Abstract
Hard cheeses may occasionally show a brown discolouration during ripening due to multifactorial phenomena
that involve bacteria and give rise to pyrazines arising from methylglyoxal. The present work aimed at developing
a novel approach to investigate the role of natural starters in browning. To this object, 11 strains of
L. helveticus were incubated in a medium containing 10 % rennet casein dissolved in whey, and then growth was
monitored by measuring pH and number of genomes/mL. Browning was assessed through CIELab analysis,
methylglyoxal production was determined by targeted mass spectrometry, and untargeted metabolomics was
used to extrapolate marker compounds associated with browning discoloration. The medium allowed the growth
of all the strains tested and differences in colour were observed, especially for strain A7 (ΔE* value 15.92 ±
0.27). Noteworthy, this strain was also the higher producer of methylglyoxal (2.44 μg/mL). Metabolomics
highlighted pyrazines and β-carboline compounds as markers of browning at 42 ◦C and 16 ◦C, respectively.
Moreover, multivariate statistics pointed out differences in free amino acids and oligopeptides linked to proteolysis,
while 1,2-propanediol and S-Lactoylglutathione suggested specific detoxification route in methylglyoxalproducing
strains. Our model allowed detecting differences in browning amid strains, paving the way towards
the study of individual L. helveticus strains to identify the variables leading to discoloration or to study the
interaction between different strains in natural whey starters.
Lingua originale | English |
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pagine (da-a) | 1-11 |
Numero di pagine | 11 |
Rivista | Food Research International |
Volume | 174 |
DOI | |
Stato di pubblicazione | Pubblicato - 2023 |
Keywords
- Grana-like cheese
- Maillard reaction
- Pyrazines
- Starter lactic acid bacteria
- UHPLC-HRMS