Blood-pressure-lowering effect of a novel fermented milk containing gamma-aminobutyric acid (GABA) in mild hypertensives

Recent Advances in the Use of Sourdough Biotechnology in Pasta Making

The growing consumers’ request for foods with well-balanced nutritional profile and functional properties promotes research on innovation in pasta making. As a staple food and a common component of diet, pasta can be considered as a vector of dietary fiber, vegetable proteins, vitamins, minerals, and functional compounds. The conventional process for pasta production does not include a fermentation step. However, novel recipes including sourdough-fermented ingredients have been recently proposed, aiming at enhancing the nutritional and functional properties of this product and at enriching commercial offerings with products with new sensorial profiles. The use of sourdough for pasta fortification has been investigated under several aspects, including fortification in vitamin B, the reduction of starch digestibility, and gluten content. Sourdough fermentation has also been successfully applied to non-conventional flours, (e.g., from pseudocereals and legumes), in which an overall increase of the nutritional value and health-promoting compounds, such as a significant decrease of antinutritional factors, were observed. Fermented non-conventional flours, obtained through spontaneous fermentation or using selected starters, have been proposed as pasta ingredients. As the result of wheat replacement, modification in textural properties of pasta may occur. Nonetheless, fermentation represents an efficient tool in improving, besides nutritional and functional profile, the sensory and technological features of fortified pasta.

Impact of bacterial probiotics on obesity, diabetes and non-alcoholic fatty liver disease related variables: a systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

To systematically review the effect of oral intake of bacterial probiotics on 15 variables related to obesity, diabetes and non-alcoholic fatty liver disease.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, EMBASE and COCHRANE from 1990 to June 2018.

ELIGIBILITY CRITERIA

Randomised controlled trials (≥14 days) excluding hypercholesterolaemia, alcoholic liver disease, polycystic ovary syndrome and children <3 years.

RESULTS

One hundred and five articles met inclusion criteria, representing 6826 subjects. In overweight but not obese subjects, probiotics induced improvements in: body weight (k=25 trials, d=-0.94 kg mean difference, 95% CI -1.17 to -0.70, I²=0.0%), body mass index (k=32, d=-0.55 kg/m², 95% CI -0.86 to -0.23, I²=91.9%), waist circumference (k=13, d=-1.31 cm, 95% CI -1.79 to -0.83, I²=14.5%), body fat mass (k=11, d=-0.96 kg, 95% CI -1.21 to -0.71, I²=0.0%) and visceral adipose tissue mass (k=5, d=-6.30 cm², 95% CI -9.05 to -3.56, I²=0.0%). In type 2 diabetics, probiotics reduced fasting glucose (k=19, d=-0.66 mmol/L, 95% CI -1.00 to -0.31, I²=27.7%), glycated haemoglobin (k=13, d=-0.28 pp, 95% CI -0.46 to -0.11, I²=54.1%), insulin (k=13, d=-1.66 mU/L, 95% CI -2.70 to -0.61, I²=37.8%) and homeostatic model of insulin resistance (k=10, d=-1.05 pp, 95% CI -1.48 to -0.61, I²=18.2%). In subjects with fatty liver diseases, probiotics reduced alanine (k=12, d=-10.2 U/L, 95% CI -14.3 to -6.0, I²=93.50%) and aspartate aminotransferases (k=10, d=-9.9 U/L, 95% CI -14.1 to -5.8, I²=96.1%). These improvements were mostly observed with bifidobacteria (Bifidobacterium breve, B. longum), Streptococcus salivarius subsp. thermophilus and lactobacilli (Lactobacillus acidophilus, L. casei, L. delbrueckii) containing mixtures and influenced by trials conducted in one country.

CONCLUSIONS

The intake of probiotics resulted in minor but consistent improvements in several metabolic risk factors in subjects with metabolic diseases.

TRIAL REGISTRATION NUMBER

CRD42016033273.

Rapid evaluation of γ-aminobutyric acid in foodstuffs by direct real-time mass spectrometry

Direct analysis in real-time ionization coupled with mass spectrometry (DART-MS) was first applied for the rapid determination of gamma-aminobutyric acid (GABA) in foods. Samples of germinated barley and fermented beans containing GABA at different levels were used, and the results were compared with those obtained by ultrahigh-performance liquid chromatography coupled with electrospray ionization triple quadrupole mass spectrometry (UHPLC-ESI-MS). After a series of optimization, a simple sample extraction procedure using 30% methanol aqueous solution was conducted, followed by direct determination of sample extracts without chromatographic separation or prior derivatization. The optimized DART-MS method exhibited low limits of detection (0.040 mg·kg^-1) and good recovery rates (88.6%-104%). The Aspergillus oryzae-fermented black beans produced the highest amount GABA. The results for the samples slightly varied between DART-MS and UHPLC-ESI-MS. Current findings indicate that DART-MS could be a high-throughput alternative to classic UHPLC-ESI-MS.

Vital parameters for high gamma-aminobutyric acid (GABA) production by an industrial soy sauce koji Aspergillus oryzae NSK in submerged-liquid fermentation

In submerged-liquid fermentation, seven key parameters were assessed using one-factor-at-a-time to obtain the highest GABA yield using an industrial soy sauce koji Aspergillus oryzae strain NSK (AOSNSK). AOSNSK generated maximum GABA at 30 °C (194 mg/L) and initial pH 5 (231 mg/L), thus was able to utilize sucrose (327 mg/L of GABA) for carbon source. Sucrose at 100 g/L, improved GABA production at 646 mg/L. Single nitrogen sources failed to improve GABA production, however a combination of yeast extract (YE) and glutamic acid (GA) improved GABA at 646.78 mg/L. Carbon-to-nitrogen ratio (C8:N3) produced the highest cell (24.01 g/L) and GABA at a minimal time of 216 h. The key parameters of 30 °C, initial pH 5, 100 g/L of sucrose, combination YE and GA, and C8:N3 generated the highest GABA (3278.31 mg/L) in a koji fermentation. AOSNSK promisingly showed for the development of a new GABA-rich soy sauce.

