Content of the flavonols quercetin, myricetin, and kaempferol in 25 edible berries

The amounts of quercetin, myricetin, and kaempferol aglycons in 25 edible berries were analyzed by an optimized RP-HPLC method with UV detection and identified with diode array and electrospray ionization mass spectrometry detection. Sixteen species of cultivated berries and nine species of wild berries were collected in Finland in 1997. Quercetin was found in all berries, the contents being highest in bog whortleberry (158 mg/kg, fresh weight), lingonberry (74 and 146 mg/kg), cranberry (83 and 121 mg/kg), chokeberry (89 mg/kg), sweet rowan (85 mg/kg), rowanberry (63 mg/kg), sea buckthorn berry (62 mg/kg), and crowberry (53 and 56 mg/kg). Amounts between 14 and 142 mg/kg of myricetin were detected in cranberry, black currant, crowberry, bog whortleberry, blueberries, and bilberry. Kaempferol was detected only in gooseberries (16 and 19 mg/kg) and strawberries (5 and 8 mg/kg). Total contents of these flavonols (100-263 mg/kg) in cranberry, bog whortleberry, lingonberry, black currant, and crowberry were higher than those in the commonly consumed fruits or vegetables, except for onion, kale, and broccoli.     

Inhibition of protein and lipid oxidation in liposomes by berry phenolics

The antioxidant activity of berry phenolics (at concentrations of 1.4, 4.2, and 8.4 mug of purified extracts/mL of liposome sample) such as anthocyanins, ellagitannins, and proanthocyanidins from raspberry (Rubus idaeus), bilberry (Vaccinium myrtillus), lingonberry (Vaccinium vitis-idaea), and black currant (Ribes nigrum) was investigated in a lactalbumin-liposome system. The extent of protein oxidation was measured by determining the loss of tryptophan fluorescence and formation of protein carbonyl compounds and that of lipid oxidation by conjugated diene hydroperoxides and hexanal analyses. The antioxidant protection toward lipid oxidation was best provided by lingonberry and bilberry phenolics followed by black currant and raspberry phenolics. Bilberry and raspberry phenolics exhibited the best overall antioxidant activity toward protein oxidation. Proanthocyanidins, especially the dimeric and trimeric forms, in lingonberries were among the most active phenolic constituents toward both lipid and protein oxidation. In bilberries and black currants, anthocyanins contributed the most to the antioxidant effect by inhibiting the formation of both hexanal and protein carbonyls. In raspberries, ellagitannins were responsible for the antioxidant activity. While the antioxidant effect of berry proanthocyanidins and anthocyanins was dose-dependent, ellagitannins appeared to be equally active at all concentrations. In conclusion, berries are rich in monomeric and polymeric phenolic compounds providing protection toward both lipid and protein oxidation.     

Oxygen radical absorbing capacity of phenolics in blueberries,cranberries, chokeberries,and lingonberries

The antioxidant activity of phenolics in fruits of blueberry (Vaccinium corymbosum cv. Sierra), cranberry (Vaccinium macrocarpon cv. Ben Lear), wild chokeberry (Aronia melanocarpa), and lingonberry (Vaccinium vitis-idaea cv. Amberland) was determined in this study. The phenolic constituents and contents among the different berries varied considerably. Anthocyanins were found to be the main components in all these berries. Chlorogenic acid in blueberry, quercetin glycosides in cranberry and lingonberry, and caffeic acid and its derivative in chokeberry were also present in relatively high concentrations. Chlorogenic acid, peonidin 3-galactoside, cyanidin 3-galactoside, and cyanidin 3-galactoside were the most important antioxidants in blueberry, cranberry, wild chokeberry, and lingonberry, respectively. The contribution of individual phenolics to the total antioxidant capacity was generally dependent on their structure and content in the berries. Phenolics such as quercetin and cyanidin, with 3',4'-dihydroxy substituents in the B ring and conjugation between the A and B rings, had highly effective radical scavenging structures in blueberries, cranberries, chokeberries, and lingonberries. Phenolic acids such as caffeic acid also showed high antioxidant activity, probably due to its dihydroxylation in the 3,4 positions as hydrogen donors.     

