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Experiment of quality properties of dehydrated fruits
7-15Views:100The lyophilization is the joint application of freezing and drying. It is an up-to-date conserving procedure, the point of which is that the humidity existing in the frozen humid material is transferred from the solid state directly into the gaseous state at a temperature below 0 oC under vacuum. Out of the procedures applied nowadays, this is the most tolerant drying process.
With regard to the high investment and operational costs, freeze drying is applied only for valuable, heat-sensitive materials when the technological aim is to preserve such properties as aroma, taste and colour as well as such components as proteins and vitamins. This procedure is suitable for drying and conserving certain foodstuffs, stimulants, organic chemicals, medicines and similar sensitive and valuable materials.
In our institute, we have been conducting freeze drying experiments with regional fruits and vegetables since the year 2005. During the first phase, we examined the heat- and material transfer as well as the abstraction of humidity, while during the second phase we analysed the rehydration ability and nutrient content of the freeze-dried materials as compared to those dried with the method of convection. Moreover we have conducted penetration measurements with a portable hardness tester.
To sum up the results gained so far, we can state that the quality of the lyophilized materials is better than those dried in the traditional way. It originates partly in the fact that the temperature and pressure applied for the freeze drying are smaller and the drying period is far longer than for the convection drying.
In contrast to convection-dried materials, freeze dried materials set in close to their original water-content, keep their original shape and size after being rehydrated. The reason of it the porous, spongy structure (flexible cell wall) of the lyophilized products which is able to take up moisture quickly. In addition, the lyophilized products can be rehydrated faster than those dried in the traditional way.
Regarding the results of the chemical analyses, the following conclusion can be drawn: the vacuum freeze drying results a small decrease of nutrient content and nutritive value for the lyophilized products.
The results of the hardness tests support the statement that the majority of agricultural materials cannot be considered as an ideal flexible body, because during the experiment the flexibility coefficient changed when going from the surface of the material inwards. In addition, the penetration tests also confirm that the surface of the convection-dried vegetables is at least 1.5-3 times harder than that of the freeze-dried products. The reason of it that it takes place during the drying denaturation processes.
The article summarizes the results of our research work listed above, in accordance with our experiments conducted by using the characteristic fruits (apple, plum) of the Nyírség Region. -
Examination of physical properties of final product and drying properties of combined (convective pre-drying and freeze finish-drying) dehydration method
5-12Views:137In this study, the effects of freeze drying (FD), hot-air drying (HAD) and combined drying (HAD-FD) on drying characteristics, energy uptake, texture, rehydration and color of carrot were investigated. Results showed that HAD-FD significantly improved the drying time compared with FD under the same operating conditions, and the HAD-FD can reduce the total cost of dehydration. The drying kinetics was described by the Henderson-Pabis and the third degree polynomial models in the case of HAD, FD and HAD-FD. The HAD carrot samples were exhibited shrinkage, case hardening, poor rehydration and brown surface. The FD carrot cubes appeared porous structure, excellent rehydration, soft texture and loose color. The HAD-FD samples were superior to HAD products and was nearer in quality to FD products with respect to appearance, rehydration and surface resistance (texture). Finally, it is concluded that HAD-FD is effective in improving the FD drying rate. However, the combined drying has a small-scale adverse effect on product quality.
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Change of antioxidant compounds of spices during drying
77-81Views:134Spices and herbs have been used by humanity for thousands of years, so they are very important plants.
In this study, the change of dry matter content and antioxidant compounds of eight spices (basil, thyme, rosemary, mint, parsley, lemongrass, chives, coriander) have been examined the raw plants and in plants preserved by three different drying methods (an oven in 50–60°C; drying at room temperature; lyophilisation between -40 and -50°C, under pressure), because we wanted to see the change of the parameters.
The water content of raw plants was very high, i.e. the dry matter content was very low. By the application of the three drying methods nearly 100% of the water has left the plants, with the exception of the lyophilized basil and rosemary.
Based on the results related to the original material, lyophilized has proved to be the best treatment for the preservation of antioxidant compounds, however air drying also showed high results for some spices.