Thirty Years of Lactobacillus rhamnosus GG: A Review

Lactobacillus rhamnosus GG (LGG) was the first strain belonging to the genus Lactobacillus to be patented in 1989 thanks to its ability to survive and to proliferate at gastric acid pH and in medium containing bile, and to adhere to enterocytes. Furthermore LGG is able to produces both a biofilm that can mechanically protect the mucosa, and different soluble factors beneficial to the gut by enhancing intestinal crypt survival, diminishing apoptosis of the intestinal epithelium, and preserving cytoskeletal integrity. Moreover LGG thanks to its lectin-like protein 1 and 2 inhibits some pathogens such as Salmonella species. Finally LGG is able to promote type 1 immune-responsiveness by reducing the expression of several activation and inflammation markers on monocytes and by increasing the production of interleukin-10, interleukin-12 and tumor necrosis factor-α in macrophages. A large number of research data on Lactobacillus GG is the basis for the use of this probiotic for human health. In this review we have considered predominantly randomized controlled trials, meta-analysis, Cochrane Review, guide lines of Scientific Societies and anyway studies whose results were evaluated by means of relative risk, odds ratio, weighted mean difference 95% confidence interval. The effectiveness of LGG in gastrointestinal infections and diarrhea, antibiotic and Clostridium difficile associated diarrhea, irritable bowel syndrome, inflammatory bowel disease, respiratory tract infections, allergy, cardiovascular diseases, nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, cystic fibrosis, cancer, elderly end sport were analyzed.

Production of Naturally γ-Aminobutyric Acid-Enriched Cheese Using the Dairy Strains Streptococcus thermophilus 84C and Lactobacillus brevis DSM 32386

The cheese-derived strains Streptococcus thermophilus 84C isolated from Nostrano cheese, and Lactobacillus brevis DSM 32386 isolated from Traditional Mountain Malga cheese have been previously reported as γ-aminobutyric acid (GABA)-producers in vitro. In the present study, the ability of these strains to produce GABA was studied in experimental raw milk cheeses, with the aim to investigate the effect of the culture and the ripening time on the GABA concentration. The cultures used consisted on S. thermophilus 84C alone (84C) or in combination with L. brevis DSM 32386 (84C-DSM). The control culture was a commercial S. thermophilus strain, which was tested alone (CTRL) or in combination with the L. brevis DSM 32386 (CTRL-DSM). The pH evolution, microbiological counts, MiSeq Illumina and UHPLC-HQOMS analysis on milk and cheese samples were performed after 2, 9, and 20 days ripening. During the whole ripening, the pH was always under 5.5 in all batches. The concentration of GABA increased during ripening, with the highest content in 84C after 9 days ripening (84 ± 37 mg/kg), in 84C-DSM and CTRL-DSM after 20 days ripening (91 ± 28 and 88 ± 24 mg/kg, respectively). The data obtained support the hypothesis that S. thermophilus 84C and L. brevis DSM 32386 could be exploited as functional cultures, improving the in situ bio-synthesis of GABA during cheese ripening.

Impact of Cereal Seed Sprouting on Its Nutritional and Technological Properties: A Critical Review

Sprouting induces activation and de novo synthesis of hydrolytic enzymes that make nutrients available for plant growth and development. Consumption of sprouted grains is suggested to be beneficial for human health. Positive consumer perceptions about sprouted cereals have resulted in new food and beverage product launches. However, because there is no generally accepted definition of "sprouting," it is unclear when grains are to be called sprouted. Moreover, guidelines about how much sprouted grain material food products should contain to exert health benefits are currently lacking. Accordingly, there is no regulatory base to develop appropriate food labeling for "sprouted foods." This review describes the nutritional and technological properties of sprouted grains in relation to processing conditions and provides guidelines to optimize sprouting practices in order to maximize nutritive value. Relatively long sprouting times (3 to 5 days) and/or high processing temperatures (25 to 35 °C) are needed to maximize the de novo synthesis and/or release of plant bioactive compounds. Nutrient compositional changes resulting from sprouting are often associated with health benefits. However, supportive data from clinical studies are very scarce, and at present it is impossible to draw any conclusion on health benefits of sprouted cereals. Finally, grains sprouted under the above-mentioned conditions are generally unfit for use in traditional food processing and it is challenging to use sprouted grains as ingredients without compromising their nutrient content. The present review provides a basis for better defining what "sprouting" is, and to help further research and development efforts in this field as well as future food regulations development.

Effects of chocolate containing Leuconostoc mesenteroides strain NTM048 on immune function: a randomized, double-blind, placebo-controlled trial

Background

Previous reports showed that oral administration of Leuconostoc mesenteroides strain NTM048 increases IgA levels and CD4+ T cell population in feces and mice, respectively, as revealed by flow cytometric analysis of splenocytes. This study aimed to evaluate the effect of chocolate supplemented with L. mesenteroides strain NTM048 (> 1.00 × 10⁹ CFU/day, NTM048) on the immune parameters of healthy subjects, using a randomized, placebo-controlled, double-blinded study design.

Methods

Participants (mean age: 46.3 years) ingested 28 g of test food daily, at a time of their own choice, for 4 weeks. The immunological parameters of all participants were evaluated two times (pre- and post- ingestion). At the end of the study, various immunological parameters of the participants were measured and scoring of immunological vigor (SIV) was performed using a comprehensive algorithm.

Results

Ingestion of NTM048-supplemented chocolate significantly improved SIV in the NTM048 group (18.6 ± 1.6) compared to that in the placebo group (17.8 ± 2.0) after 4 weeks (p = 0.049). Several immunological parameters (CD8⁺T cells, CD8⁺CD28⁺ T cells, and memory T cells) were significantly elevated in the NTM048 group as compared to the placebo group (all p < 0.05). In addition, T cell proliferation index at post-ingestion significantly increased compared with that at pre-ingestion in the NTM048 (p = 0.017) and placebo groups (p = 0.037), although no differences were observed between the two groups.

