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PubMed1998

Dietary pectin with high viscosity lowers plasma and liver cholesterol concentration and plasma cholesteryl ester transfer protein activity in hamsters.

We fed semipurified diets containing pectin with either a high or low in vitro viscosity at a level of 3 g/100 g air-dried diet to hamsters for 8 wk. A control group was fed cellulose and a positive control group was fed psyllium. The pectins used were a calcium-sensitive pectin (CS-pectin) that has a high viscosity and a noncalcium-sensitive pectin (NCS-pectin) that has a low viscosity. In the presence of calcium, CS-pectin has a more than 80-fold higher viscosity than NCS-pectin which offered the opportunity to investigate the possible role of viscosity in the hypolipidemic properties of pectin. The hamsters fed CS-pectin or psyllium had considerably lower plasma cholesterol concentrations (3.69 +/- 0.44 and 4.21 +/- 0.45 mmol/L, respectively, mean +/- SD, n = 14) than those fed NCS-pectin (5.03 +/- 1.15 mmol/L) or cellulose (5.72 +/- 1. 04 mmol/L). Differences in total plasma cholesterol were reflected in both high density lipoprotein and very low density lipoprotein cholesterol. There was no effect of fiber on low density lipoprotein cholesterol levels. Liver cholesterol concentrations paralleled the plasma cholesterol levels and were 9.91 +/- 2.48 micromol/g of liver for the CS-pectin group, 15.03 +/- 5.75 for the psyllium group, 17. 69 +/- 10.66 for the NCS-pectin group, and 25.57 +/- 9.23 for the cellulose group. Fecal bile acid and neutral steroid excretion tended to be higher in the hamsters fed CS-pectin than in their counterparts fed NCS-pectin. The hamsters fed psyllium had significantly greater fecal excretions of bile acids than the hamsters fed cellulose, CS-pectin or NCS-pectin, whereas the excretion of fecal neutral sterols tended to be lower. Plasma cholesteryl ester transfer protein activity was significantly lower in the hamsters fed CS-pectin than in those fed NCS-pectin. The results of this study suggest that the viscosity of pectins may determine their cholesterolemic effect.

Animals↗

PubMedDate not supplied

Harry M. Vars award. The effect of a pectin-supplemented elemental diet on intestinal adaptation to massive small bowel resection.

The effect of a pectin-supplemented elemental diet on intestinal adaptation to massive small bowel resection in the rat was investigated in this study. Sixty adult Sprague-Dawley rats underwent placement of a feeding gastrostomy and swivel apparatus. Control animals (N = 16) were then returned to their cages while the remaining animals underwent an 80% small bowel resection and anastomosis (resected, N = 44). Postoperatively, animals were randomly assigned to receive either a fat- and fiber-free elemental diet (no pectin) or the same diet supplemented with 2% pectin (pectin). After 8 days of full strength diet, samples of jejunum, ileum, and colon were obtained for analysis. The weights per unit length of the ileum and colon were significantly greater in the resected pectin group than either the resected no pectin or pectin control groups. Mucosal parameters (unit weight, DNA, RNA, and protein content) were significantly increased in the jejunum and ileum of both the resected pectin and resected no pectin groups relative to their respective control groups. However, jejunal and ileal mucosal parameters were significantly greater (1.3- to 2-fold) for the resected pectin group than for the resected no pectin group. All the mucosal parameters of the colons were significantly greater for the pectin resected group than for the pectin control group, while only colonic mucosal RNA was significantly greater for the no pectin resected group than for the no pectin control group. These data indicate that the addition of pectin to an elemental diet significantly enhanced intestinal adaptation to massive small bowel resection in the rat.

Adaptation, Physiological↗

PubMed1999

Immunocytochemical localization of pectins in the maturing anther of Allium cepa L.

