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Copper in grape musts can influence the fermentation efficiency of Saccharomyces cerevisiae during winemaking. The present study revealed the impact of glutathione addition on yeast strains with va...

The aim of this work was to obtain phase II metabolites of cyanidin-3-O-glucoside and its aglycone using porcine liver enzymes. For this purpose, anthocyanins extracted from blackberry concentrate and containing mostly cyanidin-3-O-glucoside were incubated with the S9, microsomal, and cytosolic fractions of porcine liver. The reactions were targeted to the direction of the respective phase II transformation by the addition of activated cofactors. LC-MSn and LC-IMS-QTOF-MS analyses showed that one methylated, three glucuronidated and three sulfated metabolites of cyanidin-3-O-glucoside were generated. The aglycone, cyanidin, was sulfated and glucuronidated by the liver enzymes. In addition, both were glucuronidated and methylated simultaneously. The detected compounds and the generated data like exact masses, mass spectra, and CCS values may serve as a basis in the search for metabolites formed in vivo. As their effects are largely unexplored, the described synthesis may contribute to a better understandin...

Oxidation of plant phenolics leads to quinones, which are unstable intermediates that may react with nucleophiles. Quinones play an important role in the enzymatic browning of fruits and vegetables and may form covalent adducts with amino acids, peptides, and proteins. These reactions may alter both the physicochemical and immunological properties of food proteins. Quinones trap odoriferous compounds and contribute to the formation of aroma compounds through Strecker degradation of amino acids. Oxidative dimerization of chlorogenic acids in the presence of amino acids leads to the formation of green benzacridines, which are a promising alternative to chlorophylls as food colorants.

The objectives of this work were to determine the phenolic profile of Schinus terebinthifolius and Schinus molle fruits and to develop a reliable method for the differentiation of these two similar spices both known as pink pepper. Anthocyanins, biflavonoids and gallotannins, some of which are reported for the first time in these species, were identified by UHPLC-UV/vis-MS/MS. Consideration of the relative and absolute amounts of phenolics as well as indicator compounds from 18 samples revealed that the relative amounts of anthocyanins and biflavonoids are the most trustworthy parameters. Principal component analysis and cluster analysis (CA) allowed a grouping of the samples according to their species, showing that the anthocyanins are most important for the identification of species. As a result, authentication of the two Schinus species can be accomplished by UHPLC analysis of the relative amounts of anthocyanins combined with CA.

The occasional greening of sweet potatoes and other plant tissues observed during cooking or other food processing has been shown to arise from the autoxidative coupling of chlorogenic,acid (CGA, 5-caffeoylquinic acid) with amino acid components, leading to trihydroxybenzacridine pigments. To explore the potential of this reaction for food coloring, we report herein the optimized biomimetic preparation of trihydroxybenzacridine pigments from CGA and amino acids such as glycine and lysine, their straightforward purification by gel filtration chromatography, the UHPLC-MS/MS analysis of the purified pigment fraction, and a detailed characterization of the pH-dependent trihydroxybenzacridine chromophore. Similar, green pigments were also obtained by analogous reaction of CGA with a low-cost protein, bovine serum albumin, and by simply adding CGA to chicken egg white.(CEW) under stirring. Neither the purified pigments' from amino acids nor the pigmented CEW exerted significant toxicity against two human cell lines, Caco-2 and HepG2, at doses compatible with common use in food coloring. Additions of the pure pigments or pigmented CEW to different food matrices imparted intense green hues, and the thermal stability of these preparations proved satisfactory up to 90 degrees C. The potential application of the greening reaction for the sensing of fish deterioration is also disclosed.

