Studies report that metabolites, such as peptides, present in fermented milk with specific lactic acid bacteria, may regulate cytokine production and exert an anti-inflammatory effect. Hence, the cytokine regulatory effect of fermented milk by specific Lactobacillus strains was evaluated in a lipopolysaccharide (LPS)-stimulated murine model. From twelve strains, three (J20, J23 and J28) were selected for their high proteolytic and acidifying capacities in milk and used for the in vivo study. Three treatments (fermented milk, FM; pasteurized fermented milk, PFM; and its 0.05) reduced pro-inflammatory cytokine (IL-6 and TNF-α) concentrations and significantly increased anti-inflammatory (IL-10) cytokine concentrations in comparison to the control; also, pro-inflammatory cytokines were reduced for animals treated with PFM10 (p < 0.05). RP-HPLC-MS/MS analysis showed that water-soluble extracts (<10 kDa) from PFM with J28 presented 15 new peptides, which may be the metabolites involved in the cytokine regulatory effect of fermented milk.

It has been reported that fermented milk (FM) with Lactococcus lactis NRRL B-50571 had an antihypertensive effect in spontaneously hypertensive rats (SHR) and prehypertensive subjects. Therefore, the objective of the present study was to evaluate the possible mechanisms involved (angiotensin converting enzyme inhibition (ACEI), enhancement of nitric oxide production, antioxidant activity and opioid effect), in the antihypertensive effect of FM with SHR. First, twenty one SHR were randomized into three groups to either receive in a single-oral dose of purified water (negative control), FM, or naloxone (opioid receptor antagonist) + FM. In a parallel study, twenty seven SHR were randomized into three groups to either receive ad libitum purified water (negative control), Captopril or FM. After six weeks of treatment ACEI activity, enhancement of nitric oxide production, and antioxidant activity were evaluated in plasma. Results indicated that opioid receptors were not involved in the hypotensive effect of FM. However, ACEI activity (94 U/L), the oxidative stress index (malondialdehyde/catalase + glutathione peroxidase) 0.9, and nitric oxide in plasma (4.4 ± 1.3 U/L), were significantly different from the negative control, and not significantly different from the Captopril group. Thus, these results suggested that these mechanisms are involved in the hypotensive effect of FM.

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.