Distribution of pectins in cell walls of maturing anther of Allium cepa L. was investigated. The monoclonal antibodies against defined epitopes of pectin were used: JIM5 recognizing unesterified pectin and JIM7 recognizing esterified pectin. It has been found that the cell walls of all anther tissues mainly contain esterified pectins. In the somatic tissues only small amounts of unesterified pectins are present in the cell wall junctions and adjacent middle lamellae and in the cell walls of the connective tissue. Thickening of the epiderm cell walls and growth of trabeculae in endothecium are completed through deposition of esterified pectins. In the cell walls of the middle layer and tapetum, unesterified pectins have been found only prior to their disintegration. The primary wall of microsporocytes is made up mainly of esterified pectins. Unesterified pectins occur outside microsporocytes only prior to the callose isolation stage. The presence of esterified pectins has also been detected on the surface of the callose wall surrounding dividing microsporocytes. Lysis of those pectins takes place after microsporogenesis, simultaneously with the lysis of the callosic walls. Before these processes pectins are unesterified. In the sporoderm of pollen grains mainly esterified pectins occur. They have been localized in the intine and aperture. The level of unesterified pectins in the intine is markedly lower.

Animals↗

PubMed1994

Comparison of utilization of pectins from various sources by pure cultures of pectinolytic rumen bacteria and mixed cultures of rumen microorganisms.

Utilization of citrus, lucerne, apple and sugar beet pulp pectins by pure strains of rumen bacteria, Prevotella ruminicola, Lachnospira multiparus and Butyrivibrio fibrisolvens was compared. Additionally, the utilization of pectins by mixed rumen microorganisms was evaluated. The comparison was based on the depletion of galacturonic acid from medium, content of cellular protein in the cultures and the amount of end products of pectin fermentation in cell-free culture fluids. It was found that citrus pectin was utilized best; utilization of lucerne, apple and sugar beet pectins was dependent on the species of bacteria. P. ruminicola and B. fibrisolvens utilized polygalacturonic acid from sugar beet pectins better than that from apple or lucerne pectin, while L. multiparus was capable of significantly better utilization of lucerne pectin than pectin from sugar beet or apple. The source of pectin was less important for mixed cultures of rumen microorganisms than for pure cultures of rumen bacteria. The amount of fermentation products in the culture fluids supported the conclusion that citrus pectin was utilized better than others. Microbial protein content in the cultures was found to be a less sensitive indicator of pectin utilization than the remaining examined parameters. P. ruminicola strains and mixed cultures of rumen microorganisms were shown to have the highest ability to utilize pectins, L. multiparus-moderate, while the B. fibrisolvens strains utilized pectin the least.

Animals↗

PubMed1995

Influence of pectin structure on the interaction with bile acids under in vitro conditions.

Structural parameters of pectin (a polysaccharide and important component of dietary fibre) influence the interaction with bile acids (BA). The effect of experimental conditions (concentration of pectin, BA and Ca2+) on such interactions was studied at pH 6.0. Series of pectins were used, prepared from virtually fully esterified pectin by gradual de-esterification with alkali or with pectinesterase from oranges. Further amidated and acetylated pectins were also tested. The greatest interaction with BA was found with a very highly esterified pectin under in vitro conditions. The interaction diminished with decreasing degrees of esterification (DE). This decrease was more intensive for pectins possessing a blockwise arrangement of free-COOH groups. Derivatives of pectin generally interacted less with BA. These results were principally confirmed with commercial pectins, with pectins prepared on a pilot-plant scale and with pectins originating from a defined botanical source. The interactions of these preparations with BA were less intensive than with those of pectins having an ideal random distribution of free -COOH groups in the polysaccharide molecules at the same DE. The interaction with pectin is also likely to be influenced by the structure of BA.

Bile Acids and Salts↗

PubMed2001

Citrus pectin: characterization and inhibitory effect on fibroblast growth factor-receptor interaction.

