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Silver linden flowers contain different pectins (PSI-PSIII) with immunomodulating properties. PSI is a low-esterified pectic polysaccharide with predominant homogalacturonan region, followed by rhamnogalacturonan I (RGI) with arabinogalactan II and RGII (traces) domains. PSII and PSIII are unusual glucuronidated RGI polymers. PSIII is a unique high molecular weight RGI, having almost completely O-3 glucuronidated GalA units with >30% O-3 acetylation at the Rha units. Linden pectins induced reactive oxygen species (ROS) and NO generation from non-stimulated whole blood phagocytes and macrophages, resp., but suppressed OZP-(opsonized zymosan particles)-activated ROS generation, LPS-induced iNOS expression and NO production. This dual mode of action suggests their anti-inflammatory activity, which is known for silver linden extracts. PSI expressed the highest complement fixation and macrophage-stimulating activities and was active on intestinal Peyer's patch cells. PSIII was active on non-stimulated neutrophils, as it induced s2-integrin expression, revealing that acetylated and highly glucuronidated RGI exhibits immunomodulating properties via phagocytes.

A pectic polysaccharide from rose hip (RH) fruits has been obtained by extraction with 1% aqueous citric acid. It was found that the polysaccharide fraction mainly consisted of galacturonic acid (45.5%) next to galactose (5.5%) and arabinose (4.7%). RH pectin is having a relatively high degree of methylesterification (62%) and acetylation (10%) and consists of different molecular weight populations in the range of 10-100 kDa. Enzymatic fingerprinting was performed using a combination of pectin lyase (PL) and endo-polygalacturonase. Detailed information about the structure and level of galacturonic acid oligomers released was obtained using LC-HILIC-MS/ELSD and HPAEC. Predominantly, unsaturated and methyl-esterified oligomers (DP 3-5) were released indicating that high proportions of methylesterified 'PL degradable' areas were present within the pectin. The data revealed that homogalacturonan is the main building block of the extracted pectin and consists of long methylesterified/acetylated GalA sequences interspersed with small blocks of non-methyl-esterified GalA units.

In the current study, an acidic polysaccharide from the in vitro suspension culture of Fumaria officinalis L. was obtained by extraction with 0.8% (w/v) aqueous ammonium oxalate. The polysaccharide fraction mainly consisted of galacturonic acid (41.0%), followed by galactose (7.3%) and arabinose (5.6%). This suggests the presence of arabinogalactan side chains in the rhamnogalacturonan-I segment of the studied pectin, which was mainly built up by homogalacturonan segments. The pectin was evaluated as low-methyl-esterified (45.0%) with degree of acetylation 3.4%. The polymer fraction was consisted of different molecular weight populations in the range of 6–600 kDa. The high amount of 4-L-hydroxyproline (11.7% of total protein) and the specific positive reaction to Yariv’s phenylglycoside reagent indicated the presence of an arabinogalactan protein in the cell walls. The functional properties of the polysaccharide fraction were evaluated, as it possessed better water-holding capacity than oil-holding capacity. The studied pectin demonstrated significant foaming ability and promising emulsifying properties in a concentration 1%. Therefore, the isolated polysaccharide fraction could be successfully used as emulsifier and foaming agent in food products and pharmaceutical supplements.

Two pectic (chPS-L1, chPS-L2) and one polyphenolic (chPP-L) fractions were obtained from lavender flowers after boiling water extraction, exhaustive removing of alcohol-soluble molecules and SEC. chPS-L1 (52.4kDa) contains mainly low-acetylated and high-methoxylated homogalacturonans (HG), and smaller rhamnogalacturonan (RG) I backbone fragments rich in 1,3,5-branched arabinan and arabinogalactan (AG) II side chains. chPS-L2 (21.8kDa) contains predominantly similarly esterified HG, followed by RGI with AGII structures and RGII. The prevalence of catechin and epicatechin in chPP-L indicates that they form weak interactions with pectins. chPS-L1 and chPS-L2 enhanced s2-integrin expression on neutrophils, inducing ROS generation and macrophage NO production. Both the effects on s2-integrin and high complement fixation activity of chPS-L1 were proposed for its inhibitory action against PMA- and OZP-activated ROS formation. This, together with suppression of NO generation after co-stimulation with chPS-L1 and LPS, suggested anti-inflammatory activity of studied pectins. Lavender polysaccharides expressed intestinal Peyer's patch immunomodulating activity.