Pigments of pericarp and pulp of pink guava (Psidium guajava L. cv. ‘Criolla’) were investigated to elucidate the profile and the accumulation of main carotenoids during four stages of fruit ripening by using HPLC-DAD and APCI-MS/MS analysis. Seventeen carotenoids were identified, and changes in their profile during fruit ripening were observed. The carotenoids all-trans-β-carotene, 15-cis-lycopene, and all-trans-lycopene were present in all ripening stages, but all-trans-lycopene was found to be predominant (from 63% to 92% of total carotenoids) and responsible for the high lipophilic antioxidant capacity determined by spectrophotometric assays. By using light and transmission electron microscopy, the development of chromoplasts in pericarp and pulp was demonstrated. The accumulation of all-trans-lycopene and all-trans-β-carotene coincided with the development of large crystals; the chromoplasts of pink guava belong, therefore, to the crystalline type. Universidad de Costa Rica/[]/UCR/Costa Rica German Academy Exchange Service/[]/DAAD/Alemania UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro Nacional de Ciencia y Tecnología de Alimentos (CITA) UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Tecnología de Alimentos

Anthocyanins determine the color and potential health-promoting properties of red fruit juices, but the juices contain remarkably less anthocyanins than the fruits, which is partly caused by the interactions of anthocyanins with the residues of cell wall polysaccharides like pectin. In this study, pectin was modified by ultrasound and enzyme treatments to residues of polysaccharides and oligosaccharides widely differing in their molecular weight. Modifications decreased viscosity and degrees of acetylation and methylation and released smooth and hairy region fragments. Native and modified pectin induced different effects on the concentrations of individual anthocyanins after short-term and long-term incubation caused by both hydrophobic and hydrophilic interactions. Results indicate that both pectin and anthocyanin structure influence these interactions. Linear polymers generated by ultrasound formed insoluble anthocyanin complexes, whereas oligosaccharides produced by enzymes formed soluble complexes with protective properties. The structure of the anthocyanin aglycone apparently influenced interactions more than the sugar moiety.

A new sample processing method for analyzing flavonol metabolites in plasma using enzymatic proteolysis was developed and validated. Four endopeptidases were examined regarding their influence on the analyte recovery of quercetin-3- O-glucuronide (Q3GlcA). Methanol was added to inactivate and precipitate the enzymes, and samples were concentrated via evaporation prior to UHPLC-MS analysis. Quercetin-3- O-rutinoside (Q3Rut) was used as an internal standard. The selectivity and accuracy of the established UHPLC-ESI-MS

Anthocyanins are frequently discussed as marker compounds for fruit product authenticity. Proper analysis including sample preparation for the determination of anthocyanin concentrations is crucial for the comparability of authenticity data. The present study determined the influence of accelerated solvent extraction (ASE) and ultrasound-assisted extraction (UAE), using two different solvent compositions on the anthocyanin profile of bilberries (Vaccinium myrtillus L.), lowbush blueberries (Vaccinium angustifolium Ait.), and American cranberries (Vaccinium macrocarpon Ait.). Besides differences in total anthocyanin concentrations in the extracts, significant deviations (p ≤ 0.05) in the individual anthocyanin concentration were observed, resulting in differing anthocyanin proportions. Linear discriminant analysis comparing the differences caused by the extraction method to the natural differences within a set of 26 bilberry and lowbush blueberry samples of different origins was conducted. It revealed that profile variations induced by the extraction methods are in a similar scale to profile variations as a result of geographic and climatic differences.

Among dietary carotenoids, lutein and zeaxanthin are known to protect against age-related macular degeneration, a leading cause of irreversible vision loss in the elderly. Egg yolk is rich in lutein and zeaxanthin, however, the effect of cooking and gastrointestinal digestion on yolk carotenoids is poorly understood. An in vitro dynamic gastrointestinal model (TIM-1) was used to investigate the digestive stability and bioaccessibility of carotenoids from boiled, fried, and scrambled eggs. Bioaccessibility but not digestive stability was significantly affected by the method of cooking. The main egg carotenoids, all-E-lutein and all-E-zeaxanthin, were stable during the digestion with average recoveries of 90 and 88%, respectively. No trans-cis isomerization of carotenoids was observed during digestion. Both all-E-lutein and all-E-zeaxanthin from scrambled eggs showed significantly lower bioaccessibility compared to boiled eggs. The results indicate that the bioaccessibility of egg carotenoids can be affected by different food preparation methods.

