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. Although the drying kinetics of a product is a crucial parameter in this process, the experimental setup to measure the drying kinetics in an environment which comes close to the drying situation in a real spry dryer, is very difficult to establish. With

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The extractable (ASTA) colour retention of four different milled spice paprikas was evaluated at 10, 20, 35, 50, and 60 °C storage temperature. The ASTA colour stability during long-term storage period strongly depended on the temperature, primary handling and drying of the fresh crop, and the applied production technology. The cooled (10 °C) or temperature-controlled (20 °C) conditions appeared to be a reasonable solution to preserve the quality of paprika powder. The kinetics study on the temperature dependence of ASTA colour loss estimated the apparent reaction order, rate constants, predicted half-life times and activation energy. The Q10 approach and shelf life-plot resulted in useful data, which can be suitable for quick and economical evaluation of further spice paprika products.

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Apple cubes were osmotically dehydrated with 40 °Bx sucrose and sorbitol solutions. Light microscopy was used to observe the microstructure of fresh and osmotically dehydrated samples. Peleg’s model could fit the experimental data and describe the mass transfer kinetics of water loss (WL) and solid gain (SG). The use the sorbitol as osmotic agent, the increase of temperature and concentration of the solution increased the WL during the osmotic dehydration. The average cellular parameters, area and perimeter (size), and circularity, elongation, roundness, and compactness (shape) of fresh samples were 14.28±6.65×103 μm2 and 0.486 mm, and 0.73, 1.56, 0.70, 0.83, respectively. The osmotically dehydrated samples presented a decrease in area, circularity, roundness and compactness and an increase in the elongation of the cells, and these changes were higher in samples treated with sorbitol.

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-drying, freeze-drying) and extraction technology under different process parameters on anthocyanins content of red cabbage. As degradation of natural antioxidants occurs as function of different thermal treatments, thermal stability and degradation kinetics were

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Agrokémia és Talajtan
Authors:
Bernadett Gyarmati
,
Zsuzsanna Hárshegyi
,
György Heltai
,
Csaba Mészáros
, and
Ágnes Bálint

A különböző N-formák mozgását és transzformációját a talaj–növény–légkör rendszerben egymással összefüggő ciklusok határozzák meg. Az olyan mesterséges beavatkozások, mint például a műtrágyák és szerves trágyák intenzív felhasználása, döntő mértékben befolyásolják a N-körforgalmat, jelentősen terhelve ezzel a ciklusok érzékeny egyensúlyát. Annak érdekében, hogy a problémákat kezelni tudjuk, a N-ciklus talajban lejátszódó folyamatainak jobb megértése, a különböző folyamatok súlyának és érzékenységének megismerése szükséges, alapot teremtve ezzel egy racionálisabb és környezetkímélőbb trágyázási és tápanyag-utánpótlási gyakorlatnak. A N-ciklus matematikai modellezése kiváló lehetőséget nyújt az egyes részfolyamatok alaposabb felderítésére. A munka során egy korábban elvégzett kísérlet adatait használtuk fel. Az inkubációs talajoszlop kísérletet a Szent István Egyetem Kémia és Biokémia Tanszékén végezték 2000-ben. A felhasznált kísérlet mérési adataira nemlineáris regresszióval illesztettünk különböző rendű kémiai kinetikai egyenleteket az Origin 4.1-es adatelemző és grafikai szoftverrel. A munka eredményeként megállapítható, hogy a részfolyamatok modellezésekor a legtöbb esetben az elsőrendű kémiai kinetikai egyenlet eredményezte a legjobb matematikai közelítést.

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Resolution and Discovery
Authors:
K. Tomolya
,
D. Janovszky
,
A. Sycheva
,
M. Sveda
,
T. Ferenczi
, and
A. Roósz

. Ciu J , Li JS , Wang J , Kou HC , Qiao JC , Gravier S , Blandin JJ : Crystallization kinetics of Cu38Zr46Ag8Al8 bulk metallic glass in different heating conditions . J Non-Cryst Sol 404 , 7 – 12 ( 2014

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parameters, e.g., chemical composition and mixing characteristic of precursor liquids, deposition temperature, needle to substrate distance, liquid flow rate, applied voltage etc. can significantly affect the initial droplet sizes and precipitation kinetics

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Fibre-rich fruit juices are playing an increasing role in healthy nutrition, and consumers are regarding them, especially citrus juices of 100% fruit content, as reliable sources of vitamin C. Nevertheless relatively few scientific data are available on vitamin C retention during the heat treatment of aseptically packed fruit juices made from fruit concentrates. Authors investigated this problem within the scope of OTKA T 014965 research project (Körmendy et al., 1998, 1999a, 1999b; Pátkai, 1998).

Instead of separate case studies on different types of fruit juices and technologies, authors analysed the vitamin C content of model solutions with similar composition to real citrus juices as a function of temperature and duration of heat treatment and that of initial oxygen and ascorbic acid concentration. Based on the measured data, they elaborated kinetic relations and determined the reaction rate constants of vitamin C decomposition under the experimental conditions. By means of the calculated kinetic relations and reaction rate constants one can estimate the losses of vitamin C in the case of known parameters of the heat treatment, packaging material, oxygen and vitamin C concentration within the investigated domain. Results may promote technology and product development in the field of citrus fruit juices.

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Abstract

The influence of hot dip galvanizing on the rebar/concrete adherence was studied. The kinetics of rebars corrosion in high chlorides content concrete was studied by electrochemical methods. Unprotected (black steel) and hot dip galvanized steel were studied. The results show a mechanical resistance improvement of reinforced concrete with hot dip galvanized rebars and a better corrosion performance of hot dip galvanized steel in concrete compared to the black steel.

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Solid phase microextraction (SPME) coupled to fast capillary gas chromatography was used for monitoring the wine fermentation process. This combination offers a simple, quick and sensitive approach suitable for characterization of head-space components of wines during the fermentation process without a complicated sample preparation procedure. In this work this method was used to observe the differences in aroma production between three different commercial yeasts and the indigenous yeast flora.

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