Antioxidant capacity and identification of radical scavenging peptides from Crema de Chiapas, Fresco and Cocido cheeses.

Bioactive peptides may positively impact bodily functions. One of these are the antioxidant peptides which are well documented for a wide variety of food matrices, mostly from plant sources. Nevertheless, information of antioxidant milk-derived peptides is still a little-known field. The present study was aimed to evaluating the antioxidant capacity (AC) in vitro of water soluble extracts < 3 kDa (WSE) from three artisanal Mexican cheeses: Crema de Chiapas (CrC), Fresco (FC) and Cocido (CC). This study was carried out for cheeses of different days of storage (0, 5, 10, 15, and 20) at 4 °C. AC was assayed to the respective WSE by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diamoniun salt (ABTS) and oxygen radical absorbance capacity (ORAC) methods and those WSE that showed the most antioxidant capacity from each cheese were analyzed by using RP-HPLC/MS to identify and characterize the novel specific peptides. All the WSE analyzed show antioxidant capacity, especially those from CrC and CC which display the highest AC at 15 days of storage. Regarding to WSE from FC, the AC was constant during storage. Identified structures reveal that these novel peptides possess high content of specific amino acids, mainly proline, valine, leucine and phenylalanine, of which it has already been shown antioxidant properties. This study demonstrate that these artisanal Mexican cheeses are sources of potential antioxidant peptides.

Protective role of lactic acid bacteria and yeasts as dietary carcinogen-binding agents - a review.

The importance of food contaminants in the link between diet and cancer has been widely demonstrated. Therefore, different physical and chemical strategies for the control of human exposure to such dietary carcinogens has been explored; however, most of these strategies are complex, costly, and have low efficiency which limited their applications. Hence, microbiological methods have been receiving more attention. Recent in vitro and in vivo studies have indicated that lactic acid bacteria (LAB) and yeast may act as dietary carcinogen-binding agents. This review describes the promising protective role of strains belonging mainly to the Lactobacillus, Bifidobacterium and Saccharomyces genera by acting as dietary carcinogen-binding agents. This property suggests that these microorganisms may have a protective role by reducing the bioaccessibility of dietary carcinogens, thereby decreasing their toxic effects. The mechanisms by which the binding process takes place have not been completely elucidated; thus, the possible underlying mechanisms and factors influencing carcinogens-binding will be addressed.

Protective Effect of the Intracellular Content from Potential Probiotic Bacteria against Oxidative Damage Induced by Acrylamide in Human Erythrocytes.

The aim of this study was to assess the protective effect of the intracellular content obtained from potential probiotic bacteria against acrylamide-induced oxidative damage in human erythrocytes. First, the antioxidant properties of 12 potential probiotic strains was evaluated. Two commercial probiotic bacteria were included as reference strains, namely, Lactobacillus casei Shirota and Lactobacillus paracasei 431. Data showed that the intracellular content from four strains, i.e., Lactobacillus fermentum J10, Lactobacillus pentosus J24 and J26, and Lactobacillus pentosus J27, showed higher (P < 0.05) antioxidant capacity in most methods used. Thereafter, the intracellular content of such pre-selected strains was able to prevent the disturbance of the antioxidant system of human erythrocytes exposed to acrylamide, thereby reducing cell disruption and eryptosis development (P < 0.05). Additionally, the degree of oxidative stress in erythrocytes exposed to acrylamide was significantly (P < 0.05) reduced to levels similar to the basal conditions when the intracellular content of Lact. fermentum J10, Lact. pentosus J27, and Lact. paracasei 431 were employed. Hence, our findings suggest that the intracellular contents of specific Lactobacillus strains represent a potential source of metabolites with antioxidant properties that may help reduce the oxidative stress induced by acrylamide in human erythrocytes.

In Silico Prediction and In Vitro Assessment of Multifunctional Properties of Postbiotics Obtained From Two Probiotic Bacteria.

In this study, a global metabolite profile using Raman spectroscopy analysis was obtained in order to predict, by an in silico prediction of activity spectra for substance approach, the bioactivities of the intracellular content (IC) and cell wall (CW) fractions obtained from Lactobacillus casei CRL 431 and Bacillus coagulans GBI-30 strains. Additionally, multifunctional in vitro bioactivity of IC and CW fractions was also assessed. The metabolite profile revealed a variety of compounds (fatty acids, amino acids, coenzyme, protein, amino sugars), with significant probable activities (Pa > 0.7) as immune-stimulant, anti-inflammatory, neuroprotective, antiproliferative, immunomodulator, and antineoplastic, among others. Moreover, in vitro assays exhibited that both IC and CW fractions presented angiotensin-converting enzyme-inhibitory (> 90%), chelating (> 79%), and antioxidant (ca. 22-57 cellular antioxidant activity units) activities. Our findings based on in silico and in vitro analyses suggest that L. casei CRL 431 and B. coagulans GBI-30 strains appear to be promising sources of postbiotics and may impart health benefits by their multifunctional properties.