Processing of Botrytis cinerea-infected grapes leads to enhanced enzymatic browning reactions mainly caused by the enzyme laccase which is able to oxidize a wide range of phenolic compounds. The extent of color deterioration depends on the activity of the enzymes secreted by the fungus. The present study revealed significant differences in the oxidative properties of secretomes of several B. cinerea strains isolated from five grape varieties. The presumed laccase-containing secretomes varied in their catalytic activity toward six phenolic compounds present in grapes. All strains led to identical product profiles for five of six substrates, but two strains showed deviating product profiles during gallic acid oxidation. Fast oxidation of caffeic acid, ferulic acid, and malvidin 3-O-glucoside was observed. Product formation rates and relative product concentrations were determined. The results reflect the wide range of enzyme activity and the corresponding different impact on color deterioration by B. cinerea.

The objective of this study was to characterize the phenolic composition of Brazilian pepper (Schinus terebinthifolius Raddi) exocarp extract. Using UHPLC-DAD-MS/MS analysis, four anthocyanins, three biflavonoids, gallic acid, and two types of hydrolyzable tannins (galloyl glucoses, galloyl shikimic acids) were tentatively identified. The structure of the so far unknown 7-O-methylpelargonidin 3-O-β-D-galactopyranoside was elucidated by 2D NMR. Within the group of gallotannins, galloyl shikimic acids with uncommon degrees of galloylation (tetra- to hexagalloyl shikimic acids) were detected. Among the biflavonoids, I3',II8-biapigenin (amentoflavone), I6,II8-biapigenin (agathisflavone), and II-2,3-dihydro-I3',II8-biapigenin were identified, which have already been described for Anacardiaceae. From the results of the present study together with previous findings on the phenolic profile of other Anacardiaceae plants, it is concluded that 7-methoxylated flavonoids are a chemotaxonomic trait frequently found in this family.

Xanthophylls are a class of bioactive compounds known to play an important role in preventing age-related macular degeneration. Egg yolk is a rich source of highly bioavailable xanthophylls including lutein and zeaxanthin. The effects of domestic cooking methods (boiling, frying, microwaving) on egg yolk xanthophyll content were investigated. A LC-(APCI)-MS/MS method was used to identify and quantify all-E- and Z-isomers of lutein, zeaxanthin, canthaxanthin, and β-apo-8'-carotenoic acid ethyl ester in fresh and cooked egg yolks. Both fresh and cooked yolks showed similar xanthophyll profiles but with higher contents of Z-isomers in cooked samples. All-E-lutein was the most affected, with 22.5%, 16.7%, and 19.3% reductions in boiled, microwaved, and fried yolk extracts, respectively. Total xanthophyll losses ranged from 6% to 18%. The results presented here could be useful in calculating the dietary intake of xanthophylls and also in assessing the xanthophyll profiles and contents of egg-containing products.

This study quantified antiotensin I-converting enzyme (ACE) inhibitory peptides in rye malt sourdoughs supplemented with gluten proteins and fermented with six strains of Lactobacillus spp. Bioinformatic analysis of prolamins from barley, rye, and wheat demonstrated that the ACE inhibitory peptides LQP, LLP, VPP, and IPP are frequently encrypted in their primary sequence. These tripeptides were quantified by liquid chromatography-tandem mass spectrometry. Tripeptide levels in sourdoughs were generally higher as compared to the chemically acidified controls. Sourdoughs fermented with different strains showed different concentrations of LQP and LLP. These differences corresponded to strain-specific differences in PepO and PepN activities. The highest levels of peptides VPP, IPP, LQP, and LLP, 0.23, 0.71, 1.09, and 0.09 mmol (kg DM)(-1), respectively, were observed in rye malt: gluten sourdoughs fermented with Lactobacillus reuteri TMW 1.106 and added protease. These concentrations were 6-7 times higher as compared to sourdough without fungal protease and exceed the IC(50) by 100-1000-fold.

Alkylamides are a class of compounds present in plants of the genus Echinacea (Asteraceae), which have been shown to have high bioavailability and immunomodulatory effects. Fast analysis to identify these components in a variety of products is essential to profile products used in clinical trials and for quality control of these products. A method based on ultrafast liquid chromatography (UFLC) coupled with diode array detection and electrospray ionization mass spectrometry was developed for the analysis of alkylamides from the roots of Echinacea angustifolia (DC.) Hell., Echinacea purpurea (L.) Moench, and commercial dietary supplements. A total of 24 alkylamides were identified by LC-MS. The analysis time for these components is 15 min. Compared to the alkylamide profiles determined in the Echinacea root materials, the commercial products showed a more complex profile due to the blending of root and aerial parts of E. purpurea. This versatile method allows for the identification of alkylamides in a variety of Echinacea products and presents the most extensive characterization of alkylamides in E. angustifolia roots so far.