Conclusion

Our results suggest that ingestion of chocolate supplemented with NTM048 is effective against the age-related decline in T cell-related immune functions.

Trial registration

UMIN Clinical Trials Registry UMIN000021989. Registered 19 April 2016, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000025321

Differential GABA concentration gradients are present in the edible parts of greenhouse melon (Cucumis melo L.) during all four seasonal croppings

Food-derived gamma-aminobutyric acid (GABA) exhibits health-promoting benefits, and melon contain high GABA concentrations. Greenhouse melons (Cucumis melo L. "Earl's Favorite") cultivated in Japan have identical or more edible parts than cultivars in other countries, however GABA distribution and the effects of seasonal variations are unclear. Thus, the present study aimed to evaluate GABA concentration gradients in four seasonal melons and how glutamic acid (Glu) influences the establishment of these gradients. GABA concentration was significantly lower near the exocarp than in the peduncle, equator, and remnant style regions in most seasons. Glu and GABA concentrations showed similar trends and were significantly correlated near the remnant style. No significant differences in GABA and Glu concentration were detected at concyclic sites across horizontal sections. These data indicate that GABA and Glu concentration differs substantially along a vertical melon section, but less so along a horizontal section, among sampling regions, sites, and cropping season.

Optimized cultural conditions of functional yogurt for γ-aminobutyric acid augmentation using response surface methodology

Yogurt, a functional dairy food product, is an effective medium for delivering beneficial functional ingredients. One ingredient, γ-aminobutyric acid (GABA), has growing appeal in the development of functional foods for its potential in reducing the risk of diabetes, hypertension, and stress as a bioactive agent. However, the concentration of GABA in existing food products is remarkably low. We developed a functional yogurt rich in GABA using Streptococcus thermophilus fmb5. The GABA yield of yogurt was enhanced by optimization of culture conditions using single factor and response surface methods. The results showed that culture temperature, monosodium glutamate concentration, and culture time are the 3 main factors that affect GABA yield. The optimal culture conditions were determined as follows: 38.8°C for culture temperature, 20 g/L of monosodium glutamate, and 120 h of culture time. Under the above optimal conditions, the actual yield of GABA production was maximized at 9.66 g/L, which was 1.2 times or higher than that of from any single factor treatment. The GABA concentration, viable bacteria number, and water-holding capacity of GABA-rich yogurt were stable throughout the whole storage time. The results show that producing yogurt with Streptococcus thermophilus fmb5 and the optimized culture conditions will achieve high GABA concentrations that maximize health benefits to consumers.

Comparative Metabolic Responses and Adaptive Strategies of Tea Leaves ( Camellia sinensis) to N2 and CO2 Anaerobic Treatment by a Nontargeted Metabolomics Approach

It is well-known that anaerobic treatment has been considered as a utility process to accumulate γ-aminobutyric acid (GABA) in tea leaves. In this article, the nonvolatile differential compounds in picked-tea leaves between filled-N₂ treatment and filled-CO₂ treatment were compared in metabolic profiles and dynamic changes via ultrahigh performance liquid chromatography linked to a hybrid quadrupole orthogonal time-of-flight mass spectrometer (UPLC-Q-TOF-MS). Multivariate analysis and heat map of hierarchical clustering analysis indicated that filled-N₂ treatment resulted in a wider range of metabolic perturbation than filled-CO₂ treatment, but GABA accumulates faster and more significantly under filled-CO₂ treatment than other treatment. The differential metabolites in anaerobic treatment were mainly reflected in the levels of glucose metabolism and amino acid metabolism, and the main differential pathway included the glyoxylate metabolism pathway, galactose metabolism, and phenylalanine metabolism. These metabolomic analyses were also evaluated to illuminate the physiological adaptive strategies of tea adopted to tolerate certain anaerobic stress types.

Enhanced accumulation of gamma-aminobutyric acid in rice bran using anaerobic incubation with various additives

An anaerobic incubation for the enzymatic production of gamma-aminobutyric acid (GABA) in rice bran with the addition of glutamate, hydrolyzed wheat protein (HWP), yeast extract (YE) and pyridoxal-5-phosphate (PLP) was investigated. Rice bran was moistened (30% moisture content) with an electrolyzed oxidizing water and anaerobically incubated under nitrogen at 40 °C for 8 h. The incubation activated the glutamate decarboxylase (GAD) in rice bran and increased the GABA content from 10.7 to 171.5 mg/100 g. The addition of glutamate and protein hydrolysates further amplified the GABA content in the treated rice bran: 974.9, 487.4, and 372.8 mg/100 g, with 2.25% glutamate, 6% HWP, and 8% YE, respectively. Furthermore, addition of PLP (1.48 mg/100 g) as a coenzyme for GAD, together with 2.25% glutamate addition, could raise the GABA accumulation in rice bran to 2242 mg/100 g. Other amino acids in rice bran were changed in their composition by the anaerobic treatment.

Lactobacillus brevis CGMCC 1306 glutamate decarboxylase: Crystal structure and functional analysis

Glutamate decarboxylase (GAD), which is a unique pyridoxal 5-phosphate (PLP)-dependent enzyme, can catalyze α-decarboxylation of l-glutamate (L-Glu) to γ-aminobutyrate (GABA). The crystal structure of GAD in complex with PLP from Lactobacillus brevis CGMCC 1306 was successfully solved by molecular-replacement, and refined at 2.2 Å resolution to an R_work factor of 18.76% (R_free = 23.08%). The coenzyme pyridoxal 5-phosphate (PLP) forms a Schiff base with the active-site residue Lys279 by continuous electron density map, which is critical for catalysis by PLP-dependent decarboxylase. Gel filtration showed that the active (pH 4.8) and inactive (pH 7.0) forms of GAD are all dimer. The residues (Ser126, Ser127, Cys168, Ile211, Ser276, His278 and Ser321) play important roles in anchoring PLP cofactor inside the active site and supporting its catalytic reactivity. The mutant T215A around the putative substrate pocket displayed an 1.6-fold improvement in catalytic efficiency (k_cat/K_m) compared to the wild-type enzyme (1.227 mM^-1 S^-1 versus 0.777 mM^-1 S^-1), which was the highest activity among all variants tested. The flexible loop (Tyr308-Glu312), which is positioned near the substrate-binding site, is involved in the catalytic reaction, and the conserved residue Tyr308 plays a vital role in decarboxylation of L-Glu.

