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Effect of addition of maltodextrins to starch gels on some textural and colour parameters

100%
Przetaczek-Roznowska I., Roznowski J., Fortuna T., Pajak P.
Acta Agrophysica
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2014
|
tom 21
|
nr 2
Systems of potato starch and potato maltodextrins saccharified to various degrees (low, medium, or high) were investigated to understand the effect of maltodextrin addition on some rheological properties of starch pastes and on chosen textural properties and colour parameters of starch gels. The samples for the study were 10% water pastes of starch alone and starch with maltodextrin added in amounts constituting 10, 20, 30, 40 or 50% (w/w) of the starch. The rheological investigations included determination of flow curves at a temperature of 50°C. The flow curves obtained were described using the Herschel-Bulkley model. The gels were subjected to texture profile determination and to colour analysis in the CIELab space using D65 illuminant and 10° observer. It was found that maltodextrin affects the properties of starch gels even if it replaces as little as 10% of starch in the system. As the proportion of maltodextrin in the gel increases, its flow strength decreases, the thinning degree increases, and the textural parameters change. The changes, however, are not proportional either to the saccharification degree or to the proportion of maltodextrin in the gel. Maltodextrin present in starch gels, regardless of its amount, influences also the values of colour parameters in the CIELab system.
2

Investigation of starch gels by means of the relaxation method

86%
Rezler R., Baranowska H. M., Surma S., Poliszko S.
Żywność Nauka Technologia Jakość. Suplement
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2000
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tom 07
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nr 2
Analysis of structural changes of starch gels of the polymer content from 0.05 g/cm3 to 0.10 g/cm3 has been performed on the basis of results of a study by the DMT A and lH NMR methods. For gels of starch concentration below 0.08 g/cm3, the changes of the rigidity modulus are insignificant; a small increase is observed only in the first three hours of measurements. Gels of a higher starch content are characterised by much higher initial value of the rigidity modulus, which significantly increases with the time of measurements. The values of the rigidity modulus are determined by the density of network segments. In the systems with starch concentration up to 0.08 g/cm3, the initial and the final concentrations of the network segments show insignificant differences, while for the gels of a higher starch content these concentrations differ significantly. As follows from results of NMR relaxometry experiment, in the gels of a polymer concentration up to 0.08 g/cm3 no changes in water dynamics in time have occurred. In those of starch concentration above 0.08 g/cm3, the relaxation rate of water has changed in time. The maximum in the water relaxation rate observed after 3-4 hours of measurements indicates the process of water fixing in hydrates. A further monotonie decrease of the relaxation rate suggests that the water initially involved in the gel structure formation is evacuated from the starch network. This process should be related to respiralisation of amylopectin chains, whose participation in the gel structure formation increases with increasing polymer concentration. The results suggest that for the starch gels of polymer content lower than 0.08 g/cm3 the gel structure formed on cooling is saved and not subject to development. In the time range studied no changes in the parameters studied which could suggest the occurrence of starch rétrogradation have been observed, which has been interpreted as a result of a small contribution of amylopectin chains in formation of the gel spatial network.
3

Molecular dynamics in dehydrated starch gels

72%
Poliszko S., Napierala D. M., Rezler R., Hoffmann G.
Żywność Nauka Technologia Jakość. Suplement
|
2002
|
tom 09
|
nr 4
We have recently developed a transformation method for representation of different relaxation processes data (DMTA, DETA and 1H-NMR) as a function of free energy of activation in freeze-dried wheat starch gel. In our previous paper [12] the method of transformation was applied for freeze-dried wheat starch gel of density of 0.13 g/cm3, while in this paper we present results of a similar analysis of relaxation parameters measured in a wide temperature range in dehydrated wheat starch gel of a twice lower density. In the system studied, we observed a decreasing value of the complex rigidity modulus, due to much lower degree of crosslinking. Similar courses of dispersion profile obtained with 1H-NMR relaxation method and DMTA method, at temperature ranging from 100 to 380 K, point to a correlation between the nuclear and mechanical relaxation processes, confirming the results of our previous work, which are related to the dynamics of hydroxymethylene groups in freeze-dried starch gel.
4

Rheological properties of cross-linked E 1422 starches in high concentration sugars systems

58%
Le Thanh-Blicharz J., Walkowski A., Voelkel E., Bryla A., Lewandowicz J.
Towaroznawcze Problemy Jakości. Polskie Towarzystwo Towaroznawcze
|
2014
|
nr 3
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