Determination of bioactive and potentially toxic
compounds in food: raw material analysis and
shelf life evaluation
Creators: name: Verardo, Vito <1977>
Publisher: name: Alma Mater Studiorum - Università di Bologna
Year: 2009
Subjects: AGR/15 Scienze e tecnologie alimentari

description: "Bioactive compounds" are extranutritional constituents that typically occur in small
quantities in food. They are being intensively studied to evaluate their effects on health.
Bioactive compounds include both water soluble compounds, such as phenolics, and lipidic
substances such as n-3 fatty acids, tocopherols and sterols.
Phenolic compounds, tocopherols and sterols are present in all plants and have been studied
extensively in cereals, nuts and oil. n-3 fatty acids are present in fish and all around the
vegetable kingdom.
The aim of the present work was the determination of bioactive and potentially toxic
compounds in cereal based foods and nuts.
The first section of this study was focused on the determination of bioactive compounds in
cereals. Because of that the different forms of phytosterols were investigated in hexaploid
and tetraploid wheats. Hexaploid cultivars were the best source of esterified sterols (40.7%
and 37.3% of total sterols for Triticum aestivum and Triticum spelta, respectively).
Significant amounts of free sterols (65.5% and 60.7% of total sterols for Triticum durum
and Triticum dicoccon, respectively) were found in the tetraploid cultivars.
Then, free and bound phenolic compounds were identified in barley flours. HPLCESI/
MSD analysis in negative and positive ion mode established that barley free flavan-3-
ols and proanthocyanidins were four dimers and four trimers having (epi)catechin and/or
(epi)gallocatechin (C and/or GC) subunits. Hydroxycinnamic acids and their derivatives
were the main bound phenols in barley flours. The results obtained demonstrated that
barley flours were rich in phenolic compounds that showed high antioxidant activity. The
study also examined the relationships between phenolic compounds and lipid oxidation of
bakery. To this purpose, the investigated barley flours were used in the bakery production.
The formulated oven products presented an interesting content of phenolic compounds, but
they were not able to contain the lipid oxidation.
Furthermore, the influence of conventional packaging on lipid oxidation of pasta was
evaluated in n-3 enriched spaghetti and egg spaghetti. The results proved that conventional
packaging was not appropriated to preserve pasta from lipid oxidation; in fact, pasta that
was exposed to light showed a high content of potentially toxic compounds derived from
lipid oxidation (such as peroxide, oxidized fatty acids and COPs).
In the second section, the content of sterols, phenolic compounds, n-3 fatty acids and
tocopherols in walnuts were reported. Rapid analytical techniques were used to analyze the
lipid fraction and to characterize phenolic compounds in walnuts. Total lipid chromatogram
was used for the simultaneous determination of the profile of sterols and tocopherols.
Linoleic and linolenic acids were the most representative n-6 and n-3 essential dietary fatty
acids present in these nuts. Walnuts contained substantial amounts of γ- and δ-tocopherol,
which explained their antioxidant properties. Sitosterol, Δ5-avenasterol and campesterol
were the major free sterols found. Capillary electrophoresis coupled to DAD and microTOF
was utilized to determine phenolic content of walnut. A new compound in walnut ((2E,4E)-
8-hydroxy-2,7-dimethyl-2,4-decadiene-1,10-dioic acid 6-O-β-D-glucopiranosyl ester,
[M−H]− 403.161m/z) with a structure similar to glansreginins was also identified. Phenolic
compounds corresponded to 14–28% of total polar compounds quantified. Aglycone and
glycosylated ellagic acid represented the principal components and account for 64–75% of
total phenols in walnuts. However, the sum of glansreginins A, B and ((2E,4E)-8-hydroxy-
2,7-dimethyl-2,4-decadiene-1,10-dioic acid 6-O-β-D-glucopiranosyl ester was in the range
of 72–86% of total quantified compounds.