GABA tea attenuates cardiac apoptosis in spontaneously hypertensive rats (SHR) by enhancing PI3K/Akt-mediated survival pathway and suppressing Bax/Bak dependent apoptotic pathway

Cardiomyocyte apoptosis is the major risk factor for the development of heart failure (HF). The purpose of this study was to evaluate the effects of Gamma-aminobutyric acid (GABA) tea on hypertension-induced cardiac apoptotic pathways in spontaneously hypertensive rats (SHR). In order to reveal the mechanisms, 36 male SHR at eight weeks of age, 200 g were divided into six groups. One group was fed water as a control group. Other rats were administered one of the following treatments: GABA tea at dose 150 and 300 mg/kg/day as low GABA tea (LGT) and high GABA tea (HGT) groups, respectively, pure GABA at dose 150 and 300 mg/kg/day as LG and HG groups, respectively, green tea (GT) as control of LGT and HGT groups. After 12 weeks, cardiac tissues were analyzed by histological analysis, western blotting, and TUNEL assays. GABA tea, GT, and pure GABA decreased hypertension-induced cardiac abnormalities, including abnormal myocardial architecture. In addition, GABA tea, GT, and pure GABA dramatically increased anti-apoptotic protein, Bcl2. Furthermore, GABA tea, GT, and pure GABA also decreased activated-caspase 9 and activated-caspase 3. Additionally, the survival associated protein IGF-I and PI3K/Akt were enhanced in cardiac tissues upon treatment. Our results showed an optimistic anti-apoptotic and pro-survival effects of GABA tea treatment against hypertensive rat hearts.

Novel insights on the functional/nutritional features of the sourdough fermentation

As one of the most traditional biotechnologies, sourdough fermentation has deep effects on rheology, sensory and shelf life attributes of baked goods. The most recent literature has also highlighted the effects of sourdough fermentations on several functional/nutritional features of baked goods. While some aspects such as the potential to lower glycemic index, increase mineral bioavailability and decrease the gluten content have been proven almost definitively, others potentialities are emerging, which deserve novel insights. This reviews reports the main evidence on the use of sourdough fermentation for salt reduction in baked goods, management of irritable bowel syndrome (IBS), synthesis/release of bioactive compounds, especially the metabolism of phenolic compounds, and exploitation of the potential of non-conventional flours (legumes and pseudo-cereals) and milling by-products (bran and germ). A brief description on the spiritual, cultural and functional/nutritional significance of leavened bread throughout centuries has also given.

Activation of GABAA Receptors in Colon Epithelium Exacerbates Acute Colitis

Emerging evidence indicates that gamma-aminobutyric acid (GABA) has many beneficial effects such as ameliorating immune and inflammatory response. But, here we reported that activation of GABA_A receptors (GABA_A Rs) aggravated dextran sulfate sodium (DSS)-induced colitis, although the expression of pro-inflammatory cytokines was inhibited. By contrast, blocking of GABA_A Rs markedly alleviated DSS-induced colitis. Notably, GABA_A Rs and glutamic acid decarboxylase 65/67 were significantly increased in colon mucosa of ulcerative colitis patients and the mouse model of colitis. Further studies showed that GABA treatment resulted in an increment of serum FITC-dextran following its oral administration, a decrement of transepithelial electrical resistance, and an increment of bacterial invasion, effects which were blocked by bicuculline. In addition, GABA inhibited the expression of tight junction proteins and mucin secretion in colitis colon. GABA also decreased the expression of ki-67 and increased cleaved-caspase 3 expression in intestinal epithelia. Our data indicate that the GABA_A Rs activation within colon mucosa disrupts the intestinal barrier and increases the intestinal permeability which facilitates inflammatory reaction in colon. Meanwhile, the suppression effect of GABA on pro-inflammatory cytokines leads to insufficient bacteria elimination and further aggravated the bacteria invasion and inflammatory damage.

Fermente Süt Ürünlerinin Kan Basıncını Düşürücü Etkisi

Hypertension (HTN) is a major risk factor for the development of cardiovascular diseases. Therefore, there is a need to lower blood pressure (BP) to reduce the risk of these degenerative diseases. Fermented milks contain several potential factors that can lower BP including calcium and microbial metabolites particularly the angiotension-converting enzyme (ACE) inhibitory peptides and γ-aminobutyric acid. &nbsp;Animal studies clearly demonstrated the BP lowering effect of fermented milk while results from clinical trials were controversial due to a large number of variables that should be considered in clinical trials. An overview on the antihypertensive effect of fermented milk products is presented and discussed in this review.

Increasing thermal stability of glutamate decarboxylase from Escherichia. coli by site-directed saturation mutagenesis and its application in GABA production

Gamma-amino butyric acid (GABA) is an important bio-product used in pharmaceuticals, functional foods, and a precursor of the biodegradable plastic polyamide 4 (Nylon 4). Glutamate decarboxylase B (GadB) from Escherichia. coli is a highly active biocatalyst that can convert l-glutamate to GABA. However, its practical application is limited by the poor thermostability and only active under acidic conditions of GadB. In this study, we performed site-directed saturation mutagenesis of the N-terminal residues of GadB from Escherichia coli to improve its thermostability. A triple mutant (M6, Gln5Ile/Val6Asp/Thr7Gln) showed higher thermostability, with a 5.6 times (560%) increase in half-life value at 45 °C, 8.7 °C rise in melting temperature (Tm) and a 14.3 °C rise in the temperature at which 50% of the initial activity remained after 15 min incubation (T¹⁵₅₀), compared to wild-type enzyme. Protein 3D structure analysis showed that the induced new hydrogen bonds in the same polypeptide chain or between polypeptide chains in E. coli GadB homo-hexamer may be responsible for the improved thermostability. Increased thermostability contributed to increased GABA conversion ability. After 12 h conversion of 3 mol/L l-glutamate, GABA produced and mole conversion rate catalyzed by M6 whole cells was 297 g/L and 95%, respectively, while those by wild-type GAD was 273.5 g/L and 86.2%, respectively.

