Characteristics of some traditional Vietnamese starch-based rice wine fermentation starters ( men)

Abstract

In the Mekong Delta region of South-Vietnam, wine from purple glutinous rice is particularly interesting because of its sherry-like taste and flavour and its attractive brown-red colour. It is manufactured at home or by small cottage industries, using traditional solid-state starters ( Men). With the objective of improving the knowledge about the functionality of traditional Men, this study deals with the properties and composition of 29 samples of Vietnamese commercial rice wine starters. We selected 6 rice wine starters for their superior ability to liquefy cooked rice, high ethanol accumulation, and production of attractive flavour and colour in the resulting wine. Ethanol contents reached 12 g/100 ml, a sweet alcoholic fragrance was noticed and the wine colour varied from red to lightly brown. Total mould, yeast and bacteria counts in Men were 3.4–6.0, 5.8–7.2 and 2.6–6.2 log CFU/g of dry weight sample, respectively. A total of 119 microbial strains, comprising 53 moulds, 51 yeasts and 15 bacteria, was isolated. Mould isolates with excellent functionality were identified as Amylomyces rouxii, Amylomyces aff. rouxii (an atypical form of A. rouxii), Rhizopus oligosporus and Rhizopus oryzae. Yeast isolates with excellent fermentation properties were all identified as Saccharomyces cerevisiae; other, less functional isolates were identified as Candida glabrata and Pichia anomala.