Cooperation between Lactococcus lactis NRRL B-50571 and NRRL B-50572 for Aroma Formation in Fermented Milk

Abstract

The aim of the present study was to characterize the aroma and volatile profiles of milk fermented by wild Lactococcus lactis NRRL B-50571 (FM-571) and NRRL B-50572 (FM-572) and co-fermented with both strains (co-FM). Milks fermented by these strains have been reported to have an antihypertensive effect, yet their sensory characteristics, which are of great importance for consumer acceptance of functional foods, have not been studied. In the study, volatiles were determined using solid-phase microextraction gas chromatography mass spectrometry (SPME-GC-MS) and aroma was determined by quantitative descriptive sensory analysis (QDA). Volatile compounds identified in FM-571, FM-572, and co-FM were mainly acids, alcohols, aldehydes, and ketones. FM-571 showed higher total relative volatile abundance than FM-572 or co-FM. Furthermore, the concentrations of specific amino acids (aa) were lower in FM-571 and co-FM than in FM-572. Thus, these results suggested that FM-571 or co-FM are more efficient in transforming specific aa into the corresponding volatiles than FM-572. Indeed, several alcohols and aldehydes, associated with the catabolism of these aa, were found in FM-571 and co-FM, but not in FM-572. Additionally, QDA showed that FM-571 and co-FM presented higher yeasty and cheesy aroma descriptors than FM-572. Also, total aroma intensity scores for FM-571 were higher than those for co-FM or FM-572. Thus, results suggested that the combination of these two specific wild L. lactis strains may complement amino acid catabolic routes that resulted in the enhancement or attenuation of aroma production of single strains, presenting new possibilities for the preparation of custom-made starter cultures.

In Vitro Antioxidant and Antihypertensive Activity of Edible Insects Flours (Mealworm and Grasshopper) Fermented with Lactococcus lactis Strains

“…It is possible to consider that the strains were indeed involved in the fermentation, because they have been widely used for milk fermentation, in which similar values have been reported. The strains were able to promote the release of bioactive compounds-in particular, NRRL B-50572 has been deemed the most proteolytic strain in milk [21,32]. This same effect was observed in our study with a different protein source (i.e., edible insects).…”

Phenotype testing, genome analysis, and metabolic interactions of three lactic acid bacteria strains existing as a consortium in a naturally fermented milk

“…The flavor components of fermented milks include volatile and non-volatile compounds; some are already present in the starting milk, but most are produced during fermentation (Settachaimongkon et al, 2014;Beltrán-Barrientos et al, 2019). The major volatile compounds commonly include lactic and acetic acids, acetaldehyde, diacetyl, acetoin, 2,3-butanediol, and 2-butanone (Chen et al, 2017).…”

The effect of Lactococcus lactis CICC 23610 fermentation on the physicochemical properties and flavor formation of oat beverage

“…Ketones in fermented oat beverages are primarily formed through the oxidation of free fatty acids and degradation of amino acids (Beltrán‐Barrientos et al, 2019). The relative abundance of 2,3‐butanedione, a ketone, has been associated with citrate metabolism in LAB (Pretorius et al, 2019).…”