Over the past decade, interest has risen in fermented dairy foods that promote health and could prevent diseases such as hypertension. This biological effect has mainly been attributed to bioactive peptides encrypted within dairy proteins that can be released during fermentation with specific lactic acid bacteria or during gastrointestinal digestion. The most studied bioactive peptides derived from dairy proteins are antihypertensive peptides; however, a need exists to review the different studies dealing with the evaluation of antihypertensive fermented milk before a health claim may be associated with the product. Thus, the objective of this overview was to present available information related to the evaluation of fermented milk containing antihypertensive peptides by in vitro and in vivo studies, which are required before a fermented functional dairy product may be introduced to the market. Although commercial fermented milks with antihypertensive effects exist, these are scarce and most are based on Lactobacillus helveticus. Thus, a great opportunity is available for the development of functional dairy products with new lactic acid bacteria that support heart health through blood pressure- and heart rate-lowering effects. Hence, the consumer may be willing to pay a premium for foods with important functional benefits.

The blood pressure-lowering effect of fermented milk with Lactococcus lactis NRRL B-50571 was evaluated in a double-blind randomized controlled clinical trial with prehypertensive subjects. Participants were randomized into 2 groups (n = 18 each group): one group treated with fermented milk with Lactococcus lactis NRRL B-50571 and a control group treated with artificially acidified milk. Results revealed that during daily consumption of fermented milk for 5 wk, systolic [(116.55 ± 12.26 mmHg vs. 124.77 ± 11.04 mmHg) and diastolic blood pressure (80.7 ± 9 vs. 84.5 ± 8.5 mmHg)] from the fermented milk group was lower than the control group. Additionally, triglyceride, total cholesterol, and low-density lipoprotein in blood serum were lower in the fermented milk group than in the control group. Results demonstrated that daily consumption of fermented milk with Lactococcus lactis (NRRL B-50571) had a blood pressure-lowering effect on prehypertensive subjects. Regular consumption of this product may be used as a potential functional food.

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 <10 kDa fractions, PFM10) were administrated daily for four weeks. After treatments, animals were induced to a systemic inflammation with LPS, and blood samples were collected 6 h post-LPS injection for cytokine analyses. Results showed that FM or PFM significantly (p > 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.

Purpose: The purpose of this study was to screen wild GABA-producing lactic acid bacteria (LAB) isolated from artisanal Mexican cheeses and to evaluate the fermentation conditions for the enhancement of the GABA yield in fermented milk. Methods: A qualitative test was carried out to select the GABA-producing LAB and the GABA was quantified by reversed-phase high-performance liquid chromatography in fermented milk (FM). Two inoculum concentrations (10 7 and 10 9 CFU/mL), two incubation temperatures (30 and 37°C), three glutamate concentrations (1, 3, and 5 g/L), and three pyridoxal 5′-phosphate (PLP) concentrations (0, 100, and 200 μM) were assessed to establish suitable conditions to enhance the GABA yield in FM. Results: Results showed that, from a total of 94 LAB strains, fermented milk with two Lactococcus lactis strains (L-571 or L-572) presented the highest GABA production. However, 37°C of incubation and 10 9 CFU/mL and 3 g/L of glutamate significantly led the highest GABA yield in FM with L-571. Further studies are needed to establish the optimum conditions for producing GABA by this strain, and in vivo studies may reveal its potential use as GABA-producing culture. Conclusion: These results highlight the importance of wild LAB strains in order to generate new alternatives and opportunities in the development of functional foods containing GABA.

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