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Background and objective: Beer is a popular drink worldwide. Due to the disadvantages of alcoholic beer consumption on pregnant women, those with cardiovascular diseases, professional athletes, driving accidents, traffic events, and work-place considerations, there has been being a trend among population to consume non-alcoholic beer with pleasant sensory characteristics. This research investigates the effects of different saccharomyces strains and fermentation conditions on production of non-alcoholic beer. Materials and methods: Four strains of saccharomyces (S. cerevisiae 70424, S. ludwigii 3447, S. rouxii 70535 and S. rouxii 70531) were added to the wort with defined gravity in two levels. The wort was fermented in three temperatures for 48 h under anaerobiosis or under periodic aeration (each 12 h). Optical density was assessed by spectrophotometry, and wort gravity and ethanol content by beer analyzer (at 12-h intervals during fermentation) over 48 h. Sensory analysis was performed by a panel group consists of 6 trained panelists. Experiments were performed in triplicate and the ranked orders of means were determined in significance level of 0.05 (p<0.05) using two-way ANOVA test from Minitab software (State College, PA, USA). The design was ‘completely randomized design’. Results: Treatments with 4×107 (cfu/mL) inoculation rate and fermentation temperature of 24˚C resulted in the greater growth rate under periodic aeration and the higher ethanol production under anaerobic condition. The greatest wort gravity was seen in treatments with inoculation rate of 107 (cfu/mL), periodic aeration and fermentation at 4˚C (p<0.05). Treatments with 107 (cfu/mL) inoculation level, fermentation at 4˚C possessed the lowest growth rate under anaerobiosis and the lowest ethanol production under periodic aeration. Among the yeasts used, the highest and lowest amounts of growth rate, ethanol production and wort gravity were related to S. cerevisiae and S. rouxii, respectively. The greatest scores for flavor in sensory analysis was observed for the sample fermented with S. cerevisiae. Conclusion: Using S. cerevisiae in restricted fermentation methodology under the conditions of 107 (cfu/mL) inoculation level, periodic fermentation and fermentation temperature of 4˚C were found suitable for production of non-alcoholic beer due to its acceptable sensory properties and the alcohol amout less than 0.5%. Keywords: Non-alcoholic beer, Ethanol, Saccharomyses

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Background and Objectives: In this research, the effects of addition of different probiotic strains (L. acidophilus, L. casei, L. reuteri, L. fermentum or L. plantarum) as well as initial pH values (4.3 or 4.8) on the biochemical and microbiological characteristics of non-alcoholic beer drink were studied during 21 days in the refrigerated storage (5°C).

Materials and Methods: Probiotics identification and incubation were done with gram staining and MRS-broth medium, respectively. pH and redox potential values were measured by pH-meter. Titrable acidity value was determined by titration with 0.1 N NaOH. Probiotic bacteria were enumerated using MRS-agar medium.

Results: The highest biochemical changes were observed in treatments with L. casei and L. acidophilus.  The second 7-day interval showed the highest amount of biochemical changes in the treatments with initial pH of 4.3 along with L. casei, L. fermentum and L. reuteri throughout the 21 days of storage; however, other species showed such characteristics only at pH=4.8. The viability of probiotic strains in all treatments, especially in those with initial pH of 4.3, decreased dramatically during the refrigerated storage. L. acidophilus and L. fermentum showed the lowest viability during refrigerated storage. While the highest viability belonged to L. reueri in the treatments with initial pH of 4.3 and to L. plantarum in those with pH=4.8.

Conclusion: The results showed that different initial pH values as well as different types of inoculated probiotic strains in non-alcoholic beer drink had effects on the amount of the biochemical changes and the viability of probiotic strains in non-alcoholic beer drink; therefore, non-alcoholic beer drink can be a good choice for growth of probiotic.

Keywords: Biochemical, Non-alcoholic beer, Probiotic, Viability