In the last years, with relation to the numerous benefits attributable to CLA (conjugated linoleic acids), the interest is increasing about the synthesis of such compounds in order to prepare healthy foods or ingredients. To date just a few studies have dealt with the possibility to use lactic acid bacteria to increase the CLA content of foods. Above all the 56 possible CLAs, two of them have been found particularly active for their anti-carcinogenic properties (1); 9-cis,11-trans 18:2, and 10- trans,12-cis 18:2. CLAs are commonly found in foods, in particular in ruminant milk and meat, because these isomers are formed during biohydrogenation of linoleic acid in the rumen and/or through conversion of vaccenic acid in the mammary gland. It is well known that several strains of Lactobacillus, Propionibacterium, Bifidobacterium and Enterococcus, usually present during dairy manufacturing, are also able to form CLAs from linoleic acid (2). Their presence during cheese production, together with processing conditions, can then influence the concentration of CLAs in the final product. Based on this preliminary statements, our studies evaluated the capability of 22 strains of Lactobacillus casei isolated from cheeses to produce, in vitro, bioactive CLA isomers (especially cis-9,trans-11 and trans-10,cis-12 C 18:2) through linoleic acid (LA) bioconversion. Four CLA isomers were separated and quantified (respect to total lipid), by using silver-ion-HPLC. LA concentration in the culture media, the effect of strain pre-cultivation and adaptation in medium added with LA, time and temperature of fermentation as well as other parameters were evaluated in order to produce CLA and/or CLA enriched cells through cultivation in bioreactor. Preliminary results showed that CLA bioconversion was strain dependent and greatly related to the conditions applied to cultivate selected strains.
Effect of different parameters on the production of conjugated linoleic acids from linoleic acid bioconversion by lactic acid bacteria
GAMBACORTA, Giuseppe;
2009-01-01
Abstract
In the last years, with relation to the numerous benefits attributable to CLA (conjugated linoleic acids), the interest is increasing about the synthesis of such compounds in order to prepare healthy foods or ingredients. To date just a few studies have dealt with the possibility to use lactic acid bacteria to increase the CLA content of foods. Above all the 56 possible CLAs, two of them have been found particularly active for their anti-carcinogenic properties (1); 9-cis,11-trans 18:2, and 10- trans,12-cis 18:2. CLAs are commonly found in foods, in particular in ruminant milk and meat, because these isomers are formed during biohydrogenation of linoleic acid in the rumen and/or through conversion of vaccenic acid in the mammary gland. It is well known that several strains of Lactobacillus, Propionibacterium, Bifidobacterium and Enterococcus, usually present during dairy manufacturing, are also able to form CLAs from linoleic acid (2). Their presence during cheese production, together with processing conditions, can then influence the concentration of CLAs in the final product. Based on this preliminary statements, our studies evaluated the capability of 22 strains of Lactobacillus casei isolated from cheeses to produce, in vitro, bioactive CLA isomers (especially cis-9,trans-11 and trans-10,cis-12 C 18:2) through linoleic acid (LA) bioconversion. Four CLA isomers were separated and quantified (respect to total lipid), by using silver-ion-HPLC. LA concentration in the culture media, the effect of strain pre-cultivation and adaptation in medium added with LA, time and temperature of fermentation as well as other parameters were evaluated in order to produce CLA and/or CLA enriched cells through cultivation in bioreactor. Preliminary results showed that CLA bioconversion was strain dependent and greatly related to the conditions applied to cultivate selected strains.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