This study was undertaken to characterize the pectin from four citrus species and to determine their in vitro inhibitory activities on the binding of fibroblast growth factor (FGF) to the FGF receptor (FGFR). Pectin from various parts of lemon, grapefruit, tangerine, and orange were isolated and characterized. Tangerine had the highest pectin content among the four citrus species. Segment membrane contained as much as or more pectin than flavedo/albedo. Anhydrogalacturonic content was highest in pectin from segment membrane of tangerine and flavedo/albedo of grapefruit. Lemon pectin contained the highest methoxyl content (MC), and grapefruit contained the largest proportion of lower molecular weight (<10000 Da) pectin. Tangerine contained the highest neutral sugar in both flavedo/albedo and segment membrane. The interdependency of heparin on factor-receptor interaction provides a means for identifying new antagonists of growth factor activity and thus for treatment of various diseases. These results showed that pectin significantly inhibited the binding of FGF-1 to FGFR1 in the presence of 0.1 microg/mL heparin. The pectin from the segment membrane of lemon was the most potent inhibitor. The inhibition activity was significantly correlated with sugar content, MC, and size of pectin. Kinetic studies revealed a competitive nature of pectin inhibition with the heparin, a crucial component of the FGF signal transduction process. The observation that the heparin-dependent biological activity of FGF signal transduction is antagonized by citrus pectin should be further investigated for the use of these pectins as anti-growth factor agents for potential health benefits.

Citrus↗

PubMed1985

The hypocholesterolaemic effects of pectins in rats.

The hypocholesterolaemic effects of pectins were studied in a series of five experiments in weanling Sprague-Dawley rats. Expt A examined the effects of differing levels of dietary fat on plasma and liver lipids. Rats were given diets containing 100 g pectin, National Formulary (NF)/kg, and either 50,100, 150 or 200 g oil/kg. All diets contained 10 g cholesterol/kg. Plasma cholesterol levels were lower in all pectin-fed groups compared with rats given the control diet containing 100 g Solkafloc and 100 g oil/kg. Liver lipid and cholesterol levels increased with increasing fat content of the diet, reaching a plateau at 150 g fat/kg diet, but were still significantly lower in all pectin-fed groups compared with the control group. Expt B. The effects of molecular weight and degree of methoxylation of pectins were studied in five groups of rats given either a control diet containing 100 g Solkafloc/kg or high molecular weight, high methoxyl pectin (HMW HMP); high molecular weight, low methoxyl pectin (HMW LMP); low molecular weight, high methoxyl pectin (LMW HMP); low molecular weight, low methoxyl pectin (LMW LMP). All diets in this and subsequent experiments contained 100 g fat and 10 g cholesterol/kg. Plasma cholesterol levels were significantly lower than control values only in the HMW HMP group. Compared with controls, animals given HMW pectins had lower levels of liver lipid and liver cholesterol; on the LMW HMP diet the liver cholesterol, but not the liver lipid, was lower. Expt C. An attempt was made to clarify the possible effect of degree of methoxylation by feeding diets containing either 100 g Solkafloc/kg, 100 g pectin NF/kg or 100 g very high methoxyl pectin/kg. Plasma cholesterol levels were significantly reduced by both pectins but there was no difference in effect between the two. Both had similar viscosities suggesting that this is a more important factor than methoxyl content. Expts D and E. Effects of dose on hypocholesterolaemic effects of HMP and LMP were studied. Diets containing 50 or 100 g Solkafloc, HMP or LMP/kg were given in Expt D, and 25 g Solkafloc or HMP/kg, 50 g Solkafloc, HMP or LMP/kg and 100 g Solkafloc or LMP/kg in Expt E. Plasma cholesterol levels were significantly reduced in groups given 50 or 100 g HMP/kg and in groups given 100 g LMP/kg. HMP were found to be more effective at lowering plasma cholesterol levels than LMP. LMW pectins were not effective. This suggests that the hypocholesterolaemic effects are at least partly due to viscosity.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed2005

Effect of abomasal pectin infusion on digestion and nitrogen balance in lactating dairy cows.

