The objective of this study was to investigate the effect of starter culture addition on proteolysis of Thai fermented sausages. Sausages inoculated with six different external starter cultures-Pediococcus pentosaceous, Pediococcus acidilactici, Weissella cibaria, Lactobacillus plantarum, Lactobacillus pentosus, and Lactobacillus sakei-were compared with naturally fermented sausages. The results of microbiological analysis indicated that the dominance of lactic acid bacteria (LAB) could inhibit the growth of pathogens and spoilage. Proteolysis was observed during fermentation by the reduction of myofibrillar and sarcoplasmic proteins and the increase in nonprotein nitrogen (NPN) and total free amino acids. The highest increase in concentration of NPN and free amino acids was obtained from sausages inoculated with LAB. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) showed a similar pattern of proteolysis of sarcoplasmic proteins in all sausages, while that of the inoculated sausages with L. plantarum, L. pentsus, and L. sakei exhibited increased degradation of myofibrillar protein bands at 200 and 45 kDa.

Improvement of the conventional sausage fermentation process was investigated by introducing six different external starter cultures including Pediococcus pentosaceous, Pediococcus acidilactici, Weissella cibaria, Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus sakei. The results of microbiological analysis indicated that the dominance of lactic acid bacteria could inhibit the growth of pathogens and spoilage. Sausages inoculated with starters exhibited lower pH (pH = 4.51–4.67) than the uninoculated control. The decrease of pH was attributed to organic acid, mainly by lactic acid production. The initial rate of lactic acid production in sausages inoculated with starter cultures was higher than the control. P. acidilactici showed the highest initial rate of lactic acid production (4.45 × 10−2 g/100g·h) and lactic acid yield (0.89), while the initial rate of lactic acid production and lactic acid yield were 2.66 × 10−2 g/100g·h and 0.63, respectively, in control experiments. The sausage inoculated with P. acidilactici recorded the highest scores for overall acceptability. PRACTICAL APPLICATIONS The fermentation of traditional fermented sausages is caused by natural, wild‐type lactic acid bacteria such as lactobacilli and pediococci that originate from the row meat, or the process apparatus or the environment and takes 2–3 days at room temperature. The use of starter cultures in sausages production has improved food safety and to standardize product properties such as flavor compound, lactic acid, color and texture. In addition, the sensory of sausages inoculated with starter cultures are more acceptable than uninoculated sausages.

The purpose of this study was to improve Thai fermented sausage flavor by adding starter cultures (i.e., Pediococcus pentosaceus, Pediococcus acidilactici, Weissella cibaria, Lactobacillus plantarum, Lactobacillus pentosus, and Lactobacillus sakei) as compared with naturally fermented sausage. The predictive mathematical models for growth of P. acidilactici and natural lactic acid bacteria (LAB) in Thai fermented sausage were developed to obtain specific prepared sausage quality. Furthermore, comparisons of sausage preparation and transportation cost between nonrefrigerated and refrigerated trucks were studied. The concentration of 3‐methyl‐butanoic acid synthesized from LAB inoculated sausage was higher than in the control sample which contributed to the flavor forming. Moreover, the proposed unstructured kinetic models of Thai fermented sausage substrates and products describing the consumption of total protein and glucose, and the production of nonprotein nitrogen responsible for flavor enhancer, lactic acid and formic acid concentration were successfully fitted with two selected experimental data sets of the in situ fermentation of Thai fermented sausage. Finally, the transportation of inoculated sausages in a nonrefrigerated truck by combining fermentation process and transportation was more cost efficient for delivering sausages in a long distance.

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