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Improving the processing of four fermented beverages from Eastern European countries

Final Report Summary - FERBEV (Improving the processing of four fermented beverages from Eastern European countries)

The project aimed to improve three traditional fermented beverages and implement the production of an innovative soy-based fermented drink. These products are Boza, a Turkish cereal-based beverage, Ayran, a Turkish mildly-fermented milk based, consumed as a drink after water and salt addition, and Matsony, a Georgian milk-based beverage; these drinks usually contain a high number of viable microorganisms. Additionally, a fermented soy beverage developed in Poland has been the object of analyses, standardisation and implementation into production in one SME established in Czeck Republic.

The project involved seven SMEs (beverage manufacturers, technologies and plant suppliers) and six RTD public bodies and institutes, who have studied and characterized fermented beverages and from their natural microflora have collected about eight hundred microbial colonies from different steps of each drink production; colonies have been isolated, identified, and biotyped by molecular and biotechnological techniques. A high microbial diversity at species and strain level was found in Boza whereas a lower biodiversity was detected in Ayran and Matsony. The new fermented soy beverage was produced by using starters including two lactic acid bacteria and one Bifidobacterium strain.

Interestingly, bacterial strains endowed with acidifying, proteolytic activities and / or ability of exopolysaccharide production as well as antimicrobial activity against pathogens were selected, and yeasts able to turn L-phenylalanine into a rose-like flavour were highlighted. A FERBEV microbial culture collection, including more than 200 strains of bacteria and yeasts, was set up. Boza heat and drying treatments lowered microbial cell counts; in this way shelf-life of Boza was extended up to six months, as planned. Good sensory characteristics and high probiotic viable cell counts were found in fermented soy beverage stored at 4 degrees Celsius for 30 days. Shelf-life of Ayran and Matsony was extended up to one month under correct production and storage practices. More than twenty autochthonous microbial combinations were tested as starters for Boza, Ayran, Matsony and fermented soy beverage under laboratory conditions. On the basis of the results, two selected starters for each beverage were chosen and successfully used to manufacture drinks with the pilot-plant appositely set up in the FERBEV project.

Chemical, microbiological and sensory analyses of the beverages were carried out for at least six weeks on the cold stored beverage samples. As concerns Boza, the two autochthonous selected starters had a positive impact on shelf-life that was longer than 42 days under cold storage. In addition, Boza revealed a low and stable ethanol content and viscosity during all storage. As concerns Ayran, microbiological and chemical features were stable up to 42 days and sensory analyses showed a good consumer acceptance up to 30 days of beverage cold storage. Very interesting results were obtained as concerns Matsony in the course of the project the cooperation of beverage producer, with the other partners allowed to modernise its equipment and improve the hygienic manufacturing conditions. Furthermore, the use of selected autochthonous starters allowed to produce samples that maintained chemical, microbiological and sensory characteristics of the beverage for one month at 6 degrees Celsius instead of two-three days as at the beginning of the project. During the project, fermented soy beverage was for the first time produced and marketed by a SME, as described on a website appositely realised for consumers (please see http://www.sojo.cz online). The new starters set up, both comprising one Streptococcus thermophilus strain and one Bifidobacterium as FSB biotum supplement, allowed to produce FSB samples in which both Bifidobacterium and Str. Thermophilus strains maintained their population for one month of cold storage, and a well perceived sensory profile.

Furthermore, the finding of high content of resistant starches in Boza, polyunsaturated fatty acids in FSB and more than 90 % of L(+) lactic acid in both these beverages, provide preliminary information about potential beneficial effects on human health. Finally, all fermented beverages produced met the EU regulation concerning food hygiene and safety, requirement essential for introducing these drinks into new markets.

Several promising and sometimes unexpected interesting results were obtained in the course of the project. Novel microbial starters for Boza, Ayran, Matsony and fermented soy beverage were set up in the course of the project research activities. Boza and fermented soy beverage are produced fermenting cereal and soy proteins, respectively whereas Ayran and Matsony are milk based yogurt type drinks. In order to obtain a good fermentation process and a palatable beverage, different microbial combinations were analysed and tested in pilot scale productions. Boiled cereal mixtures were fermented with more than 10 different microbial starters with or without yeasts evaluating the better combinations able to produce a good Boza stable under cold storage conditions. At the end of the assays, two different autochthonous starters were obtained mixing homofermentative and heterofermentative lactic acid bacteria and a single yeast strain. From Ayran and Matsony microbiota several bacterial strains belonging to homofermentative thermophilic lactic acid bacteria were tested in different combinations. On the basis of the study of autochthonous microorganisms occurring in traditional beverage samples and technological characteristics displayed by single strains, three starters were produced for these milk-based beverages able to ferment milk under standardised conditions; they improve beverage quality avoiding post-acidification occurring during fridge storage.

Fermented soy beverage was produced in different versions as pure or fruity drink. FSB was fermented by using several combinations of different lactic acid bacteria and adding, before cold storage, adequate amounts of bifidobacteria strains. Among all versions evaluated, the best combination was able to maintain a good taste and flavour during cold storage and high viable bifidobacteria cell counts.