Storage of yeast

Storage of yeast stock cultures between propagations... 

Russell, L, Stewart, G. G. (1981). Liquid nitrogen storage of yeast cultures compared to more traditional methods. Journal of the American Society of Brewing Chemists, 39, 19-24. 

The production of heers and ciders requires the fermentation of sugary fluids hy the action of yeasts, and the cooling, filtration, clarification and storage of the resulting alcohol-water mixture. 

YEASTS AND MOLDS. These are very important plant organisms that make both positive and negative contributions to mammalian life processes. Their plus and minus values are particularly noted in connection with the production and storage of food products. 

Fleet, G. H., Lafon-Lafourcade, S., and Ribereau-Gayon, P. (1984). Evolution of yeasts and lactic acid bacteria during fermentation and storage of Bordeaux wines. Appl. Environ. Microbiol. 48,1034-1038. 

In the lower eukaryotes, cation sequestration and storage are observed in vacuoles. Vacuoles of yeast accumulate amino acids (Wiemken and Durr, 1974), K, Mg2+ and Mn2+ (Okorokov et al, 1980 Lichko et al, 1982) (Table 7.1), and Ca2+ (Ohsumi and Anraku, 1983 Dunn et al, 1994). PolyP, which is able to confine different cations in an osmotic inert form, was also found in these storage organelles (Indge, 1968a,b,c Westenberg et al, 1989). 

Influence of Cryoprotectants on Viability and Heterologous Activity of Lyophilized Yeasts in Simulated Gastrointestinal Conditions To evaluate the influence of cryoprotectants on both the survival rate and CA4H activity of WRP45073A1 in simulated gastrointestinal conditions, 1010 viable freeze-dried yeasts and 200 pmol of franx-cinnamic acid were simultaneously introduced into the TIM. Yeast cells were lyophilized in the presence of the milk protein-trehalose mix, trehalose, lactose, or maltose, as previously explained (see above). The freeze-dried samples were introduced into the artificial stomach suspended in 300 mL of yeast culture medium without any storage period. The number of viable cells introduced into the TIM was determined from previously obtained survival rates (cf. Section 5.5.3.1). 

Nowadays, precoated filters with diatomaceous earth are mainly used for the separation of yeast. For overseas exportation, the product is pasteurized after prior adsorptive elimination of on-heat-resisting colloids through treatment with bentonite, silica gel etc. Essential for the quality of the beer is the elimination of temperature fluctuations during storage and transport. 

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