Gut production of GABA by a probiotic formula: an in vitro study.

The objective of this study was to evaluate the influence of a probiotic formula on the production of neuroactive compounds in different parts of the colon in batch culture and in vitro gut simulator experiments. Thirteen lactic acid bacterial strains, belonging to the species Levilactobacillus brevis, Lactiplantibacillus plantarum, Lacticaseibacillus paracasei, Ligilactobacillus salivarius, Streptococcus thermophilus, were characterised for their in vitro ability to produce neurotransmitters. L. brevis P30021 and L. plantarum P30025 were selected based on their capability to produce γ-aminobutyric acid (GABA) and acetylcholine in vitro. A probiotic formulation with potential psychobiotic activity was prepared and tested in a batch culture of human microbiota monitoring the formation of GABA and acetylcholine. Samples of the three colonic tracts were taken from the Simulator of the Human Intestinal Microbiota (SHIME®) evaluating the production of GABA and other neurotransmitters by LC-MS. Short chain fatty acids (SCFA) by GC and microbiota composition by 16S rRNA gene sequencing were also determined. Probiotic supplementation led to the formation of GABA and acetylcholine with a decrease in glutamate concentrations in the in vitro batch fermentation. Production of GABA after the treatment with probiotics was confirmed in the SHIME® short-term experiment. No differences in short-chain fatty acids were observed up to 72 h of fermentation. Different microbiota composition was found in the three different parts of the colon, with a higher abundance of Veillonellaceae in the ascending colon vessels. The probiotic-exposed microbiota showed higher levels of Bacteroides, a gut microbe associated with anti-inflammatory activities and a potential GABA producer. Results demonstrate the impact of the tested probiotic formula on gut microbiota structure and GABA production. In conclusion, the probiotic treatment changed the microbiota composition and increased neuroactive metabolites production, indicating promising potential as psychobiotics, even if further clinical evidence is needed to confirm the effectiveness of these probiotics in improving mental health.

Short communication: Short-time freezing does not alter the sensory properties or the physical stability of ultra-high-temperature hydrolyzed-lactose milk.

In this study, the effect of milk freezing was studied, focusing on the changes in 1% and 3% fat UHT hydrolyzed-lactose milk after slow- (-20°C) and fast-rate freezing (-80°C) for 72 h. Changes on the sensory properties were first assessed by discriminant analysis (triangle test), and then by volatile organic compounds and color analysis. The milk emulsion stability was characterized by optical centrifugation, particle size analysis, and confocal microscopy. The sensory panel was not able to distinguish the milk subjected to freezing from the control (72 h at 20°C). The volatile organic compounds and color analysis demonstrated that both freezing rates did not cause any significant changes in the milk aroma or color characteristics. The results of physical properties confirmed that short-time freezing did not lead to a distinct destabilization, except for a slight increase in the mean particle diameter at -80°C. Taking all the results together, UHT hydrolyzed-lactose milk was not significantly altered during the operation of freezing and thawing and, therefore, short-time freezing at both -20°C and -80°C can be used for milk storage without altering the product.

Frozen storage of lesser mealworm larvae (Alphitobius diaperinus) changes chemical properties and functionalities of the derived ingredients.

The effect of frozen storage on the chemical properties and ingredient functionalities of Lesser mealworms was investigated at -20 °C for 2 months. Major changes occurred in the first week of frozen storage. Proteins, among which heavy chain myosin, underwent denaturation and aggregation, as shown by a decrease in solubility, SDS-PAGE pattern, and Confocal Laser Scanning Microscopy. The ice melting point in larvae was -32.5 °C as determined by DSC: 25% of water is not frozen at -20 °C, possibly due to anti-freezing proteins preventing ice formation. The presence of unfrozen water favoured various enzymatic activities as shown by a pH decrease, indicating protein hydrolysis. The molecular changes during frozen storage increased the browning reactions due to phenoloxidase activity. Foaming ability, foam stability and gel network stability increased upon frozen storage due to protein denaturation. Results provide important information regarding the opportunity of frozen storage of insect larvae for both research and industrial purposes.

