Semina: Ciências Exatas e Tecnológicas (Jan 2001)
Influence of NaCl and NaCO2 on the Lactic Acid Fermentation of Lactobacillus curvatus Grown in MRS Medium
Abstract
Lactic acid bacteria are microorganisms of major importance in food industry, mainly for its lactic acid production which contributes for food preservation and organoleptic properties. In the case of meat products, these bacteria are useful because they reduce nitrates and nitrites. The reduction of nitrites decreases formation of carcinogenics compounds as the nitrosamines. The objective of this work was to evaluate the use of NaCl and NaNO2 as suplementation of the MRS medium (Man-Rogosa-Sharpe), in order to improve the lactic fermentation by Lactobacillus curvatus. The optimization of the concentration of these salts in the medium was obtained by the response surface methodology with fatorial design 32. The cultures were developed during 48h at 37ºC and initial pH of 6.2 in MRS liquid medium. The lactic acid was measured by spectrophotometry at 425 nm. Better acid lactic production, 3.3%, was obtained using 0.87 % (w/v) of NaCl and 156ppm of NaNO2. It was observed that levels of NaCl up to 4 % (w/v) and NaNO2 up to 300ppm, recommended in the meat preservation, did not significantly affected the lactic acid production at the 5% level, which demonstrates the possibility of using L. curvatus as starter culture in meat products.