Identification of procyanidins and anthocyanins in blueberries and cranberries (Vaccinium spp.) using high-performance liquid chromatography/mass spectrometry

Blueberries and cranberries were analyzed for procyanidins using normal-phase HPLC/MS. Monomers, identified as (+)-catechin and (-)-epicatechin, and a series of oligomers were detected in blueberries, and MS data confirmed that the oligomers consisted of (epi)catechin units that were exclusively singly linked (B-type). The procyanidin "fingerprints" were similar for Tifblue and Rubel but higher than that for lowbush blueberries. In whole cranberries, (-)-epicatechin was present, along with a complex series of oligomers. Both A-type (contained only one double linkage per oligomer) and B-type oligomers were present. Two commercial cranberry juices exhibited similar procyanidin profiles, except that one contained increased quantities. There were processing effects on the procyanidin content of cranberry extract and juices when compared to those of the unprocessed fruits. Monomer, dimers, and A-type trimers were the primary procyanidins, with only trace levels of the B-type trimers and A-type tetramers and with an absence of the higher oligomers in cranberry extract and juices.     

Berry phenolics and their antioxidant activity

Phenolic profiles of a total of 26 berry samples, together with 2 apple samples, were analyzed without hydrolysis of glycosides with HPLC. The phenolic contents among different berry genera varied considerably. Anthocyanins were the main phenolic constituents in bilberry, bog-whortleberry, and cranberry, but in cowberries, belonging also to the family Ericaceae genus Vaccinium, flavanols and procyanidins predominated. In the family Rosaceae genus Rubus (cloudberry and red raspberry), the main phenolics found were ellagitannins, and in genus Fragaria (strawberry), ellagitannins were the second largest group after anthocyanins. However, phenolic acids were dominant in rowanberries (genus Sorbus) and anthocyanins in chokeberry (genus Aronia). In the family Grossulariaceae genus Ribes (currants and gooseberry), anthocyanins predominated, as well as in crowberries (family Empetraceae genus Empetrum). In apples, hydroxycinnamic acids were the main phenolic subgroup. Extraction methods for berries and apples were studied to produce phenolic extracts with high antioxidant activity. Evaluation of antioxidant activity was performed by autoxidazing methyl linoleate (40 degrees C, in the dark). The extraction method affected remarkably both the phenolic composition and the antioxidant activity, but with statistical analysis the observed activity could not be well explained with the contents of individual phenolic subgroups.     

Cutin composition of five finnish berries

The raw cutin (i.e., extractive-free isolated cuticular membrane) fraction from Finnish berries, sea buckthorn (Hippopha? rhamnoides), black currant (Ribes nigrum), cranberry (Vaccinium oxycoccos), lingonberry (Vaccinium vitis-idaea), and bilberry (Vaccinium myrtillus), was depolymerized by NaOMe-catalyzed methanolysis. The composition of cutin monomers was determined by GC-(EI)MS analysis either as methyl esters or as TMSi esters, with OH groups derivatized to TMSi ethers. There was a notable difference in the degree of depolymerization, ranging from 6 to 47%. The extractive-free berry cuticle, that is, raw cutin, thus contains <50% polyester polymer cutin. The predominant cutin monomers were C(16) and C(18) omega-hydroxy acids with midchain functionalities, mainly epoxy and hydroxyl groups. Typically, the major compounds were 9,10-epoxy-18-hydroxyoctadecanoic acid, 10,16-dihydroxyhexadecanoic acid, 9,10,18-trihydroxyoctadecanoic acid, 9,10-epoxy-18-hydroxyoctadec-12-enoic acid, and 18-hydroxyoctadec-9-enoic acid. The amount of epoxyacids was rather high in sea buckthorn ( approximately 70%) and cranberry ( approximately 60%), compared with the other berries. The black currant cutin differed from that of the other berries with a significant portion of hydroxyoxohexadecanoic acid ( approximately 12% of total monomers). This investigation of the cuticular hydroxy acids of five Finnish berries is part of the exploitation of the northern natural resources related to the chemical composition, nutritional value, and sensory properties.     

