Research on the Preparation and Application of Lyoprotectants for Hanseniaspora uvarum BF-345 Derived from Indigenous Grape Juice

The extensive use of imported commercial Saccharomyces cerevisiae active dry powder preparations has led to a serious homogenization of wine products in China.

In recent years, there has been growing interest in developing and applying indigenous non-Saccharomyces yeasts to enhance the diversity and distinctive character of wines.

In this study, a promising indigenous strain, Hanseniaspora uvarum BF-345, previously isolated from local grape juice, was investigated due to its desirable fermentation properties, robust stress tolerance, and high β-glucosidase activity. Response surface methodology (RSM) was employed to optimize the composition of a cryoprotectant formulation for the vacuum freeze-drying of BF-345.

The optimal protectant formulation was determined as follows: 5.63% skim milk powder, 12.89% maltitol, and 7.02% sucrose. Under these conditions, the viability of the freeze-dried cells reached 85.2%, representing a 27.3% increase compared to the pre-optimized formulation.

The prepared active dry yeast complied with the Chinese national standard GB/T 20886.2-2021 and maintained a viability above 70% after 6 months of sealed storage at 4°C.

In micro-vinification trials with cabernet sauvignon, the fermentation system inoculated with the freeze-dried powder exhibited higher yeast cell counts and more favorable fermentation kinetics than that inoculated with a liquid seed culture.