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Today the consumption of fresh vegetables is highly recommended not only for the intake of nutrients, but also for the healthy properties of secondary metabolites involved in the prevention of many disorders. In the present work, phenolic acids and flavonoids extracted from four green ( Cichorium intybus var. sativus and var. foliosum ) and a red spotted (a cross between C. intybus var. silvestre cv “Treviso” and C. endivia var. foliosum ) salads were characterized by high-performance liquid chromatography–electrospray ionization/mass spectrometry. Among the 76 compounds detected in this work, five organic acids (two malic acid derivatives, two pyroglutamic hexoside isomers, and cis -aconitic acid), ten hydroxycinnamic acid derivatives (ferulic, malonyl caffeoylquinic, and caffeoylmethylglutaroylquinic acids, cinnamoyl- and caffeoyl-malate, coumaroyl, sinapoyl, feruloyl, and coumaroylcaffeoyl glycosides, dicaffeoyl lactone, 3- O -caffeoyl-4- O -(3-hydroxyglutaroylquinic acid), four flavonols (quercetin-di- O -glucoside, quercetin-3- O -malonylh exo syl-7- O -h exo side, myricetin-3- O- glucoside, and isorhamnetin-3- O -glucoside), and cyanidin-3- O -glucuronyl-5- O -h exo side have been identified in chicory salads for the first time. These data, together with the results obtained in our previous investigations on Cichorium genus Italian salads, provide a contribution to a more exhaustive identification of the secondary metabolites profile of each considered plant, that could be also useful in building/selecting hybrids with agronomic and peculiar healthy features, even using traditional methods of cultivation.

A new method using Hydrophilic Interaction Liquid Chromatography and UV detection was developed for the determination of free quinic acid in fourteen commercial beverages (fruit juices, red wine, coffee, vinegar, and edible mushroom extract). Samples were directly injected into the HPLC system after dilution and centrifugation. All separations were carried out by gradient elution on a ZIC®-cHILIC column, using an eluent consisting of acetonitrile and aqueous phosphate buffer at pH 6. Quinic acid eluted in 12 min as a symmetric peak well separated from all other peaks in the chromatograms. The total turnaround time per sample was 60 min. The method was validated using cranberry juice as model beverage matrix. Linearity was demonstrated on spiked juice between 200 and 600 μg/mL (r2 = 0.999), and precision and accuracy were satisfactory (RSD ≤ 10% and recovery 100 ± 1%, respectively). The method was proven to be suitable for its purpose. Quinic acid levels ranged from undetectable (

The present study investigated the compounds present in the low molecular mass fraction of Lentinus edodes mushroom (shiitake) extract and their anti-virulence activity against oral pathogens (reference and clinical Streptococcus mutans, Actinomyces naeslundii, and Prevotella intermedia strains). Oxalic, succinic, and quinic acids, and adenine, inosine, and uridine were identified by HPLC-DAD-ESI-MS/MS. Their anti-biofilm production and preformed biofilm disaggregation activities were studied using commercial standard compounds at different concentrations. As regards S. mutans, the highest activity was shown by adenine at 5 mg mL-1 both in the biofilm inhibition (BI 50%) and biofilm disaggregation tests (BD 20%). Considering A. naeslundii, BI values close to 80% were registered for oxalic acid at 1 mg mL-1 and 2 mg mL-1 and BD 50% for quinic acid at 3 mg mL-1. A weaker activity was found against P. intermedia. Furthermore, different mixtures of the commercial standards were tested showing that the activity of a compound can be strongly and sometimes negatively affected by the presence of the other compounds.

α-Dicarbonyl (α-DC) compounds were characterised in roasted (coffee, barley coffee) and in fermented (soy sauce) food matrices. Glyoxal (GO), methylglyoxal (MGO), diacetyl (DA) and 3-deoxyglucosone (3-DG) were found in all samples, and hydroxypyruvaldehyde and 5-hydroxypentane-2,3-dione in barley and soy. Cis and trans 3,4-dideoxyglucosone-3-ene (3,4-DGE) isomers and 4-glucosyl-5,6-dihydroxy-2-oxohexanal (4-G,3-DG) were found only in barley, and 3,4-DGE only in soy sauce with molasses. GO, MGO, and DA were quantified. Findings indicate that i) α-DC profiles depend on the food matrix and any technological treatments applied; ii) α-DC quantitation by HPLC requires matrix-specific, validated methods; iii) GO and MGO were the most abundant α-DCs; and iv) barley coffee was the matrix richest in α-DCs both qualitatively and quantitatively. In vitro simulated digestion reduced (coffee) or strongly increased (barley, soy sauce) free α-DC content. These findings suggest that α-DC bioavailability could actually depend not on food content but rather on reactions occurring during digestion.

