Stabilitatea conţinutului în acid ascorbic pe parcursul fluxului tehnologic de obţinere a produsului „conopidă în oţet”

La teneur des produits horticolesen vitamine C estinfluencée par divers facteurs, tels que: les différences génotypiques, les conditions climatiques, lespratiques agricoles, les techniques de récolte et de stockage, ainsi que les technologies de fabrication et de conservation. L'objectif principal de la présente recherche est l’étude de la stabilité de l'acide ascorbique au cours des processus technologiquesd'obtention du produit "Chou-fleur au vinaigre". L'échantillonnage pendant différentes étapes du flux technologique a eu lieu à l'unité de traitement des légumes et des fruits de S.C. Contec Foods S.R.L. Tecuci. Les échantillons ont été prélevés pendant deux années consécutives, au mois d’octobre, à partir de 4 points du flux technologique. Le produit fini "Chou-fleur au vinaigre" a été aussi analysé après une période de stockage de 3 mois à 10°C ou 25°C pour étudier la stabilité de l'acide ascorbique

Dinamica variaţiei conţinutului de vitamina C pe parcursul proceselor tehnologice de fabricare a produsului „Gogoşari în oţet”

The content of vitamin C in processed horticultural products is influenced by multiple factors. Besides the factorsconcerning the raw material (cultivar, climatic conditions, agricultural practices, harvesting and storage techniques),the processingand preservation technologies are essential. The objective of the present study is to analysethe variation of vitamin C content during the technological processesof obtaining the product "Romanian peppers in vinegar". The samples from5 different steps of the technological flow were supplied by a company for processing vegetables and fruits (S.C. Contec Foods S.R.L. Tecuci),during two consecutive years. The finished product was also analysedafter storage at two temperatures (10°C and 25°C), by using two different methods for vitamin C assessment.The results proved that vitamin C content decreased by 76% during the technological flow. All technological phases decreased the content of ascorbic acid, but the most important reduction was registered after the thermal processing(blanching and pasteurization).The storage of the finished product for 3 months determined the diminution of vitamin C content: at 10 ºC by5% and at 25 ºC by 14%

Studies on the Physical Changes in Corn Seeds during Hybrid Drying (Convection and Microwave)

Hybrid seed drying technology, based on convection and microwave drying, is a modern method, and the research on the physical changes in cereal seed resulting from hybrid drying is still in its infancy. The aim of the present paper is to study the uniformity of the drying process by examining the physical changes occurring in corn seeds. An innovative drying equipment, combining convective and microwave drying, was used to dry corn seeds (variety DKC5068). The convective drying was performed during the pneumatic transport of the seeds, using hot air at a maximum temperature of 50 °C; the microwave-based drying was performed using 2.45 GHz microwaves. Thus, the seeds were volumetrically heated at a temperature which does not exceed 44 °C. The physical changes in corn seeds were measured in terms of moisture, volume, cracking and color. The results regarding the moisture and volume changes in the seeds during the drying process proved that moist seeds are more homogeneous than dry seeds. The change in volume also changed the stiffness of the seeds, which showed greater homogeneity after drying compared to wet seeds. Hybrid drying led to an average shrinkage of 8.76% compared with the original seed volume, while the percentage of seeds showing cracks after drying increased by 22%. Generally, the drying process also led to color changes, but in the case of hybrid drying the results were inconclusive. Hybrid drying of corn seeds requires a shorter time and does not significantly influence physical characteristics, compared to other drying technologies

Research on the operation of an innovative equipment hybrid drying

The study of the operating parameters of an innovative equipment hybrid drying for cereal seeds is important for drying technology. An optimal operation of the hybrid dryer model requires the monitoring of essential technological parameters such as the velocity, temperature and humidity of the drying agent at the entrance to the dryer, as well as the temperature plus humidity of the drying agent at its exit. The energy consumption of the hybrid drying equipment is also monitored. Equipping the hybrid dryer with sensors to track these technological parameters is important, and knowing the accuracy of their measurement both in stationary and non-stationary regimes, leads to the evaluation of the degree of variability of the acquired numerical data. An important role in the evaluation of the technological parameters of the installation is also given by the mounting position of the sensors in the hybrid drying installation. The innovative equipment hybrid drying has both a convective pre-drying component and a final drying component through high frequency currents (microwaves). In the convective drying component, the cold air is heated in a heating battery with electrical resistances to a maximum of 44.9°C at an average dryer air inlet velocity of 16.54 m/s. In the final part of the drying plant, after passing through the microwave component, the maximum temperature reaches 39.3°C. The average energy consumed in idle operation of the hybrid dryer is 1.52 kWh

Research on the physical changes of cereal seeds dried in the innovative equipment hybrid drying

Hybrid drying of cereal seeds is a modern drying method. Over time, more research has been carried out in the field of grain drying, moving from convective drying as the commonly used method, to hybrid drying that combines the convective phenomenon with that of thermal conduction or radiation. Current technology offers the possibility of using hybrid methods of drying cereal seeds, which have the advantage of lower energy consumption and shorter drying time compared to the convective drying method. The paper proposes the analysis of the physical changes that occur after the hybrid drying of cereal seeds. The research was carried out by drying cereal seeds on an innovative hybrid drying facility that uses both convection and microwaves. In this sense, the physical changes that occur in corn seeds were studied, through determinations of humidity, changes in color, dimension, as well as changes related to the mechanical resistance of the seeds. The maximum drying temperatures inside the dryer were between 48 and 50 °C, obtained at a maximum microwave power of 2400 W, and a drying time of 3 seconds

Performance assessments and the effect on barley seed quality regarding a new developed grain dryer