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The purple coneflower’s (Echinacea purpurea L.) nutrient requirements investigation in a small plot trial
95-99Views:135During our research, we investigated the purple coneflower's (Echinacea purpurea L.) drug yield and drying loss change with different fertilization settings in a small-plot trial. We measured the raw and dry drug yield, which we harvested in 2016 and in 2017, as well as the drying loss of these yields. Harvest and all other works were performed manually. We dried the harvested herba under prenumbra for three weeks. Based on the obtained data, every fertilization settings’ yield was less than that of the control plots in 2016. We measured the highest drying loss in relation to the N60P80K120 supply in this year. In 2017, we measured the highest yield data in the N75P100K150 fertilization setting.We made single-factor variance analysis to investigate the connection between the quantity of the raw, the dried herba, the drying loss and the different nutrient settings -
Novel Applications of Microwave Techniques in the Food and Environmental Industries
29-34Views:90During the microwave processing, despite the conventional heating, the material heats consistently inside. This property of microwave is utilized by drying and dehydration processes. The thermal sensitivity of raw materials of food industry requires development of gentle, fast and controllable technologies, which is realizable by means of combination of conventional and microwave techniques. The other important application area of the microwave technique is food industrial practice is enhancing the microbial safety of products, mainly by pasteurization processes. In recent time the strict environmental regulation necessitate developing more effective treatment of wastes, waste waters and sewage sludge. Because a part of these techniques are heat and power demanded, the microwave technique may be an alternative process in execution of sludge conditioning, drying or gasification and pyrolysis.
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The examination of the marigold’s (Calendula officinalis L.) nutrient requirement in small-plot trial
61-66Views:150During our research we investigated the marigold's (Calendula officinalis L.) nutrient requirements with different fertilization treatments in small-plot trial. We measured the harvested marigold's drug's raw and dry weight on a weekly basis from July 6th until August 17th. We were using SPME (Solid phase microextraction) and GC-MS (gas chromatograph-mass spectrometer) to examined the effects of the different fertilization settings for the herb's main active ingredients of essential oil's percentage.
It was concluded, based on the results, the N30P40K60 fertilization setting is ideal in terms of the quantity of the marigold drug. Both the raw and the dry weights' measurements of the case, this fertilization setting have the most important effect on the herb's yield. The analysis of variance didn't show significant differences between the plots with different fertilization settings. We discovered relationship between the drying loss and the increasing quantities of nutrients. We think it may be possible the Alpha-thujon's and Alpha-cadinol's production and the drying loss's data are connected, which appear to confirm the N15P20K30 treatment's data.
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Determining factors of test weight in maize (Zea mays L.)
40-42Views:92Most domestic maize production products are sold on markets abroad. Among the increasingly restrictive quality requirements, the demand for the measurement of test weight has also appeared. This measurement is not unfamiliar in the case of other cereals, such as wheat and barley, but it has not been applied widely in maize. It is likely for this reason that we have such little information and research available on this topic. In this study, we show the current state of this field with references from domestic and international literature.
The density of maize is the weight of a particular volume and the most frequent unit is the test weight (kg/hl). This physical quality factor plays important roles in the storage, transport and mill industries. The value of test weight is influenced by many factors. The most important ones are the moisture content of grains, drying temperature, drought, precipitation, early frost, and the hybrid characters of a given genotype (grain type, FAO number). In general, the grain with higher moisture content has lower test weight and the higher temperature during (above 82°C) desiccation also leads to unfavourable values. Factors such as a drought interval after flowering, early frost in the case of hybrids with higher FAO numbers, injuries by insects, as well as fungal infections also influence the structure and moisture content of the maize grain.
In the future, broader studies (hybrid testing, application of new agrotechnical elements) will be needed for understanding of the factors effecting test weight. -
Evaluation of dry matter accumulation of maize (Zea mays L.) hybrids
35-41Views:336The increase of the grain yield of maize is closely correlated with its seasonal dry matter accumulation. Dry matter is accumulated into the grain yield during the grain filling period. The following maize hybrids were involved in the experiment: Armagnac FAO 490, Loupiac FAO 380 and Sushi FAO 340. In order to determine dry matter content, two samples per week were taken on the following days: 22nd, 25th, 28th, 31st August, 4th, 7th, 14th, 18th, 22nd, 25th, 29th September and 2nd, 6th, 9th, 13th October. In the course of sampling the weight of 100 grains from the middle section of 4 ears was measured in 4 replications. Dry matter content was determined after drying to constant weight in a drying cabinet at 60 °C. Harvesting was performed on 13th October 2017.
