Potravinarstvo Slovak Journal of Food Sciences
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Effects of traditional fish processing methods on the proximate composition and ph of fish Black pomfret (Parastromateus niger)
Get PDFFish is an important food in many Iranian diets. This is a good source of protein. Fish is the main source of animal protein in Iran. The effects of three different traditional processing methods (freezing, brining and frying) on nutritive composition of halva sia fish stored under ambient room conditions were determined. Fresh halva sia fish were obtained from Behbahan fish market. Cooking and processing techniques were carried out on fish Halva sia Parastromateus niger. The proximate composition of raw Parastromateus niger was affected by cooking and processing techniques that were carried out by AOAC methods. Moisture contents decreased in fried and brined fillet while protein, fat and ash contents were significantly increased in fried fillet. The loss of moisture in fried and brined samples amounted to the highest levels; also the protein and fat value was proportionally high. The fish Parastromateus niger showed a decrease in their contents of moisture and fat as affected by frozen storage periods while ash and protein contents were increased after frozen storage periods. The nutritional value fish Parastromateus niger preserved until the end of the storage period
Effect of fuzzy-controlled slow freezing on pumpkin (Cucurbita Moschata Duch) cell disintegration and phenolics
Get PDFFreezing has been widely used to preserve vegetables including seasonal pumpkins. This work aimed to investigate the effects of freezing on pumpkin cell disintegration and phenolics. A fuzzy logic control (FLC) system was built to obtain better temperature control of the freezing system. Changes in cellular disintegration, electrical conductivity and phenolics content were evaluated. The angle measure technique and principal component analysis were used to delineate the surface texture changes of the frozen pumpkin cells. The results showed that FLC offered reliable temperature control performance. Freezing at -18 °C for 7 h caused the highest cell degradation of 0.467 on the disintegration scale. Decomposition was also indicated by an almost double increase in electrical conductivity. The changes in texture were accurately reflected in the mean angle spectra and 81.3% and 7.4% of the variability due to treatments could be explained by two principal components respectively. Freezing pumpkin at -18 °C for 6 h correlated to the maximum increase in total phenolics of 70.44%. The increased phenolics were dominated by caffeic acid, chlorogenic acid and p-coumaric acid. In conclusion, as the freezing system exhibits positive effects on the phenolics content of pumpkin, it may be employed to process seasonal pumpkin to obtain higher value from the produce
Antioxidant properties of processed cheese spread after freeze-dried and oven-dried grape skin powder addition
Get PDFProcessed cheese spread (PCS) is a popular product with high nutritional value and containing protein, fat and minerals. Grape skin is waste from winery processing plants that still has phenolic substances with significant antioxidant activity that could be used for valorisation of processed cheese and increasing the content of nutrients, phenolics and overall antioxidant properties. Both oven-dried (OD) and freeze-dried (FD) grape skin (GS) powder was characterised by the principal ingredients, the content of phenolic compounds and antioxidant capacity. Similarly, the influence of the addition of OD-GS and FD-GS powders on processed cheese spread (PCS) at 1% and 2% (w/w) levels were examined. The OD-GS and FD-GS powders were characterised by protein content, fat content, moisture and dietary fibre, thus showing that drying technique did not affect those parameters. The OD-GS powder exhibited higher content of rutin, (+)-catechin, (-)-epicatechin and total flavonoid content (TFC), while higher total phenolic content (TPC) and ABTS radical cation were observed for freeze-dried GS powder. Fortification of PCS with 1% and 2% (w/w) of GS powder increased protein content. An ANOVA procedure revealed that addition of FD-GS powder to processed cheese spread was superior to TPC values together with rutin, (+)-catechin, and (-)-epicatechin contents. The higher phenolic contents reflected the higher antioxidant capacity of PCS samples fortified with FD-GS powder. Freeze-dried gape skin powder was the better choice for valorisation of processed cheese spread
The influence of honey enrichment with bee pollen or bee bread on the content of selected mineral components in multifloral honey