Characterization of phenolic profiles of Northern European berries by capillary electrophoresis and determination of their antioxidant activity

Berries are known to contain phenolic substances (i.e., flavonoids and phenolic acids), which comprise two large and heterogeneous groups of biologically active nonnutrients. This investigation evaluated the content and profile of the phenolic compounds present in six different berries found in Northern Europe. The latter included bilberry (Vaccinium myrtillus), cowberry (Vaccinium vitis-idaea), cranberry (Vaccinium oxycoccus), strawberry (Fragaria ananassa), black currant (Ribes nigrum), and red currant (Ribes rubrum). The study was focused on two areas. The first involved the extraction and analysis of berries for total phenolic content and determination of their antioxidant activity. The total phenolic level of berries was correlated with their antioxidant activity. Second, the berry extracts were analyzed by capillary electrophoresis to determine the content and profile of selected bioactive compounds. The analytes of interest included trans-resveratrol, cinnamic acid, ferulic acid, p-coumaric acid, quercetin, and morin.     

Resveratrol, pterostilbene, and piceatannol in vaccinium berries

A study was conducted to determine the presence of resveratrol, pterostilbene, and piceatannol in Vaccinium berries. Samples representing selections and cultivars of 10 species from Mississippi, North Carolina, Oregon, and Canada were analyzed by gas chromatography/mass spectrometry. Resveratrol was found in Vaccinium angustifolium (lowbush blueberry), Vaccinium arboretum (sparkleberry), Vaccinium ashei (rabbiteye blueberry), Vaccinium corymbosum (highbush blueberry), Vaccinium elliottii (Elliott's blueberry), Vaccinium macrocarpon (cranberry), Vaccinium myrtillus (bilberry), Vaccinium stamineum (deerberry), Vaccinium vitis-ideae var. vitis-ideae (lingonberry), and Vaccinium vitis-ideae var. minor (partridgeberry) at levels between 7 and 5884 ng/g dry sample. Lingonberry was found to have the highest content, 5884 ng/g dry sample, comparable to that found in grapes, 6471 ng/g dry sample. Pterostilbene was found in two cultivars of V. ashei and in V. stamineum at levels of 99-520 ng/g dry sample. Piceatannol was found in V. corymbosum and V. stamineum at levels of 138-422 ng/g dry sample. These naturally occurring stilbenes, known to be strong antioxidants and to have cancer chemopreventive activities, will add to the purported health benefits derived from the consumption of these small fruits.     

Impact of different stages of juice processing on the anthocyanin, flavonol, and procyanidin contents of cranberries

Juice is the most common form in which cranberries are consumed; however there is limited information on the changes of polyphenolic content of the berries during juice processing. This study investigated the effects of three different pretreatments (grinding plus blanching; only grinding; only blanching) for cranberry juice processing on the concentrations of anthocyanins, flavonols, and procyanidins throughout processing. Flavonols and procyanidins were retained in the juice to a greater extent than anthocyanins, and pressing resulted in the most significant losses in polyphenolics due to removal of the seeds and skins. Flavonol aglycones were formed during processing as a result of heat treatment. Drying of cranberry pomace resulted in increased extraction of flavonols and procyanidin oligomers but lower extraction of polymeric procyanidins. The results indicate that cranberry polyphenolics are relatively stable during processing compared to other berries; however, more work is needed to determine their fate during storage of juices.     

