Development of defined mixed-culture fungal fermentation starter granulate for controlled production of rice wine

Abstract

As a first step in the development of defined fungal starter granules for controlled winemaking from purple glutinous rice, the interaction of moulds and yeasts isolated from Vietnamese rice wine starters and the effect of some representative oriental herbs on the growth of moulds and yeasts were examined. Amylomyces rouxii and Saccharomyces cerevisae were shown to be compatible in mixed cultures, and the herbs “Tieu Hoi” (Fennel: Foeniculum vulgare Miller) and “Dinh Huong” (Clove: Syzygium aromaticum L.) which are used as supplementary ingredients by some local starter producers, were observed to stimulate the mould and yeast growth. Based on traditional starter manufacturing methods and modified on the basis of optimization experiments, a laboratory-scale manufacturing process for defined mixed-culture starter granules was established. In accordance with the national standard method, the wine produced with new experimental starter granules was found to have superior flavour and overall acceptability, compared with local commercial rice wines. Industrial relevance One of the major problems faced by commercial brewers of rice wine in Vietnam, is the variable quality and performance of the traditional starter tablets that are commonly used. The relevance of the present paper is that a stable, granulated starter has been developed, containing a defined mixture of mould and yeast cultures. This has proven to be shelf stable for more than 3 months, producing a very well accepted quality of wine.