Potential role of natural bioactive peptides for development of cosmeceutical skin products.

In recent years, consumers' demand for cosmeceutical products with protective and therapeutic functions derived from natural sources have caused this industry to search for alternative active ingredients. Bioactive peptides have a wide spectrum of bioactivities, which make them ideal candidates for development of these cosmeceutical products. In vitro studies have demonstrated that bioactive peptides (obtained as extracts, hydrolysates, and/or individual peptides) exhibit biological properties including antioxidant, antimicrobial, and anti-inflammatory activities, in addition to their properties of inhibiting aging-related enzymes such as elastase, collagenase, tyrosinase and hyaluronidase. Some studies report multifunctional bioactive peptides that can simultaneously affect, beneficially, multiple physiological pathways in the skin. Moreover, in vivo studies have revealed that topical application or consumption of bioactive peptides possess remarkable skin protection. These properties suggest that bioactive peptides may contribute in the improvement of skin health by providing specific physiological functions, even though the mechanisms underlying the protective effect have not been completely elucidated. This review provides an overview of in vitro, in silico and in vivo properties of bioactive peptides with potential use as functional ingredients in the cosmeceutical field. It also describes the possible mechanisms involved as well as opportunities and challenges associated with their application.

Modulatory Effect of the Intracellular Content of Lactobacillus casei CRL 431 Against the Aflatoxin B1-Induced Oxidative Stress in Rats.

It has been recognized that lactic acid bacteria exhibit antioxidant properties, which have been mainly endorsed to the intact viable bacteria. However, recent studies have shown that intracellular content (IC) may also be good sources of antioxidative metabolites, which may potentially contribute to oxidative homeostasis in vivo. Hence, the modulatory effect of the intracellular content of Lactobacillus casei CRL 431 (IC431) on aflatoxin B1 (AFB1)-induced oxidative stress in rats was evaluated on the basis of its influence on hepatic lipid peroxidation (LPO), antioxidant status-antioxidant capacity (TAC), catalase (CAT), and glutathione peroxidase (GPx) activities; and on the oxidative stress index (OSi). Results demonstrated that CAT and GPx activities, and TAC, determined in plasma samples, were significantly (P < 0.05) higher in rats treated with AFB1 plus IC431 (3.98 µM/min/mg protein, 1.88 µM/min/mg protein, and 238.7 µM Trolox equivalent, respectively) than AFB1-treated rats (3.47 µM/min/mg protein, 1.46 µM/min/mg protein, and 179.7 µM Trolox equivalent, respectively). Furthermore, plasma and liver tissue samples from rats treated with AFB1 plus IC431 showed significantly (P < 0.05) lower LPO values (52 and 51%, respectively) and OSi (59 and 51%, respectively) than AFB1-treated rats. Hence, our results proved that the intracellular content of Lact. casei CRL 431 contains metabolites that are capable to modulate the antioxidant defense systems in living organism, which may help to ameliorate the damage associated to AFB1-induced oxidative stress.

Assessment of multifunctional activity of bioactive peptides derived from fermented milk by specific Lactobacillus plantarum strains.

Milk-derived bioactive peptides with a single activity (e.g., antioxidant, immunomodulatory, or antimicrobial) have been previously well documented; however, few studies describe multifunctional bioactive peptides, which may be preferred over single-activity peptides, as they can simultaneously trigger, modulate, or inhibit multiple physiological pathways. Hence, the aim of this study was to assess the anti-inflammatory, antihemolytic, antioxidant, antimutagenic, and antimicrobial activities of crude extracts (CE) and peptide fractions (<3 and 3-10 kDa) obtained from fermented milks with specific Lactobacillus plantarum strains. Overall, CE showed higher activity than both peptide fractions (<3 and 3-10 kDa) in most of the activities assessed. Furthermore, activity of <3 kDa was generally higher, or at least equal, to the 3 to 10 kDa peptide fractions. In particular, L. plantarum 55 crude extract or their fractions showed the higher anti-inflammatory (723.68-1,759.43µg/mL of diclofenac sodium equivalents), antihemolytic (36.65-74.45% of inhibition), and antioxidant activity [282.8-362.3µmol of Trolox (Sigma-Aldrich, St. Louis, MO) equivalents]. These results provide valuable evidence of multifunctional role of peptides derived of fermented milk by the action of specific L. plantarum strains. Thus, they may be considered for the development of biotechnological products to be used to reduce the risk of disease or to enhance a certain physiological function.