Ethnicity, gender and physiological parameters: Their effect on in vivo flavour release and perception during chewing gum consumption.

In this study, the impact of physiological parameters, ethnicity and gender on flavour perception and flavour release of chewing gum was investigated. Proton Transfer Reaction Mass Spectrometry in-nose monitoring of volatile organic compounds was coupled to discontinuous time intensity sensory evaluation for mint flavour and sweetness perception. Each of the 29 subjects, 14 European and 15 Chinese panelists (13 male and 16 females, age 24 ±â€¯1.4 years old) consumed the samples in triplicates. Physiological parameters (oral cavity volume, salivary flow, acetone and isoprene concentration and fungiform papillae density) were measured. Significant differences for in vivo flavour release between Chinese and European panelists after 90 s of consumption and after the gum was removed from the mouth were found. Significant differences were observed also in flavour and sweetness perception while no gender effect was detected. In this work, for the first time an effect of ethnicity on in-nose flavour release monitored through PTR-MS was noticed during chewing gum consumption, in agreement with the findings from sensory evaluation. Single physiological parameters do not explain the relation between flavour in nose release and perception during consumption.

Rapid and noninvasive quality control of anhydrous milk fat by PTR-MS: The effect of storage time and packaging.

In this study, proton transfer reaction-mass spectrometry (PTR-MS), coupled with a time-of-flight mass analyzer and a multipurpose automatic sampler, was evaluated as a rapid and nondestructive tool for the quality control of anhydrous milk fat. Anhydrous milk fats packed in cardboard and bag-in-box were compared during refrigerated shelf life at 4°C for 9 months. Anhydrous milk fat samples were taken at 120, 180, and 240 days and measured by PTR-MS during storage at 50°C for 11 days. Univariate and multivariate data analysis were performed in order to classify samples according to the packaging type and compare aromatic profiles. Markers related to both packaging and storage duration were identified, and all stored samples were clearly distinguishable from reference fresh samples. Significant differences in some key butter aroma compounds such as 2-pentanone, 2-heptanone, 2/3-methylbutanal, acetoin, and butanoic acid were observed between different types of packaging. During the refrigerated storage, differences related to packaging are more evident, while during the storage at 50°C, the fat oxidation induced by the high temperature becomes the most relevant phenomenon independently of the packaging type. These results indicate the importance of avoiding anhydrous milk fat storage at 50°C for long times during industrial production processes. All together data demonstrated the viability of PTR-MS as a rapid and high-sensitivity tool in agroindustry quality control program.

Consumption of extra-virgin olive oil rich in phenolic compounds improves metabolic control in patients with type 2 diabetes mellitus: a possible involvement of reduced levels of circulating visfatin.

AIM: Phenolic compounds naturally contained in extra-virgin olive oil (EVOO) have demonstrated anti-inflammatory and antioxidant properties. The present study aimed at evaluating the effects of a polyphenol-rich extra-virgin olive oil (EVOO) (high-polyphenol EVOO, HP-EVOO) on the metabolic control and the production of specific pro-/anti-inflammatory adipokines in overweight patients with type 2 diabetes mellitus (T2D). METHODS: Eleven overweight T2D patients not in treatment with insulin were invited to follow their habitual diet for a total of 8 weeks. During the first 4 weeks (wash-out period), they were asked to consume refined olive oil (ROO, polyphenols not detectable) and then to replace ROO with HP-EVOO (25 mL/day, 577 mg of phenolic compounds/kg) for the remaining 4 weeks. Anthropometric parameters, fasting glycaemia, glycated haemoglobin (HbA1c), high-sensitive C-reactive protein, plasma lipid profile, liver function and serum levels of TNF-α, IL-6, adiponectin, visfatin and apelin were assessed at the end of each 4-week period. RESULTS: HP-EVOO consumption significantly reduced fasting plasma glucose (P = 0.023) and HbA1c (P = 0.039) levels as well as BMI (P = 0.012) and body weight (P = 0.012). HP-EVOO ingestion determined a reduction in serum level of aspartate aminotransferase (AST, P = 0.0056) and alanine aminotransferase (ALT, P = 0.024). Serum visfatin levels strongly decreased after HP-EVOO ingestion (P = 0.0021). CONCLUSIONS: Daily consumption of polyphenol-rich EVOO might improve metabolic control and circulating inflammatory adipokines profile in overweight T2D patients.

