Factors influencing the extent of biohydrogenation of linoleic acid by rumen micro-organisms in vitro.

Abstract

AbstractThe major factors influencing the extent of biohydrogenation of linoleic acid have been investigated by a series of in vitro incubations.Two distinct patterns of biohydrogenation were obtained; one in which biohydrogenation was complete and 18:0 was the major end‐product and one in which trans‐11 octadecenoic acid was the major end‐product.The major factor affecting the pattern of hydrogenation was the initial concentration of 18:2 used; at concentrations less than 1.0 mg/ml of rumen contents 18:0 was the major end‐product of hydrogenation, at concentrations of 1.0 mg/ml of rumen contents or greater the major end‐product of hydrogenation was the trans‐11 monoenoic acid. That the availability of hydrogen played an important role in the extent to which 18:2 was hydrogenated was investigated by the addition of sucrose either at the start of incubation or continuously throughout the 6‐h period of incubation. Addition of sucrose throughout the incubation increased the extent of conversion of 18:2 to 18:0. Extending the duration of incubation to 10 h had no effect on the amount of 18:0 produced.Evidence is presented to suggest that large amounts of 18:2 prevent hydrogenation of 18:1 to 18:0 by irreversible inhibition rather than by simply competing for hydrogen.