Prosopis alba flour as a novel food matrix to vitamin B12 production by Lactobacillus reuteri CRL1098

TORINO, MARIA INES; AVILA, ANA MAGDALENA; TARANTO, MARIA PIA; TORES, ANDREA CAROLINA

Campinas

Congreso; São Paulo School of Advanced Sciences on Reverse Engineering of Processed Foods; 2017

School of Food Engineering UNICAMP

Prosopis (P) alba (algarrobo) is a native tree from the northwestern region of Argentina. The pod of this plant, containing a sweet edible pulp, is used to produce flour and others food products due to their nutritional, functional and biological properties, but in spite of its characteristics this products are marketed as handicrafts with low incidence in the regional economy. P. Alba flour presents high concentration of carbohydrates, principally sucrose which make this flour a good substrate for the development of beneficial bacteria. Lactobacillus (L) reuteri CRL1098 is a Gram-positive, facultative heterofermentative species of lactic acid bacteria (LAB), isolated from sourdough. It has been demonstrated that the CRL1098 strain has the ability to produce vitamin B12, one of the most complex no polymeric macromolecule that humans are not able to produce but they need in vital enzymatic reactions. In this context, the aim of this study was to investigate the suitability of P. alba flour as a novel substrate for vitamin B12 production by L. reuteri CRL1098 in order to further develop and optimize a technological process that will be scaled-up. Culture media were prepared employing both commercial and not commercial P. alba flour (10 % w/v), sterilized and inoculated with an initial cell density of 106 CFU/ml of CRL1098 strain previously activated in MRS broth (37ºC, 16 h). Fermentation experiments were carried out in batch systems without agitation using 250 ml flasks containing 100 ml of the P. alba medium. Samples were aseptically withdraw immediately at time 0 and every 2 h up to 24 h to determine the cell viability (CFU/ml) and pH in order to obtain a growth curve and define the kinetic parameters. A bioassay using Salmonella Typhimurium AR2680 (a mutant strain unable to grow in the absence of vitamin B12) as indicator was conducted after 16 h of fermentation to prove the presence of vitamin B12 in the fermented matrix. Experiments were performed in duplicate using MRS broth as a control medium. L. reuteri CRL1098 grew in P. alba medium reaching 108 CFU/mL when using both kind of flours and after 16 h of fermentation this strain was able to produce compounds with vitamin B12 activity as it was confirmed by the presence of growing halos of mutant AR2680 in the presence of the fermented matrix. These results demonstrated that the strain was able to grow and produce vitamin B12 on the proposed matrix, therefore the Prosopis alba medium is suitable with high potential for the design of fermented food bio-enriched with vitamin B12 using the cobalamin producer strain Lactobacillus reuteri CRL1098.