Transport of cranberry A-type procyanidin dimers, trimers, and tetramers across monolayers of human intestinal epithelial Caco-2 cells

A-type procyanidin oligomers in cranberries are known to inhibit the adhesion of uropathogenic bacteria. B-type procyanidin dimers and trimers are absorbed by humans. The absorption of A-type procyanidins from cranberries in humans has not been demonstrated. This study examined the transport of A-type cranberry procyanidin dimers, trimers, and tetramers on differentiated human intestinal epithelial Caco-2 cell monolayers. Procyanidins were extracted from cranberries and purified using chromatographic methods. Fraction I contained predominantly A-type procyanidin dimer A2 [epicatechin-(2-O-7, 4-8)-epicatechin]. Fraction II contained primarily A-type trimers and tetramers, with B-type trimers, A-type pentamers, and A-type hexamers being minor components. Fraction I or II in solution was added onto the apical side of the Caco-2 cell membranes. The media at the basolateral side of the membranes were analyzed using HPLC-MS(n) after 2 h. Data indicated that procyanidin dimer A2 in fraction I and A-type trimers and tetramers in fraction II traversed across Caco-2 cell monolayers with transport ratio of 0.6%, 0.4%, and 0.2%, respectively. This study demonstrated that A-type dimers, trimers, and tetramers were transported across Caco-2 cells at low rates, suggesting that they could be absorbed by humans after cranberry consumption.     

Lingonberry (Vaccinium vitis-idaea) and European cranberry (Vaccinium microcarpon) proanthocyanidins: isolation, identification, and bioactivities

European, small-fruited cranberries (Vaccinium microcarpon) and lingonberries (Vaccinium vitis-idaea) were characterized for their phenolic compounds and tested for antioxidant, antimicrobial, antiadhesive, and antiinflammatory effects. The main phenolic compounds in both lingonberries and cranberries were proanthocyanidins comprising 63-71% of the total phenolic content, but anthocyanins, hydroxycinnamic acids, hydroxybenzoic acids, and flavonols were also found. Proanthocyanidins are polymeric phenolic compounds consisting mainly of catechin, epicatechin, gallocatechin, and epigallocatechin units. In the present study, proanthocyanidins were divided into three groups: dimers and trimers, oligomers (mDP 4-10), and polymers (mDP > 10). Catechin, epicatechin, A-type dimers and trimers were found to be the terminal units of isolated proanthocyanidin fractions. Inhibitions of lipid oxidation in liposomes were over 70% and in emulsions over 85%, and in most cases the oligomeric or polymeric fraction was the most effective. Polymeric proanthocyanidin extracts of lingonberries and cranberries were strongly antimicrobial against Staphylococcus aureus, whereas they had no effect on other bacterial strains such as Salmonella enterica sv. Typhimurium, Lactobacillus rhamnosus and Escherichia coli. Polymeric fraction of cranberries and oligomeric fractions of both lingonberries and cranberries showed an inhibitory effect on hemagglutination of E. coli, which expresses the M hemagglutin. Cranberry phenolic extract inhibited LPS-induced NO production in a dose-dependent manner, but it had no major effect on iNOS of COX-2 expression. At a concentration of 100 μg/mL cranberry phenolic extract inhibited LPS-induced IL-6, IL-1β and TNF-α production. Lingonberry phenolics had no significant effect on IL-1β production but inhibited IL-6 and TNF-α production at a concentration of 100 μg/mL similarly to cranberry phenolic extract. In conclusion the phenolics, notably proanthocyanidins (oligomers and polymers), in both lingonberries and cranberries exert multiple bioactivities that may be exploited in food development.     

Antioxidant activity and phenolic content of Oregon caneberries

Five types of caneberries [evergreen blackberries (Rubus laciniatus), marionberries (Rubus ursinus), boysenberries (Rubus ursinus x idaeus), red raspberries (Rubus idaeus), and black raspberries (Rubus occidentalis)] were analyzed for antioxidant activity by measuring their oxygen radical absorbance capacity (ORAC). In addition, the berries were analyzed for total phenolics, anthocyanins, procyanidins, and ellagic acid content. All of the berries had high ORAC activity ranging from 24 to 77.2 micromol of Trolox equiv/g of fresh berries. Anthocyanin content ranged from 0.65 to 5.89 mg/g, and phenolics ranged from 4.95 to 9.8 mg/g. Black raspberries had the highest ORAC and anthocyanin and phenolic contents. Only red raspberries had detectable amounts of procyanidin oligomers (monomer, dimers, and trimers). All berries had high levels of ellagic acid (47-90 mg/g), but boysenberries had the highest level prior to hydrolysis. The results from this study indicate that these caneberries were high in antioxidant activity and were rich sources of anthocyanins and phenolics.     