High-speed countercurrent chromatography (HSCCC) was used for the separation of alkylamides from the roots of Echinacea angustifolia (DC.) Hell. For this purpose, the alkylamides were extracted with hexane and subjected to semipreparative HSCCC using a two-phase solvent system consisting of n-hexane, ethyl acetate, methanol, and water (4:1:2:1). The lower aqueous phase was used as the mobile phase at a flow rate of 3 mL/min and a rotary speed of 1000 rpm. This procedure led to the isolation of four pure alkylamides, that is, dodeca-2E,4E,8Z,10E/Z-tetraenoic acid isobutylamide (38.9 mg, 97% purity), dodeca-2E,4E,8Z-trienoic acid isobutylamide (4.4 mg, 92% purity), dodeca-2E,4E-dienoic acid isobutylamide (3.2 mg, 99% purity), and dodeca-2E,4E-dienoic acid 2-methylbutylamide (0.3 mg, 92% purity). The identity and purity of the isolated alkylamides were confirmed by LC-ESI-MS and (1)H NMR and (13)C NMR data. To the best of the authors' knowledge, this is the first report of dodeca-2E,4E-dienoic acid 2-methylbutylamide in E. angustifolia roots.

Gallotannins were extracted from mango ( Mangifera indica L.) kernels with aqueous acetone (80%, v/v) and purified using liquid-liquid extraction and two-step low-pressure liquid chromatography (LPLC) on Sephadex LH-20. Analytical high-performance liquid chromatography and mass spectrometry confirmed the presence of hydrolyzable tannins with a degree of galloylation ranging from 4 to 9 and additionally revealed the presence of deca-, undeca-, and dodeca-O-galloylglucose. Further purification using two-step semipreparative HPLC resulted in three pure hydrolyzable tannins, penta-, hexa-, and hepta-O-galloylglucose, with antibacterial activity, as evidenced from the agar spot and critical dilution assays. Although the growth of lactic acid bacteria was not inhibited, the proliferation of Gram-positive food spoilage bacteria was prevented and the growth of Gram-negative Escherichia coli was reduced. Because bacterial growth could be restored by the addition of iron to the medium, this study strongly supports the view that the inhibitory effects of hydrolyzable tannins are due to their iron-complexing properties.

The seeds of 17 cultivars of Saskatoon berries ( Amelanchier alnifolia Nutt.) were evaluated for their seed mass, oil content, fatty acid and triacylglycerol (TAG) composition, tocopherol profile, and sterol content. The oil content of the seeds ranged from 9.4% (cv. 'Pasture') to 18.7% (cv. 'Thiessen'). The seed oils contained mainly linoleic acid in the range from 47.3% (cv. 'Success') to 60.1% (cv. 'Lee 3') and oleic acid in the range from 26.3% (cv. 'Lee 3') to 38.1% (cv. 'Success'). The total tocopherol content ranged from 1053 to 1754 mg/kg of oil. alpha-Tocopherol was the major vitamin E compound in all berry seed oils investigated, accounting for 87% of total tocopherols. The predominant sterols were beta-sitosterol, Delta(5)-avenasterol, and campesterol. The sterols content in seed oil ranged from 7357 mg/kg of oil (cv. 'Success') to 15771 mg/kg of oil (cv. 'Lee 3'). Thirteen triacylglycerols (TAG) were identified in seed oils, among which LLL, LLO, LOO, LLP, LOP (L, linoleoyl; O, oleoyl; P, palmitoyl) represented 88% of the total TAG. TAG composition suggests good oxidative stability of the Saskatoon berry seed oil, which could be suitable for food and industrial applications. Moreover, Saskatoon berry seed oil may serve as potential dietary source of tocopherols, sterols, and unsaturated fatty acids.