Get PDFBee products, such as honey, pollen, and bee bread, are an excellent source of bioactive ingredients, including minerals, having a health-supporting effect. However, due to the specific sensory properties of bee pollen and bee bread, the best way to include them in a diet is to add them to honey. Therefore, the aim of this paper was to evaluate the influence of the added bee pollen or bee bread on selected minerals content in multifloral honey. The mineral content was analyzed using absorption atomic spectrometry (FAAS) with prior dry mineralization. On the basis of obtained results, it was found that the addition of bee pollen or bee bread to honey significantly influences the content of selected macro- and microelements, excluding sodium. The greatest increase in mineral content was observed for magnesium, iron, and zinc. Enrichment of honey with the highest dose of bee pollen or bee bread resulted in an over 20-fold increase in the Mg and Fe content, and an over 14-fold increase in the Zn content. Honey enriched with the maximum addition of bee pollen was characterized by a higher content of K, Ca, Mg, Fe, and Cu compared to honey with bee bread. Due to a fact that both bee pollen and bee bread are good sources of minerals, their addition to honey significantly increases its ability to cover daily demand for macro- and microelements
The evaluation of extraction of some nut oils using screw pressing
Get PDFToday's consumers prefer low-sugar, low-calorie, natural, and so-called safe products. These trends are also reflected in nuts products and groceries. Globally, the European Union is the largest importing market of edible nuts. Considering the increasing demand for new sources of food, the importance becomes the efficiency of production. This study evaluates the influence of rotation speed in the extraction of almond nut, walnut, hazelnut, cashew nut, and peanut oils using screw pressing. In tested samples, the oil content was on average between 69.14 ±0.79% (walnut) and 46.7 ±1.45% (peanut). From the pressing of oils, it is seen that the oil yield decreased when pressing speed increased (from 30 rpm to 90 rpm, for example in walnut from 0.36 kg to 0.16 kg.h-1) and that the oil sediment yield increased when speed increased (for example in hazelnut nut from 8.51% to 17.37%). The highest amount of oil yields had hazelnut with 3.03 ±0.05 kg.h-1, then walnut with 2.05 ±0.02 kg.h-1, almond nut with 2.34 ±0.05 kg.h-1, peanut with 2.15 ±0.01 kg.h-1, and finally cashew nut with 2.07 ±0.03 kg.h-1
Identification of the needs of primary milk producers in the new common agricultural policy 2021 – 2027
Get PDFAlthough Slovakia belongs to the smallest milk producers in the EU, we have to bear in mind the importance of the milk industry for the economy of Slovakia. Current expectations in Slovakia are that primary milk producers are able to produce milk at the lowest possible price, with state support on the same level as in other EU states, processing companies have a good purchasing price for the raw materials, retailers are able to share margins and to increase the market share of Slovak dairy products and last but not least that consumers buy milk and dairy products produced in Slovakia. Milk production in primary production has a profound ecological and social benefit for our countryside but the most important is the contribution of milk and dairy products to human health. The Slovak dairy sector has experienced three dairy crises and one butter crisis in the last ten years, what caused that up to 37% of milk producers in Slovakia cease their production. Currently, there are 401 approved primary milk producers in Slovakia. This sector is in long-term condition weakened by market fluctuation and by previous crises. Slovakia has a large investment debt in this sector. That is why in order of food security and maintaining employment it should be in the interest of the new government to do everything possible to stabilize this sector. Therefore, the primary objective of this scientific paper is to identify the needs of primary milk producers in Slovakia in relation to the strategic objective – to increase the competitiveness of the milk producers. The research aims to transform the voice of primary milk producers into the new programming documents for the upcoming period of the Common Agricultural Policy (CAP) for the years 2021 – 2027
Diversity of winter common wheat varieties for resistance to leaf rust created in the V. M. Remeslo myronivka institute of wheat
Get PDFThe results of the investigations of resistance winter common wheat varieties to leaf rust are given. The high resistance to the pathogen manifest varieties that contain resistance genes: Lr9, Lr19, Lr37, Lr42 + Lr24, Lr43 (Lr21 + Lr39) + Lr24, Lr9 + Lr26, Lr10 + Lr24 are ascertained. The genes Lr13, Lr34, Lr37 in combination with other resistance genes provides long-term protection to leaf rust wheat. Winter wheat varieties, created at the V. M. Remeslo Myronivka Institute of Wheat, contain resistance genes Lr23, Lr24, Lr26, Lr34. The varieties Vesta, Snizhana, Demetra are protected by the resistance genes Lr26 + Lr34, variety Zolotokolosa– Lr24 + Lr34, Ekonomka – Lr3 + Lr26, Myronivska storichna – Lr3 + Lr23 + Lr10 + Lr26. The allele Lr34 (+) is contained in varieties: Kryzhynka, Vesta, Snizhana, Volodarka, Demetra, Vdiachna, Pamiati Remesla, Sviatkova, Podolianka, Berehynia myronivska, MIP Dniprianka, and Balada myronivska. Sustainability is an important element of an integrated system of plant protection against many diseases, and to ensure increased yields it is necessary to create and distribute sustainable varieties that will be an environmentally promising way to develop the agro-industrial complex of Ukraine
