Influences of protectants, rehydration media and storage on the viability of freeze-dried Oenococcus oeni for malolactic fermentation

Abstract

Malolactic fermentation (MLF) is an important process in wine production. To achieve successful MLF, expanding interest in ready-to-use Oenococcus oeni starter cultures has placed greater emphasis on developing starter production and preservation methods. In this study, influences of protectants, rehydration media and storage on the viability of O. oeni H-5 when subjected to freeze-drying were investigated. It was found that sodium glutamate (2.5%) was the best protectant, giving the cell viability 72.4%. Adding polysaccharides and disaccharides in suspension media also improved significantly the cell viability. Rehydration is an important step in recovery after freeze-drying. When freeze-dried O. oeni was rehydrated in GYM medium, the highest viability (87.1%) was obtained. Rehydration in the disaccharide solutions tested made the cell viability obviously decrease. After 6 months storage at 4°C, loss of viability occurred, the extent of which depended on protectants used, sodium glutamate again being the most effective.

Spray‐drying for the production of dried cultures

“…2001; Carvalho et al. 2004; Zhao and Zhang 2005, 2009). In fact, rehydration is a critical step in the recovery of dried micro‐organisms, because cells that were previously subjected to a sublethal injury may not be able to repair in inappropriate rehydration conditions (Costa et al.…”

Optimization of a protective medium for freeze-dried Pichia membranifaciens and application of this biocontrol agent on citrus fruit

“…). A possible explanation was the difference in the water‐binding capacity and prevention of cellular ice crystal formation of each saccharide and polyol (Zhao and Zhang ). Among the antioxidants, sodium glutamate and ascorbic acid played important roles in protecting freeze‐dried micro‐organisms (Berny and Hennebert ; Costa et al .…”

“…Viable yeast counts were determined prior to freezing ( N 0 ) and after freeze‐drying ( N f ) and were expressed as colony forming units per millilitre (CFU ml −1 ) according to the method of Zhao and Zhang (). Before freezing, suitable dilutions of yeast samples were spread on the surface of the NYDA plate.…”

Effect of Sodium Tripolyphosphate, Glycerol, Vitamin B2, Mannitol and Solid Malt Extract on Survival of Bifidobacterium bifidum During Freeze-Drying

“…The same result was confirmed from our study. However, Zhao et al (2009) found that when add of sodium glutamate was 2.5% (W/V), the survival rate of Oenococcus oeni reach high at 72.4%. The reason may be due to individual differences of strains.…”