Production of a Potentially Probiotic Product for Animal Feed and Evaluation of Some of Its Probiotic Properties.

Nowadays, probiotics have been proposed for substituting antibiotics in animal feed since the European Union banned the latter compounds in 2006 to avoid serious side effects on human health. Therefore, this work aimed to produce a probiotic product for use in animal feed by fed-batch fermentation of whey with a combination of kefir grains, AGK1, and the fermented whole milk used to activate these kefir grains. The probiotic culture obtained was characterized by high levels of biomass (8.03 g/L), total viability (3.6 × 108 CFU/mL) and antibacterial activity (28.26 Activity Units/mL). Some probiotic properties of the probiotic culture were investigated in vitro, including its survival at low pH values, under simulated gastrointestinal conditions, after freezing in skim milk at -20 °C, and in the commercial feed during storage at room temperature. The viable cells of lactic and acetic acid bacteria and yeasts exhibited higher tolerance to acidic pH and simulated gastrointestinal conditions when the cells were protected with skim milk and piglet feed, compared with washed cells. The results indicated the feasibility of producing a probiotic product at a low cost with a potential application in animal feed.

Production of a highly concentrated probiotic culture of Lactococcus lactis CECT 539 containing high amounts of nisin.

In this study, probiotic biomass and nisin productions by Lactococcus lactis CECT 539 were followed in two realkalized fed-batch cultures in diluted whey (DW) supplemented with KH2PO4 up to a total phosphorus concentration of 0.459 g/L. Increased biomass (5.12 g/L, 2.18 × 1010 CFU/mL) and nisin (235.23 BU/mL) concentrations were obtained in the culture fed concentrated whey and concentrated mussel processing waste (CMPW) medium supplemented with glucose up to a concentration of 400 g/L (CMPW + G medium) compared with similar fed-batch fermentations in DW medium. In the second fed-batch fermentation, the feeding medium CMPW + G was supplemented with KH2PO4 up to a TP concentration of 3.21 g/L. With this approach, increased production of biomass (5.49 g/L, 2.33 × 1010 CFU/mL) and nisin (257.59 BU/mL) was obtained. Considering the substantial availability of these wastes at very low prices from local dairy and mussel processing plants in Galicia, their use as culture media could offer an attractive alternative for a low-cost production of probiotic biomass and nisin at a high scale.

Nisin production in realkalized fed-batch cultures in whey with feeding with lactose- or glucose-containing substrates.

Nisin production by Lactococcus lactis CECT 539 was followed in batch cultures in whey supplemented with different concentrations of glucose and in two realkalized fed-batch fermentations in unsupplemented whey, which were fed, respectively, with concentrated solutions of lactose and glucose. In the batch fermentations, supplementation of whey with glucose inhibited both the growth and bacteriocin production. However, fed-batch cultures were characterized with high productions of biomass (1.34 and 1.51 g l(-1)) and nisin (50.6 and 60.3 BU ml(-1)) in comparison to the batch fermentations in unsupplemented whey (0.48 g l(-1) and 22.5 BU ml(-1)) and MRS broth (1.59 g l(-1) and 50.0 BU ml(-1)). In the two realkalized fed-batch fermentations, the increase in bacteriocin production parallels both the biomass production and pH drop generated in each realkalization and feeding cycle, suggesting that nisin was synthesized as a pH-dependent primary metabolite. A shift from homolactic to heterolactic fermentation was observed at the 108 h of incubation, and other metabolites (acetic acid and butane-2,3-diol) in addition to lactic acid accumulated in the medium. On the other hand, the feeding with glucose improved the efficiencies in glucose, nitrogen, and phosphorus consumption as compared to the batch cultures. The realkalized fed-batch fermentations showed to be an effective strategy to enhance nisin production in whey by using an appropriate feeding strategy to avoid the substrate inhibition.

Production and characterization of distilled alcoholic beverages obtained by solid-state fermentation of black mulberry (Morus nigra L.) and black currant (Ribes nigrum L.).

The present study was conducted to appraise the potential of black mulberry and black currant to be used as fermentation substrates for producing alcoholic beverages obtained by distillation of the fruits previously fermented with Sacchromyces cerevisiae IFI83. In the two distillates obtained, the volatile compounds that can pose health hazards are within the limits of acceptability fixed by the European Council (Regulation 110/2008) for fruit spirits. However, the amount of volatile substances in the black currant distillate (121.1 g/hL absolute alcohol (aa)) was lower than the minimum limit (200 g/hL aa) fixed by the aforementioned regulation. The mean volatile composition of both distillates was different from other alcoholic beverages such as four commercial Galician orujo spirits, Portuguese bagaceiras, and two distillates obtained from fermented whey and blackberry. The results obtained showed the feasibility for obtaining distillates from fermented black mulberry and black currant, which have their own distinctive characteristics.