The daily precipitation sum was determined by local measurements, while the daily radiation and temperature data were provided by the Meteorological Observatory Debrecen of the National Meteorological Service in Budapest. Among the agrometeorological parameters, an analysis was made of the precipitation during the growing season, effective heat sums during the vegetative and generative phase, and the water supplies. The daily heat sums were determined using the algorithm proposed.
The amount of precipitation in the winter period before the 2017 growing season was 210 mm. The soil was saturated until its field capacity. The rather dry and warm March and April had a favourable effect, but there was no worthy amount of precipitation until May (51 mm) due to the condition of the dried seedbed. Sowing was performed on the 5th of May 2017 in a randomised small plot experiment. There was favourable precipitation and temperature during the growing season, thereby providing ideal conditions for maize development, growth and yield formation. There was near average amount of precipitation in each year. The total amount of precipitation in the summer period is 342 mm. Temperature was mostly above the average, but there was no long and extremely warm period.
The Armagnac hybrid reached its highest dry matter mass 126 days after emergence. Physiological maturity was reached sooner (on the 119th day) in the case of Loupiac, and even sooner in the case of Sushi (116th day). The thousand grain weight of Sushi (which has the shortest ripening period) was 286 g at the time of physiological maturity, while that of Loupiac was 311 g. Compared to Sushi, Armagnac showed 12 g more dry matter accumulation (306 g). In the case of all three examined hybrids, physiological maturity was preceded by an intensive phase, when the dynamics of dry matter accumulation was rather quick. On average, Sushi gained 2.8 g dry matter per day between 103 days following emergence and physiological maturity, while the same values were 3.2 g for Armagnac and 3.3 g for Loupiac. The aim of the regression line slope is to predict the behavior of the dependent variable with the knowledge of the values and characteristics of the independent variables using the regression line equation. Furthermore, to determine how the location affected the dynamic of dry matter accumulation in the Armagnac, Loupiac and Sushi hybrids. In regression analysis, the coefficient of explanation showed that the effect of day in the Armagnac was 97%, in the Loupiac 94%, in the Sushi 90 %. The determination coefficient (R2) is useful in determing how the regression equation fits. But, as we have seen, the determination coefficient alone is not sufficient to verify the model’s accuracy, in addition to the determination coefficient (R2), the normality of the data or the residuals, the variance of the variables at different levels, the independence of the data relative to time and non-oblique. Observations are evaluated for the correctness of the fitted model.
Dry matter values decreased evenly and slightly following physiological maturity. According to our research results, it was established that physiological maturity is followed by a moderate dry matter loss. Until harvesting, Armagnac lost 40 g of its thousand mass weight in 29 days, while the same value pairs were 69 g in 36 days for Loupiac and 29 g in 39 days for Sushi. Loupiac – which had the highest weight at the time of physiological maturity – lost the most of its dry weight; therefore, Armagnac and Sushi had higher values at the time of harvesting.
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Impact of nitrogen and sulphur fertilization on the growth and micronutrient content of spring wheat (Triticum aestivum L.)
211-219Views:166Micronutrients are as important as macronutrients for crops. Each micronutrient has its own function in plant growth. Zinc is important for membrane integrity and phytochrome activities. Copper is an essential micronutrient required for the growth of wheat. Manganese is required for enzyme activation, in electron transport, and in disease resistance. The pot experiment was set up in greenhouse on calcareous chernozem soil Debrecen-Látókép with a spring wheat. In certain development stages (according to BBCH growth scale of wheat), at the beginning of stem elongation (29–30), at the heading (51–59), at the flowering (61–69) stage three average plants were removed from all pots for analysis. Fresh and dry weight of the plant samples were measured. Plant leaves after drying were digested by HNO3-H2O2 methods and manganese, zinc and copper contents of plant were quantified by atomic absorption spectrophotometry. At the flowering stage, when the nutrient uptake of plants is the most intensive, the weight of wheat ranged between 0.94–1.57 g plant-1. In this development stage, the NS2 treatment produced the highest weight of wheat, and compared to this the NS3 treatment decreased that value already. The results show unfavourable effect of NS3 treatment. On the basis of microelement content of wheat and the weight of a plant, nutrient uptake by plant were calculated. At the beginning of growth the starter treatment had positive effect on Cu-uptake compared to the NS1 treatment, where the same dose of fertilizer was stirred into the soil. Wheat is very sensitive to copper deficiency, so copper dissolved by starter treatment could be favourable to the early development of wheat. At flowering stage the Zn-uptake of wheat became the highest and it was between 133.7–234.6 mg plant-1. The Mn-uptake of wheat plant was higher than the Cu- and Zn-uptake of wheat.
