Technological variables influencing the growth and stability of a silage inoculant based on spray‐dried lactic acid bacteria

Abstract

Aims To investigate the influence of different culture media and fermentation conditions on growth performance and viability of three lactic acid bacteria (LAB) strains with potential as silage inoculants, and to optimize spray‐drying in order to enhance survival to dehydration and storage stability. Methods and Results In house‐formulated MRS was a suitable low‐cost culture medium for Lactobacillus plantarum Hv75, Pediococcus acidilactici 3903 and L. buchneri B463. Uncontrolled pH biomass production conferred enhanced stability during storage at 4°C after spray‐drying. The use of whey protein concentrate 35 (WPC)‐maltodextrin (M) as matrix, inlet temperature of 145‐150°C and air flow rate of 601 l h−1 was adequate for the production of dehydrated LAB. According to the desirability function, at this optimized condition, moisture content, yield and solubility were predicted to be 3·96, 73·68 and 90·36% respectively. Those conditions also showed a decrease of 0·855 log CFU per gram after drying, no loss in viability at 4°C for 6 months and 1 log CFU per gram reduction at 25°C. Conclusions Stable and economically feasible dehydrated LAB cultures were obtained using alternative culture media, fermentation under uncontrolled pH and optimizing spray‐drying process conditions through the desirability function method. Significance and Impact of the Study Our results can be utilized for efficient production and commercialization of several dry LAB.

A Multi-Sensor Mini-Bioreactor to Preselect Silage Inoculants by Tracking Metabolic Activity in situ During Fermentation

“…A few studies tested silage inoculants using MRS broth or the aqueous extract of silage crop ( Oude Elferink et al, 2001 ; Danner et al, 2003 ; Holzer et al, 2003 ; Graves et al, 2006 ; Arasu et al, 2015 ; Blajman et al, 2020 ). Fermentation characteristics, such as production of organic acids, decreasing dynamics of pH, and CO 2 production, depend on medium composition ( Danner et al, 2003 ; Blajman et al, 2020 ).…”

“…A few studies tested silage inoculants using MRS broth or the aqueous extract of silage crop (Oude Elferink et al, 2001;Danner et al, 2003;Holzer et al, 2003;Graves et al, 2006;Arasu et al, 2015;Blajman et al, 2020). Fermentation characteristics, such as production of organic acids, decreasing dynamics of pH, and CO 2 production, depend on medium composition (Danner et al, 2003;Blajman et al, 2020). The next step of our study is to replace MRS broth with the aqueous extract of silage, creating a testing condition that may be closer to the natural culture of silage ensiling for LAB.…”

Impact of native spray‐dried lactic acid bacteria, packing density and wilting time on fermentation characteristics of experimental maize and lucerne silages

“…Strains were cultured together without pH control in formulated MRS (Blajman, Vinderola, Cuatrin, et al, 2020), and cell counts were performed after fermentation. Subsequently, biomass was harvested (6000x g, 15 min, 4°C), washed twice with PBS (pH 7.4) and resuspended in 10% (w/v) maltodextrin 14.7 dextrose equivalent (Ingredion) plus 10% (w/v) WPC 35 (whey protein concentrate, Saputo).…”

“…Cell suspensions were spray-dried in a laboratory scale spray dryer (Büchi mini spray dryer model B290). Drying conditions used were: feeding rate: 270 ml/h, constant inlet air temperature: 150°C, outlet temperature: 83°C and air flux: 601 l/h (Blajman, Vinderola, Cuatrin, et al, 2020). Cell suspensions were atomized and sprayed into the drying chamber by using a two-fluid nozzle.…”

Probiotic characterization of indigenous lactic acid bacteria isolates from chickens to be used as biocontrol agents in poultry industry

“…whereas in the other culture media its growth was lower than both ligilactobacilli. In general, alternative growth media used milk or whey permeate, a by-product of the cheese manufacture (Blajman et al, 2020;Heenan et al, 2002). This product has been previously employed for LAB biomass production (Cerdeira et al, 2019), showing that its application is feasible at industrial levels.…”