Evaluation of acrylamide-removing properties of two Lactobacillus strains under simulated gastrointestinal conditions using a dynamic system.

The aim of this study was to evaluate the capability of Lactobacillus reuteri NRRL 14171 and Lactobacillus casei Shirota to remove dietary acrylamide (AA) under simulated gastrointestinal conditions using a dynamic system. The effects of different AA levels or bacteria concentration on toxin removal by Lactobacillus strains were assessed. Thereafter, AA-removing capability of bacteria strains under either fasting or postprandial simulated gastrointestinal conditions was evaluated. Commercial potato chips were analyzed for their AA content, and then used as a food model. Average AA content (34,162µg/kg) in potato chips exceeded by ca. 34-fold the indicative values recommended by the EU. Toxin removal ability was dependent on AA content and bacterial cell concentration. A reduction on bacterial viability was observed in the food model and at the end of both digestive processes evaluated. However, bacteria survived in enough concentrations to remove part of the toxin (32-73%). Both bacterial strains were able to remove AA under different simulated gastrointestinal conditions, being L. casei Shirota the most effective (ca. 70% removal). These findings confirmed the risk of potato chips as dietary AA exposure for consumers, and that strains of the genus Lactobacillus could be employed to reduce the bioavailability of dietary AA.

Invited review: Fermented milk as antihypertensive functional food.

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.

Screening of Lactobacillus strains for their ability to produce conjugated linoleic acid in milk and to adhere to the intestinal tract.

Conjugated linoleic acid (CLA) has been shown to provide beneficial effects on health; however, the amount consumed in food is far from that required for the desired effects. Thus, increasing the CLA content in dairy foods through milk fermentation with specific lactic acid bacteria (LAB) offers an interesting alternative. Moreover, some LAB may be able to adhere to the intestinal mucosa and produce CLA through endogenous synthesis. Therefore, the objective of this study was to screen LAB isolates for their ability to produce CLA in skim milk and in simulated gastrointestinal conditions. Additionally, the ability of selected CLA-producing LAB to adhere to the intestinal mucosa in a murine model was assessed. Results showed that of 13 strains of Lactobacillus tested, only 4 were able to produce CLA in skim milk supplemented with linoleic acid (13.44 ± 0.78 to 50.9 ± 0.26 µg/mL). Furthermore, these 4 Lactobacillus strains were able to survive and produce CLA in simulated gastrointestinal conditions and to adhere to the intestinal mucosa of Wistar rats after 7 d of oral inoculation with fluorescently labeled bacteria. Accordingly, these 4 Lactobacillus strains may be used to manufacture fermented dairy foods to increase CLA content, and consumption of these fermented milks may result in CLA produced endogenously by these LAB.

Antifungal activity of lactobacilli and its relationship with 3-phenyllactic acid production.

In this study, 13 lactic acid bacteria (LAB) strains (including 5 Lactobacillus casei, 2 Lactobacillus rhamnosus, 2 Lactobacillus fermentum, 1 Lactobacillus acidophilus, 1 Lactobacillus plantarum, 1 Lactobacillus sakei, and 1 Lactobacillus reuteri species) were assessed for both their antifungal activity against four food spoilage molds (Colletotrichum gloeosporioides, Botrytis cinerea, Penicillium expansum, and Aspergillus flavus) and their capability to produce the novel antimicrobial compound 3-phenyllactic acid (PLA). Results demonstrated that all molds were sensitive to varying degrees to the cell-free supernatants (CFS) from LAB fermentations (p<0.05), with growth inhibitions ranging from 2.65% to 66.82%. The inhibition ability of CFS was not affected by a heating treatment (121°C, 20 min); however, it declined markedly when the pH of CFS was adjusted to 6.5. With the exception of L. plantarum NRRL B-4496 and L. acidophilus ATCC-4495, all other LAB strains produced PLA ranging from 0.021 to 0.275 mM. The high minimum inhibitory concentration for commercial PLA (3.01-36.10mM) suggests that it cannot be considered the only compound related with the antifungal potential of studied LAB and that synergistic effects may exist among other metabolism products.

