Valutazione degli effetti biologici dei cereali minori
Author(s)
Manzi, Laura
Date Issued
December 16, 2008
Type
Doctoral Thesis
Abstract
In recent years there is a renewed interest for minor cereals. These crops, which are much
used in the past, are currently underutilized but held an important position as a staple food for
certain regions. The excellent nutritional value of minor cereals are quite well know but the
presence of minor components with functional properties has been less investigated. For this
reasons the research on the functional properties of minor cereals become of great interest for
the food industry in the development of new products with functional effects. The
consumption of whole cereals in general is associated with reduced risk of chronic diseases,
due to presence of bioactive compounds such as dietary fiber and phytochemicals. However
different studies have indicated for many phytochemicals that the relationships between “in
vitro” content and “in vivo” activity are not consistent. These compounds are potentially
available in the gut, but the degree to which they produce antioxidant physiological effects
depends on the rate of absorption and distribution.
In the present study we have analyzed the biological effects of diets rich in whole barley and
emmer flours, compared with diets rich in whole and refined wheat, on physiological
parameters of the redox status and immune response, utilizing growing rats as experimental
model.
The chemical composition in basic nutrients and in total phenolic content, have been
analyzed in the four flours. Such flours have been utilized in the preparation of experimental
diets and fed for 6 weeks to four groups of growing rats. After the experimental period of
feeding the animals were sacrificed and blood and mesenteric lymphonodes collected in
order to prepare plasma, utilized to analyse parameter of oxidative status (carbonyl content)
and of antioxidative status (total polyphenols and total antioxidant capacity), and
lymphocytes to analyse the rate of proliferation and the type of immune response.
Analysis of total phenolic content in flours show that the whole wheat, barley and emmer
showed higher polyphenols contents than the refined wheat, with the maximum value for
barley. Analysis of plasma polyphenols concentration show that the diets rich in three whole
cereals determinate significantly higher values respect to diets rich in refined wheat without
any difference among them. Each diets determinate a significantly different plasma
antioxidant capacity: barley induced highest value, followed by emmer, whole wheat and
refined wheat. There is a significant reduction of plasma carbonyl proteins of rats fed with
diets rich in whole cereals, respect to those of rats fed diet rich in refined wheat, furthermore
plasma of rats fed with diets rich in minor cereals has a level of protein carbonyl significantly
lower than plasma of rats fed the diets rich in whole wheat.
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The results of immune parameters studied show that whole cereals induce a significant
increase, in comparison with refined wheat, of lymphocytes proliferation and of CD4+/CD8+
ratio.
These results indicate that minor cereals, in particular barley, induce elevate plasmatic
antioxidant capacity, and that the antioxidant status depends, in addition to polyphenols, on
other phytochemicals present in whole cereals. The diets rich in barley and emmer induce the
same stimulating effects on the immune parameters of diets rich in whole wheat; these results
suggest that the immune modulation it is not due simply to the antioxidant activity of the
polyphenols, but also to the major content in fiber in whole cereals.
Additional information
Dottorato di ricerca in Biotecnologia degli alimenti
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