Despite a number of serious case reports of mango dermatitis, no attempts at the identification and quantification of allergenic 5-alk(en)ylresorcinols in mango fruits have so far been made. Therefore, total alk(en)ylresorcinol content and relative homologue composition in 13 mango peel samples and 7 samples of mango pulp were determined by HPLC and LC-MS/MS analyses. Furthermore, mango puree and nectar prepared on pilot plant scale were also analyzed and compared with commercially available thermally preserved products. Depending on cultivar, alk(en)ylresorcinol contents ranged from 79.3 to 1850.5 mg/kg of dry matter (DM) in mango peels and from 4.9 to 187.3 mg/kg of DM in samples of mango pulp. The profile of alk(en)ylresorcinols was found to be highly characteristic, with an average homologue composition of C15:0 (6.1%), C15:1 (1.7%), C17:0 (1.1%), C17:1 (52.5%), C17:2 (33.4%), C17:3 (2.4%), C19:1 (2.1%), and C19:2 (0.8%). Mango puree samples prepared from peeled and unpeeled fruits revealed contents of 3.8 and 12.3 mg/kg of fresh weight, respectively. Content and homologue composition were not significantly affected during puree processing and thermal preservation. In nectar samples prepared from peeled and unpeeled fruits, contents of 1.4 and 4.6 mg/L, respectively, were found.

Dietary supplements are among the most rapidly growing products in the food and personal care market with an estimated worldwide volume exceeding $60 billion. The main problem associated with dietary supplements is their legal classification. Being neither food nor medicine, they often inhabit a gray area between the two, which makes legal regulatory extremely difficult. Thus, a coexistence of products processed from the same botanical source on the same market as dietary supplement or pharmaceutical is possible. In the present study, various artichoke-based dietary supplements were investigated for their phenolic profile and compared to artichoke phytopharmaceuticals. Quantification of individual hydroxycinnamic acids and flavonoids was carried out by external calibration. For the first time, determination of several apigenin derivatives was included. Chlorogenic acid represented the major constituent in all samples investigated with the exception of juice derived from fresh flower heads, which exhibited a higher cynarin content. Furthermore, a distinction between products made from artichoke leaves or flower heads was possible. The results obtained revealed great diversity of pharmaceuticals and dietary supplements, highlighting the need of standardized quality requirements.

Because the impact of agronomical factors on bakery products quality is still an insufficiently studied field, acrylamide contents of breads produced from flours of nine wheat, two rye, and two spelt varieties harvested in 2003 and 2004 were investigated. It could be demonstrated that acrylamide content in bread strongly depends on the cultivar, with extremes differing by a factor of 5.4 due to marked differences in free asparagine and crude protein contents. Nitrogen fertilization also resulted in elevated amino acid and protein contents, thus increasing acrylamide levels from 10.6 to 55.6 mug/kg. Independent of fertilization, harvest year turned out to be another factor influencing acrylamide formation. Breads produced from 2003 flours showed significantly higher acrylamide contents than those of 2004, which was ascribed to favorable light and temperature conditions during the cultivation period, thus enhancing amino acid and protein contents. Sprouting of the grain also resulted in significantly higher acrylamide levels, which was attributed to elevated enzyme activities and the formation of precursors from protein and starch. Furthermore, bakery products made from flours with higher extraction rates were shown to contain higher acrylamide levels resulting from extracted free asparagine and protein from the aleuron layers of the cereal grain.

With respect to their browning potential and in consideration of a combined recovery of pectin and phenolic compounds, peels of 14 cultivars and the flesh of nine cultivars of mango (Mangifera indica L.) fruits were analyzed for their contents of flavonol O- and xanthone C-glycosides by high-performance liquid chromatography (HPLC)-diode array detection-electrospray ionization mass spectrometry (ESI-MS). While total amounts of up to 4860 mg/kg dry matter demonstrated the peels to be a rich source of phenolic compounds, only traces could be detected in the flesh. The profile of flavonol glycosides of the peels proved to be highly characteristic and may therefore serve as a tool for authenticity control of mango puree concentrate, which is often produced from unpeeled fruits and represents an important intermediate for the production of mango nectars. Two compounds were isolated by preparative HPLC, and their structures were elucidated on the basis of ESI-MS as well as NMR spectroscopy, establishing the two compounds as rhamnetin 3-O-beta-galactopyranoside and rhamnetin 3-O-beta-glucopyranoside, respectively. In the peels of red-colored cultivars, cyanidin 3-O-galactoside and an anthocyanidin hexoside so far not reported in mango could tentatively be identified. The contents and degrees of esterification of pectins extracted from the lyophilized peels ranged from 12.2 to 21.2% and from 56.3 to 65.6%, respectively, suggesting mango peels also as a promising source of high-quality pectin.

