The interest in new types of functional beverages has increased especially in Western Europe. Extracts made of malted cereals contain natural sugars and provide an excellent source of health-promoting compounds, such as antioxidants and vitamins. However, untreated wort is susceptible to spoilage organisms. Bioacidification with selected lactic acid bacteria (LAB) could be a potential tool to increase the shelf life of cereal extracts and malt-based beverages. In addition, LAB-fermentations increase the amount of health-promoting compounds, such as L-lactic acid, and enhance the flavour characteristics of cereal extracts. The aim of this study was to screen and select LABs having good antimicrobial properties and flavour profiles in wort fermentations. To avoid beer spoilage, LABs selected for production of functional beverage bases in a brewery environment should not be hop tolerant. Therefore, we studied the growth and adaptation of LABs in the presence of hop compounds. Eleven LAB strains were surveyed. Lactobacillus amylovorus VTT E-95576 or Lactococcus lactis VTT E-072626 showed good antimicrobial potential and efficiently inhibited the growth of two typical beer spoiling bacteria: Obesumbacterium proteus and Lactobacillus brevis. Lb. amylovorus E576 required ca. 45 °C for optimal growth. Lc. lactis E2626 was able to acidify wort (below pH 4) at 15 - 25 °C. The lower temperature was more practical in industrial scale. In addition, Lc. lactis was sensitive to hops, it did not grow in beer, it produced only L-Lactic acid and generated a pleasant flavour profile, described as acidic, fresh and fruity.
|Conference||1st International Symposium for Young Scientists and Technologists in Malting, Brewing and Distilling|
|Period||6/11/08 → 7/11/08|