Acrylamide mitigation strategies: critical appraisal of the FoodDrinkEurope toolbox.

FoodDrinkEurope Federation recently released the latest version of the Acrylamide Toolbox to support manufacturers in acrylamide reduction activities giving indication about the possible mitigation strategies. The Toolbox is intended for small and medium size enterprises with limited R&D resources, however no comments about the pro and cons of the different measures were provided to advise the potential users. Experts of the field are aware that not all the strategies proposed have equal value in terms of efficacy and cost/benefit ratio. This consideration prompted us to provide a qualitative science-based ranking of the mitigation strategies proposed in the acrylamide Toolbox, focusing on bakery and fried potato products. Five authors from different geographical areas having a publication record on acrylamide mitigation strategies worked independently ranking the efficacy of the acrylamide mitigation strategies taking into account three key parameters: (i) reduction rate; (ii) side effects; and (iii) applicability and economic impact. On the basis of their own experience and considering selected literature of the last ten years, the authors scored for each key parameter the acrylamide mitigation strategies proposed in the Toolbox. As expected, all strategies selected in the Toolbox turned out to be useful, however, not at the same level. The use of enzyme asparaginase and the selection of low sugar varieties were considered the best mitigation strategies in bakery and in potato products, respectively. According to authors' opinion most of the other mitigation strategies, although effective, either have relevant side effects on the sensory profile of the products, or they are not easy to implement in industrial production. The final outcome was a science based commented ranking which can enrich the acrylamide Toolbox supporting individual manufacturer in taking the best actions to reduce the acrylamide content in their specific production context.

The health and technological implications of a better control of neoformed contaminants by the food industry.

The recent discovery of the presence of variable amounts of the carcinogenic compound acrylamide in a wide range of severely heat-treated food products, such as fried potatoes, biscuits, bread and coffee or malt, as a result of the heat process, has induced an important research in the area of the Maillard reaction in food. The interaction between a specific food composition and the heat process applied results in the development of complex oxidation and glycation reactions, which give rise to a mixture of flavoured compounds and possible neoformed contaminants (NFC). Recommendations by the European Commission aim at monitoring the content of major NFC, such as acrylamide and furan, in a list of food products commercialized in Europe. On the other hand, the Commission for European Normalization (CEN) has created recently a new workgroup (WG13) responsible for normalization of analytical method for NFC assessment. The European collective research ICARE was carried out to identify the possible health consequences of the ingestion of heat-treated products, characterize the reaction kinetics leading to NFC and evaluate some mitigation procedures proposed by the CIAA toolbox, and finally develop a simple, rapid and non destructive control method based on fluorescence acquisition on the crushed food products and chemometric analysis of the spectral information. This paper summarizes the objectives and essential results obtained in the scope of the project, highlighting the need for evaluating the distribution of NFC in food products commercialized in Europe, as well as the impact of the food formula/recipe and process on Maillard derived NFC food levels. The potential of the Fluoralys sensor regarding its ability to control food contamination with NFC is presented. A decrease in NFC concentration of heat processed food should allow significantly limiting the exposure of populations to NFC and consequently the potential related health risk.

Potential prebiotic activity of oligosaccharides obtained by enzymatic conversion of durum wheat insoluble dietary fibre into soluble dietary fibre.