Use of Selected Lactic Acid Bacteria and Quinoa Flour for Manufacturing Novel Yogurt-Like Beverages

This study aimed at investigating the suitability of quinoa for making yogurt-like beverages. After the selection of the adequate technological parameters, the fermentation was carried out by using different lactic acid bacteria strains: a probiotic (Lactobacillus rhamnosus SP1), an exopolysaccharides (EPS)-producing (Weissella confusa DSM 20194), and one isolated from quinoa (Lactobacillus plantarum T6B10). During the 20 h of fermentation, W. confusa caused the highest viscosity increase. All the strains had improved concentration of free amino acids and γ-Aminobutyric acid (GABA), polyphenols availability, antioxidant activity (up to 54%), and protein digestibility. The nutritional index (NI) was the highest when L. rhamnosus SP1 was used. The starch hydrolysis index in vitro ranged from 52 to 60. During storage at 4 °C, viscosity and water holding capacity decreased with the exception of the beverage fermented with W. confusa, while all the nutritional characteristics remained stable or slightly increased. Sensory analyses showed that beverages had good textural and organoleptic profiles. Besides the well-known positive properties of the raw matrix, fermentation allowed the obtainment of beverages with different features. Due to the nutritional and functional characteristics conferred to the quinoa beverages, the use of the probiotic and EPS-producing strains showed adequate potential for the industrial application.

Current Perspectives on Antihypertensive Probiotics

Hypertension is a major risk factor for cardiovascular diseases. Optimizing blood pressure results in an overall health outcome. Over the years, the gut microbiota has been found to play a significant role in host metabolic processes, immunity, and physiology. Dietary strategies have therefore become a target for restoring disturbed gut microbiota to treat metabolic diseases. Probiotics and their fermented products have been shown in many studies to lower blood pressure by suppressing nitrogen oxide production in microphages, reducing reactive oxygen species, and enhancing dietary calcium absorption. Other studies have shown that hypertension could be caused by many factors including hypercholesterolemia, chronic inflammation, and inconsistent modulation of the renin-angiotensin system. This review discusses the antihypertensive roles of probiotics and their fermented products via the reduction of serum cholesterol levels, anti-inflammation, and inhibition of angiotensin-converting enzyme. The ability of recombinant probiotics to reduce high blood pressure has also been discussed.

Expression and characterization of glutamate decarboxylase from Lactobacillus brevis HYE1 isolated from kimchi

A putative gene (gadlbhye1) encoding glutamate decarboxylase (GAD) was cloned from Lactobacillus brevis HYE1 isolated from kimchi, a traditional Korean fermented vegetable. The amino acid sequences of GADLbHYE1 showed 48% homology with the GadA family and 99% identity with the GadB family from L. brevis. The cloned GADLbHYE1 was functionally expressed in Escherichia coli using inducible expression vectors. The expressed recombinant GADLbHYE1 was successfully purified by Ni-NTA affinity chromatography, and had a molecular mass of 54 kDa with optimal hydrolysis activity at 55 °C and pH 4.0. Its thermal stability was determined to be higher than that of other GADs from L. brevis, based on its melting temperature (75.18 °C). Kinetic parameters including K_m and V_max values for GADLbHYE1 were 4.99 mmol/L and 0.224 mmol/L/min, respectively. In addition, the production of gamma-aminobutyric acid in E. coli BL21 harboring gadlbhye1/pET28a was increased by adding pyridoxine as a cheaper coenzyme.

Invited review: Bioactive compounds produced during cheese ripening and health effects associated with aged cheese consumption

Traditionally, cheese is manufactured by converting fluid milk to a semisolid mass through the use of a coagulating agent, such as rennet, acid, heat plus acid, or a combination thereof. Cheese can vary widely in its characteristics, including color, aroma, texture, flavor, and firmness, which can generally be attributed to the production technology, source of the milk, moisture content, and length of aging, in addition to the presence of specific molds, yeast, and bacteria. Among the most important bacteria, lactic acid bacteria (LAB) play a critical role during the cheese-making process. In general, LAB contain cell-envelope proteinases that contribute to the proteolysis of cheese proteins, breaking them down into oligopeptides that can be subsequently taken up by cells via specific peptide transport systems or further degraded into shorter peptides and amino acids through the collaborative action of various intracellular peptidases. Such peptides, amino acids, and their derivatives contribute to the development of texture and flavor in the final cheese. In vitro and in vivo assays have demonstrated that specific sequences of released peptides exhibit biological properties including antioxidant, antimicrobial, anti-inflammatory, immunomodulatory, and analgesic/opioid activity, in addition to angiotensin-converting enzyme inhibition and antiproliferative activity. Some LAB also produce functional lipids (e.g., conjugated linoleic acid) with anti-inflammatory and anticarcinogenic activity, synthesize vitamins and antimicrobial peptides (bacteriocins), or release γ-aminobutyric acid, a nonprotein amino acid that participates in physiological functions, such as neurotransmission and hypotension induction, with diuretic effects. This review provides an overview of the main bioactive components present or released during the ripening process of different types of cheese.

