2 research outputs found
Selected physical properties of oat flour and its interactions with hydrocolloids compared with wheat and rye flours
W pracy przedstawiono wyniki badań wybranych właściwości fizycznych mąki
owsianej oraz jej interakcje z hydrokoloidami, w porównaniu z mąkami używanymi powszechnie do
wypieku chleba. Określono właściwości fizyczne kleików mącznych – lepkość, tiksotropię, spektrum
mechaniczne oraz twardość żeli. Zbadano także wpływ dodatku wybranych hydrokoloidów (gumy guarowej
i gumy ksantanowej) na powyższe właściwości fizyczne wszystkich mąk. Stwierdzono, że mąka
owsiana odznaczała się największą lepkością maksymalną kleików, oznaczoną w amylografie Brabendera.
Dodanie pojedynczych hydrokoloidów wywarło zróżnicowany wpływ na lepkość poszczególnych
mąk, przy czym zaobserwowano synergistyczny efekt oddziaływania użytych hydrokoloidów na tę cechę.
Oznaczenie tiksotropii kleików mącznych wykazało, że 5% kleik z mąki owsianej odznaczał się największą
granicą płynięcia i największą powierzchnią pętli histerezy. Dodatek zarówno pojedynczych
hydrokoloidów jak i ich mieszanki do kleików z mąki owsianej, zmniejszył ich powierzchnię pętli histerezy,
natomiast te same hydrokoloidy dodane do kleików z mąki pszennej i żytniej wpłynęły na zwiększenie
ich powierzchni pętli histerezy. Uzyskane podczas badań reologicznych spektrum mechaniczne,
wykazało najsilniejszą i najbardziej stabilną strukturę kleików z mąki owsianej, zarówno bez dodatku, jak
i z udziałem stosowanych hydrokoloidów. Badając twardość żeli kleików mącznych stwierdzono najmniejszą
twardość żeli z mąki owsianej, zarówno bez udziału, jak z dodatkiem hydrokoloidu, co może
korzystnie wpływać na odczucia sensoryczne konsumentów.The aim of the research was to compare the oat flour, constituting remains after
the b-D-glucans concentrate production, with common wheat and rye flours and selected hydrocolloids
in order to check its applicability as a food thickener. Presented findings concern comparison
as well as determination of the influence of applied polysaccharides hydrocolloids (xanthan -– GX
and guar gum – GG) on mechanical spectrum, viscosity, hardness and flow curves of pastes made
from wheat, rye and oat flours, respectively. The highest viscosity was noted for paste of oat flour at
92oC and also after cooling to 30oC. Diverse influence was observed for hydrocolloid additives. The
synergistic interaction phenomenon was also observed in the case of both applied hydrocolloids.
The paste of oat flour may be characterised by the smallest hardness, which could have an important
influence on consumers’ sensory analyses. The phenomenon was hydrocolloid-independent. The
paste of oat flour was characterised by the highest pseudoplasticity, thixotropy as well as smaller
ability for structure rebuilding. The flow behaviour was not modified by hydrocolloids additives but
the thixotropy was reduced in the case of guar gum addition (reduction up to 50%) and xathan (reduction
up to 80%). The results of mechanical spectrum research clearly show that all flour pastes
were almost frequency-independent. Additionally we have noted that oat flour paste showed the
lowest value of tangent delta (G"/G') in the whole tested frequency range when compared with other
tested samples. This testifies that such a paste has the strongest and the most stable structure even
without hydrocolloids
Lupane-Type Pentacyclic Triterpenes in Langmuir Monolayers: A Synchrotron Radiation Scattering Study
Lupane-type pentacyclic triterpenes (lupeol, betulin, and betulinic acid) are
natural products isolated from various plant sources. The terpenes exhibit a vast spectrum
of biological activity and are applied in therapies for different diseases, among which the
anticancer, anti-HIV, antihypercholest
eremic, and antiinflammatory are the most
promising. These chemicals possess amphiphilic structure and were proved to interact
strongly with biomembranes, which can be the key stage in their mechanism of action. In
our studies, we applied Langmuir monolayers as versatile models of biomembranes. It
turned out that the three investigated terpenes are capable of stable monolayer formation;
however, these monolayers differ profoundly regarding their physicochemical character-
istics. In our research, we applied the Langmuir technique (surface pressure
−
mean
molecular area (
π
−
A) isotherm registration) coupled with Brewster angle microscopy
(BAM), but the main focus was on the synchrotron radiation scattering method, grazing
incidence X-ray diffraction (GIXD), which provides information on the amphiphilic
molecule ordering in the angstro
m scale. It was proved that all the investigated terpenes
form crystalline phases in their monolayers. In the case of lupeol, only the closely packed upright phase was observed, whereas for
betulin and betulinic acid, the phase situation was more complex. Betulinic acid molecules can be organized in an upright phase,
which is crystalline, and in a tilted phase, which is amorphous. The betulin film is a conglomerate of an upright crystalline
monolayer phase, tilted amorphous monolayer phase, and a crystalline tilted bilayer. In our paper, we discuss the factors leading
to the formation of the observed phases and the implications of our results to the therapeutic applications of the native lupane-
type triterpenes