Study On Organic Acids And Flavor Modification Of Original Gravity Beers

At present, low gravity beer becomes more and more prevalent, however, it has many flavor deficiencies, such as too light, sour feeling etc. This research studied on the kinds and contents of organic acids, and tried to find the reason of flavor differences between different original gravity beers.Adjusting saccharification and appending polyphosphates were adopted to improve the flavor of the low gravity beer. The main results were as follows:1 With the same ratio of raw materials, 6.0, 6.5, 7.0, 7.5, 8.0, and 10.0oP beers were brewed by bottom fermentation. The total acidities of the samples increased following the original gravity increasing. With the original gravity lower than 7.5oP, the sourness of beers was more heavier in sequence. Ten organic acids were detected in each of the samples by reverse phase high performance liquid chromatography (RP-HPLC), including oxalic, tartaric, pyruvic, malic, ketoglutaric, lactic, acetic, citric, fumaric, and succinic acids. The total content of these acids ranged 738.17 to 799.50 mg/L. The significant differences were found on the individual organic acid content among the samples. Succinic acid had the top content in the 10 organic acids detected in each of the beers, followed by citric, lactic, malic, pyruvic and oxalic acid in sequence. The content of pyruvic and oxalic acid increased with the original gravity of the samples increasing, respectively. The content of lactic acid in the 7.0, 7.5, 8.0, and the 10.0oP samples were similar, however, it increased sharply in the 6.0 and 6.5oP samples. It indicated that the metabolization of beer yeast was impacted by original gravity and attenuation of beer.2 With the same raw materials, material-water ratio, and same pH value of mash water, through changing mash-in temperature, incubation time, proteolysis temperature and proteolysis time in saccharification, the effect of saccharification technology on wort buffering component and buffering capacity were studied. The titratable acids, phosphates, amino nitrogen and...