Identification and in vitro biological activities of hop proanthocyanidins: inhibition of nNOS activity and scavenging of reactive nitrogen species

Oligomeric proanthocyanidins constitute a group of water-soluble polyphenolic tannins that are present in the female inflorescences (up to 5% dry wt) of the hop plant (Humulus lupulus). Humans are exposed to hop proanthocyanidins through consumption of beer. Proanthocyanidins from hops were characterized for their chemical structure and their in vitro biological activities. Chemically, they consist mainly of oligomeric catechins ranging from dimers to octamers, with minor amounts of catechin oligomers containing one or two gallocatechin units. The chemical structures of four procyanidin dimers (B1, B2, B3, and B4) and one trimer, epicatechin-(4beta-->8)-catechin-(4alpha-->8)-catechin (TR), were elucidated using mass spectrometry, NMR spectroscopy, and chemical degradation. When tested as a mixture, the hop oligomeric proanthocyanidins (PC) were found to be potent inhibitors of neuronal nitric oxide synthase (nNOS) activity. Among the oligomers tested, procyanidin B2 was most inhibitory against nNOS activity. Procyanidin B3, catechin, and epicatechin were noninhibitory against nNOS activity. PC and the individual oligomers were all strong inhibitors of 3-morpholinosydnonimine (SIN-1)-induced oxidation of LDL, with procyanidin B3 showing the highest antioxidant activity at 0.1 microg/mL. The catechin trimer (TR) exhibited antioxidant activity more than 1 order of magnitude greater than that of alpha-tocopherol or ascorbic acid on a molar basis.     

Fractionation of polymeric procyanidins from lowbush blueberry and quantification of procyanidins in selected foods with an optimized normal-phase HPLC-MS fluorescent detection method

The polymeric procyanidins were fractionated from lowbush blueberry on a Sephadex LH-20 column. The degree of polymerization (DP) for the polymers was determined by thiolysis to be in a range of 19.9 to 114.1. Normal-phase HPLC analysis indicated that the polymeric procyanidins did not contain oligomeric procyanidins with DP < 10. The polymers eluted as a single peak at the end of the chromatogram. The normal-phase HPLC gradient was modified to improve the separation of procyanidin monomers through decamers and to elute all the polymers beyond those as a distinct peak. Monomers through decamers were quantified individually. All the polymers (DP > 10) were quantified using a mixture of purified polymers as an external standard. Polymers were found to be the dominant procyanidins in brown sorghum bran, cranberry, and blueberry. Thiolysis of the polymer peaks indicated that epicatechin was present as extension units in these foods, however, the composition of terminal units varied considerably between catechin and epicatechin, or an A-type dimer linkage in the case of cranberry.     

Phenolic compounds of barley grain and their implication in food product discoloration