BACKGROUND AND AIMS: Epidemiological evidence indicates that cereal dietary fibre (DF) may have several cardiovascular health benefits. The underlying mechanisms have not yet been elucidated. Here, the potential nutritional effects of physico-chemical properties modifications of durum wheat dietary fibre (DWF) induced by enzyme treatment have been investigated. METHODS AND RESULTS: The conversion of the highly polymerised insoluble dietary fibre into soluble feruloyl oligosaccharides of DWF was achieved by a tailored enzymatic treatment. The in vitro fermentation and release of ferulic acid by intestinal microbiota from DWF before and after the enzymatic treatment were assessed using a gut model validated to mimic the human colonic microbial environment. Results demonstrated that, compared to DWF, the enzyme-treated DWF (ET-DWF) stimulated the growth of bifidobacteria and lactobacilli. Concurrently, the release of free ferulic acid by ET-DWF was almost three times higher respect to the control. No effect on the formation of short chain fatty acids was observed. CONCLUSIONS: The conversion of insoluble dietary fibre from cereals into soluble dietary fibre generated a gut microbial fermentation that supported bifidobacteria and lactobacilli. The concurrent increase in free ferulic acid from the enzyme-treated DWF might result in a higher plasma ferulic acid concentration which could be one of the reasons for the health benefits reported for dietary fibre in cardiovascular diseases.

Alcoholic beverages and gastric epithelial cell viability: effect on oxidative stress-induced damage.

UNLABELLED: Alcohol is known to cause damage to the gastric epithelium independently of gastric acid secretion. Different alcoholic beverages exert different damaging effects in the stomach. However, this has not been systematically evaluated. Moreover, it is not known whether the non-alcoholic components of alcoholic beverages also play a role in the pathogenesis of gastric epithelial cell damage. Therefore, this study was designed to evaluate whether different alcoholic beverages, at a similar ethanol concentration, exerted different damaging effect in gastric epithelial cells in vitro. Moreover, we evaluated whether pre-treatment of gastric epithelial cells with alcoholic beverages prevented oxidative stress-induced damage to gastric cells. Cell damage was assessed, in MKN-28 gastric epithelial cells, by MTT assay. Oxidative stress was induced by incubating cells with xanthine and xanthine oxidase. Gastric cell viability was assessed following 30, 60, and 120 minutes incubation with ethanol 17.5-125 mg/ml(-1) or different alcoholic beverages (i.e., beer, white wine, red wine, spirits) at comparable ethanol concentration. Finally, we assessed whether pre-incubation with red wine (with or without ethanol) prevented oxidative stress-induced cell damage. Red wine caused less damage to gastric epithelial cells in vitro compared with other alcoholic beverages at comparable ethanol concentration. Pre-treatment with red wine, but not with dealcoholate red wine, significantly and time-dependently prevented oxidative stress-induced cell damage. CONCLUSIONS: 1) red wine is less harmful to gastric epithelial cells than other alcoholic beverages; 2) this seems related to the non-alcoholic components of red wine, because other alcoholic beverages with comparable ethanol concentration exerted more damage than red wine; 3) red wine prevents oxidative stress-induced cell damage and this seems to be related to its ethanol content.

Lipodepsipeptides from Pseudomonas syringae are partially proteolyzed and are not absorbed by humans: an in vitro study.

There are some concerns about the use of Pseudomonas-based products as biocontrol agents because of the hemolytic activity shown by their metabolites. The effects of Pseudomonas lipodepsipeptides (LDPs) on mammals via ingestion and the LDP degradation during the digestion and intestinal permeability have not been evaluated. In this research, the susceptibility of different LDPs to degradation was assayed with enzymatic gastrointestinal digestion, and intestinal permeability to LDPs was investigated in an in vitro system based on an intestinal cell layer system. Results demonstrated that trypsin and chymotrypsin hydrolyze up to 50% of the various LDPs, and that proteolysis was further increased by pronase E treatment. A decrease in LDP hemolytic activity matched LDP degradation during the various steps of the digestion process. Moreover, it was shown that syringomycin E (SRE), the main known LDP, was not able to cross the intestinal cell layer, suggesting that SRE does not reach the bloodstream in vivo. It was concluded that the Pseudomonas-based biocontrol products do not represent a serious risk for consumer health. In fact, LDPs possibly present on biocontrol-treated agricultural commodities would likely be partially digested by gastrointestinal enzymes and would not be absorbed at the intestinal level.

