OPTIMIZING A LACTIC FERMENTATION of SLICED CARROTS

Response surface methods were utilized in the statistical optimization of several quality factors pertaining to the preservation of carrot slices using a brine containing lactic acid produced by in situ fermentation. These factors were the concentrations of salt, acid, and reducing sugars, and the texture of the carrot material, and the pH, concentrations of acid, reducing sugars, and biomass (at two different times) of the brine. the processing variables considered were the temperature, the salt concentration of the brine, and the ratio of volumes of brine to the carrot material. the starting (corner and center) factorial design has indicated that, within the experimental range of practical interest, a linear model failed to provide a good fit to the experimental data; hence, this design was complemented with an axial design. Checks of the residuals and estimates of third‐order parameters have indicated that no apparent reason existed to question the statistical adequacy of the quadratic empiric model. the loci of the optima (and the characterization of such optima) were then obtained for this model, and the general directions for the variation of the values of the processing parameters were presented. This study has indicated that temperature may be manipulated to give rise to any desired increase or decrease of the quality factor chosen, a conclusion that may be relevant in attempts to industrially improve carrot preservation processes based on lactic acid fermentation.