Biodiversity of lactococci in flavour formation for dairy products innovation

الملخص EN

Biodiversity of 37 Lactococcus lactis strains, included 31 strains isolated from various environment (dairy and non dairy ecosystems) so-called “wild” strains and 6 industrial strains, in flavour production capacities was investi-gated in milk cultures.

Organoleplic evaluation revealed that many strains produced different flavours distinct from those produced by industrial strains.

Most dairy wild strains showed proteolytic activity and were good producers of lactic acids in contrast with non dairy wild strains.

Some strains produce bacteriocin-like compound and exopolysac-charides.

GC-MS analysis showed a variation between strains for formation of flavour compounds which correspond to the sensory descriptions.

The major volatile compounds produced by strains were derived from amino acids.

Since various LAB differ in amino acid converting abilities (leading to flavour components) and these activities are linked to the ability to synthesize amino acids, the amino acids-forming capacities of strains were determined.

The results showed that the wild strains had much larger potential to synthesize amino acids as compared to industrial strains. Some strains were selected and applied in Domiati cheese.

A good correlation between organoleplic description and GC-MS volatile compounds of cheese samples and milk cultures prepared with the same strain was found.

The natural biodiversity found within the strains reflect their functional diversity and offers good possibilities for flavour diver-sification and product innovation.

This knowledge with genome data which will become available for various LAB allows prediction of flavour forming capacity and leading to the design of improved tailor-made industrial cultures with attractive or selected flavour.