Two experiments were conducted to test the hypothesis that increasing carbohydrate fermentation in the large intestine would increase intestinal conversion of blood urea N to microbial protein, thereby reducing urinary N output. In experiment 1, 3 multiparous Holstein cows were used in an incomplete 4 x 4 Latin square with 14-d periods. Cows were fed the same basal diet and treatments were the abomasal infusion of 0, 0.5, or 1 kg/d of citrus pectin, or the addition of 1 kg/d of molasses to the basal diet. Experiment 2 used 6 cows in a double reversal design with four 21-d periods. Cows were fed one basal diet and treatments were the abomasal infusion of either 0 or 1 kg/d of pectin. In experiment 1, pectin infusion linearly decreased basal ration intake from 25.0 to 23.2 kg/d. This was prevented in experiment 2 by restricted feeding, and basal ration intake was 22.2 kg/d. Abomasal pectin caused numeric decreases in total tract apparent digestibility of neutral detergent fiber and neutral detergent solubles in experiment 1 and significantly decreased starch digestibility in experiment 2, suggesting that pectin may have reduced postruminal nutrient digestibility. Pectin infusion did not affect milk yield but decreased milk fat percentage from 3.69 to 3.53% in experiment 2. Increasing abomasal pectin tended to decrease urinary N and increase fecal N in experiment 1 and these effects were significant in experiment 2. For both experiments, urinary N decreased 26 g/d, approximately 10% of daily urine N output. Abomasal pectin did not affect fecal pH or DM content; however, in experiment 2, pectin decreased fecal ammonia from 19.8 to 13.4 mmol/kg of DM and increased fecal purines from 13.8 to 15.8 mmol/kg of DM. In both experiments, excretion of fecal purines was increased from 15 g/d for 0 kg/d pectin to 18 g/d for 1 kg/d pectin, although this increase was only significant in experiment 2. These results suggest that manipulating dairy diets to increase postruminal fermentation may reduce urinary N and consequently manure ammonia losses. However, abomasal pectin tended to decrease both ruminal ammonia concentration and urinary purine derivative output in experiment 2, suggesting that postruminal pectin fermentation may have compromised rumen microbial protein production.

Abomasum↗

PubMed2001

Immunocytochemical localization of esterified and unesterified pectins in unpollinated and pollinated styles of Petunia hybrida Hort.

Localization of pectins in the style of Petunia hybrida before and after pollination was investigated by immunocytochemistry using two primary monoclonal antibodies specific to highly (JIM7) and weakly (JIM5) methylesterified pectins. In the unpollinated style, esterified pectins occurred mainly in the cell walls of cortex tissue, while unesterified pectins were present mainly in the extracellular matrix (ECM) of the transmitting tract. After pollination no remarkable differences were found in pectin distribution in the ground tissue of the style. On the other hand, in the transmitting tract a reduction in the quantity of unesterified pectins was observed. Unesterified pectins in the extracellular regions of the transmitting tissue decreased before the penetration of the pollen tubes, indicating that pollination induces a reduction in the amount of unesterified pectins in the transmitting-tract ECM. The correlation between the degradation of strongly Ca2+-binding pectins and the growing level of those ions in the extracellular regions of the transmitting tract in the pollinated pistil of P. hybrida (M. Lenartowska et al. 1997) suggests that this process may constitute a mechanism for creating an optimum calcium medium for in vivo-growing pollen tubes. Both pectin categories were localized in pollen tubes. Esterified pectin epitopes were localized mainly in the vesicles of the tip cytoplasm. Unesterified pectin epitopes were found in the external fibrillar wall of pollen tubes.

Antibodies, Monoclonal↗

PubMed2003

Monovalent salt-induced gelation of enzymatically deesterified pectin.

Pectin gels were induced by monovalent salts (0.2 M) concurrently with deesterification of high methoxy pectin using a salt-independent orange pectin methylesterase (PME). Constant pH was maintained during deesterification and gelation. If salt or PME was absent, the pectin did not form a gel. The gel strength was influenced by both pH and species of monovalent cation. At pH 5.0, the pectin gel induced by KCl was significantly stronger than the NaCl-induced gel. In contrast, a much stronger gel was produced in the presence of NaCl as compared to KCl at pH 7.0. LiCl did not induce pectin gelation at either pH. Molecular weights of pectins increased from 1.38 x 10(5) to 2.26 x 10(5) during NaCl-induced gelation at pH 7. One proposal to explain these pectin molecular weight changes is a hypothetical PME transacylation mechanism. However, these pectin molecular weight changes can also be explained by metastable aggregation of the enzymatically deesterified low methoxy pectin. We postulate that gelation was induced by a slow deesterification of pectin under conditions that would normally salt out (precipitate) low methoxy pectin in the absence of PME.