Red skin radishes (Raphanus savitus L. var. “Cherry Belle”) were extracted employing an environmentally friendly method and the obtained polyphenolic extract was characterized and studied for its applicability as a natural antioxidant colorant in nutraceutical/food and cosmetic fields. Fourteen anthocyanins, fourteen phenolic acid derivatives, and twelve flavonoids were detected. Color stability of the extract submitted to different stress conditions (thermal treatment, light and oxygen exposure) was studied both in liquid and in solid state by monitoring the absorbance at the wavelength of maximum absorption of anthocyanins when present in solutions and by estimating CIEL*a*b* parameters when mixed with mPEG. The investigation indicated a good stability at low temperatures and up to 20 °C, that was higher in the absence of oxygen and at the solid state, whereas the stability decreased at higher temperature. Therefore the extract could be used to color or improve the color of packaged food and cosmetic products to be stored at room temperature.

We investigated the influence of an in vitro simulated digestion process on the content of the free α-dicarbonyl compounds most frequently found in food. A Glyoxal (GO), methylglyoxal (MGO), and diacetyl (DA) aqueous standard mixture and 2 brands of balsamic vinegar were analyzed before and after exposure to digestive enzymes. A strong matrix effect required adoption of validated RP-HPLC-DAD standard addition methods. The results showed that the digestive enzymes markedly alter the concentrations of the exogenous free α-dicarbonyl compounds ingested with food; the extent of such changes varied with the α-dicarbonyl compound itself and the diet components, which determined important but different food matrix effects also during digestion. The data also indicate that digestion can reduce the bioavailability of the toxic α-dicarbonyl compounds ingested with food. However, no firm conclusions can be drawn about a putative positive influence of digestion on the toxic potential of dietary α-dicarbonyl compounds, because their reaction in the presence of digestive enzymes likely gives rise to advanced glycation end products, which are involved in the development of chronic diseases.

The low molecular mass (LMM) extract of Cichorium intybus var. silvestre (red chicory) has been shown to inhibit virulence-linked properties of oral pathogens including Streptococcus mutans, Actinomyces naeslundii and Prevotella intermedia. In the present study HPLC-DAD-ESI/MS(2) was used to investigate the compounds contained in this extract for their anti-virulence activity. The extract contained a number of components, including oxalic, succinic, shikimic and quinic acids, which interfere with the growth and virulence traits (i.e., biofilm formation, adherence to epithelial cells and hydroxyapatite) of oral pathogens involved in gingivitis and tooth decay. Succinic and quinic acid seem to be the most potent, mainly by interfering with the ability of oral pathogens to form biofilms (either through inhibition of their development or promotion of their disruption). Our findings suggest that one or more of these compounds may modulate plaque formation in vivo, which is a prerequisite for the development of both caries and gingivitis.

Coffee brew is a widely consumed beverage with multiple biological activities due both to naturally occurring components and to the hundreds of chemicals that are formed during the roasting process. Roasted coffee extract possesses antibacterial activity against a wide range of microorganisms, including Staphylococcus aureus and Streptococcus mutans, whereas green coffee extract exhibits no such activity. The naturally occurring coffee compounds, such as chlorogenic acids and caffeine, cannot therefore be responsible for the significant antibacterial activity exerted by coffee beverages against both bacteria. The very low minimum inhibitory concentration (MIC) found for standard glyoxal, methylglyoxal, and diacetyl compounds formed during the roasting process points to these alpha-dicarbonyl compounds as the main agents responsible for the antibacterial activity of brewed coffee against Sa. aureus and St. mutans. However, their low concentrations determined in the beverage account for only 50% of its antibacterial activity. The addition of caffeine, which has weak intrinsic antibacterial activity, to a mixture of alpha-dicarbonyl compounds at the concentrations found in coffee demonstrated that caffeine synergistically enhances the antibacterial activity of alpha-dicarbonyl compounds and that glyoxal, methylglyoxal, and diacetyl in the presence of caffeine account for the whole antibacterial activity of roasted coffee.