Utilization of a Genome-Edited Tomato (Solanum lycopersicum) with High Gamma Aminobutyric Acid Content in Hybrid Breeding

γ-Aminobutyric acid (GABA) is a nonproteogenic amino acid with health-promoting functions. Although tomato fruits have a relatively high GABA content compared with other crops, levels must be further increased to effectively confer the health-promoting functions. In this study, we evaluated the potential of the genome-edited tomato as a breeding material for producing high-GABA hybrid tomatoes. Hybrid lines were produced by crossing the genome-edited tomato with a pure line tomato cultivar, "Aichi First", and were evaluated for GABA accumulation and other fruit traits. The hybrid lines showed high GABA accumulation in the fruits, which was sufficiently high for expecting health-promoting functions and had minimal effects on other fruit traits, suggesting that the high GABA is a dominant trait and that the genome-edited tomato would be useful as a parental line of hybrid cultivars. These results also indicate that genome editing technology is useful for the rapid breeding of high-GABA hybrid tomato cultivars.

High-resolution spatiotemporal transcriptome mapping of tomato fruit development and ripening

Tomato (Solanum lycopersicum) is an established model for studying fruit biology; however, most studies of tomato fruit growth and ripening are based on homogenized pericarp, and do not consider the internal tissues, or the expression signatures of individual cell and tissue types. We present a spatiotemporally resolved transcriptome analysis of tomato fruit ontogeny, using laser microdissection (LM) or hand dissection coupled with RNA-Seq analysis. Regulatory and structural gene networks, including families of transcription factors and hormone synthesis and signaling pathways, are defined across tissue and developmental spectra. The ripening program is revealed as comprising gradients of gene expression, initiating in internal tissues then radiating outward, and basipetally along a latitudinal axis. We also identify spatial variations in the patterns of epigenetic control superimposed on ripening gradients. Functional studies elucidate previously masked regulatory phenomena and relationships, including those associated with fruit quality traits, such as texture, color, aroma, and metabolite profiles.

Cell-type transcriptome profiling greatly elucidate organismal development. Here, the authors report a spatiotemporally resolved comprehensive transcriptome analysis of tomato fruit ontogeny and suggest a new model of fruit maturation which initiates in internal tissues then radiates outwards.

Production of angiotensin I converting enzyme inhibitory (ACE-I) peptides during milk fermentation and their role in reducing hypertension

Fermented milk is a potential source of various biologically active peptides with specific health benefits. Angiotensin converting enzyme inhibitory (ACE-I) peptides are one of the most studied bioactive peptides produced during milk fermentation. The presence of these peptides is reported in various fermented milk products such as, yoghurt, cheese, sour milk, etc., which are also available as commercial products. Many of the ACE-I peptides formed during milk fermentation are resistant to gastrointestinal digestion and inhibit angiotensin converting enzyme (ACE) in the rennin angiotension system (RAS). There are various factors, which affect the formation ACE-I peptides and their ability to reach the target tissue in active form, which includes type of starters (lactic acid bacteria (LAB), yeast, etc.), substrate composition (casein type, whey protein, etc.), composition of ACE-I peptide, pre and post-fermentation treatments, and its stability during gastrointestinal digestion. The antihypertensive effect of fermented milk products has also been proved by various in vitro and in vivo (animal and human trials) experiments. This paper reviews the literature on fermented milk products as a source of ACE-I peptides and various factors affecting the production and activity of ACE-I peptides.

High γ-aminobutyric acid production from lactic acid bacteria: Emphasis on Lactobacillus brevis as a functional dairy starter

γ-Aminobutyric acid (GABA) and GABA-rich foods have shown anti-hypertensive and anti-depressant activities as the major functions in humans and animals. Hence, high GABA-producing lactic acid bacteria (LAB) could be used as functional starters for manufacturing novel fermented dairy foods. Glutamic acid decarboxylases (GADs) from LAB are highly conserved at the species level based on the phylogenetic tree of GADs from LAB. Moreover, two functionally distinct GADs and one intact gad operon were observed in all the completely sequenced Lactobacillus brevis strains suggesting its common capability to synthesize GABA. Difficulties and strategies for the manufacture of GABA-rich fermented dairy foods have been discussed and proposed, respectively. In addition, a genetic survey on the sequenced LAB strains demonstrated the absence of cell envelope proteinases in the majority of LAB including Lb. brevis, which diminishes their cell viabilities in milk environments due to their non-proteolytic nature. Thus, several strategies have been proposed to overcome the non-proteolytic nature of Lb. brevis in order to produce GABA-rich dairy foods.

Study on oligomerization of glutamate decarboxylase from Lactobacillus brevis using asymmetrical flow field-flow fractionation (AF4) with light scattering techniques

In this work, asymmetrical flow field-flow fractionation (AF4) coupled with UV/Vis, multi-angle light scattering (MALS), and differential refractive index (dRI) detectors (AF4-UV-MALS-dRI) was employed for analysis of glutamate decarboxylase (LbGadB) from Lactobacillus brevis (L. brevis). AF4 provided molecular weight (MW) (or size)-based separation of dimer, hexamer, and aggregates of LbGadB. The effect of pH on oligomerization of LbGadB was investigated, and then AF4 results were compared to those from molecular modeling. The MWs measured by AF4-UV-MALS-dRI for dimeric and hexameric forms of LbGadB were 110 and 350 kDa, respectively, which are in good agreements with those theoretically calculated (110 and 330 kDa). The molecular sizes determined by AF4-UV-MALS-dRI were also in good agreement with those obtained from molecular modeling (6 and 10 nm, respectively, for dimeric and hexameric from AF4-UV-MALS-dRI and 6.4 × 7.6 and 7.6 × 13.1 nm from molecular modeling). The effects of temperature, salt type, and salt concentration on oligomerization of LbGadB were also investigated using dynamic light scattering (DLS). It was found that the hexameric form of LbGadB was most stable at pH 6 and in presence of NaCl or KCl. The results indicate that AF4, in combination of various online detectors mentioned above, provides an effective tool for monitoring of oligomerization of LbGadB under different conditions, such as temperature, pH, type of salts, and salt concentrations.