The effects of enzymatic mash treatments on yield, turbidity, color, and polyphenolic content of cloudy apple juice were studied. Using HPLC-ESI-MS, cryptochlorogenic acid was identified in cv. Brettacher cloudy apple juice for the first time. Commercial pectolytic enzyme preparations with different levels of secondary protease activity were tested under both oxidative and nonoxidative conditions. Without the addition of ascorbic acid, oxidation substantially decreased chlorogenic acid, epicatechin, and procyanidin B2 contents due to enzymatic browning. The content of chlorogenic acid as the major polyphenolic compound was also influenced by the composition of pectolytic enzyme preparations because the presence of secondary protease activity resulted in a rise of chlorogenic acid. The latter effect was probably due to the inhibited protein-polyphenol interactions, which prevented binding of polyphenolic compounds to the matrix, thus increasing their antioxidative potential. The results obtained clearly demonstrate the advantage of the nonoxidative mash maceration for the production of cloud-stable apple juice with a high polyphenolic content, particularly in a premature processing campaign.

A method for the determination of beta-carotene, lutein, and zeaxanthin including their cis-isomers and alpha-carotene in commercial dietary supplements by HPLC has been developed. The study comprises 11 oral dosage forms, including 9 soft gelatin capsules, 1 dragée, and 1 effervescent tablet formulation. The capsule content was extracted with an acetone-hexane mixture, and the gelatin shell was digested with papain to release carotenoids that had migrated into the coat. Sample preparation for tablets and dragées was carried out as described for the capsule content. Extraction recoveries exemplified for all-trans-beta-carotene and all-trans-lutein were 95 +/- 5% and 93 +/- 2%, and 95 +/- 2% and 79 +/- 5% after enzymatic treatment, respectively. Apart from all-trans-beta-carotene, its 9-cis- and 13-cis-isomers were detected in all samples, whereas no evidence for cis-isomerization of lutein and zeaxanthin could be obtained. Migration of carotenoids into the shells was only observed in the case of beta-carotene. With the exception of one preparation, the beta-carotene contents determined exceeded the dosage specified on the label by up to 48%, which results from stability overages necessary to compensate for losses during storage.

The phenolic profile of strawberry fruits (Fragaria x ananassa Duch., Rosaceae) was investigated by high-performance liquid chromatography with photodiode array detection. A peak displaying retention time and UV spectral data identical to those of phloridzin (phloretin 2'-O-beta-d-glucoside), a dihydrochalcone glucoside so far considered characteristic of apples, was monitored. For further characterization, crude extracts of strawberries were purified on polyamide, and the target compound was isolated by preparative and analytical HPLC. Structure elucidation was performed on the basis of APCI- and ESI-MS in the negative ion mode as well as by 1D and 2D NMR spectroscopy using authentic phloridzin for comparison. The d-configuration of the sugar moiety was established by HPLC analysis of the corresponding acyclic 1-deoxy-1-(N-acetyl-alpha-methylbenzylamino)alditol acetate. Apart from its chemotaxonomic relevance, this first report on the occurrence of phloridzin in strawberries is of particular interest for the authenticity control of strawberry products such as juices, jams, and fruit preparations since phloridzin has so far been used for the detection of fraudulent admixtures.