Assessment of in vitro removal of cholesterol oxidation products by Lactobacillus casei ATCC334.

Cholesterol oxidation products (COPs) are a group of compounds formed during processing and storage of foods from animal origin. After ingestion, COPs are absorbed in the intestine and can be distributed to serum and various tissues, potentially promoting a variety of toxic effects. Therefore, inhibition of their intestinal absorption may contribute to reduce the health risks associated with dietary intake of COPs. Some studies have shown that drugs and dietary compounds may inhibit the intestinal absorption of dietary COPs. However, proven cholesterol- and/or food toxins-binding lactic acid bacteria have not been previously evaluated as potential COPs removal agents. The aim of this study was to assess the ability of Lactobacillus casei ATCC334 to remove COPs in aqueous solution. Results showed the ability of both growing and resting cells to remove COPs (ca. 30-60%). All COPs-bacterium interactions were specific and partly reversible, being resting cells the most efficient for COPs removal in a ranking order of 7-KC > 7α-OH/7ß-OH > triol > 5,6ß-EP > 5,6α-EP > 25-OH. Binding to the cell wall and/or cell membrane incorporation appears to be the most likely mechanisms involved on COPs removal by L. casei ATCC 334.

Antihypertensive and hypolipidemic effect of milk fermented by specific Lactococcus lactis strains.

The antihypertensive and hypolipidemic effects of milk fermented by specific Lactococcus lactis strains in spontaneously hypertensive rats (SHR) were investigated. The SHR were fed ad libitum milk fermented by Lc. lactis NRRL B-50571, Lc. lactis NRRL B-50572, Captopril (40mg/kg of body weight, Sigma-Aldrich Co., St. Louis, MO) or purified water for 4 wk. Results suggested that Lc. lactis fermented milks presented a significant blood pressure-lowering effect. No significant difference was noted among milk fermented by Lc. lactis NRRL B-50571 and Captopril by the second and third week of treatment. Additionally, milk fermented by Lc. lactis strains modified SHR lipid profiles. Milk fermented by Lc. lactis NRRL B-50571 and B-50572 were able to reduce plasma low-density lipoprotein cholesterol and triglyceride contents. Thus, milk fermented by Lc. lactis strains may be a coadjuvant in the reduction of hypertension and hyperlipidemia and may be used as a functional food for better cardiovascular health.

Angiotensin-converting enzyme inhibitory activity in Mexican Fresco cheese.

The objective of this study was to evaluate if Mexican Fresco cheese manufactured with specific lactic acid bacteria (LAB) presented angiotensin I-converting enzyme inhibitory (ACEI) activity. Water-soluble extracts (3 kDa) obtained from Mexican Fresco cheese prepared with specific LAB (Lactococcus, Lactobacillus, Enterococcus, and mixtures: Lactococcus-Lactobacillus and Lactococcus-Enterococcus) were evaluated for ACEI activity. Specific peptide fractions with high ACEI were analyzed using reverse phase-HPLC coupled to mass spectrometry for determination of amino acid sequence. Cheese containing Enterococcus faecium or a Lactococcus lactis ssp. lactis-Enterococcus faecium mixture showed the largest number of fractions with ACEI activity and the lowest half-maximal inhibitory concentration (IC(50); <10 µg/mL). Various ACEI peptides derived from ß-casein [(f(193-205), f(193-207), and f(193-209)] and α(S1)-casein [f(1-15), f(1-22), f(14-23), and f(24-34)] were found. The Mexican Fresco cheese manufactured with specific LAB strains produced peptides with potential antihypertensive activity.

Biotin starvation with adequate glucose provision causes paradoxical changes in fuel metabolism gene expression similar in rat (Rattus norvegicus), nematode (Caenorhabditis elegans) and yeast (Saccharomyces cerevisiae).

