns with the topic of gender differences more frequently. The article is based on a research of consumers' overall attitude to dairy products in Slovakia and Russia. The important role of gender differences underlines the outcomes of the questionnaire survey. Kruskal-Wallis test and Bonferroni correction was applied to verify the hypothesis whether there is a dependency between gender of the respondents and their attitude while choosing the dairy products in both countries. Analysis showed that in both countries women tend to buy dairy products more often than men. Also consumers prefer more domestic products, but Russian not as significantly as Slovakian. In both countries consumers consider the price of dairy products as high, but they don”™t outline the price as the most important factor when choosing dairy products. At the same time, both genders consider quality as the most important factor. These results indicate the existence of a niche at the Russian market, which could be used by Slovak dairy producers who can possibly penetrate Russian market. In addition, the similar marketing strategy for both, Slovak and Russian market can be used if the advertisement will be sensitively focused on the gender
Loop-mediated isothermal amplification (LAMP) for rapid detection of L. monocytogenes in meat
Get PDFThere is a continued need to develop improved rapid methods for detection of foodborne pathogens. Rapid and sensitive methods for enumeration of Listeria monocytogenes are important for microbiological food safety testing purpose. The aim of this project was to evaluate a commercial loop-mediated isothermal amplification (LAMP) based system with bioluminescence, named as 3M™ Molecular Detection Assay (MDA), was validated for the detection of L. monocytogenes in food products with a standard GOST 32031-2012 method as reference. The results of this study revealed that a commercial LAMP-based method performed equally effective compared with method, showing from 94% to 100% specificity and sensitivity, respectively. The LAMP-based method was shown to be rapid and reliable detection technique for L. monocytogenes present at low numbers (10 CFU.g-1) on raw meat and meat products and can be applicable in meat industry. Thus, compared with the microbiological method based GOST 32031-2012, the LAMP assay is a relatively rapid and highly sensitive method for detecting L. monocytogenes and will facilitate the surveillance for contamination of L. monocytogenes in food. The 3M MDS result and culture-based detection (GOST 32031-2012) did not differ significantly (p >0.05) regarding the number of positive samples
Rural production of tropically adapted breeds of chickens in rural areas of Kwara state, Nigeria
Get PDFChicken keeping is a common thing with most household in rural areas of Nigeria. The birds are raised under extensive system of production with little or no feed provided by the farmers for the birds, hence there is the need to compare the rate of egg production of six different breeds of chickens reared under the same conditions in the rural areas. Twelve villages were randomly selected from the long list of villages in Kwara, 20 households per village and 4 villages per senatorial district, with a total coverage of 240 households for the study. The birds that were used for the study were indigenous chicken (Fulani), improved indigenous chickens (Shika Brown, Funaab Alpha and Noiler) and imported tropically adapted birds (Sasso and Kuroiler). Thirty six weeks old pre-vaccinated and brooded chickens of different breeds given to the farmers were managed under the traditional poultry scavenging system in all the three senatorial districts. The non-parametric Kruskal-Wallis test was used for the comparison between districts and breeds. There were no significant differences in egg production per senatorial district, egg production from different breeds and production from different senatorial districts remained averagely low. Low egg production by all the breeds showed that scavenging way of rural chicken production should be improved on for better productivity. This can be achieved through supplemental feed formulated and produced from locally available feed ingredients for the chickens.