M. Knee (Ed.): Fruit quality and its biological basis; Sheffield Academic Press Ltd., Sheffield, UK, 2002, ISBN 1-84127-230-2, 279 pages; CRC, Boca Raton, Fl., USA, ISBN-0-8493-9781-2; L.M.M. Tijskens, M.L.A.T.M. Hertog and B.M. Nicolai (Eds): Food process modelling; CRC Press Boca Raton Boston, New York, Washington, DC; Woodhead Publishing Ltd., Cambridge, England, 2001, ISBN 1-85573-533-4, 496 pages; K.V. Peter (Ed.): Handbook of herbs and spices; CRC Press, Boca Raton, USA, ISBN 0-8493-1217-5; Woodhead Publishing Ltd, Cambridge, England, 2001, ISBN 1-85573-5628, 319 pages
In this paper a complex drive chain is modelled with Local Linear Neuro-Fuzzy Model (LLNF). The developed models were used for detecting different faults that may occur in the system. The models were developed based on measurements carried out on the real system. Using feed-forward neural networks with perceptron neuron structure, model-based fault diagnosis of the analysed system was developed to separate the different faults. The performance and efficiency of the developed different types of artificial neural network's structures were compared using gradient based edge detection method.
Apples were harvested at three different times (1 st, 2 nd and 3 rd) then stored at 1-3 °C, 85-90% R.H. for 5 months. Firmness, ethylene productivity, the distribution of calcium and potassium and the ion leakage were measured. The ultrastructure of the cell wall was studied by SEM and TEM and he activity of β-galactosidase and polygalacturonase and pectin content were determined. The ethylene evolution of fruits decreased by the harvest and storage time. At the beginning of storage, the ethylene productivity in the 1 st harvest apple increased up to a maximum value then declined. The 2 nd harvest fruits produced less ethylene than that observed in 1 st harvest fruits. No ethylene production was found in the 3 rd harvest fruits. Firmness was different according to harvest time, but that difference disappeared during storage. The permeability of membranes increased as a function of harvests and storage. The distribution of calcium was typical at the beginning, the highest concentration of calcium being near the core and skin, but by the end of the storage calcium moved from the skin towards the core. Potassium content was the highest near the core and decreased towards the skin, both in the fresh and stored apples. The activities of polygalacturonase and β -galactosidase were not influenced by the harvest time, but changed as a function of storage time. The autolysis of pectin and soluble carbohydrates increased during storage, mostly in the 3 rd harvest. At the beginning of storage, the cell wall and middle lamellae of the 1 st harvest fruits' flesh were not damaged. Large degradation of the middle lamellae was observed in the 2 nd and 3 rd harvest fruits. Lower membrane permeability, pectin degradation and PG enzyme activity were found in the 1 st harvest apples. The Idared apple should be harvested close to the climacteric maximum for better and longer storage.
The effect of organic growing was studied on the storability of apple cv. Jonica, Liberty, Mutsuand Pinova. Fruits from integrated and organic orchards were stored at 2-4 °C, 95-99% relative humidity for 6 months. Firmness, activity of b-galactosidase and polygalacturonase enzymes were examined. There was no difference in the activity of β-galactosidase and polygalacturonase enzymes at harvest between the organic and integrated apples, but a significant difference was noted between the cultivars except for Mutsu and Pinova. The activity of b-galactosidase enzyme increased significantly during storage except for cv. Pinova and that of polygalacturonase enzyme also increased significantly. The difference in the activity of polygalacturonase became significant between the cultivars during storage except for cv. Jonica and Pinova. The firmness decreased significantly during storage, with the least change in case of cv. Liberty. It can be established that there is, in general, neither a considerable difference between the growing systems nor between varieties at harvest. The differences became higher during storage. It can be stated that the effect of cultivar on the storability is much more considerable than the effect of growing system.
Authors:K. Takács, E. Némedi, D. Márta, É. Gelencsér, and E. Kovács
Yellow pea flour contains very low quantity of prolamins, thus it could be a good alternative dietary source for individuals suffering from celiac disease or wheat allergy. Beside emulsifiers, enzymes can be used for developing noodle structure with high quality. Transglutaminase (TG) enzyme was tested in model systems for improving noodle structure by using beneficial cross-linking property of the enzyme. Sensory-and cooking properties and biochemical attributes of proteins were evaluated to characterize structure-function relationships in accordance with the concentration of the applied enzyme. The amount of water and salt soluble protein fractions was reduced meaningfully and the molecular weight distributions assessed by SDS PAGE were changed by addition of 50–200 mg kg
TG enzyme. At the same time, sensory properties were improved and high water uptake and low cooking loss were also observed. Forasmuch an increase has been expected in the amount of the cross-linked molecules, the cross-reactivity of prolamins with anti-gliadin antibody was also tested to reduce the risk related to gluten sensitivity. Finally, the possible contamination with wheat was controlled by DNA-based PCR.