Gels↗

PubMed1997

Chemistry and uses of pectin--a review.

Pectin is an important polysaccharide with applications in foods, pharmaceuticals, and a number of other industries. Its importance in the food sector lies in its ability to form gel in the presence of Ca2+ ions or a solute at low pH. Although the exact mechanism of gel formation is not clear, significant progress has been made in this direction. Depending on the pectin, coordinate bonding with Ca2+ ions or hydrogen bonding and hydrophobic interactions are involved in gel formation. In low-methoxyl pectin, gelation results from ionic linkage via calcium bridges between two carboxyl groups belonging to two different chains in close contact with each other. In high-methoxyl pectin, the cross-linking of pectin molecules involves a combination of hydrogen bonds and hydrophobic interactions between the molecules. A number of factors--pH, presence of other solutes, molecular size, degree of methoxylation, number and arrangement of side chains, and charge density on the molecule--influence the gelation of pectin. In the food industry, pectin is used in jams, jellies, frozen foods, and more recently in low-calorie foods as a fat and/or sugar replacer. In the pharmaceutical industry, it is used to reduce blood cholesterol levels and gastrointestinal disorders. Other applications of pectin include use in edible films, paper substitute, foams and plasticizers, etc. In addition to pectolytic degradation, pectins are susceptible to heat degradation during processing, and the degradation is influenced by the nature of the ions and salts present in the system. Although present in the cell walls of most plants apple pomace and orange peel are the two major sources of commercial pectin due to the poor gelling behavior of pectin from other sources. This paper briefly describes the structure, chemistry of gelation, interactions, and industrial applications soft pectin.

Chemical Phenomena↗

PubMed2002

The degree of methylation influences the degradation of pectin in the intestinal tract of rats and in vitro.

We investigated the degradation, metabolism, fate, and selected effects of pectin in the intestinal tract of rats. Conventional and germfree rats were fed for 3 wk diets containing 6.5% pectin (degree of methylation 34.5, 70.8 and 92.6%, respectively) or pectin-free diets. Pectin passes the small intestine as a macromolecule. The molecular weight distribution of pectins isolated from intestinal contents of germfree rats were unaffected by diet. No or very little galacturonan was found in cecum, colon or feces of most of the conventional rats. In colon contents of some conventional rats, di- and trigalacturonic acid were present. Total anaerobic and Bacteroides counts were greater in groups fed pectin. The concentration of short-chain fatty acids (SCFA) was higher in cecum and feces in all pectin-fed groups. With increasing degree of methylation, the formation rate of SCFA decreased in the cecum of conventional rats. During in vitro fermentation of pectin with fecal flora from rats, unsaturated oligogalacturonic acids appeared as intermediate products. Low-methoxyl pectin was fermented faster than high-methoxyl pectins in vivo and in vitro. Pectin-fed rats had greater ileum, cecum and colon weights. We conclude that structural parameters of pectin influence its microbial degradation in the intestinal tract.

Animals↗

PubMed2001

Pectin secretion and distribution in the anther during pollen development in Lilium.

Using the monoclonal antibodies JIM 5 and 7, pectin was immunolocalized and quantitatively assayed in three anther compartments of Lilium hybrida during pollen development. Pectin levels in both the anther wall and the loculus increased following meiosis, were maximal during the early microspore stages and declined during the remainder of pollen ontogenesis. In the microspores/pollen grains, pectin was detectable at low levels during the microspore stages but accumulated significantly during pollen maturation. During early microspore vacuolation, esterified pectin epitopes were detected both in the tapetum cytoplasm and vacuoles. In the anther loculus, the same epitopes were located simultaneously in undulations of the plasma membrane and in the locular fluid. At the end of microspore vacuolation, esterified pectin epitopes were present within the lipids of the pollenkitt, and released in the loculus at pollen mitosis. Unesterified pectin epitopes were hardly detectable in the cytoplasm of the young microspore but were as abundant in the primexine matrix as in the loculus. During pollen maturation, both unesterified and esterified pectin labelling accumulated in the cytoplasm of the vegetative cell, concurrently with starch degradation. In the mature pollen grain, unesterified pectin epitopes were located in the proximal intine whereas esterified pectin epitopes were deposited in the distal intine. These data suggest that during early microspore development, the tapetum secretes pectin, which is transferred to the primexine matrix via the locular fluid. Further, pectin is demonstrated to constitute a significant component of the pollen carbohydrate reserves in the mature grain of Lilium.