Enhancement of gama-aminobutyric acid (GABA) and other health-related metabolites in germinated red rice (Oryza sativa L.) by ultrasonication

Red rice (Oryza sativa L.) that has a red (reddish brown) bran layer in de-hulled rice is known to contain rich biofunctional components. Germination is an effective technique to improve the nutritional quality, digestibility, and flavor of de-hulled rice. Ultrasonication, a form of physical stimulation, has been documented as a novel approach to improve the nutritional quality of plant-based food. This study was undertaken to test the use of ultrasound to enhance the nutritional value of red rice. Ultrasonication (5min, 16W/L) was applied to rice during soaking or after 66h germination. Changes of metabolites (amino acids, sugars, and organic acids) in red rice treated by ultrasonication were determined using a GC/MS plant primary metabolomics analysis platform. Differential expressed metabolites were identified through multivariate statistical analysis. Results showed that γ-aminobutyric acid (GABA) and riboflavin (vitamin B₂) in red rice significantly increased after germination for 72h, and then experienced a further increase after treatment by ultrasound at different stages during germination. The metabolomics analysis showed that some plant metabolites, i.e. GABA, O-phosphoethanolamine, and glucose-6-phosphate were significantly increased after the ultrasonic treatment (VIP>1.5) in comparison with the untreated germinated rice. The findings of this study showed that controlled germination with ultrasonic stress is an effective method to enhance GABA and other health-promoted components in de-hulled rice.

Effects of natural peptides from food proteins on angiotensin converting enzyme activity and hypertension

Cardiovascular diseases are the leading cause of death. The underlying pathophysiology is largely contributed by an overactivation of the renin-angiotensin-aldosterone-system (RAAS). Herein, angiotensin II (AngII) is a key mediator not only in blood pressure control and vascular tone regulation, but also involved in inflammation, endothelial dysfunction, atherosclerosis, hypertension and congestive heart failure. Since more than three decades suppression of AngII generation by inhibition of the angiotensin-converting enzyme (ACE) or blockade of the AngII-receptor has shown clinical benefit by reducing hypertension, atherosclerosis and other inflammation-associated cardiovascular diseases. Besides pharmaceutical ACE-inhibitors some natural peptides derived from food proteins reduce in vitro ACE activity. Several animal studies and a few human clinical trials have shown antihypertensive effects of such peptides, which might be attractive as food additives to prevent age-related RAAS activation. However, their inhibitory potency on in vitro ACE activity does not always correlate with an antihypertensive impact. While some peptides with high inhibitory activity on ACE-activity in vitro show no antihypertensive effect in vivo, other peptides with only a moderate ACE inhibitory activity in vitro cause such effects. The explanation for this conflicting phenomenon between inhibitory activity and antihypertensive effect remains unclear to date. This review shall critically address the effects of natural peptides derived from different food proteins on the cardiovascular system and the possible underlying mechanisms. A central aspect will be to point to conceptual gaps in the current understanding of the action of these peptides with respect to in vivo blood pressure lowering effects.

Effects of controlled germination on selected physicochemical and functional properties of whole-wheat flour and enhanced γ-aminobutyric acid accumulation by ultrasonication

Using hard red spring (HRS), hard white (HW), and soft white (SW) wheat, this study examined how germination time affected the functionality of whole-wheat flour (WWF) and enhancement of γ-aminobutyric acid (GABA) content through ultrasonication. The falling number values significantly decreased and the glucose content increased by 227-357% after 15h of controlled germination. The setback value of WWF paste decreased from 654 to 6cP (HW), 690 to 9cP (SW), and 698 to 7cP (HRS), respectively, showing significant decreases of starch retrogradation in an aqueous system. The gluten quality and dough mixing performance of WWF after 5-15h of controlled germination was enhanced since gluten is less weakened during the dough heating stage of Mixolab testing. After a 72h germination, the GABA content increased by 339% of the non-sprouting counterpart. Furthermore, the GABA content in the ultrasound-treated SW sample was 30.7% higher than that without ultrasound treatment.

Efficient increase of ɣ-aminobutyric acid (GABA) content in tomato fruits by targeted mutagenesis

γ-Aminobutyric acid (GABA) is a non-proteinogenic amino acid that has hypotensive effects. Tomato (Solanum lycopersicum L.) is among the most widely cultivated and consumed vegetables in the world and contains higher levels of GABA than other major crops. Increasing these levels can further enhance the blood pressure-lowering function of tomato fruit. Glutamate decarboxylase (GAD) is a key enzyme in GABA biosynthesis; it has a C-terminal autoinhibitory domain that regulates enzymatic function, and deleting this domain increases GAD activity. The tomato genome has five GAD genes (SlGAD1–5), of which two (SlGAD2 and SlGAD3) are expressed during tomato fruit development. To increase GABA content in tomato, we deleted the autoinhibitory domain of SlGAD2 and SlGAD3 using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas)9 technology. Introducing a stop codon immediately before the autoinhibitory domain increased GABA accumulation by 7 to 15 fold while having variable effects on plant and fruit size and yield. This is the first study describing the application of the CRISPR/Cas9 system to increase GABA content in tomato fruits. Our findings provide a basis for the improvement of other types of crop by CRISPR/Cas9-based genetic modification.

Quantitation of γ-aminobutyric acid in equine plasma by hydrophilic interaction liquid chromatography with tandem mass spectrometry

γ-Aminobutyric acid is the principal inhibitory neurotransmitter in the central nervous system and regulates the neuronal excitability. There has been anecdotal evidence that γ-aminobutyric acid has been used within a few hours prior to competition in equine sports to calm down nervous horses. However, regulating the use of γ-aminobutyric acid is challenging because it is an endogenous substance in the horse. γ-Aminobutyric acid is usually present at low ng/mL levels in equine plasma; therefore, a sensitive method has to be developed to quantify these low background levels. Measuring low concentrations of endogenous γ-aminobutyric acid is essential to establish a threshold that can be used to differentiate levels attributable to exogenous administrations of γ-aminobutyric acid. A hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry method was developed and validated for the quantitation of γ-aminobutyric acid in equine plasma. Calibrators were prepared in artificial surrogate matrix consisting of 35 mg/mL equine serum albumin in phosphate buffered saline. Samples were prepared by protein precipitation with acetonitrile. Utilizing this methodology, a total of 403 equine plasma samples collected post-competition from horses participating in equestrian events in Canada were analyzed.

