Models of Ph and Lactic Acid Dynamics Determined During Lactic Acid Fermentation of Various Juices with Lactobacillus Acidophilus

Abstract

The dynamics of the lactic acid fermentation of different vegetable juices inoculated with Lactobacillus acidophilus - that are not constitutive from the epiphytic microbiota of vegetables - were evaluated through some physical and chemical parameters: pH and titratable acidity, expressed in lactic acid. Because the stability and the preservation of the lacto-fermented juices are important from the technological point of view, the evolution of those ones should be monitored. In this sense, this work targets to find prediction models and curve fittings that express the pH and lactic acid dynamics during lactic acid fermentation of various juices with Lactobacillus acidophilus. With a view to obtain probiotic products, all the vegetable juices (obtained from carrots, red beet, white and red cabbage) were suitable for lactic acid fermentation. Excepting the red beet fermented juice, the others become highly stable after 24 hours, the pH values being 3.74 - 3.84, while the lactic acid content was comprised between 6.3 and 8.01g/l. Whether for the consumer the taste should be qualified as excessively sour, the remnant sugars mask this characteristic, ensuring a good taste of the lacto-fermented vegetable juices. At the same time, the red beet juice fermented with Lactobacillus acidophilus has reached values of the analyzed indicators that can provide stability to refrigeration. The models illustrated in the paper were obtained using specific software application for statistical processing - CurveExpert -, a cross-platform solution for curve fitting and data analysis.