Additionally, SFA reduction in muscles derived from lambs fed linseed oil may also reflect an incomplete biohydrogenation
process, as an effect of the high consumption of unprotected fats rich in linolenic acid.
(2007), the lower levels of stearic acid we found in the muscle could have been caused by a greater amount of linoleic acid escaping ruminal biohydrogenation
, and given that stearic acid acts as a I9 desaturase substrate (Cook, 1996) in the synthesis of oleic acid, lower levels of C18:0 in muscle tissue can also determine lower concentrations of C18:1 n-9 cis 9.
A possible explanation for the greater concentration of UFA may be the fact that the diet contains 70% concentrate, which contributes to reduction of the rumen pH, which reduces the biohydrogenation
and promotes the absorption of UFA in the post-rumen.
The linear decrease in the Octadecanoic acid concentration in meat according to oils supply demonstrates that small amounts of DHA present in diets with flaxseed and sunflower oils (Table 2) were effective in reducing ruminal biohydrogenation
of 11-Octadecenoic acid to Octadecanoic acid.
with hydrogens on opposite sides of the double bond (trans configuration).1They arise either by partial hydrogenation of unsaturated oils (usually in the presence of nickel) or by biohydrogenation
in the rumens of cows and sheep.2 Due to their ability to pack more tightly than other unsaturated fatty acids they have a higher melting point (45C) than oleic acid and therefore would add granularity (semisolid form) to the hydrogenated oil.3 TFA arising due to biohydrogenation
in stomach of ruminant animals are present in small amounts in dairy fat (milk butter) and meat fat.
Trans-fatty acids are found in ruminant fat as a result of biohydrogenation
by rumen bacteria.
(2) This isomer originates from CLA produced by rumen bacteria as an intermediate in the biohydrogenation
of LA or from tissue synthesis of CLA by [[DELTA].sup.9]-desaturase conversion of trans-11 18:1 fatty acid (1).
: Saturation of fatty acids by microbial activity.
Research shows that endogenous synthesis of CLA in the mammary gland of dairy cattle accounts for the majority of the cis-9, trans-11 CLA present in milkfat with about 70% to more than 90% derived from the conversion of vaccenic acid (18:1, trans-11), a rumen biohydrogenation
Many consumers do not know trans fats also occur in nature and are naturally present in dairy meat, and poultry products as the result of bacterial biohydrogenation
produces trans fats that differ chemically from those produced commercially and generally in levels well below the labeling threshold.