Wine contains a number of biologically active compounds with beneficial effects on human health. The antibacterial action of commercial red and white wines against oral streptococci responsible for caries development and against S. pyogenes responsible for pharyngitis was studied. Its postcontact effect against S. mutans was also studied. Both wines displayed activity. The compounds responsible for such activities were succinic, malic, lactic, tartaric, citric, and acetic acid. The synthetic mixtures of the organic acids tested at the concentrations found in wine had greater antibacterial activity than the beverages, indicating that in wine they are inhibited by other components. Wine polyphenols displayed no activity against oral streptococci or S. pyogenes. Findings show that wine is active against oral streptococci and S. pyogenes and suggest that it enhances oral health.

The antiradical activity of water-soluble components contained in mushrooms (Psalliota campestris), onions (Allium cepa), white cabbage (Brassica oleracea var. alba), and yellow bell peppers (Capsicum annuum) against hydroxyl radicals was tested in a chemical and biological system. The vegetable juices were obtained by centrifugation of a vegetable homogenate processed at 2 degrees C or heated at 102 degrees C. The chemical system consisted of a buffered reaction mixture composed of Fe(III)-EDTA, 2-deoxy-D-ribose, ascorbic acid, and H(2)O(2) generating the hydroxyl radical. The antiradical activity was expressed as an inhibition of deoxyribose degradation. The biological system consisted of IMR32 neuroblastoma cells exposed to H(2)O(2) in the presence or absence of the vegetable juices. Cells were pretreated for either 24 h or 1 h with the vegetable juices, and reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was used as a cell viability assay. All vegetable juices inhibited the degradation of deoxyribose and increased the viability of H(2)O(2) treated cells. Raw mushroom juice proved to be the most active in both cases. Boiling significantly affected the activity of mushroom juice, but did not change significantly the effect on onions and yellow bell peppers, and partially increased the activity of white cabbage juice. Mushroom antiradical activity was also confirmed by a cytofluorimetric analysis.

Green and roasted coffees of the two most used species, Coffea arabica and Coffea robusta, several commercial coffee samples, and known coffee components were analyzed for their ability to interfere with Streptococcus mutans' sucrose-independent adsorption to saliva-coated hydroxyapatite (HA) beads. All coffee solutions showed high antiadhesive properties. The inhibition of S. mutans' adsorption to HA beads was observed both when coffee was present in the adsorption mixture and when it was used to pretreat the beads, suggesting that coffee active molecules may adsorb to a host surface, preventing the tooth receptor from interacting with any bacterial adhesions. Among the known tested coffee components, trigonelline and nicotinic and chlorogenic acids have been shown to be very active. Dialysis separation of roasted coffee components also showed that a coffee component fraction with 1000 Da < MW < 3500 Da, commonly considered as low MW coffee melanoidins, may sensibly contribute to the roasted coffee's antiadhesive properties. The obtained results showed that all coffee solutions have antiadhesive properties, which are due to both naturally occurring and roasting-induced molecules.

The formulation of quinic acid, a food constituent demonstrating potential anticaries and antigingivitis properties, was investigated in an adhesive microparticulate delivery system with the goal of improving its effect by prolonging its residence time at the site of action. Alginate and chitosan were selected as mucoadhesive polymers. The microspheres were prepared by coacervation. Different types of alginates, polymers blends and crosslinking agent concentrations were considered and evaluated. The best results in terms of encapsulation efficiency, in vitro active agent release profile and in vitro adhesive properties, both to oral mucosa and to teeth surface, were obtained with a blend of Alginate Protanal LF200S: Alginate Protanal LF120LS 1:1.5 w/w, 0.1 M CaCl2, and chitosan coating, prepared by a one-step complex coacervation method. This microparticulate delivery system showed prolonged release of quinic acid, and could be used as an active component in chewing gums or mouthwashes for both caries and gingivitis prevention. © 2012 Elsevier Ltd. All rights reserved

Chicory is a widely consumed vegetable and a source of phenolic compounds. Phenolic acid and flavonoid derivatives were identified in Cichorium endivia var. crispum and var. latifolium and fully characterized using complementary information from two different high-performance liquid chromatography detectors, diode array and mass spectrometer, in positive and negative modes. We describe about 40 phenolic compounds, some of which have never previously been reported in these plants, such as hydroxycinnamic acid derivatives (i.e., different mono- and dicaffeoylquinic acid isomers) and mono- and diglycosides of quercetin, kaempferol, and myricetin (differing also by the glycosylation site). These data provide a contribution to a more exhaustive identification of phenolic compounds in C. endivia vegetables.

