The dairy industry is among the most polluting within the food sector, mainly because of the high quantities of effluents, waste and by-products arising from milk processing. A dairy by-product poorly studied is the ricotta whey, or "scotta", the liquid fraction remaining after the production of ricotta. Approximately 1 ton of scotta are yearly produced in Italy from Ricotta manufacture. Presently, most of the scotta are used in animal feeding whereas alternative approaches for its valorisation are at their early beginning. We tested the possibility to use the residual lactose of this by-product for the production of galacto-oligosaccharides (GOS), a class of well-known prebiotic molecules able to promote the activity of the intestinal microbiota. GOS are generally obtained by enzymatic transglycosylation using ?-galactosidase enzyme (EC 3.2.1.23) from different microorganisms. In this work, our attention was focused on 23 strains belonging to the genus Bifidobacterium, mostly new isolated from bovine colostrum. Strains showing higher ?-galactosidase activity were selected for GOS production in lactose solutions and in scotta. The compositional profile and the yield of GOS mixture was evaluated by HPAEC-PAD chromatography technique. This analysis revealed an increase of GOS production with increasing lactose concentration. Scotta seems to be unsuitable for the production of GOS, while its retentate of nanofiltration (lactose concentration of about 20%) resulted a good substrate for GOS accumulation. NMR allowed to identify the different molecular forms of GOS present in the reaction solutions. This study aims to provide new knowledge about the possibility of an alternative and targeted use of the residual lactose present in scotta (or other dairy by-products), allowing for restoration and valorisation of this by-product, while reducing disposal problems.
Production of galacto-oligosaccharides (GOS) from dairy by-products by bacterial strains related to the genus Bifidobacterium
Cagliani L;Consonni R;
2017
Abstract
The dairy industry is among the most polluting within the food sector, mainly because of the high quantities of effluents, waste and by-products arising from milk processing. A dairy by-product poorly studied is the ricotta whey, or "scotta", the liquid fraction remaining after the production of ricotta. Approximately 1 ton of scotta are yearly produced in Italy from Ricotta manufacture. Presently, most of the scotta are used in animal feeding whereas alternative approaches for its valorisation are at their early beginning. We tested the possibility to use the residual lactose of this by-product for the production of galacto-oligosaccharides (GOS), a class of well-known prebiotic molecules able to promote the activity of the intestinal microbiota. GOS are generally obtained by enzymatic transglycosylation using ?-galactosidase enzyme (EC 3.2.1.23) from different microorganisms. In this work, our attention was focused on 23 strains belonging to the genus Bifidobacterium, mostly new isolated from bovine colostrum. Strains showing higher ?-galactosidase activity were selected for GOS production in lactose solutions and in scotta. The compositional profile and the yield of GOS mixture was evaluated by HPAEC-PAD chromatography technique. This analysis revealed an increase of GOS production with increasing lactose concentration. Scotta seems to be unsuitable for the production of GOS, while its retentate of nanofiltration (lactose concentration of about 20%) resulted a good substrate for GOS accumulation. NMR allowed to identify the different molecular forms of GOS present in the reaction solutions. This study aims to provide new knowledge about the possibility of an alternative and targeted use of the residual lactose present in scotta (or other dairy by-products), allowing for restoration and valorisation of this by-product, while reducing disposal problems.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