Rescuing fluoride-induced damages in liver with gamma aminobutyric acid

Fluorine poisoning affects human health all over the world and an urgent task is to develop alleviative medicine to recover or ameliorate the damages to the body. Here we studied the effects of gamma-aminobutyric acid (GABA), a liver protector reported previously, on fluoride-induced damage in the mouse liver. Through microscope imaging of the liver tissue, TUNEL immunostaining, real-time RT-PCR, enzyme immunoassay and colorimetric method, we found that GABA supplementation prevented the metabolic toxicity caused by fluoride treatment in mice. This detoxification was reflected by the reduced oxidative stress and apoptosis, enhanced neuron protection and liver function. Collectively, this study provided evidence of the beneficial effects of GABA supplement on liver damage, implicating its therapeutic potential in fluorosis.

Current and Forward-Looking Approaches to Technological and Nutritional Improvements of Gluten-Free Bread with Legume Flours: A Critical Review

The gluten-free market currently offers a range of products which can be safely consumed by patients affected by celiac disease. Nevertheless, challenges for optimal formulation remain on the way in terms of appreciable texture, flavor, and adequate nutritional characteristics. Within that framework, legumes have recently attracted attention among scientists as structure- and texture-forming agents, as source of nutrients and bioactive compounds, and as a low-glycemic-index ingredient. This work aims at providing an updated and comprehensive overview of the advantages and disadvantages in the use of legumes in gluten-free breadmaking. It also shows how legumes can contribute to tackling the main technological, nutritional, and organoleptic challenges. From this critical analysis, it emerged that viscoelastic properties of gluten-free bread batter can be enhanced by the use of carob germ, chickpea, lupin, and soybean. Gluten-free bread organoleptic acceptability can be improved by incorporating leguminous flours, such as carob, chickpea, lupin, and soybean. Moreover, a better nutritional quality of gluten-free bread can be obtained by the addition of chickpea and soybean. Gaps and needs in the use of legumes in gluten-free breadmaking emerged and were gathered together to have a sound basis for future studies. The technological and nutritional potential of sourdough should be more extensively exploited. Moreover, in vitro and in vivo studies should be prompted to understand the health benefits of bread formulated with legumes. A holistic approach, interfacing food science, nutrition, and health might help to have, on the market, products with improved sensory properties and nutritional profile.

Recent advances in γ-aminobutyric acid (GABA) properties in pulses: an overview

Beans, peas, and lentils are all types of pulses that are extensively used as foods around the world due to their beneficial effects on human health including their low glycaemic index, cholesterol lowering effects, ability to decrease the risk of heart diseases and their protective effects against some cancers. These health benefits are a result of their components such as bioactive proteins, dietary fibre, slowly digested starches, minerals and vitamins, and bioactive compounds. Among these bioactive compounds, γ-aminobutyric acid (GABA), a non-proteinogenic amino acid with numerous reported health benefits (e.g. anti-diabetic and hypotensive effects, depression and anxiety reduction) is of particular interest. GABA is primarily synthesised in plant tissues by the decarboxylation of l-glutamic acid in the presence of glutamate decarboxylase (GAD). It is widely reported that during various processes including enzymatic treatment, gaseous treatment (e.g. with carbon dioxide), and fermentation (with lactic acid bacteria), GABA content increases in the plant matrix. The objective of this review paper is to highlight the current state of knowledge on the occurrence of GABA in pulses with special focus on mechanisms by which GABA levels are increased and the analytical extraction and estimation methods for this bioactive phytochemical. © 2017 Society of Chemical Industry.

From Genome to Phenotype: An Integrative Approach to Evaluate the Biodiversity of Lactococcus lactis

Lactococcus lactis is one of the most extensively used lactic acid bacteria for the manufacture of dairy products. Exploring the biodiversity of L. lactis is extremely promising both to acquire new knowledge and for food and health-driven applications. L. lactis is divided into four subspecies: lactis, cremoris, hordniae and tructae, but only subsp. lactis and subsp. cremoris are of industrial interest. Due to its various biotopes, Lactococcus subsp. lactis is considered the most diverse. The diversity of L. lactis subsp. lactis has been assessed at genetic, genomic and phenotypic levels. Multi-Locus Sequence Type (MLST) analysis of strains from different origins revealed that the subsp. lactis can be classified in two groups: “domesticated” strains with low genetic diversity, and “environmental” strains that are the main contributors of the genetic diversity of the subsp. lactis. As expected, the phenotype investigation of L. lactis strains reported here revealed highly diverse carbohydrate metabolism, especially in plant- and gut-derived carbohydrates, diacetyl production and stress survival. The integration of genotypic and phenotypic studies could improve the relevance of screening culture collections for the selection of strains dedicated to specific functions and applications.

Lactic Acid Bacteria and Bifidobacteria with Potential to Design Natural Biofunctional Health-Promoting Dairy Foods

Consumer interest in healthy lifestyle and health-promoting natural products is a major driving force for the increasing global demand of biofunctional dairy foods. A number of commercial sources sell synthetic formulations of bioactive substances for use as dietary supplements. However, the bioactive-enrichment of health-oriented foods by naturally occurring microorganisms during dairy fermentation is in increased demand. While participating in milk fermentation, lactic acid bacteria can be exploited in situ as microbial sources for naturally enriching dairy products with a broad range of bioactive components that may cover different health aspects. Several of these bioactive metabolites are industrially and economically important, as they are claimed to exert diverse health-promoting activities on the consumer, such as anti-hypertensive, anti-inflammatory, and anti-diabetic, anti-oxidative, immune-modulatory, anti-cholesterolemic, or microbiome modulation. This review aims at discussing the potential of these health-supporting bacteria as starter or adjunct cultures for the elaboration of dairy foods with a broad spectrum of new functional properties and added value.