Use of autolytic starter systems to accelerate the ripening of Cheddar cheese

The rapid release of intracellular enzymes due to autolysis of lactic acid bacteria in the cheese matrix post-manufacture is thought to play a role in the acceleration of cheese ripening. To investigate this hypothesis Cheddar cheese was manufactured using three related starter systems which varied with respect to their autolytic properties. Starter system A contained a blend of two Lactococcus lactis strains (223 and 227) which had a low level of autolysis. System B was identical to A but included an adjunct of a highly autolytic strain of Lactobacillus helveticus (DPC4571). System C consisted only of strain DPC4571 as starter. The cheeses were evaluated during ripening for key ripening indices including autolysis of starter cells by release of intracellular marker enzyme lactate dehydrogenase (LDH), composition, proteolysis and flavour development by descriptive sensory analysis. Populations of Lb. helveticus DPC4571 decreased rapidly in cheeses B and C and were not detected by 8 weeks. The level of starter culture autolysis proceeded in the order C much greater than B > A. Levels of proteolysis were elevated in cheeses B and C relative to A. Principal component analysis of the sensory data separated the character of cheese A from that of cheeses B and C. Cheeses B and C developed a unique 'balanced' 'strong' flavour early in ripening with a 'caramel' and 'musty' odour and 'sweet' 'astringent' flavour compared to cheese A. Hierarchical cluster analysis grouped C at 2 months with B at 6 and 8 months reflecting accelerated flavour development. Proteolytic and sensory data support the hypothesis that autolysis accelerates the rate of cheese ripening. (C) 2003 Elsevier Science Ltd. All rights reserved.