Phenolic acids and flavonoids extracted from several types of Cichorium intybus var. silvestre salads ("Chioggia", "Treviso", "Treviso tardivo", and "Verona") were characterised by high-performance liquid chromatography-electrospray ionisation/mass spectrometry. Among the 64 compounds detected, several hydroxycinnamic acid derivatives including 8 mono- and dicaffeoylquinic acids, 3 tartaric acid derivatives, 31 flavonol and 2 flavone glycosides, as well as 10 anthocyanins were characterised based on UV spectra and MS(n) fragmentation patterns. Furthermore, several isomers of caffeic acid derivatives were distinguished for the first time by their specific mass spectral data. This is the first study reporting the glycosylation type and position of mono- and diglycosylated flavonoids in red salads.

One of the most extensively studied and best-established properties of coffee is its antioxidant activity. We have shown that coffee brew has the ability to inhibit lipid peroxidation completely in a rat liver microsome biological system. The inhibitory activity was mainly due to the high molecular weight (HMW) fraction; this consisted of five components that were isolated, purified, and seen to occur in different amounts in the brew. Each component had different spectra and element compositions, although they all contained nitrogen. HMW, nitrogen content, and brown color enabled three components to be attributed to the melanoidin family; the two nonbrown components could not be considered as melanoidins. Each melanoidin and nonmelanoidin component contributes to a different extent to the protective action exerted by coffee brew. None of the isolated components completely inhibited microsomal lipid peroxidation alone, suggesting that each acts at different sites and/or possesses different mechanisms of action. The protective activity of coffee brew is thus underpinned by the antiradical properties, reducing power, and metal chelating ability of the individual components, each contributing to a different extent.

Polyphenols are biologically active compounds found in plants and present in plant-derived foods that are intrinsic components of human diets. Among these, hydorxycinnamic acids are widely distributed in the plant kingdom (seeds, fruits, tubers, and the herbaceous parts of many vegetable species), but the levels and chemical forms vary markedly depending on the plant source. Hydroxycinnamic acids occur naturally in combination with other compounds, usually in the form of esters. These compounds can act as antioxidants because they act as free radical scavengers, singlet oxygen quencers, or metal chelators (1). These actions make plant foods of particular importance in our diet because it has been demonstrated that their consumption protects living organisms from oxidative damage, resulting in the prevention of chronic pathologies (2). So to know hydroxycinnamic acid derivatives edible vegetable composition results of great interest. In this work we analyzed the methanolic extract of two endive varieties, i.e. Cichorium endivia var. crispum and Cichorium endivia var. latifolium largely consumed in Italian diet. The investigation was carried out using HPLC/DAD/MS. The obtained results indicated that 5-caffeoylquinic acid, 5-feruloylquinc acid, and 3,4-dicaffeoylquinic acid are present in both the vegetables, while 3,5-dicaffeoylquinc acid is present only in Cichorium endivia var. crispum, and 3-caffoylquinc acid and cis-caftaric acid only in Cichorium endivia var. latifolium.

