Microbiological Studies on Traditional Cereal-based Fermented Beverage
V. GOTCHEVA, S. S. PANDIELLA1, A. ANGELOV and Z. ROSHKOVA
Higher Institute of Food and Flavour Industries, Dept. of Biotechnology, BG-4002 Plovdiv, Bulgaria
1Satake Centre for Grain Process Engineering, UMIST, Dept. of Chemical Engineering, PO Box 88, Manchester M60 1QD, UK
GOTCHEVA, V., S. S. PANDIELLA, A. ANGELOV and Z. ROSHKOVA, 2000. Microbiological studies on traditional cereal-based fermented beverage. Bulg. J. Agric. Sci., 6: 53-58
Many of the indigenous foods consumed around the world are produced by natural fermentation, and in many cases the manufacturing procedure remains even today as a household art. There is not always information about the microorganisms involved, which makes it very difficult to maintain the product quality. In this work the microflora of the traditional Bulgarian cereal-based beverage boza was investigated. 458 lactic acid bacteria (LAB) and 194 yeast strains were isolated from three samples obtained from local boza producers in the Plovdiv region. The quantification of microorganisms show that the number of LAB vary from 6.0 to 8.8 x 107 cfu/cm3, while yeast counts fall between 2.6 and 3.9 x 107 cfu/cm3. The number of LAB was always higher than the number of yeasts and the ratio LAB/yeasts was found to be more or less constant. The lactic acid bacteria isolated were identified as Lactobacillus plantarum (24% of the total LAB), Lb. acidophilus (23%), Lb. fermentum (19%), Lb. coprophilus (11%), Leuconostoc raffinolactis (9%), Ln. mesenteroides (9%), and Lb. brevis (5%). The yeasts isolated comprise Saccharomyces cerevisiae (47% of the total yeasts), Candida tropicalis (19%), C. glabrata (14%), Geotrichum penicillatum (12%), and G. candidum (9%). Though further work is needed to identify what microorganisms are responsible for the beneficial properties of the Bulgarian boza, these results could form the basis for the improvement of product quality and consistency.
Key words: boza, yeast, lactic acid bacteria, identification, cereals, fermentation