This study determined the fate of deoxyanthocyanidins in sorghum sourdoughs. Sourdoughs prepared from the red sorghum variety Town were fermented with the caffeic acid-decarboxylating strains Lactobacillus plantarum FUA3171 and the decarboxylase negative L. casei FUA3166. Deoxyanthocyanidins were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Apigeninidin and methoxyapigeninidin were the major deoxyanthocyanidins prior to fermentation. During fermentation, novel deoxyanthocyanidins were formed. Purification by preparative LC, followed by NMR analysis and high-resolution MS identified two of the compounds as 6-deoxyanthocyanidin-vinylphenol and pyrano-3-deoxyanthocyanidin. To identify pathways for their formation, sorghum was fermented with single strains, L. plantarum or L. casei. 6-Deoxyanthocyanidin-vinylphenol and pyrano-3-deoxyanthocyanidin were formed only during fermentation with L. plantarum FUA3171, indicating a role of vinylphenol in their formation. Chemical synthesis confirmed that 6-deoxyanthocyanidin-vinylphenol and pyrano-3-deoxyanthocyanidin are formed from apigeninidin with vinylphenol but not with p-coumaric acid as reactants. In conclusion, the products of microbial decarboxylation of hydroxycinnamic acids convert apigeninidin and methoxyapigeninidin to pyrano-3-deoxyanthocyanidins and vinylphenol adducts.

This study aimed to identify phenolic acids and flavonoids in the red sorghum variety PAN 3860 and to determine changes in their concentrations during fermentation with lactobacilli. Sorghum sourdoughs fermented with two binary strain combinations, Lactobacillus plantarum and Lactobacillus casei or Lactobacillus fermentum and Lactobacillus reuteri , were compared to chemically acidified controls. Four glycerol esters were tentatively identified, caffeoylglycerol, dicaffeoylglycerol, coumaroyl-caffeoylglycerol, and coumaroyl-feruloylglycerol, that have previously not been detected in sorghum. Chemical acidification resulted in hydrolysis of phenolic acid esters and flavonoid glucosides. During lactic fermentation, phenolic acids, phenolic acid esters, and flavonoid glucosides were metabolized. Analysis of ferulic acid, caffeic acid, and naringenin-glucoside contents in single-strain cultures of lactobacilli demonstrated that glucosidase, phenolic acid reductase, and phenolic acid decarboxylase activities contributed to polyphenol metabolism. This study demonstrates that microbial fermentation of sorghum affects the content of polyphenols and can influence the nutritional value and antimicrobial activity of sorghum.

High-speed counter-current chromatography was applied to the separation of gallotannins from mango (Mangifera indica L.) kernels. The kernels were defatted and subsequently extracted with aqueous acetone [80% (v/v)]. The crude extract was purified by being partitioned against ethyl acetate. A hexane/ethyl acetate/methanol/water solvent system [0.5:5:1:5 (v/v/v/v)] was used in the head-to-tail mode to elute tannins according to their degree of galloylation (tetra-O-galloylglucose to deca-O-galloylglucose). The compounds were characterized using liquid chromatography and mass spectrometry in the negative ionization mode. Purities ranged from 72% (tetra-O-galloylglucose) to 100% (octa-O-galloylglucose). The iron binding capacity of gallotannins was dependent on the number of galloyl groups in the molecule, with a larger capacity at lower degrees of galloylation. The minimum inhibitory concentration against Bacillus subtilis did not change among the different gallotannins tested and was in the range of 0.05-0.1 g/L in Luria-Bertani broth but up to 20 times higher in media containing more iron and divalent cations.

The seeds from five black currant (Ribes nigrum L.) cultivars grown in western Canada were evaluated for their oil content, fatty acid and triacylglycerol (TAG) composition, and tocopherol and phytosterol profiles and contents. Moreover, polyphenolic compounds and antioxidant activity in the seed extracts remaining after oil extraction were determined. Oil contents of black currant seeds ranged from 27 to 33%. The gamma-linolenic acid content varied significantly among the cultivars (from 11% for Ben Conan to 17% for Ben Tirran). Among the 44 TAGs identified, LLalphaLn, alphaLnLgammaLn, and PLgammaLn (where L = linoleoyl, alphaLn = alpha-linolenoyl, gammaLn = gamma-linolenoyl, and P = palmitoyl) were the predominant ones. Black currant seed oil was a good source of tocopherols (1143 mg/100 g of oil on average) and phytosterols (6453 mg/100 g of oil on average). Quercetin-3-glucoside and p-coumaric acid were the main phenolic components in the seed residues. The high concentration of flavonols and phenolic acids was correlated with a high antioxidant activity of seed residue (average ABTS value of 1.5 mM/100 g and DPPH value of 1.2 mM/100 g). The data obtained from this study indicate that Canadian black currant seed oil is a good source of essential fatty acids, tocopherols, and phytosterols. Extraction of phenolic antioxidants from the seed residues even allows the recovery of additional valuable components from the byproduct of fruit processing.

