Study on Different Inoculation Levels of Lactobacillus sakei on the Improvement of Quality Characteristics of Low-sodium Dry Sausages

The effects of different inoculation levels (10⁵, 10⁶ and 10⁷ CFU/g) of Lactobacillus sakei on the quality characteristics of low-sodium dry sausages were investigated in this study. The uninoculated dry sausage was the control, and the moisture content, water activity, pH, lactic acid bacteria count, color and shear force were measured on days 0, 3, 6 and 9, respectively. Meanwhile, the flavor characteristics of the dry sausages on day 9 were analyzed by combination of gas chromatography-mass spectrometry and electronic nose. The results showed that pH of dry sausages inoculated with 10⁶ and 10⁷ CFU/g L. sakei significantly decreased at the end of fermentation (P<0.05), and the inoculation of 10⁶ CFU/g could promote the improvement of moisture content and water activity of final product compared with the control. In addition, the color and shear force of all dry sausages did not change significantly with the inoculation levels (P>0.05). The inoculation of L. sakei reduced the contents of aldehydes, and only the inoculation of 10⁶ CFU/g increased the contents of alcohols, acids and esters (P<0.05), which caused a stronger characteristic odor than the control. Sensory evaluation results showed that inoculation of 10⁶ CFU/g had the best effect on improving the bitterness and metallic taste, which resulted in the best overall acceptability of low-sodium dry sausages. Partial least squares regression analysis of physicochemical and sensory characteristics of dry sausages were consistent with the above results. The inoculation of 10⁶ CFU/g had a positive effect on improving quality and developing good flavor of dry sausages.