Fuscopeptins, antimicrobial lipodepsipeptides from Pseudomonas fuscovaginae, are channel forming peptides active on biological and model membranes.

FP-A and FP-B are LDPs produced by the plant pathogen Pseudomonas fuscovaginae. As expected from their primary structure, they shared a similar mechanism of action with the better characterized SPs, synthesized by strains of Pseudomonas syringae pv. syringae. Indeed, they displayed hemolytic activity on human erythrocytes and were able to induce calcein release from LUVs: the effect was dependent on the concentration of the FPs and the lipid composition of the liposome and, in particular, it increased with the SM content of the membrane. The permeabilizing activity was further investigated on PLMs. FPs were able to open pores on pure POPC membranes. Pore opening was strongly voltage dependent: by switching the potential from negative to positive values, an increase in the absolute amplitude of transmembrane current was induced with simultaneous closure of pores. In 0.1 M KCl both FPs' pores had a conductance of 4 and 9 pS at - 140 mV and + 140 mV, respectively. Studies on ion selectivity indicated that FPs formed cation-selective channels.

Development of a tomato-based food for special medical purposes as therapy adjuvant for patients with HCV infection.

OBJECTIVE: The present study aimed to develop a food for special medical purposes (FSMP) and to assess its efficacy as adjuvant therapy in patients with chronic hepatitis C virus (HCV). DESIGN: Open randomized clinical trials with a tomato-based FSMP used as adjuvant treatment to the pharmacological therapy with pegilated interferon and ribavirin. SUBJECTS: Eight healthy volunteers and 39 HCV patients. INTERVENTIONS: For the bioavailability study, healthy subjects consumed 100 g/die FSMP for a week and their serum carotenoid profile at baseline, after the week of administration and 7 days later was determined. The same quantity of FSMP for 6 months by 20 of the 39 HCV patients was consumed in the clinical trial. Serum transaminase, haemoglobin (Hb) and hydroperoxide concentrations during the therapy were monitored in all patients. RESULTS: FSMP consumption caused a fourfold increase of lycopene serum concentration in healthy subjects. A significant increase of carotenoids after 1 month of consumption also in patients with HCV was recorded. Transaminase and Hb serum levels, as well as therapeutic response, were not influenced by FSMP. The decrease in serum hydroperoxides was independent from FSMP consumption in long-term responder patients, whereas nonresponder (NR) patients of FSMP group showed higher reductions than NR patients of Control group. CONCLUSIONS: The FSMP was effective in improving carotenoid status in healthy subjects. In HCV patients, it did not influence the therapeutic response, but it prevented carotenoid serum depletion and it was effective in improving the oxidative status during antiviral therapy in NR patients.

Apple polyphenol extracts prevent damage to human gastric epithelial cells in vitro and to rat gastric mucosa in vivo.

BACKGROUND: Fresh fruit and vegetables exert multiple biological effects on the gastrointestinal mucosa. AIM: To assess whether apple extracts counteract oxidative or indomethacin induced damage to gastric epithelial cells in vitro and to rat gastric mucosa in vivo. METHODS: Apple extracts were obtained from freeze dried apple flesh of the "Annurca" variety. Cell damage was induced by incubating MKN 28 cells with xanthine-xanthine oxidase or indomethacin and quantitated by MTT. In vivo gastric damage was induced by indomethacin 35 mg/kg. Intracellular antioxidant activity was determined using the (2,2'-azinobis (3-ethylbenzothiazolin-6-sulfonate) method. Malondialdehyde intracellular concentration, an index of lipid peroxidation, was determined by high pressure liquid chromatography with fluorometric detection. RESULTS: (1) Apple extracts decreased xanthine-xanthine oxidase or indomethacin induced injury to gastric epithelial cells by 50%; (2) catechin or chlorogenic acid (the main phenolic components of apple extracts) were equally effective as apple extracts in preventing oxidative injury to gastric cells; and (3) apple extracts (i) caused a fourfold increase in intracellular antioxidant activity, (ii) prevented its decrease induced by xanthine-xanthine oxidase, (iii) counteracted xanthine-xanthine oxidase induced lipid peroxidation, and (iv) decreased indomethacin injury to the rat gastric mucosa by 40%. CONCLUSIONS: Apple extracts prevent exogenous damage to human gastric epithelial cells in vitro and to the rat gastric mucosa in vivo. This effect seems to be associated with the antioxidant activity of apple phenolic compounds. A diet rich in apple antioxidants might exert a beneficial effect in the prevention of gastric diseases related to generation of reactive oxygen species.