Sweet cherry fruits (
cv. Vera, Carmen, Linda and Krupnoplodnaja) were harvested in different ripeness stages after anthesis 39, 42, 49, 56 days (Carmen); 37, 40, 47, 52, 59 days (Krupnoplodnaja); 32, 36, 44, 53, 58 days (Linda); 38, 42, 50, 52, 57 days (Vera). The colour, total soluble solids, dry matter content, β-galactosidase and polygalacturonase activity were determined. The dry matter content and total soluble solids content (Brix
) increased during development. The L* values significantly decreased as a function of ripening while a* values increased up to 3 rd harvest, then they decreased, b* values continuously decreased as a function of development. The a*/b* values linearly increased as a function of development, indicating reddening of fruits. Hue angle (h
) increased rapidly between harvest one and two. The measured (a*, b*, L*) and calculated parameters (h
, a*/b*, chroma) well represented the colour development of sweet cherries. Linear and strong correlation was found between a*/b*, L* values and the Brix
, exponential correlation was found between h
, chroma and Brix
. Activity of β-galactosidase was different among cultivars and as a function of development. The two maximums might β-galactosidase isoenzymes. The role of PG (polygalacturonase) could not be explained clearly enough, further investigations are needed to find the exact role of the enzyme in the cell wall metabolism of sweet cherry.
Authors:András Kovács, Zi-An Li, Kiyou Shibata, and Rafal E. Dunin-Borkowski
Magnetic skyrmions are vortex-like spin structures that are of great interest scientifically and for applications in low-power magnetic memories. The nanometer size and complex spin structure require high-resolution and quantitative experimental methods to study the physical properties of skyrmions. Here, we illustrate how Lorentz TEM and off-axis electron holography can be used to study the spin textures of magnetic skyrmions in the noncentrosymmetric B20-type helimagnet FeGe as a function of temperature and applied magnetic field. By reversing the magnetic field inside the microscope, the switching mechanism of the skyrmion lattice at 240 K is followed, showing a transition of the skyrmion lattice to the helical structure before the anti-skyrmion lattice is formed.
Authors:E. Kovács, P. Merész, Z. Kristóf, and E. Németh-Szerdahelyi
Colour, texture, pectin autolysis, membrane permeability and microstructure (SEM, TEM), β-galactosidase and polygalacturonase were studied in apricots (cv. Magyar kajszi) harvested in mature green, straw yellow, bright orange and deep orange stages. The L* increased from mature green to straw yellow then decreased from straw yellow to deep orange state. The a* values increased with ripening. The bright and deep orange apricots were significantly softer than the mature green and straw yellow ones and the membrane permeability increased with ripening. The presence of β-galactosidase enzyme was proved by immunoblotting analysis using monoclonal anti-β-galactosidase clone GAL-13 (Sigma) in all ripening stages. The enzyme activity was very low in mature green stage and increased significantly (P>95%) with increasing ripeness and during storage. The PG activity was very low in the mature green apricot. A significant (P>95%) increase was observed in the straw yellow apricot and in the riper fruits. The mature green apricot showed a regular, the straw yellow and bright orange samples showed a moderately regular tissue structure, while the tissue of the deep orange apricot collapsed (SEM). The cell wall and the middle lamella of the green apricot (TEM) were intact. Generally, there were intact cytoplasm membranes with some damaged parts. In the straw yellow apricot, the cell wall started to loosen, the middle lamella lost pectic polysaccharides. The structure of the cytoplasm was not recognisable, the tonoplast and the cytoplasm membrane were injured. The cell wall of the bright orange apricot was similar to that of the straw yellow ones. The middle lamella dissolved and hairy, fibrillar structure of cell wall was found in the deep orange samples.
Authors:E. Szabó, É. Gelencsér, E. Kovács, A. Jánosi, K. Takács, and E. Kiss
In our research we studied the occurrence of the main apple allergen coding gene-families (Mal d 1, Mal d 2, Mal d 3, Mal d 4) in 16 different and most preferably consumed apple varieties. After the DNA isolation by Wizard method the simple PCR reaction was used to examine the apple allergen-coding genes. To identify the presence of the four allergenic protein-coding genes two primer pairs were chosen. The presence of these allergens in most apple varieties could be confirmed. According to our results two varieties — Jonathan and Granny Smith — were found to contain the lowest amount of the coding genes of the allergenic apple proteins studied by us. Besides this, polymorph pattern was obtained by the use of Mal d 1 primer, which may lead to determine apple varieties with small amount of Mal d 1 allergens.The confirmation study of the presence of potential apple allergens by RNA and protein techniques is our plan in the near future.