As an alternative to thermal pasteurization, pulsed electric fields (PEF) were applied to apple juices on laboratory and pilot plant scale, investigating the effects on juice quality. PEF application still falls under the EU Novel Food Regulation. Consequently, extensive investigation of quality parameters is a prerequisite to prove substantial equivalence of juices resulting from the novel process and conventional production, respectively. Juice composition was not affected by PEF treatment. However, browning of the juices provided evidence of residual enzyme activities. On laboratory scale, complete deactivation of peroxidase (POD) and polyphenoloxidase (PPO) was achieved when PEF treatment and preheating of the juices to 60 degrees C were combined. Under these conditions, a synergistic effect of heat and PEF was observed. On pilot plant scale, maximum PPO deactivation of 48% was achieved when the juices were preheated to 40 degrees C and PEF-treated at 30 kV/cm (100 kJ/kg). Thus, minimally processed juices resulted from PEF processing, when applied without additional conventional thermal preservation. Since this product type was characterized by residual native enzyme activities and nondetectable levels of 5-hydroxymethylfurfural, also when preheating up to 40 degrees C was included, it ranged between fresh and pasteurized juices regarding consumers' expectation of freshness and shelf life. Consistent with comparable iron contents among all juice samples, no electrode corrosion was observed under the PEF conditions applied.

A method for the identification and quantification of phenolic compounds from artichoke (Cynara scolymus L.) heads, juice, and pomace by HPLC with diode array and mass spectrometric detection was developed. Among the 22 major compounds, 11 caffeoylquinic acids and 8 flavonoids were detected. Quantification of individual compounds was carried out by external calibration. Apigenin 7-O-glucuronide was found to be the major flavonoid in all samples investigated. 1,5-Di-O-caffeoylquinic acid represented the major hydroxycinnamic acid, with 3890 mg/kg in artichoke heads and 3269 mg/kg in the pomace, whereas in the juice 1,3-di-O-caffeoylquinic acid (cynarin) was predominant, due to the isomerization during processing. Total phenolic contents of approximately 12 g/kg on a dry matter basis revealed that artichoke pomace is a promising source of phenolic compounds that might be recovered and used as natural antioxidants or functional food ingredients.

Flavonol O- and xanthone C-glycosides were extracted from mango (Mangifera indica L. cv. "Tommy Atkins") peels and characterized by high-performance liquid chromatography-electrospray ionization mass spectrometry. Among the fourteen compounds analyzed, seven quercetin O-glycosides, one kaempferol O-glycoside, and four xanthone C-glycosides were found. On the basis of their fragmentation pattern, the latter were identified as mangiferin and isomangiferin and their respective galloyl derivatives. A flavonol hexoside with m/z 477 was tentatively identified as a rhamnetin glycoside, which to the best of our knowledge, has not yet been reported in mango peels. The results obtained in the present study confirm that peels originating from mango fruit processing are a promising source of phenolic compounds that might be recovered and used as natural antioxidants or functional food ingredients.

Betaxanthins, the yellow-orange water-soluble pigments from yellow beet (Beta vulgaris ssp. vulgaris cv. Bejo Zaden) and cactus pear (Opuntia ficus-indica cv. Gialla) have been investigated using an HPLC system compatible with mass spectrometry. Five novel betaxanthins were found and characterized as the immonium adducts of betalamic acid with serine, gamma-aminobutyric acid, valine, isoleucine, and phenylalanine. To enable concentration of betalain samples, desalting was performed by solid-phase extraction. With this technique, betacyanins could be separated from the betaxanthins using the pH-dependent retention characteristics of red and yellow betalains. The betaxanthin fraction was taken for the preparation of betalamic acid as a precursor for semisynthetic standards. The HPLC method was applied to yellow beet and cactus pear, revealing a more complex betalain profile than described earlier, thus proving its suitability for screening of betaxanthin-containing plants as potential sources for natural food colors.