Casein-breakdown by Lactococcus lactis

摘要: Mixed starter cultures used to manufacture Dutch cheeses are composed of lactic acid bacteria which Lactococcus spp. the dominant organisms (Hugenholtz 1986). Several metabolic properties lactococci serve special functions directly or indirectly have impact on processes such as flavour development and ripening cheese (Olson 1990). These (i) fermentation depletion milk sugar lactose, (ii) reduction redox potential, (iii) citrate fermentation, (iv) degradation casein. The casein by yields peptides amino acids that sources essential growth-stimulating for lactis (Thomas Pritchard 1987; Chopin 1993). In addition being an important nutritional source culture bacteria, products also play a crucial role in cheese. Certain contribute formation typical flavour, whereas others, undesirable bitter-tasting peptides, can result off-flavour. need better understanding leading these has prompted various research groups study components proteolytic pathway. Research pathway L.lactis is most advanced. Most, if not all, this been identified, majority enzymes purified biochemically characterized, genetics corresponding genes studied (Table I).