This phenomenon can be explained by the fact that the untreated soil had higher Mn-content, than Cu- and Zn-content. To summarize the results, it can be stated, that the copper uptake of wheat was more affected by the different treatments in the stage of stem elongation, while Mn- and Zn-uptake of wheat were influenced primarily in the stage of heading and flowering.
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Microbial assessment of potential functional dairy products with added dried herbs
59-63Views:114The market of dairy products is a dynamically developing sector of the food industry. Potential, functional dairy products, made by adding herbs or spices, will have antimicrobial and antioxidant effect due to the active biochemical agents of the plant additives. Furthermore, these active components will widen the storage life of food products and enhance their organoleptic properties too. We worked out a technology for creating fresh cheeses using a gentle pasteurizing method by treating the mixture of raw milk and 1.5% fat contained in commercial milk. As herb additives, we used citronella (Melissa officinalis), and peppermint (Mentha x piperita) harvested by us and dried them via Tyndall-method in convective dryer on 40 °C for 5.5 hours per day. The drying period took three days. We bought dried citronella and mint from the supermarket, which were dried by ionizing radiation, to compare the microbiological pollution with the herbs dried by us.
The main target of this research was to create a microbiologically stable, potential functional dairy product. However, because of the bad quality of the raw milk and the gentle heat treatment we used for sterilizing bulk milk, or else, cheeses were not safe for human consumption. As a consequence, we need further studies to modify our technology and get a microbiologically stable product.
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Evaluation of decreasing moisture content of different maize genotypes
147-151Views:225An experiment was conducted to evaluate the decrease in grain moisture content in three maize hybrids in Debrecen in 2017. Armagnac, Sushi and Loupiac were the examined hybrids in this study. The culture medium and temperature conditions were applied uniformly for all three hybrids. According to the results obtained from the ratio of moisture content of seeds per day, the Armagnac variety in the intensive drying down phase loses more time and moisture content, so it can be concluded that the produced dry matter is more than in the case of other varieties. Armagnac requires more time to achieve yield, while the Sushi and Loupiac hybrids produce less harvest. Regarding the slope of the regression line, the rate of loss of moisture in the grain has been negatively correlated with the amount of “b” in the three examined hybrids. In regression analysis, the coefficient of explanation showed that the effect of day in the Armagnac was 97% in the Loupiac, 95% and in the Sushi 90% of the total dynamic value of moisture motion.
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Weed control possibilities of „energy willow” (Salix viminalis L.)
108-112Views:108In Spring 2005, the owner of the Szalka-Pig Ltd. of Mateszalka, decided to import the willow species Salix viminalis L. and to create a plantation for energy production purposes on the humid arable lands in his ownership. In 2006, he enlarged this area by 43 hectares. The owner further decided not only to plant this species on the more adherent (KA 70), but also onto the incoherent structured sand (KA 30-35). His main argument was that the cost of coal tar derivatives as energy sources was rapidly increasing in Hungary, so he needed to find a cheaper energy source for the drying of his products and for the heating of his buildings. He also planned to change his gas and oil heating equipment.
The willow’s cropping technology is being established in our country. One of our tasks is to work out an adequate weed control plan. The professional and safe use of herbicides can increase the success of production. In our paper, we discuss the data collected on treatments applied in the pre-emergent stage. The applied herbicide combinations (terbutilazin+S-metolaklór, mezotrion+ S-metolaklór, pendimetalin+S-metolaklór, oxyfluorfen+ S-metolaklór) yielded good results in large scale experiments. -
The Effect of Changes in Forest Area on the Transcarpathian Tisza River Basin
181-185Views:66Forests are unique global factors which ensure life for almost every living being on Earth. They play a major role in controlling water flows, preventing erosion and controlling the oxygen content of Earth’s atmosphere. By the end of the XXth century, it was realized that forests help to nature maintain and are vital parts of our natural environment. By the time societies realized this fact, economic and environmental effects had amplified which endanger forests. Due to their good water control and water protection abilities, and their function in climate control, mountain forests can provide a suitable environment for themselves, for their successful growth.