Evaluation of the foliar nutrition influence on selected quantitative and qualitative paprameters of sugar mayze (Zea mays SK saccharata)
Get PDFWe evaluated the effect of foliar application of fertilizer Tecnokel amino Zn on selected quantitative (weight of one corn cob, average length of corn cob, number of grains per row and number of rows per cob) and qualitative (total yield, total carotenoid content, total sugar content) parameters of sweetcorn. The small trail experiment was founded in 2016 in the Botanical Garden of the Slovak University of Agriculture. We observed 7 selected varieties of sweetcorn and two variants: control and with leaf nutrition. 15 plants we revaluated for each variety under both variants. The corn was grown in three repetitions for each variant. Based on the obtained results, we found that both the qualitative and quantitative parameters were mainly dependent on the genotype. Statistically significant was effect of the variety on the total sugar content in maize grains. Influence of foliar nutrition was not confirmed as statistically significant, but Tecnokel amino Zn has a positive impact on several quantitative parameters as weight of one maize ear or average length of corncobs. Content of total carotenoid doesn´t depend on genotype or variant
Antioxidant activities of snakehead (Channa striata) fish skin: peptides hydrolysis using protease tp2 isolate from swamp plant silage
Get PDFThe purpose of this research was to study the antioxidants activities of peptides from skin fish of snakehead (Channa striata), using hydrolysis of protease TP2 isolate from swamp plant silage. This research 5 treatments hydrolysis time (0, 30, 60, 90, 120 min, respectively), with two replicates, which included several stages of preparation and pre-treatment of the snakehead fish skin production of protease enzymes which were isolated from swamp water, preparation of protein hydrolysates, measurement of hydrolysis degrees, analysis of peptides content and analysis of the antioxidant activity. Results showed that the treatment had given a significant effect on the 5% level of the degree of hydrolysis production (13.98% – 27.08%), with peptides content of 2.73% – 3.78% and antioxidant activity (10.75% – 20.7%). The results of the degree of hydrolysis indicate that the longer the hydrolysis time, the percent degree of hydrolysis will increase. Peptide content and antioxidant activity were increased with increasing hydrolysis time
Research on milk homogenization in the stream homogenizer with separate cream feeding
Get PDFHomogenization, which is used in the technological schemes of production of most dairy products, is the most energy-intensive of the processes of mechanical processing of milk. One promising way to increase the energy efficiency of homogenization is to use separate homogenization and to use a little-researched stream homogenizer with separate cream feeding. The principle of its action is to pre-divide milk into cream and skim milk, and feed the fat phase with a thin stream into the stream of skim milk. This creates the conditions for achieving the high value of the Weber criterion - the main factor in the dispersion of milk fat. The purpose of these researches is to conduct experimental studies and determine the energy consumption and quality of homogenization of milk after treatment in a stream homogenizer. To achieve this goal, a designed experimental setup was used. The dispersive indices of the milk emulsion were determined by computer analysis of micrographs of milk samples obtained with an optical microscope and a digital camera using Microsoft Office Excel and Microsoft Visual Studio C # software using the OpenCV Sharp library. As a result of experimental studies, the critical value of the Weber criterion for homogenization of milk was determined, which is 28. The regularities of dispersion of milk fat in a stream homogenizer with separate feeding of the fat phase have been established. It is determined that the milk treatment in the experimental homogenizer allows us to achieve an emulsion with an average size of fat globules of about 0.8 μm (at the level of valve homogenizers). The value of the homogenization coefficient is obtained for the disruption of the fat globule in the conditions: subject to a single effect on the emulsion, without the influence of vibration and cavitation. This homogenization coefficient equals 3300 m3/2.s-1