Antibodies, Monoclonal↗

PubMed2005

High-methoxyl pectin has greater enhancing effect on glucose uptake in intestinal perfused rats.

OBJECTIVE: Pectins have been known to decrease blood glucose levels. However, the mechanism of this effect is unclear. The direct action of various pectins (high- or low-methoxyl pectins) on the intestinal absorption of glucose was investigated in gut-perfused rats. METHODS: After equilibrium, jejunal and ileal segments were simultaneously perfused with an isotonic electrolyte solution (pH 7.4) containing glucose (10 mM/L) and high- or low-methoxyl pectins (10 g/L). Each test or control solution was perfused in a random sequence, with perfusion times of 30 min. Changes in glucose concentration of perfusate solution reservoir were determined over the experimental period. RESULTS: High- and low-methoxyl pectins in the perfusate significantly inhibited jejunal uptake of glucose compared with the control (P < 0.05). High-methoxyl pectins had greater inhibitive effect on intestinal absorption of glucose than low-methoxyl pectins. The observed changes in glucose and water absorptions caused by high- or low-methoxyl pectins were reversible by switching to a pectin-free perfusate. In addition, net water absorption changed to secretion after addition of high- or low-methoxyl pectins. CONCLUSIONS: These results suggest that the decrease in intestinal absorption of glucose observed after perfusion of high- or low-methoxyl pectins may be caused by viscosity-related increases in mucosal unstirred layer thickness.

Animals↗

PubMed2003

Chemically methylated and reduced pectins: preparation, characterisation by 1H NMR spectroscopy, enzymatic degradation, and gelling properties.

The gelling properties of pectins are known to be closely related to the degree of methylation (DM) and the distribution of the ester groups. In order to investigate this dependency, a natural citrus pectin (DM 64%) has been methylated to pectins with higher DM or saponified to achieve pectins with lower DM. A simple method for determination of DM by 1H NMR spectroscopy is presented. New modified pectins have been prepared by treatment of pectins having different DM with NaBH(4) to reduce selectively the methyl esters to primary alcohols in the presence of free acids. The degree of reduction (DR) and the DM of the remaining carboxylic acids could likewise be determined by 1H NMR spectroscopy. The new reduced pectins are recognized by the pectin degrading enzymes polygalacturonase PGI and PGII as well as by pectin lyase, all from Aspergillus niger, but the enzymes exhibit lower specific activities as compared with unmodified pectin. The new reduced pectins exhibit high gelling properties.

Aspergillus niger↗

PubMed2003

Production and characterization of oil-in-water emulsions containing droplets stabilized by beta-lactoglobulin-pectin membranes.