Barley grains contain significant amounts of phenolic compounds that may play a major role in the discoloration of food products. Phenolic acid and proanthocyanidin (PA) composition of 11 barley genotypes were determined, using high-performance liquid chromatography and liquid chromatography-mass spectrometry, and their significance on food discoloration was evaluated. Abraded grains contained 146-410 microg/g of phenolic acids (caffeic, p-coumaric, and ferulic) in hulled barley and 182-282 microg/g in hulless barley. Hulled PA-containing and PA-free genotypes had comparable phenolic acid contents. Catechin and six major barley PAs, including dimeric prodelphinidin B3 and procyandin B3, and four trimers were quantified. PAs were quantified as catechin equivalents (CE). The catechin content was higher in hulless (48-71 microg/g) than in hulled (32-37 microg/g) genotypes. The total PA content of abraded barley grains ranged from 169 to 395microg CE/g in PA-containing hulled and hulless genotypes. Major PAs were prodelphinidin B3 (39-109 microg CE/g) and procyanidin B3 (40-99 microg CE/g). The contents of trimeric PAs including procyanidin C2 ranged from 53 to 151 g CE/g. Discoloration of barley flour dough correlated with the catechin content of abraded grains (r = -0.932, P < 0.001), but not with the content of individual phenolic acids and PAs. Discoloration of barley flour dough was, however, intensified when total PA extracts and catechin or dimeric PA fractions were added into PA-free barley flour. The brightness of dough also decreased when the total PA extract or trimeric PA fraction was added into heat-treated PA-free barley flour. Despite its low concentration, catechin appears to exert the largest influence on the discoloration of barley flour dough among phenolic compounds.     

Procyanidins as antioxidants and tumor cell growth modulators

Five procyanidin fractions with different structural complexities were obtained after fractionation of a grape seed extract. The procyanidin fraction's abilities to inhibit lipid peroxidation induced by 2,2'-azobis-2-methyl-propanimidamide dihydrochloride in a liposomal membrane system were examined. The antioxidant capacities of all fractions were evaluated through monitoring oxygen consumption and by measuring the formation of conjugated dienes. All tested fractions provided protection of membranes against peroxyl radicals by increasing the induction time of oxidation. This effect increased up to fraction II but decreased with the increase of the structural complexity of further procyanidin fractions, possibly due to steric hindrance effects exhibited by the more complex fractions. In addition, the antiradical properties and the reducing power of these fractions were determined by using 2,2-diphenyl-1-picrylhydrazyl and ferric reducing/antioxidant power methods, respectively. Moreover, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide reduction and DNA synthesis were measured in Michigan Cancer Foundation 7 (MCF-7), a human breast cancer cell line, treated with catechin or procyanidin fractions in order to evaluate the effect of these compounds on cell viability and proliferation. The results obtained showed that at 30 microg/mL, fractions I and II decreased cell viability and proliferation, which was not observed with 60 microg/mL of the same fractions. Catechin was also able to decrease cell viability and proliferation at 30 and 60 microg/mL. It is interesting to notice that the procyanidin fractions that exhibited higher antioxidant activity were the same to affect cell viability and proliferation.     

Isolation and structure elucidation of procyanidin oligomers from Saskatoon berries (Amelanchier alnifolia)

Proanthocyanidin oligomers with different degrees of polymerization were isolated from Saskatoon berries (Amelanchier alnifolia) by means of gel adsorption and normal-phase liquid chromatography. The proanthocyanidins were identified using electrospray ionization mass spectrometry, nuclear magnetic resonance spectroscopy, and thiolytic degradation coupled with reversed-phase liquid chromatography. The results established that Saskatoon berries contain proanthocyanidins from dimers through heptamers and higher polymers. Saskatoon proanthocyanidins are essentially of procyanidin type, consisting mainly of epicatechin units linked by B-type bonds. The simple procyanidin profile of Saskatoon berries allowed the procyanidins to be separated precisely according to their degrees of polymerization. In the future they can be used as standard compounds for qualitative and quantitative analysis of procyanidins as well as for elucidation of the biological activities of proanthocyanidins.     

