Process Optimization To Reduce The TBA Value Of Beer

During storage, flavor substances of beer were oxidized easily by reactive oxygen and free radicals, which brought a unpleasant taste, that is beer aging. The shelf life of beer would be shorten seriously as a result of beer aging. As beer aging reactions were very complex, to solve the beer aging was still a important problem for beer industry.TBA value (The value of Thiobarbituric acid) could response to the situation of beer aging effectively. As the precursors of beer aging substances existed in every process of beer brewing, we studied every process of beer brewing to reduce TBA value of beer. The main contents of this paper were as follows:(1) To select the best raw material. In this paper, three kinds of different beer adjuncts were used for beer brewing. By measuring and analyzing the TBA value and the color of wort, and the concentration of Polyphenol and the shelf life of beer, it was easy to be found that the beer produced by the wheat malt had the lowest TBA value and the longest shelf life. So compared with malted barley and Sweetcorn, wheat malt was the best beer adjunct.(2) To determine the optimum feeding temperature of raw material and the optimum way of mashing. In this paper, we chose 35℃, 45℃, 55℃and 65℃as the feeding temperature of raw material, and determined the TBA value. The results showed that 35℃was the optimum feeding temperature to reduce the TBA value. This temperature was also good forβ-glucanase to solve the problem of inadequate malt lytic.Compared with the decoction mashing, Infusion mashing raised temperature by adding hot water in several times, which was really good for reducing the concentration of carboxides. As a result, Infusion mashing not only could reduce the TBA value, but also could save energy and cut down the cost.(3) Determine the optimal intensity and boiling time to get the best boiling method. By measuring and analyzing the TBA value, we found that the wort produced by boiling intensity of 8.2% and boiling time of 60min had the lowest TBA value. We also found that economic boiling method could control the TBA value more effectively than conventional boiling method.(4) Optimization of fermentation parameters. During the fermentation, the variation trend of TBA value was from tender to senescent and leveled off at the end of fermentation. Compared to other fermentation conditions, the fermentation temperature 8℃, pH 4.8 and dissolved oxygen at the level of 0.3ppm could control the TBA value of beer most effectively. As SO₂ had antioxygenic property, the concentration of SO₂ in beer and the TBA value of beer showed significantly negative correlations.(5) Antioxidants addation and combinatorial optimization. By design of orthogonal experiment, we got the optimal combination of Sodium Erythorbate 15ppm and Sodium Pyrosulfite 10ppm. Beer with this combination had the strongest reducing power and oxidationresistance, as a result, the TBA value of beer was the lowest. What the most important was the concentration of other substances in line with national standard GB4927-2008. Besides, the beer had the appearance of clean and transparent and a perfect taste.