Abstract:
The presented study shows a simple way for optimiza
tion of extrusion process, which
was used for deterioration of cyanogenic glycosides
– antinutritive components of linseed,
with minimum damage of essential Alpha-Linolenic Ac
id (ALA) at the same time.
Extrusion of the material was done on a laboratory
single screw extruder. Content of
Hydrogen cyanide (HCN) as a measurement of cyanogen
ic glycosides in produced co-
extrudate and fatty acid composition were determine
d, together with basic chemical
analyses, which were done in accordance with AOAC m
ethods. Statistical analysis showed
that HCN content in the product was the most depend
ent (P= 0.0002) on quadratic
influence of moisture content of starting material.
The highest HCN content (126 mg kg
-1
)
was measured at the lowest moisture content (7%) an
d the lowest screw speed (240 rpm).
Low moisture content caused weak volatilization of
HCN along with the evaporating
water, which was intensified with higher values of
moisture content. However, increase in
moisture content from 11.5 to 16% slightly increase
d the amount of present HCN, due to
the lower material viscosity. Extrusion process cau
sed some changes in fatty acid
composition, but even the highest degradation of AL
A did not exceed 4%. Linear and
quadratic influence of moisture content on ALA redu
ction was significant (P< 0.05), as
well as quadratic influence of screw speed. Specifi
c attention has to be paid to selecting
appropriate levels of screw speed and moisture cont
ent of the material which contains
linseed, in order to achieve both detoxification of
linseed and preservation of essential
fatty acids.
Keywords
: Cyanogenic Glycosides, Essential fatty acids, Ext
rusion, Linseed, Sunflower
meal.