Berry fruits: compositional elements, biochemical activities, and the impact of their intake on human health, performance, and disease

An overwhelming body of research has now firmly established that the dietary intake of berry fruits has a positive and profound impact on human health, performance, and disease. Berry fruits, which are commercially cultivated and commonly consumed in fresh and processed forms in North America, include blackberry ( Rubus spp.), black raspberry ( Rubus occidentalis), blueberry ( Vaccinium corymbosum), cranberry (i.e., the American cranberry, Vaccinium macrocarpon, distinct from the European cranberry, V. oxycoccus), red raspberry ( Rubus idaeus) and strawberry ( Fragaria x ananassa). Other berry fruits, which are lesser known but consumed in the traditional diets of North American tribal communities, include chokecherry ( Prunus virginiana), highbush cranberry ( Viburnum trilobum), serviceberry ( Amelanchier alnifolia), and silver buffaloberry ( Shepherdia argentea). In addition, berry fruits such as arctic bramble ( Rubus articus), bilberries ( Vaccinuim myrtillus; also known as bog whortleberries), black currant ( Ribes nigrum), boysenberries ( Rubus spp.), cloudberries ( Rubus chamaemorus), crowberries ( Empetrum nigrum, E. hermaphroditum), elderberries ( Sambucus spp.), gooseberry ( Ribes uva-crispa), lingonberries ( Vaccinium vitis-idaea), loganberry ( Rubus loganobaccus), marionberries ( Rubus spp.), Rowan berries ( Sorbus spp.), and sea buckthorn ( Hippophae rhamnoides), are also popularly consumed in other parts of the world. Recently, there has also been a surge in the consumption of exotic "berry-type" fruits such as the pomegranate ( Punica granatum), goji berries ( Lycium barbarum; also known as wolfberry), mangosteen ( Garcinia mangostana), the Brazilian a?aí berry ( Euterpe oleraceae), and the Chilean maqui berry ( Aristotelia chilensis). Given the wide consumption of berry fruits and their potential impact on human health and disease, conferences and symposia that target the latest scientific research (and, of equal importance, the dissemination of this information to the general public), on the chemistry and biological and physiological functions of these "superfoods" are necessary.     

Phenolic composition and antioxidant properties of Polish blue-berried honeysuckle genotypes by HPLC-DAD-MS, HPLC postcolumn derivatization with ABTS or FC, and TLC with DPPH visualization

In this study, different Polish cultivars of blue-berried honeysuckles (Lonicera caerulea L.), wild and bog bilberry, were analyzed for bioactive compounds. The chemical properties verified included composition of anthocyanins and other polyphenols, antioxidant activity, and profiles of antioxidants by HPLC postcolumn derivatization or TLC. The antioxidant activities of different blue-berried honeysuckle cultivars were similar to that of wild-growing bilberries (ranging from 170 to 417 μmol TE/g dm in ABTS and from 93 to 166 μmol TE/g dm in DPPH and Folin-Ciocalteu tests). The major anthocyanin in the blue-berried honeysuckle was cyanidin-3-glucoside, which constituted 84-92% of the total anthocyanins. The TLC and HPLC postcolumn antioxidant profiles indicated that anthocyanins are the major antioxidants in all berries studied. Wild berries and the cultivars of the blue-berried honeysuckles are also a similar source of such minerals as K, Mg, and Ca.     

Impact of noncovalent interactions between apple condensed tannins and cell walls on their transfer from fruit to juice: studies in model suspensions and application

The adsorption of procyanidins (condensed tannins) on cell-wall material was quantified by bringing into contact solutions of procyanidins and suspensions of cell-wall material. A model was developed on the basis of the Langmuir isotherm formulation and a factorial experimental design. The parameters that influenced the adsorption were the concentration and molecular weight of the procyanidins, the ionic strength of the solution, the temperature, and the apple cell-wall concentration. The model was applied to partitioning of procyanidins from apple between juice and mash. The parameters to be taken into account are the composition of the apples and, specifically, (i) the concentration and molecular weight of the procyanidins, (ii) their acidity and pH as a determinant of the ionic strength, and (iii) their cell-wall content and the temperature at pressing. To estimate the ability of the model to relate procyanidin concentrations in the juice to their concentration in the apple, apples of three varieties of widely different procyanidin compositions were pressed in conditions that prevent oxidation. In these conditions, yields in the juice were >80% for phenolic acids or catechin monomers but <50% for procyanidins, with the lowest rates obtained for the higher polymers in accordance with the model.