Influence of microbial in-situ heteropolysaccharide production on textural properties of raw fermented sausages (salami)

The purpose of the study was to investigate the influence of a heteropolysacchride (HePS)-forming lactic acid bacteria (LAB) on the quality attributes of raw fermented sausages. Therefore, salamis with the HePS-producing strain Lactobacillus plantarum TMW 1.1478 or the non-EPS-producing strain Lactobacillus sakei TMW 1.2037 (control) were manufactured using two different inoculation concentrations: more precisely, 10 CFU/g (typical starter culture concentration) or 10 CFU/g. Growth behavior, a and pH development were recorded until a weight loss of 31% was reached and in-situ-formed EPS detected using confocal laser scanning microscopy. Moreover, the influence of the HePS formed on texture (texture profile analysis; TPA) and sensory attributes (26 panelists, ranking test) was investigated. The final products containing L. plantarum TMW 1.1478 were found to be significantly softer (p < 0.05) than the respective control samples, an effect that was even more pronounced at the higher inoculation level of 10 CFU/g. The semi-quantitative data interpretation of the CLSM pictures revealed that the EPS were predominantly formed during the first 72 h of fermentation at 24 °C until the final pH of 4.95 ± 0.05 was reached (stationary phase). The sensory evaluation (consistency) was in accordance with the TPA results and taste was not negatively influenced by the HePS-forming strain. Results clearly indicate that EPS-producing LAB can have a negative influence on the quality of raw fermented sausages. However, these strains (in the present case L. plantarum TMW 1.1478) might be interesting for application in the field of spreadable raw sausage manufacturing.