Use of antioxidants to minimize the human health risk associated to mutagenic/carcinogenic heterocyclic amines in food.

Heterocyclic amines (HAs) are mutagenic/carcinogenic compounds formed in meat during cooking. Several efforts have been made to minimize the risk associated to HA human exposure. Supplementation with antioxidants is considered a promising measure to reduce HA exposure because of their ability as inhibitors of HA formation or as blocking/suppressing agents on HA biotransformation/metabolism. The aim of this review is to present the current knowledge on the capability of synthetic and natural antioxidants to modulate HA-induced mutagenicity/carcinogenicity. Data show a general trend towards a reduction of HA formation both in model systems and in real foods as well as an effective modulation of biotransformation and metabolism. Phenolic compounds, particularly those from tea and olive oil, seem to be the most effective, although a great variability is observed because of the concentration-dependent pro- and antioxidant effects.

Supercritical fluid extraction of Beauvericin from maize.

Beauvericin (BEA), a supercritical fluid extraction with supercritical carbon dioxide from maize was investigated. Extraction efficiencies under several different extraction conditions were examined. Pressure, temperature, extraction time, organic modifier and water matrix content (10%) were investigated. The best extraction conditions were at a temperature of 60 degrees C, 3200psi, for 30min static extraction time and methanol as modifier solvent. Extraction recovery of 36% without modifier by adding water to the matrix in the extraction vessel (reproducibility relative standard deviations (R.S.D.)=3-5%) were recorded. Extraction recovery of 76.9% with methanol as co-solvent (reproducibility R.S.D.=3-5%) was obtained. Data shows that SFE gives a lower BEA recovery compared to conventional extraction protocol with organic solvents while SFE with modifier and conventional extraction yields are comparable. BEA extract contents were determined by high pressure liquid chromatography (HPLC) with a diode array detector (DAD) at 205nm and BEA peak confirmed by LC-MS. Acetonitrile-water as mobile phase and column C-18 were both tested. Instrumental and analytical parameters were optimized in the range linear interval from 1 to 500mgkg(-1) and reached a detection limit of 2ng.

Influence of antioxidants in virgin olive oil on the formation of heterocyclic amines in fried beefburgers.

An association between the intake of heterocyclic amines (HAs) and the development of cancer has been observed in some epidemiological studies, while in other studies no such correlation has been found. HAs are mutagenic/carcinogenic compounds formed at low levels via the Maillard reaction and a free radical mechanism during cooking of animal tissue. The addition of pure antioxidants or foods containing antioxidants has previously been shown to decrease the amount of HAs formed during cooking. In this study, beefburgers were fried in six different oils: refined olive oil, virgin olive oil, virgin olive oil depleted of phenols, rapeseed oil, virgin olive oil with rosemary extract and refined olive oil with rosemary extract. The content of antioxidative compounds in the virgin olive oil and the rosemary extract was determined. The beefburgers were analysed with regards to 12 different HAs by solid phase extraction and HPLC analysis. MeIQx, 4,8-DiMeIQx, PhIP, Harman and Norharman were detected in all beefburgers fried in the different oils, but the relative amounts varied. Frying in virgin olive oil reduced the formation of HAs compared with refined olive oil. This effect is probably due to the content of phenols in the virgin olive oil. The HA-reducing effect of virgin olive oil decreased during storage, but the addition of rosemary extract may prevent this decrease.

