Viability of bifidobacteria in soft-frozen ice cream supplemented with a Saccharomyces cerevisiae cell wall product

Abstract

The purpose of this research was to monitor the changes during storage in survival of bifidobacteria in a soft-frozen ice cream supplemented with a yeast cell wall-based product claimed to contribute to the functioning of the immune system. An ice cream mix was prepared and pasteurised. After overnight aging at 4 °C, it was inoculated with Bifidobacterium animalis subsp. lactis Bb-12. Two batches of the mix were supplemented with a commercial Saccharomyces cerevisiae cell wall product at 2.0% and 4.0% (w/w), whereas a third batch was left unsupplemented and served as control. The final mixes were frozen, and the three products were stored at –13 °C for 7 days. The ice creams contained viable bifidobacteria cells at levels exceeding 106 CFU g–1 throughout the storage throughout the storage period. Although the yeast supplement decreased the loss of viability of bifidobacteria during frozen storage of ice creams, it imparted a slightly bitter off-flavour to the samples and it also negatively influenced the original white colour of the product, thereby necessitating further work to develop flavoured varieties of the Saccharomyces cell wall-containing synbiotic ice cream.