MEAT PROTEIN DEGRADATION BY TWO DIFFERENT AUTOCHTHONOUS STARTER CULTURES IN A LOW SALT DRY FERMENTED SAUSAGE MODEL

MARCIO AURELIO DE ALMEIDA; JULIETA BONACINA ; LUCILA SAAVEDRA; PATRICIA CASTELLANO ; CARMEN J CONTRERAS-CASTILLO; SILVINA FADDA

Congreso; X Congreso Argentino de Microbiología General SAMIGE; 2014

The objective of this work was to evaluate the proteolytic activity of two different Lactic Acid Bacteria (LAB) strains to be applied as starter culture in fermented sausage production with reduced sodium contents (1%), using an in vitro Beaker Sausage model. Ground meat with additives was divided into three batches: (T1) Lactobacillus curvatus CRL 705/ Staphylococcus vitulinus GV 318; (T2) Lactobacillus sakei CRL1862/ Staphylococcus vitulinus GV 318 and (T3) un-inoculated control with antibiotics. Each strain was inoculated at a concentration of 8 log CFU/ml and incubated at 22°C. Analysis of pH and bacterial counts on differential agar media was performed at 0, 3, 6 and 10 days. Total Protein was analyzed by Bradford and the proteolysis was evaluated by Tricine-SDS-PAGE (sodium dodecyl sulfate, polyacrylamide electrophoresis) at 0 and 10 days. Results showed that Lactobacillus curvatus (T1) counts remained stable (8 log CFU/ml) and Staphylococcus vitulinus decreased 3 logs after 10 days of incubation. The pH decreased rapidly from 5.8 to 4.7 in ten days, due to the acidogenic metabolism of LAB. The acidic environment resulted in the inhibition of Staphylococcus vitulinus. On the other hand, Lactobacillus sakei CRL1862 (T2) showed a slight decrease after 10 days whereas S. vitulinus demonstrated a similar behavior than the observed in T1. In this treatment (T2) the pH decreased from 5.8 to 4.7 in 10 days. Regarding the proteolytic activity after 10 days of incubation, T2 (L. sakei CRL 1862) showed a more intense meat protein degradation profiles than T1 (L. curvatus CRL705). A similar tendency was observed in total protein contents, where T2 showed slight higher drop in this parameter (T0:6.65 mg/ml; T10days: 2.92 mg/ml) than T1 (T0: 8.47 mg/ml; T10 days: 2.92 mg/ml). With respect to amino acids analysis, T2, demonstrated the highest ability to enrich amino acid contents after 10 days. In fact, beaker sausages inoculated with L. sakei CRL1862 increased 7 times the amino acid contents of the meat system (T0:220mg/100g; T10:1566 mg/100g). However, T1 also demonstrated a good potential for amino acid production (T0:246mg/100g; T10: 560 mg/100g). In conclusion, the starter culture constituted by Lactobacillus sakei CRL1862 + Staphylococcus vitulinus GV 318 has an appropriate growth performance on Beaker Sausage model with reduced NaCl contents, optimal pH drop and demonstrated to have the ability to hydrolyze meat proteins. All this features together with the increment in free amino acids, related to flavor development, make this starter culture a candidate for the production of low-sodium fermented sausages.