Acid production and proteolytic activity of lactobacilli strains isolated from dry sausages

GRACIELA MARGARITA VIGNOLO; DE RUIZ HOLGADO, AIDA ARGENTINA PESCE; G OLIVER,

JOURNAL OF FOOD PROTECTION

International Association for Food Protection

Lugar: Des Moines, Iowa; Año: 1988 vol. 51 p. 481 - 484

0362-028X

The acid-producing capacity and proteolytic activity of 13 strains of lactobacillus plantarum and 5 strains of Lactobacillus casei isolated from dry sausages was determined at different temperatures and at different NaCl concentrations. Most strains exhibited a maximum acid-producing rate at 30ºC. According to the acidification rate atthis temperature, strains were divided into three rates groups: fast (I), medium (II) and slow(III), with tritrable acidity values above 1.7, between 0.7 and 1.4 and below 0.7, respectively. The decrease in pH ranged between 3.1 and 3.95 according to the group to which the strains belonged. the addition of 3.0% of NaCl produced a marked decrease in the rate of acidification of strains in gropup II, a slight decrease for those in group I and no effect for those in group III. The proteolytic acitivity of strains under study reached a maximum at 40ºC with values between 5.2 and  and 10 mg% tyrosine released. At 30ºC,and in the presence of 3% NaCl the greatest activity (5.4 mg% tyrosine) was observed in L. plantarum GV417 and the lowest (3.4 mg% tyrosine) in L. plantarum GV420. A decrese in approximately 80% in proteolytic activity for all strains was observed in the presence of 5% NaCl.