Influence of homopolysaccharide-producing lactic acid bacteria on the spreadability of raw fermented sausages (onion mettwurst).

The purpose of the study was to investigate the effect of a reduced pH value (5.1 instead of 5.5 to 5.6) on the properties of highly perishable, spreadable raw fermented sausages (onion mettwurst) with or without the addition of homopolysaccharide (HoPS)-producing lactic acid bacteria (LAB). Hence, sausages with HoPS-producing LAB and a pH value of 5.1 were produced and compared to sausages (pH 5.1) produced with a non-exopolysaccharide (EPS)-forming strain (Lactobacillus sakei TMW 1.2037). Microbial growth and pH values were monitored during processing (24 °C for 48 hr, 10 °C for 24 hr) and storage (14 days at 0 to 2 °C). Furthermore, fat (Weibull-Stoldt) and EPS contents were determined in the final products. Sausages were characterized using texture profile and sensory analysis. The fat contents ranged from 16% to 19% and the determined EPS concentrations ranged from 0.17 to 0.59 g/kg for L. sakei TMW 1.411 and Lactobacillus curvatus TMW 1.1928 and from 0.67 to 1.58 g/kg for L. curvatus TMW 1.51. The strains L. sakei TMW 1.411 and L. curvatus TMW 1.51 reduced the hardness of the samples significantly (P < 0.05) compared to the control samples. Regarding spreadability and mouthfeel, sausages containing an EPS-forming culture were rated slightly better than the control samples and the taste was not negatively influenced. PRACTICAL APPLICATION: This study clearly demonstrated that it is promising to apply HoPS-producing LAB to maintain the spreadability of pH-reduced (pH 5.1) spreadable raw fermented onion mettwurst, which may prospectively give the opportunity to increase the safety of this highly perishable product.