Glyoxal, methylglyoxal, and diacetyl formed as Maillard reaction products in heat-treated food were determined in coffee extracts (coffee brews) obtained from green beans and beans with different degrees of roast. The compounds have been reported to be mutagenic in vitro and genotoxic in experimental animals in a number of papers. More recently, alpha-dicarbonyl compounds have been implicated in the glycation process. Our data show that small amounts of glyoxal and methylglyoxal occur naturally in green coffee beans. Their concentrations increase in the early phases of the roasting process and then decline. Conversely, diacetyl is not found in green beans and forms later in the roasting process. Therefore, light and medium roasted coffees had the highest glyoxal and methylglyoxal content, whereas dark roasted coffee contained smaller amounts of glyoxal, methylglyoxal, and diacetyl. For the determination of coffee alpha-dicarbonyl compounds, a reversed-phase high performance liquid chromatography with a diode array detector (RP-HPLC-DAD) method was devised that involved the elimination of interfering compounds, such as chlorogenic acids, by solid phase extraction (SPE) and their derivatization with 1,2-diaminobenzene to give quinoxaline derivatives. Checks of SPE and derivatization conditions to verify recovery and yield, respectively, resulted in rates of 100%. The results of the validation procedure showed that the proposed method is selective, precise, accurate, and sensitive.

The antiradical properties of water-soluble components of both natural and roasted barley were determined in vitro, by means of DPPH* assay and the linoleic acid-beta-carotene system, and ex vivo, in rat liver hepatocyte microsomes against lipid peroxidation induced by CCl4. The results show the occurrence in natural barley of weak antioxidant components. These are able to react against low reactive peroxyl radicals, but offer little protection against stable DPPH radicals deriving from peroxidation in microsomal lipids. Conversely, roasted barley yielded strong antioxidant components that are able to efficiently scavenge free radicals in any system used. The results show that the barley grain roasting process induces the formation of soluble Maillard reaction products with powerful antiradical activity. From roasted barley solution (barley coffee) was isolated a brown high molecular mass melanoidinic component, resistant to acidic hydrolysis, that is responsible for most of the barley coffee antioxidant activity in the biosystem.

A water-soluble lipoxygenase enzyme (EC 1.13.11.12; LOX) occurring in the red cultivar produced in the geographical area of Chioggia (Italy) of Cichorium intybus var. silvestre was isolated and characterized. The molecular mass of the enzyme was estimated to be 74,000 Da by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration chromatography. The isoelectric point was pH 6.85. The optimum values of pH, ionic strength, and temperature, shown by isoresponse surface calculated by a randomized multilevel factorial design, were 7.58, 30 mM, and 38.5 degrees C, respectively. The enzyme showed high specificity toward linoleic acid, and the study of the variation of linoleic acid concentration between 30 and 300 microM, in the presence of Tween 20 at a concentration lower than the critical micelle concentration (0.01 v/v), resulted in a typical Michaelis-Mentem curve with KM and Vmax values of 1.49 x 10(-4) M and 2.049 microM min(-1) mg(-1), respectively. The biochemical properties, the kinetic parameters found, and the carotene-bleaching activity shown in aerobic conditions seem to indicate that the isolated enzyme is a lipoxygenase type III according to the indications given for soybean isoenzymes.

The specific antiradical activity against the hydroxyl radical of the water soluble components in green and dark roasted Coffea arabica and Coffea robusta coffee samples, both in vitro by the chemical deoxiribose assay and ex vivo in a biological cellular system (IMR32 cells), were determined. All the tested coffee solutions showed remarkable antiradical activity. In the deoxiribose assay, all the tested solutions showed similar inhibitory activity (IA%) against the sugar degradation (IA values ranged from 45.2 to 46.9%). In the cell cultures, the survival increase (SI%) ranged from 197.0 to 394.0% with C. robusta roasted coffee being significantly more active than the other samples. The coffee solutions underwent dialysis (3500 Da cutoff membrane) to fraction their components. In both systems, the dialysates (MW < 3500 Da) either from green or roasted coffee, showed antiradical activity, while the only retentates (MW > 3500 Da) from the roasted coffee samples were active. The preparative gel-filtration chromatography of roasted coffee C. robusta dialysate gave three fractions active in the biological system, all containing chlorogenic acid derivatives. The most active fraction was found to be that containing the 5-O-caffeoilquinic acid, which shows a linear relation dose-response ranging from 0.02 to 0.10 mM. The results show that both green and roasted coffee possess antiradical activity, that their more active component is 5-O-caffeoyl-quinic acid, and moreover that roasting process induces high MW components (later Maillard reaction products, i.e., melanoidins), also possessing antiradical activity in coffee. These results could explain the neuroprotective effects found for coffee consumption in recent epidemiological studies.