Various foodstuffs and raw materials contain both pectic substances and different nitrogen-containing organic compounds: proteins, peptides, amino acids, alkaloids and many other amino compounds. Various non-enzymatic interactions between pectin and an amino compound in aqueous medium could occur during the processing of these foodstuffs and their storage. Amidation (aminolysis) or hydrolysis of the pectin ester groups, decarboxylation of the free carboxyl groups, β-elimination or hydrolysis of glycosidic bonds are among the theoretically expected reactions of pectin. Their identification and extent has been studied on model reactions. The results on the interaction between pectin and lysine, methyl glycine, guanidine and some amines in water at 18, 40, 85 and 90 °C are presented. All above-mentioned reactions were observed under the conditions investigated and with all amino compounds studied, but the rates of the reactions varied widely. β-Elimination proceeded very slowly even at high temperature, while amidation, hydrolysis of ester groups (saponification) or of glycosidic bonds (pectin degradation) and decarboxylation of the free carboxyl groups took place at measurable rates. Amidation was more pronounced in the case of lysine, glycine methyl ester, methylamine and diaminoethane, while hydrolysis of ester groups of pectin was more prominent with guanidine as well as with primary amines. Decarboxylation took place at a slow rate in all examined cases (from 3 to 11%). Indexes degree of hydrolysis of pectin ester groups and degree of decarboxylation of pectin are introduced. The results indicate that it should be studied whether or not similar processes possibly occur during the thermal treatment of pectin- and protein-rich plant raw materials.

The effect of microwave pretreatment of fruit raw material on some physical properties of the orange tissue was investigated. Scanning electron micrographs showed that microwave heating led to destruction of the parenchymal cells. It was also found that specific surface and the water absorption capacity of the orange tissue, and the endogenous enzymes of the peels were inactivated. As a result of this pectin extraction was facilitated. Considerable increasing in pectin yield and was attained (190% from oranges from crop of 1996 and over 250% for oranges of crop 1997 as compared with control). The quality of the pectin was also improved.

The dynamics of the impact of highly esterified apple pectin on lipid metabolism by humans was studied. The experiments involved 109 patients (54 women and 55 men) with hyperlipoproteinaemia. The lipid metabolism of 73 healthy persons (35 men and 38 women) and 36 persons (17 men and 19 women) with hyperlipoproteinaemia was investigated as a control. A granulated form of a mixture of pectin and sorbitol in a ratio of 2:1 was used. The results confirmed the favourable effect of apple pectin on the major characteristics of lipid metabolism by humans: the levels of serum cholesterol, high-density lipoprotein-cholesterol and triglycerides. Sorbitol manifests synergism regarding the hypolipidaemic effect of pectin. It was established that the model y=x(A+Bx), where x is time and y the parameter under investigation, best explained the dynamics of the studied characteristics of lipid metabolism under the impact of granulated highly esterified apple pectin. (A and B are experimental constants).

Investigations were carried out on the chemical and physico-chemical characteristics of pectin extracts obtained from apple pressings by extraction with diluted acids and on their effect on the technological properties of tobacco. It was established that the pectin yield from extraction with nitric and phosphoric acids is higher than from citric acid extraction. The content of reducing substances, monosaccharides, proteins and amino acids is higher with nitric acid extraction and this can be explained by the greater hydrolysing capacity of nitric as compared to phosphoric and citric acids. With respect to the dynamic viscosity, surface tension and angle of wetting, the extracts studied were close to aqueous glycerol solutions. The tobacco treated with nitric acid extract containing enzyme hydrolysate and with nitric acid extract had better moisture-retaining properties than the tobacco treated with phosphoric acid extract or with citric acid extract. The addition of pectin extracts caused no significant changes in the chemical composition of the tobacco blends studied. The extracts reduced tar and carbon monoxide in tobacco smoke compared with the diethyleneglycol treated control.

Laboratory studies on the extraction of pectin from orange, lemon and apple wastes pretreated in an electromagnetic field of super-high frequency were carried out. A 10-min preliminary microwave heating (2450 MHz, 0·5 kW) of crushed fruit materials was found to provide a higher pectin yield. The extracted pectin exhibited higher values for degree of esterification and gel strength compared with the control sample. The effect depends on the kind of raw material. The favourable effect of microwave heating on the yield and quality of pectin is assumed to be due first to the partial disintegration of the plant tissue and hydrolysis of protopectin, and second, to the rapid inactivation of the pectolytic enzymes in the raw material. The second hypothesis has been partly confirmed by model experiments. The results presented can serve as a basis for improving pectin manufacturing. It is expedient that fresh pectinous raw materials should be subjected to microwave heating before drying.