Convective dryers are widely used in various fields, such as for drying pasta, fruit, vegetables, agricultural plant seeds etc. Several variants of dryers have been designed so far, such as: dryers with intermediate heating of the drying agent, dryers with partial recirculation of the drying agent, closed circuit dryers and those ones with combined technical solutions. None of the above solves the problem regarding the drying agent flow uniformity. In the case of existing world-wide tower dryers, drying is more intense towards the end of the drying agent mixing chamber. To overcome this shortcoming, an innovative cylindrical tower dryer was conceived, which evens the drying agent parameters. The dryer contains a conical device mounted inside the perforated cylinder above the burner. This device is based on the Coandă effect according to which, a fluid jet has the tendency to stay attached to a convex surface. The device has been designed after Computational Fluid Dynamics simulations (CFD), after which optimum setting adjustments have been made to achieve uniformity of the speed and temperature profiles across the entire interior surface of the perforated cylinder, regardless the porosity of the seed layer. Experiments were conducted using barley seeds with three initial moisture contents, five air temperatures (40oC to 80oC) and four fan speeds (1 m/s to 2.5 m/s). The obtained results showed a reduction of protein loss of up to 1.77%, a reduction of germination capacity loss of up to 9.87%, a decrease of the energy consumption of up to 10-15% and a decrease of the drying time of up to 20%, compared to the results obtained with a conventional tower dryer. The advantages of using the new developed dryer are: drying process uniformity, energy consumption and drying time reduction, seed quality improvement, construction cost reduction and material economy

Comparison of two microwave drying techniques for cereal seeds and determination of their physical parameters

The microwave drying of wheat and corn seeds by two technologies at different working powers is studied here. The main objective is to evaluate the effect of microwaves on variations in the moisture, colour and size of the seeds after microwave drying. The tests are performed in microwave ovens with and without inverter technology at three drying powers (260, 440 and 620 W). It has been observed that increasing drying power results in a ~50% reduction in drying time and a seed moisture level below 14%. The colour variation of the seeds is insignificant between microwave drying with and without the inverter. However, there is also an unacceptable decrease in size for both types of seeds with increasing drying power, which can lead to increased shrinkage of the seeds and the appearance of cracks, especially in the corn seeds

Drying Process Modeling and Quality Assessments Regarding an Innovative Seed Dryer

The dehydration of agricultural products is a topic of research covering the preservation and conservation of the quality of agricultural and food items. The actual tasks of environmental protection include creating novel solutions to reduce the energy needs and exothermic consequences of the bulk of industrial processes. Due to the fact that air temperature and velocity in the seed layer are not uniform, the currently employed seed dryers have significant energy requirements and generate a lot of heat. A device that addresses this problem was developed and is now the subject of a patent application. The Coandă effect-based tronconic plates used in the dryer enable warm air to be dispersed uniformly throughout the product mass. Mathematical modeling was used for the design, operation, and optimization of the baffled drying unit. The investigations, which were conducted by modifying and observing the operational parameters (the velocity and temperature of the warm air) used four distinct types of seed with three different beginning moisture concentrations. Following the completion of the CFD simulation, the unit’s design was created in SolidWorks. The seed and air humidity were measured using sensors, and the air speed was measured using an anemometer. The current lines and fields were used to express the speed and temperature results. The unit with deflectors reduced the amount of heat released by up to 15.38% and reduced the amount of energy used by up to 14%

Drying Process Modeling and Quality Assessments Regarding an Innovative Seed Dryer

The dehydration of agricultural products is a topic of research covering the preservation and conservation of the quality of agricultural and food items. The actual tasks of environmental protection include creating novel solutions to reduce the energy needs and exothermic consequences of the bulk of industrial processes. Due to the fact that air temperature and velocity in the seed layer are not uniform, the currently employed seed dryers have significant energy requirements and generate a lot of heat. A device that addresses this problem was developed and is now the subject of a patent application. The Coandă effect-based tronconic plates used in the dryer enable warm air to be dispersed uniformly throughout the product mass. Mathematical modeling was used for the design, operation, and optimization of the baffled drying unit. The investigations, which were conducted by modifying and observing the operational parameters (the velocity and temperature of the warm air) used four distinct types of seed with three different beginning moisture concentrations. Following the completion of the CFD simulation, the unit’s design was created in SolidWorks. The seed and air humidity were measured using sensors, and the air speed was measured using an anemometer. The current lines and fields were used to express the speed and temperature results. The unit with deflectors reduced the amount of heat released by up to 15.38% and reduced the amount of energy used by up to 14%

Assessment of quality characteristics of new Vitis vinifera L. cultivars for temperate climate vineyards

Since quality requirements for table grapes are mainly related to their physico-chemical and mechanical features, the aim of this work was to provide useful data for grape producers and consumers concerning the quality characteristics of table grapes of five new Vitis vinifera L. cultivars created in Romania and tending to spread within the temperate climate vineyards. During grape maturation, sugar content increased in a lesser extent than the reducing of total acidity, a balanced taste of grapes was given by the decrease in total acidity rather than sugar accumulation. Grapes of analysed cultivars showed lower concentrations of ascorbic acid and a higher content of organic nitrogenous compound. Berries with higher weight and volume (Transilvania cv.) incurred a higher mechanical deformation, while long berries (Gelu cv.) showed higher resistance to detachment from the pedicel, indicating higher resistance of grapes to packing, transport and storage. Antioxidant activity of mature grapes was high, but involvement of nonflavonoids in increasing the antioxidant capacity was statistically non-significant. Seeded table grapes of new Vitis vinifera L. cultivars showed superior physico-chemical and mechanical characteristics, indicating their high quality in the conditions of temperate continental climate, and promoting the studied cultivars as important grapevine germplasm resources