BACKGROUND/AIM: Biotin affects the genetic expression of several glucose metabolism enzymes, besides being a cofactor of carboxylases. To explore how extensively biotin affects the expression of carbon metabolism genes, we studied the effects of biotin starvation and replenishment in 3 distantly related eukaryotes: yeast Saccharomyces cerevisiae, nematode Caenorhabditis elegans and rat Rattus norvegicus. METHODS: Biotin starvation was produced in Wistar rats, in C. elegans N2 and S. cerevisiae W303A fed with abundant glucose. High-density oligonucleotide microarrays were used to find gene expression changes. Glucose consumption, lactate and ethanol were measured by conventional tests. RESULTS: In spite of abundant glucose provision, the expression of fatty oxidation and gluconeogenic genes was augmented, and the transcripts for glucose utilization and lipogenesis were diminished in biotin starvation. These results were associated with diminished glucose consumption and glycolysis products (lactate and ethanol in yeast), which was consistent across 3 very different eukaryotes. CONCLUSION: The results point toward a strongly selected role of biotin in the control of carbon metabolism, and in adaptations to variable availability of carbon, conceivably mediated by signal transduction including soluble guanylate cyclase, cGMP and a cGMP-dependent protein kinase (PKG) and/or biotin-dependent processes.

Key role of teichoic acids on aflatoxin B binding by probiotic bacteria.

AIMS: To assess the ability of five probiotic bacteria to bind aflatoxin B(1) and to determine the key role of teichoic acids in the binding mechanism. METHODS AND RESULTS: The strains were incubated in aqueous solutions containing aflatoxin B(1) (AFB(1)). The amount of free toxin was quantified by HPLC. Stability of the bacteria-aflatoxin complex was evaluated by repeated washes with buffer. In order to understand the binding process, protoplasts, spheroplasts and cell wall components of two strains were analysed to assess their capacity to bind AFB(1). Additionally, the role of teichoic acids in the AFB(1) binding process was assessed. Lactobacillus reuteri strain NRRL14171 and Lactobacillus casei strain Shirota were the most efficient strains for binding AFB(1). The stability of the AFB(1)-bacteria complex appears to be related to the binding ability of a particular strain; AFB(1) binding was also pH-dependent. Our results suggest that teichoic acids could be responsible for this ability. CONCLUSIONS: Our results provide information concerning AFB(1) binding by previously untested strains, leading to enhanced understanding of the mechanism by which probiotic bacteria bind AFB(1). SIGNIFICANCE AND IMPACT OF THE STUDY: Our results support the suggestion that some probiotic bacteria could prevent absorption of aflatoxin from the gastrointestinal tract.

Screening of Lactobacillus casei strains for their ability to bind aflatoxin B1.

It has been proposed that the consumption of lactic acid bacteria capable of binding or degrading foodborne carcinogens would reduce human exposure to these deleterious compounds. In the present study, the ability of eight strains of Lactobacillus casei to bind aflatoxin B1 in aqueous solution was investigated. Additionally, the effect of addition of bile salts to the growth medium on aflatoxin B1 binding was assessed. The eight strains tested were obtained from different ecological niches (cheese, corn silage, human feces, fermented beverage). The strains exhibited different degrees of aflatoxin binding; the strain with the highest AFB1 binding was L. casei L30, which bound 49.2% of the available aflatoxin (4.6 microg/mL). In general, the human isolates bound the most aflatoxin B1 and the cheese isolates the least. Stability of the bacterial-aflatoxin complex was assessed by repeated washings. Binding was to a limited degree (0.6-9.2% release) reversible; the L. casei 7R1-aflatoxin B1 complex exhibited the greatest stability. L. casei L30, a human isolate, was the strain least sensitive to the inhibitory effects of bile salts. Exposure of the bacterial cells to bile significant increased aflatoxin B1 binding and the differences between the strains was reduced.

[Genetic diversity of 3 DNA probes in the DNA fingerprinting of a Mexican population]. / Diversidad genética de tres sondas de DNA en la huella digital de DNA de una población mexicana.

Each individual may be identified by characterizing its genetic material by DNA fingerprinting technology. Its application in Mexico demands a knowledge of the allelic and genotypic diversity of the DNA markers and the probability that two individuals may have the same fingerprint. In the present study the allelic and genotypic diversities of the loci D12S11 (MS43A), D7S22 (g3) and D1S7 (MS1) were determined in 100 Mexican students of the military school of medicine (Escuela Médico Militar de México). The mean allelic frequency of the loci MS43A, g3, and MS1 was 0.01, 0.008 and 0.006, respectively. The heterozygosity of MS43A and g3 was 98 and 99% for MS1. The probability that two individuals might have the same genetic pattern was 2.0 x 10(-4), 1.3 x 10(-4) and 7.2 x 10(-5) for the loci MS43A, g3 and MS1, respectively, and as low as 1.9 x 10(-12) for the three taken together. These data indicate that the genetic diversity of these DNA fingerprinting markers in the Mexican population is high enough to warrant its use in paternity testing and in the identification of individuals in forensic medicine.