Suitability of whey and buttermilk for the production and frozen storage of cultures of probiotic lactobacilli

BURNS, P.; MOLINARI, F.; VINDEROLA, G.; REINHEIMER, J.

INTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY

Blackwell Publishing

Año: 2008 vol. 61 p. 156 - 164

1364-727X

The growth of six probiotic commercial strains of lactobacilli was assessed in reconstituted dried wheyand buttermilk supplemented with yeast extract, meat peptone, soy peptone, tryptone or casein acidhydrolysate at 0.3%, 0.6% or 1%. The addition of 1% glucose was also tested. Growth and acidificationkinetics were determined at 37°C using MRS broth and a commercial culture medium as references. Thesuitability of whey and buttermilk as cryoprotectants at –20°C and –70°C was also assessed. Whey andbuttermilk with 0.3% yeast extract were chosen for the growth of probiotic lactobacilli, since nosatisfactory growth was observed without an external nitrogen source, whereas glucose did not improvethe growth of any of the strains assayed. In general, buttermilk performed as satisfactorily as thereference media. The effectiveness of these media as cryoprotectants was strain dependent: skimmed milkand whey were the most suitable ones, especially for long-term storage at –20°C. However, at –70°C, nosignificant differences were observed between the culture media assessed. The use of whey or buttermilkas culture media for the production of probiotic lactic acid bacteria and for their cryopreservationimplies a novel use of these low-cost products, offering an alternative way of utilizing the by-products ofthe dairy industry, helping to minimize their negative impact on the environment.