Oil-in-water emulsions containing droplets stabilized by beta-lactoglobulin (beta-Lg)-pectin membranes were produced using a two-stage process. A primary emulsion containing small droplets (d(32) approximately 0.3 microm) was prepared by homogenizing 10 wt % corn oil with 90 wt % aqueous solution (1 wt % beta-Lg, 5 mM imidazole/acetate buffer, pH 3.0) using a high-pressure valve homogenizer. The primary emulsion was then diluted with pectin solutions to produce secondary emulsions with a range of pectin concentrations (5 wt % corn oil, 0.45 wt % beta-Lg, 5 mM imidazole/acetate buffer, 0-0.22 wt % pectin, pH 3.0). The electrical charge on the droplets in the secondary emulsions decreased from +33 +/- 3 to -19 +/- 1 mV as the pectin concentration was increased from 0 to 0.22 wt %, which indicated that pectin adsorbed to the droplet surfaces. The mean particle diameter of the secondary emulsions was small (d(32) < 1 microm) at relatively low pectin concentrations (<0.04 wt %), but increased dramatically at higher pectin concentrations (e.g., d(32) approximately 13 microm at 0.1 wt % pectin), which was attributed to charge neutralization and bridging flocculation effects. Emulsions with relatively small mean particle diameters (d(32) approximately 1.2 microm at 0.1 wt % pectin) could be produced by disrupting flocs formed in secondary emulsions containing highly negatively charged droplets, for example, by sonication, blending, or homogenization. The particles in these emulsions probably consisted of small flocs containing a number of protein-coated droplets bound together by pectin molecules. These emulsions had good stability to further particle aggregation up to relatively high ionic strengths (< or =500 mM NaCl) and low pH (pH 3). The interfacial engineering technology used in this study could lead to the creation of food emulsions with improved physicochemical properties or stability.

Chemical Phenomena↗

PubMed2005

Stabilization of caseinate-covered oil droplets during acidification with high methoxyl pectin.

Polysaccharides are widely used in the food industry to modify the stability of protein-based drinks. However, an in depth knowledge of the interactions occurring in the system is still lacking. In this study, the interactions between sodium caseinate and high methoxyl pectin under acidification conditions were studied nondestructively and without dilution using transmission diffusing wave spectroscopy. Oil-in-water emulsions were prepared with 10% soybean oil and 0.5% sodium caseinate. Various concentrations of pectin (ranging from 0 to 0.2%) were added, and the emulsions were acidified with glucono-delta-lactone. With acidification, a "sol-gel" transition occurred and emulsions containing pectin were more stable at lower pH than those without pectin. Furthermore, the sol-gel transition of the mixtures was more sudden for control emulsions without pectin. While in control samples the final solidlike emulsion after gelation tended to be more inhomogeneous and more dissimilar to the starting emulsion, emulsions with pectin in solution gelled later under acidification. With a sufficient amount of pectin, the emulsions showed no aggregation and the destabilization pH varied depending on the amount of pectin present in the emulsions. At intermediate pH values (pH > 5.5), the emulsions displayed a decrease in particle size, more pronounced in samples containing pectin. The results collected using light scattering in concentrated systems, 10% (v/v) in our case, suggested that pectin stabilizes the emulsion oil droplets forming a network of oil droplets loosely connected by strands of pectin.

Caseins↗

PubMed1981

The effect of dietary citrus pectin on the excretion of human fecal neutral and acid steroids and the activity of 7alpha-dehydroxylase and beta-glucuronidase.

The purpose of this study was to investigate the effects of citrus pectin on human fecal neutral and acid steroid excretion and beta-glucuronidase and 7alpha-dehydroxylase activity. Eight healthy male subjects (age 20 to 27 yr) were used in a switchback design with or without 15 g citrus pectin added to a mixed low fiber diet. There were three successive 18-day periods preceded by a 4-day adjustment period. Half of the subjects followed a pectin-nonpectin-pectin protocol and the other half followed a nonpectin-pectin-nonpectin protocol. Fecal samples were collected throughout the study under anaerobic conditions. Compared to the control diet, mean fecal weight, percentage moisture, transit time, and fecal fat for both groups of subjects were not significantly different by analysis of variance when subjects were fed pectin diet. Mean beta-glucuronidase activity was increased (35%) when subjects were fed the pectin. Mean 7alpha-dehydroxylase activity showed no definite trend. Mean neutral steroid concentration was slightly decreased (8%) when the pectin diet was fed but total excretion was unchanged. End of period neutral steroid concentration was decreased 9% and total excretion was decreased 3.5%. Mean acid steroid concentration was not changed but total excretion was increased (11%) on the pectin diet. End of period acid steroid concentration and excretion was increased 6% on the pectin diet. This study shows that there were interrelationships between dietary pectin, neutral and acid steroid metabolism, and bacterial enzyme activity.

Adult↗