Glycoalkaloids and acclimation capacity of hybrids between Solanum tuberosum and the incongruent hardy species Solanum commersonii.

F(1) and backcross hybrids between sexually incompatible species Solanum commersonii and Solanum tuberosum were characterized for glycoalkaloid content and capacity to cold acclimate. Glycoalkaloid (GA) analysis revealed that F(1) triploids and BC(1) pentaploids contained the glycoalkaloids of both parents. In BC(2) (near) tetraploids the situation was different, in that some hybrids produced the GAs of both parents, whereas others contained only the GAs of S. tuberosum. This suggested that the GAs from S. commersonii may be lost rapidly, and that they may have a simple genetic control. The total tuber GA content of BC(1) and BC(2) groups averaged quite acceptable levels (165.9 mg/kg in BC(1) and 192.8 mg/kg in BC(2)), with six genotypes having a GA content <200 mg/kg fresh weight. The F(1) triploid hybrids expressed a capacity to cold acclimate similar to S. commersonii, whereas BC(1) and BC(2) genotypes generally displayed an acclimation capacity higher than the sensitive parent but lower than S. commersonii. However, one BC(1) and two BC(2) genotypes with an acclimation capacity as high as S. commersonii were identified. The polar lipid fatty acid composition in S. commersonii and its hybrid derivatives showed that, following acclimation, there was a significant increase in 18:3. Correlation analysis between the capacity to cold acclimate and the increase in 18:3 was significant, suggesting that the increase in 18:3 can be used as a biochemical marker for the assisted selection of cold-acclimating genotypes in segregating populations.

Characterization of coloured compounds obtained by enzymatic extraction of bakery products.

Melanoidins, the brown-colored polymers formed through Maillard type reaction in several heat-treated foods, represent a significant part of our diet, with an average intake of grams per day. Most of the studies on the physiological effects of these compounds have been performed using the water soluble melanoidin fractions. But dietary melanoidins formed on the surface of bakery products are poorly soluble in water as well as in organic solvents. In this work, an enzymatic solubilization procedure was developed on a gluten-glucose model system and it was applied to bread and biscuits. The soluble material obtained was tested for its antioxidant activity, for its effect on phase-I and phase-II xenobiotic enzymes and for potential cytotoxic effects. Soluble melanoidins from model system and biscuits exhibit a strong antioxidant activity and do not show any cytotoxicity on Caco-2 cells. Melanoidins extracted from biscuits was able to inhibit the activity of Phase I (NADPH-cytochrome-c reductase) and Phase II (Glutathione-S-transferase) enzymes, whereas the low molecular weight melanoidins isolated from gluten-glucose model system inhibit the activity of NADPH-cytochrome-c reductase.

Moderate coffee consumption increases plasma glutathione but not homocysteine in healthy subjects.

BACKGROUND: The consumption of unfiltered coffee, containing bioactive diterpenes, causes an increase in plasma homocysteine concentration. A slight increase in plasma homocysteine is also caused by large quantities of filtered coffee. Coffee terpenes also raise plasma glutathione in mice. AIM: To verify the effect of Italian-style coffee consumption on the plasma concentration of glutathione and homocysteine in healthy subjects. METHODS: Twenty-two volunteers consumed five cups of coffee per day for 1 week and maintained their usual diet. Five subjects were enrolled as controls. The intervention trial was preceded and followed by seven coffee-free days. RESULTS: Plasma glutathione increased by 16% (P < 0.05) on coffee consumption, and returned to the original concentration after the washout period. The increase in plasma homocysteine concentration (13% after 1 week of coffee intake) was not significant. No differences in glutathione or homocysteine concentration were observed in the control group. No variation of plasma hydroperoxide concentration was detectable. CONCLUSIONS: A coffee intake regimen, representing the average consumption of coffee drinkers in Italy, increased the plasma concentration of glutathione, but no significant increase in the plasma homocysteine concentration was detected.