Enzymatic activity of lactic acid bacteria (with antimicrobial properties) isolated from a traditional Spanish cheese
Departamento de Higiene y Tecnología de Alimentos, Facultad de Veterinaria, Universidad de León, Campus de Vegazana, 24071 León, Spain. Food Microbiology
(Impact Factor: 3.33).
08/2010; 27(5):592-7. DOI: 10.1016/j.fm.2010.01.004
Twenty-four strains of lactic acid bacteria (LAB) isolated from a traditional Spanish cheese (Genestoso cheese) were evaluated for their enzymatic activities (acidifying and proteolytic abilities and carboxypeptidase, aminopeptidase, dipeptidase, caseinolytic and esterase activities), in order to select indigenous strains of technical interest for the manufacture of cheese. These strains were selected on the basis of their antimicrobial activity relative to five reference strains and were identified as Lactococcus lactis subsp. lactis (thirteen strains), Leuconostoc mesenteroides (two strains), Leuconostoc pseudomesenteroides (one strain), Lactobacillus paracasei (two strains), Lactobacillus plantarum (one strain) and Enterococcus faecalis (five strains). Lactococcus strains were those that showed the greatest degree of acidifying and proteolytic activity. The cell-free extracts (CFE) of L. paracasei exhibited the highest level of aminopeptidase activity. The highest level of caseinolytic activity was shown by the CFE of one strain of L. lactis. High values were also obtained with the CFE of Lactobacillus and of several Leuconostoc. The highest level of dipeptidase activity was found amongst the strains of L. lactis. Carboxypeptidase activity was generally very low or undetectable for the majority of strains. The greatest degree of esterolytic activity was detected for Enterococcus.
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- "Both Leuconostoc and Lactococcus strains presented low proteolytic activity in general, with the former presenting the lowest activity, yielding values that did not exceed 0.2 mMGly@BULLETL −1 , while values for the Lactococcus strains were below 0.5 mMGly@BULLETL −1 , with the exception of one Lactococcus lactis strain that presented values of 0.80 mMGly@BULLETL −1 . These values differed between strains but were generally slightly lower than those detected by various authors for other strains of Lactococcus isolated from traditional cheeses of different origins   , although they were similar to those detected by Mayo et al. (1990) . The majority of the Lactobacillus strains presented a proteolytic activity of between 0.1 and 0.5 mMGly@BULLETL −1 , and one Lb. "
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- "Jednocześnie najwyższe wartości aktywności aminopeptydaz stwierdzili w stosunku do Leu-pNa, a niewielkie – wobec Ala-pNa. W niniejszej pracy również stwierdzono nieznaczną aktywność dipeptydaz względem Leu-Gly, ale, w przeciwieństwie do badań przedstawionych przez Gonzáleza i wsp., wykazano stosunkowo niską aktywność enzymów badanych kultur bakterii względem Leu-Leu oraz Ala-pNa. W badaniach własnych wykazano, że w przypadku aktywności dipeptydaz Lb. casei czynnikiem statystycznie istotnym (p < 0,05) był rodzaj użytego substratu. "
- "Furthermore, LAB play a major role in releasing specific compounds responsible for cheese flavour development . LAB contribute to proteolysis and lipolysis events in cheeses as they can degrade the products derived from rennet action on casein and hydrolyse milk fat or, at least, some triglycerides (Gonz alez et al. 2010). LAB autolysis in cheese is also of particular importance because it allows key intracellular enzymes involved in cheese ripening to reach their substrates more easily. "
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ABSTRACT: AimEvaluate technologically relevant properties from bacteriocin-producing strains to use as starter/adjunct cultures in cheese making. Methods and ResultsEight isolates obtained from Pico cheese produced in Azores (Portugal) were found to produce bacteriocins against Listeria monocytogenes and three isolates against Clostridium perfringens. They were identified as Lactococcus lactis and Enterococcus faecalis and submitted to technological tests: growth at different conditions of temperature and salt, acid production, proteolysis, lipolysis, coexistence, enzymatic profile and autolytic capacity. Safety evaluation was performed by evaluating haemolytic, gelatinase and DNase activity, resistance to antibiotics and the presence of virulence genes. Some isolates presented good technological features such as high autolytic activity, acid and diacetyl production. Lactococcus lactis was negative for all virulence genes tested and inhibit the growth of all Lactic acid bacteria (LAB) isolates. Enterococci were positive for the presence of some virulence genes, but none of the isolates were classified as resistant to important antibiotics. Conclusions
The bacteriocin-producing Lc. lactis present good potential for application in food as adjunct culture in cheese production. The study also reveals good technological features for some Enterococcus isolates. Significance and Impact of the StudyBacteriocin-producing strains presented important technological properties to be exploited as new adjunct culture for the dairy industry, influencing flavour development and improve safety.
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