BACKGROUND: Leek (Allium porrum) is very commonly used vegetable in Bulgaria and is distinctive with high content of bioactive components. Previously we obtained five crude pectic polysaccharides from leek through consecutive extraction. Some of them appeared to be good stimulators of the immune system. Schols and Voragen investigated the composition of modified hairy regions of pectic polysaccharides isolated from leek cell walls. Samuelson et al. identified the polysaccharide structures encountered in hairy regions as bioactive. The aim of this work was to study the isolation, composition and biological activities of pectic polysaccharides from leek. RESULTS: Two pectic polysaccharides from leek were isolated through consecutive water and acid extraction. The water extractable pectin had higher polyuronic content, higher protein content and lower neutral sugar content. It was found that next to galacturonic acid they also contain glucuronic acid in ratio 9:1 for the water- and 3:1 for the acid-extractable polysaccharide. The main neutral sugar was galactose. The water-extractable pectic polysaccharide had higher molecular weight (10(6) Da) and homogeneity. It was shown that the pectic polysaccharides from leek have considerable immunostimulating activities. CONCLUSION: Leek polysaccharides have relatively high galacturonic and glucuronic acid content and are distinguished with high biological activity.

Peels and fruit pulp of two Guinean mango varieties (Ceni and Springfield) were studied. The polyuronide content of the dried fruit material varied from 14·6 to 21·3% depending on the type of raw material (variety and part of the fruit) and methods of treatment prior to drying. By hydrochloric acid extraction at 85°C and pH = 1·5, the pectic substances were extracted most fully from the dried mango peels (Ceni, 24·5% and Springfield, 22·3%) and least fully from the fleshy part of ordinary mango (Ceni, 5·8%). The molecular mass of the pectins obtained ranged from 72 000 to 83 000 and the gel strength was between 162 and 232° according to Tarr-Baker. The content of bound amino acids in the pectic preparations obtained was in the 1–7% range and did not depend on the degree of esterification of pectin. The carbohydrate composition of the pectins obtained was estimated to be in the following ranges: galacturonic acid (40–70%); arabinose (2–4%); rhamnose (1–2%); xylose (1–7%); mannose (1–3%); galactose (14–22%) and glucose (8–22%).

Laboratory studies on the extraction of pectin from orange peels, pretreated in an electromagnetic field of hyper frequency, were carried out. The influence of intensity of microwave treatment (Pw) and time on pectin yield and pectin quality was investigated. It was established that the increase of Pw and time lead to increase in the pectin yield with 180–240% in comparison with the control. Apparently, the microwave treatment leads to a considerable increase in the soluble form of pectin, characterized by increase in the jelly strenght and in the polyuronic content.

The present study provides a comprehensive data on the antioxidant, antimicrobial and neutrophil-modulating activities of extracts from six medicinal plants--blackberry (Rubus fruticosus) leaves, chokeberry (Aronia melanocarpa) leaves, hawthorn (Crataegus monogyna) leaves, lady's mantle (Alchemilla glabra) aerial parts, meadowsweet (Filipendula ulmaria) aerial parts and raspberry (Rubus idaeus) leaves. In order to analyze the antioxidant activity of the herbs, several methods (ORAC, TRAP, HORAC and inhibition of lipid peroxidation) were used. Blackberry leaves and meadowsweet extracts revealed the highest antioxidant activities via all methods. All extracts studied blocked almost completely the opsonized zymosan particle-activated ROS production by neutrophils from human whole blood. On the other hand, the effect of extracts on phorbol myristate acetate-activated ROS production was much milder and even nonsignificant in the case of chokeberry leaves. This latter result suggests that extracts (apart from their antioxidative activity) interfere with the signaling cascade of phagocyte activation upstream of the protein kinase C activation. The antimicrobial activity of the investigated extracts against 11 human pathogens was investigated using three different methods. Meadowsweet and blackberry leaves extracts had the highest antimicrobial effect and the lowest minimal inhibiting concentrations (MICs) against the microorganisms tested.

Summary Amidated apple pectins were prepared in aqueous and aqueous-alcoholic media, and the factors influencing both ammonolysis and hydrolysis of the ester groups of apple pectin by ammonia were studied. In aqueous solution, the extent of ammonolysis and hydrolysis was very dependent upon ammonia concentration. In aqueous alcohol, the products were also dependent upon the particular alcohol and its concentration, increasing concentrations suppressing hydrolysis; the overall rate of reaction is much slower than in the absence of alcohol. The product balance between amonolysis and hydrolysis of the ester groups is influenced by the polarity of the medium, and by the concentration of NH+4 and OH−. It was shown that the extents of ammonolysis and hydrolysis of the ester groups are significantly affected by the polarity of the medium and the acid-base equilibrium of the interaction of ammonia with water, i.e. NH3+H2O ↔ NH+4+OH−. The content of free ester and amidated carboxyl groups in the pectin can be regulated by varying the concentration of ammonia, temperature, reaction time and the polarity of the medium. The rate of enzymic hydrolysis of amidated pectins decreases with increasing amide content. A mechanism for the reaction is proposed.