Forests play a major role in soil protection, especially in mountain areas where they prevent soil erosion. By converting surface waters into subsurface waters, forests help with the accumulation of subsurface waters, which are the sources of springs, rivers and streams. In the summer, they protect the soil from drying out by creating a special microclimate. They positively affect the climate of surrounding territories. -
The changes of the purple coneflower’s (Echinacea purpurea L.) herb and radix drug yield under different fertilization conditions
79-83Views:157In this research, the purple coneflower’s (Echinacea purpurea L.) nutrient requirement was examined under different fertilization conditions in a small plot experiment. We measured the medicinal plant’s raw and dry herb and root drug mass and drying loss under different fertilization settings and meteorological factors.
From the drug’s raw and dry mass perspective, based on the results, in our opinion, the control setting exceeded all nutrient settings’ results in 2016. In 2017 and 2018, the N75P100K150 nutrient setting has the biggest herb yield. As for the root yield, it was also the N75P100K150 setting which produced the biggest yield.
The Pearson's correlation test was performed to investigate the connection between the quantity of the raw, the dried herbs, the different nutrient settings and meteorological factors.
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The Effect of Sowing Time and Nutrient Supply on the Yield Stability of Maize
75-80Views:114Sowing time, nutrient supply and plant number play crucial roles in the yield stability of maize. The productivity of various hybrids, each with its own genetic characteristics, was tested for three different sowing times and five different fertilizer doses. The highest yields were achieved at the third sowing time (17. V.), which is unusual, because the second half of the summer was rainy and was favourable for late sowing. The seed moisture content at harvest was higher than the optimal 14-15% at the third sowing time, the hybrids, which have intensive bleeding dynamics, couldn’t reach the lower seed moisture content at harvest of the early sowing. In that case we have to decision whether the plus yield of the third sowing time cover the drying costs.
Some hybrids produced the highest yields by N 120, P2O5 75, K2O 90 kg/ha active agent but the higher fertilizer doses depress the yield. The other part of the hybrids were able to produce high yield by bigger fertilizer doses. On the whole the agro-ecological optimum of the NPK fertilization was N 120-160, P 25-100, K 90-120 kg/ha active agent, but the N 80, P2O5 50, K2O 60 kg/ha fertilizer doses was the most effective. -
Effect of Soil Covering on the Soil Enzyme Activity of Integrated Orchard
20-29Views:82The purpose of our experiments is to discover the effect of different soil cover matters (agrofoil and black polyethylene) on the activity of some enzymes (phosphatase, saccharase, urease, catalase, dehydrogenase) occuring in soil. Soil samples were taken from a cider apple plantation of the Fruit Producing Research and Advisory Kht Újfehértó. The enzyme activity was measured according to Krámer and Erdei (1959a), Kuprevič and Tsherbakova (1956), Kuprevič et al. (1966), Frankenberger and Johanson (1983), Mersi and Schinner (1991). Soil moisture content was by conventional (drying chamber) method measured during every sampling and enzyme activity was transpolated to absolute dry soil. Results were estimated by mathematical methods (variation analysis, correlation counting). Soil samples were taken by trials 5 times (in every two months) a year in the vegetation period from March to November.
By recording the monthly changes of the enzyme activity we have observed the following. The activity of the phosphatase was generally the highest in May and the lowest in November. Depending on the trials, high values were also measured in March and September. The activity of the saccharase was generally the highest in November and the lowest in June, but at the same time peaks even occured in May and September. The highest urease avtivity was measured in September and November, and the lowest activity in May and July, also depending on the trials. In the year 2000, after a deep point in March, the activity of the catalase was the highest in November or by certain trials in September. In 2001, the lowest activity was also measured in March, but the highest activity appeared in November in case of one-minute trial, and in May in consequence of two-minute trial. Finally the activity of dehydrogenase was the highest in November and the lowest in July apart from the model years.
There were essential differences in rainfall of the two experimental years which was reflected in the enzyme activities. There was a poor positive significant relationship between soil moisture content and enzyme activity values in case of phosphatase, saccharase, urease (r=0,426; 0,480; 0,396) respectively. In case of catalase1 (r=0,518), catalase (r=0,556), dehydrogenase (r=0,559) we obtained a medium strong positive relationship between soil moisture content and enzyme activity values. By evaluating the effect of different trials in case of every examined enzyme significantly higher values were detected in soils covered by agrofoil (a porous black polyethylene) than in soils covered by black polyethylene or in uncovered soils. Moreover, the soil covered by black polyethylene showed significantly higher enzyme activities (besides phosphatase) than the control soil. Thus soil-covering meant statistically significant advantages in enzyme activity as opposed to uncovered soil proved.