Both the pro- and antiradical water soluble activity, toward DPPH(*), ROO(*), OH(*) radicals found in seven diet vegetables belonging to the Cichorium genus, and the effects of boiling, freezing, and freeze-drying on such activities were investigated. The vegetables were three red cultivars of Cichorium intybus var. silvestre from three different areas of production, that is, chicory from Chioggia, Treviso, and Verona, C. intybus var. foliosum (Belgian chicory), C. endivia var. latifolium (escarole), C. endiviavar. crispum ("crispa"), and a hybrid vegetable obtained by the cross between C. intybus var. silvestre and C. endivia var. latifolium (chicory from Castelfranco). The juices obtained by simple centrifugation of vegetables operating at 2 or 25 degrees C and submitted to the thermal technological treatments were assessed for antiradical activity using the DPPH(*) assay, the linoleic acid-beta-carotene system, and the deoxyribose assay. In all three assays used, each vegetable juice was shown to possess antiradical activity; there was a significant level in the C. endivia and the Belgian chicories and higher levels in the red C. intybus vegetables and the hybrid vegetable. All juice behaviors in the linoleic acid-beta-carotene system indicate that they also contain a thermally unstable component, which in a cold medium promptly promoted and accelerated linoleic acid peroxidation, therefore masking the presence of any thermally stable antiperoxyl radical components. The presence of these components, which efficiently protect linoleic acid from peroxidation, can be singled out only after inactivation by heating, or separation by dialysis, of the pro-oxidant components. Dialysis fractions showed that the pro-oxidant component has MW > 50000 Da and that the juices contain a number of antioxidant components which contribute to their antiradical activity.

The antioxidant properties of green and roasted coffee, in relation to species (Coffea arabica and Coffea robusta) and degree of roasting (light, medium, dark), were investigated. These properties were evaluated by determining the reducing substances (RS) of coffee and its antioxidant activity (AA) in vitro (model system beta-carotene-linoleic acid) and ex vivo as protective activity (PA) against rat liver cell microsome lipid peroxidation measured as TBA-reacting substances. RS of C. robustasamples were found to be significantly higher when compared to those of C. arabica samples (p < 0.001). AA for green coffee samples were slightly higher than for the corresponding roasted samples while PA was significantly lower in green coffee compared to that of all roasted samples (p < 0.001). Extraction with three different organic solvents (ethyl acetate, ethyl ether, and dichloromethane) showed that the most protective compounds are extracted from acidified dark roasted coffee solutions with ethyl acetate. The analysis of acidic extract by gel filtration chromatography (GFC) gave five fractions. Higher molecular mass fractions were found to possess antioxidant activity while the lower molecular mass fractions showed protective activity. The small amounts of these acidic, low molecular mass protective fractions isolated indicate that they contain very strong protective agents.

The water soluble antioxidant properties of Cichorium intybus var. Silvestre, whose production zone is around Chioggia, Italy, were investigated. Vegetable juices were obtained by centrifugation, and (1) filtration at 2 degrees C; (2) filtration at 25 degrees C, and stored for 3 h; (3) boiled for 30 min at 102 degrees C, and then analysed. The antioxidant properties were evaluated in vitro as antioxidant activity (AA) (model system beta-carotene-linoleic acid) and ex vivo as protective activity (PA) against rat liver cell microsome lipid peroxidation measured as 2-thiobarbituric acid-reactive substances (TBA-RS) generated by peroxide degradation. All the vegetable juices showed high but very variable AA (83%) and PA (64%). After dialysis and analysis of fractions it was shown that the vegetable contained both biological antioxidant and prooxidant compounds. The prooxidants had MW3000, conversely the very active antioxidants (PA = 100%) had MW15,000. Electrophoretic analysis revealed that the most active fraction was a complex mixture of brown components at MW300,000.

