Annals of the University Dunarea de Jos of Galati. Fascicle VI: Food Technology (Oct 2017)
Improvement of lactic acid fermentation with Lactobacillus paracasei ssp. paracasei MIUG BL5 on enriched rye flour medium
Abstract
The aim of this study was to improve the biotechnological conditions in order to increase the organic acid production with a wild Lactobacillus paracasei ssp. paracasei strain isolated from pickle juice. The Plackett-Burman Experimental Design (PB), Central Composite Design (CCD) and Response Surface Methodology (RSM) were applied in order to enhance the lactic acid fermentation on a rye flour enriched medium. Among the screened variables, the concentrations of soy protein isolate and KH2PO4 as nutrients, time and the temperature of fermentation were identified as the most significant variables that influence the fermented product acidity. The optimized levels of the significant parameters were determined as following: 0.5% soy protein isolate, 0.43% KH2PO4, 36 h of fermentation at 31°C, which improved the fermented product acidity approximately with 1.3 folds, compared to the non-optimized fermented product. Furthermore, a good level of cell multiplication rate (10.21 of log N/N0) was achieved.