A coffee beverage obtained from instant dark coffee that had been previously shown to possess high antibacterial activity, was acidified (pH 2) and extracted with ethyl acetate. After alkalinization (pH 12) the aqueous phase was re-extracted with the organic solvent. The acidic and basic extracts were evaporated to dryness and the aqueous phase freeze-dried. Residues were dissolved in sterile water and assayed for antibacterial activity against two reference bacteria (Staphylococcus aureus ATCC 25923 and Streptococcus mutans 9102). The acidic extract was found to be highly active and was separated by gel permeation chromatography (GPC) into five fractions. Fractions GPC4 and GPC5 were found to possess antibacterial activity: most of the activity was evident in fraction GPC5. These fractions were separated by RP-HPLC using a gradient elution with methanol–water as mobile phase. Both GPC fractions gave an active subfraction with methanol–water (70:30, v/v). The experimental conditions used to separate the antibacterial compound that originates during the roasting process, indicate that it possesses low molecular mass (probably no more than 200 Da), weak acidic properties and an λmax at 205 nm. The very small amount of this compound isolated from roasted coffee, indicates that it may be a very strong antibacterial agent.

The water soluble antioxidant properties of carrot, cauliflower, celery, eggplant, mushroom, garlic, onion, white cabbage, white potato, tomato, yellow bell pepper, and zucchini were investigated. Vegetable juices were obtained by centrifugation, and each antioxidant property was determined in terms of the protective activity (PA%) against rat liver microsome lipid peroxidation induced by CCl4 and measured by malondialdehyde release. All juices were found to be active. PA was very high (90−100%) and constant (relative standard deviation (RSD) = 4−7) for mushroom, garlic, cauliflower, and potato. For white cabbage, zucchini, and eggplant the PA reached similar values (80%) but was less constant (RSD = 12−15). Onion and yellow bell pepper showed high PA (75%) which was more variable (RSD = 20−24), and the PA for tomato and celery was less high (50%) and very variable (RSD = 25), especially in the case of carrot juice (6%) (RSD = 50). The juices were also analyzed after different technological treatments (bo...

The effect of water activity (aw 0.98, 0.84 and 0.60) and reaction temperature (100, 120, 140 and 160 degrees C) on the mutagenic activity of the Maillard reaction products in heated ribose-lysine and glucose-lysine model systems, was investigated. In the ribose-lysine system, heated at 100 degrees C, the mutagenic activity of the mixture increased as the water activity was lowered. On the contrary, no dependence between mutagenic activity and water activity was observed in the glucose-lysine system. At higher temperatures, in both systems, the presence in the browned mixtures of an antibacterial activity interfering with the bacterial mutagenicity assay was observed. Under all the conditions tested, the ribose-lysine system turned out to be the most reactive by producing higher levels of mutagens. Furthermore, in this system, the antimicrobial interference was more easily detectable. In the model systems used, the browning reaction mixtures were analysed for their absorption spectrum between 200-460 nm, and for the accumulation of furfurals. The results obtained showed that, at temperatures between 120 and 140 degrees C there is a correlation among reaction temperature, absorbance at 420 and around 280 nm, mutagenic activity of the mixture and the level of furfurals. Changes in the levels of furfurals can be related to changes in mutagenicity of the browned mixtures.

Mutagenic activity of Maillard browning products from ribose-lysine and glucose-lysine mixtures, heated at l00°C, was evaluated with the Salmonella assay. For both mixtures optimal conditions for producing mutagenic derivatives were observed at equimolar concentrations of reactants. Ribose-lysine browning products showed a higher mutagenic activity than the glucose-lysine mixture and were more active in inducing gene conversion and mitotic crossing-over in Sacccharo-rnyces cerevisae. The higher mutagenic activity of the browning products of ribose was also demonstrated with several amino acids: alanine, aspargine, aspartic acid, cysteine, cystine, leucine, methionine, phen-ylalanine, proline, hydroxyproline, serine, valine. A DNA-damaging activity of the browning mixtures of ribose with histidine, proline, hydroxyproline, valine, was also detected in the Bacillus subtilis rec-assay.

The stability with time of browned mixtures characterized by different water activities (aw 0.98, 0.84 and 0.60) and heating temperatures (100, 120, 140 and 160 degrees C) was analysed using the ribose-lysine model system. The results obtained demonstrated the occurrence, during storage, of changes both in the composition of the browned mixtures and in their mutagenic properties, as detected with the Ames test. Only the browned mixtures obtained at 100 degrees C showed a progressive increase in mutagenicity during storage, matched by an increase in ultraviolet and visible light absorbance and of furfural content. In the browning mixtures characterized by a more advanced stage of the Maillard reaction, in which mutagenic activity had initially been found to be undetectable, such activity became evident during storage.