Different Degree Of Esterification Research Articles

Sucrose and Ca2+ synergistically regulate the rheological properties of apple high-methoxyl pectin

The thickening and gelling mechanism of high-methoxyl pectins (HMPs) with different degree of esterification (DE) values (60.6 %, 66.1 %, and 72.4 %) synergistically affected by calcium ion (Ca2+) and sucrose was investigated using several technical methods. Rheological measurements, including steady-shear flow, thixotropy and dynamic viscoelasticity tests, texture analysis, water-holding capacity (WHC), thermal analyses (TG), and microstructure observation (TEM), were all systemically conducted. The results showed that the main thickening and gelling mechanism of Ca2+ on different HMPs was complex and the presence of sucrose had a synergistic effect on structure formation in HMP systems. Ca2+ was not always conducive to structure formation, and excessive Ca2+ addition may hinder structure formation. HMP systems with lower DE values had higher gel strengths due to the presence of more binding domains. The results of the texture properties, WHC, and thermal characteristics coincided with those obtained from the rheological measurements, which reflect the variations in HMPs affected by Ca2+ and DE. All of these results showed that Ca2+ addition at an appropriate concentration in the presence of sucrose favors HMP gelation even in the absence of acid. The results obtained here are expected to broaden the application of HMPs in acid-free gel food products.

Effect of degree of esterification on the stability of high internal phase Pickering emulsions (HIPPEs) fabricated with pectin‐whey protein isolate complexes

SummaryThis study examined the effects of different degree of esterification (DE) on the stability of high internal phase Pickering emulsions (HIPPEs) fabricated using pectin‐whey protein isolate complexes. The modified pectin with different DE was prepared using the alkali de‐esterification method with high methoxyl pectin (HMP). The impact of DE on the conformational changes of pectin and whey protein isolate (WPI) during the complexes formation was examined using Fourier transform infrared spectroscopy (FTIR) and fluorescence spectroscopy. Citrus pectin (CP)–WPI complexes and camellia oil were used to create an emulsion with a self‐supporting structure of 75% internal phase volume. The thermal, centrifugal, storage and freeze–thaw stabilities of CP–WPI stabilised HIPPEs with different DE were evaluated and the results revealed that the low methoxyl pectin (LMP) produced via alkali de‐esterification altered the charge density of pectin. Compared with the untreated pectin, the electrostatic interaction between CP–WPI complexes was enhanced and the stability of CP–WPI stabilised HIPPEs was improved. The study will help to better understand the interaction between CP and WPI, enhance the efficiency of the pectin–protein delivery system and improve the utilisation rate of citrus pectin, which has important guiding significance.

Enzymatic de-esterification and depolymerization of apple pomace (Malus domestica var. Blanca de Asturias) pectin impacts lipid digestion invitro

Different degree of esterification (DE) and molecular weight (Mw) of apple pomace pectin (APP) were evaluated for the effect on lipid digestibility. APP was isolated from variety “Blanca de Asturias” by acidic extraction to obtain pectin with 66% of DE, and 348 kDa Mw. APP was de-esterified with pectinmethylesterase (PME) obtaining APP with DE of 57, 42, and 39%. APP was depolymerized by endo-polygalacturonase (PG) or pectate lyase (PL), and three modified APP fractions were obtained with Mw of 309, 166, and 162 kDa or 241, 205, and 184 kDa for PG-APP or PL-APP fractions, respectively. A considerable reduction in the composition of neutral sugars was observed in the modified samples, which is related to the reduction of the branched region of the pectin. Oil-in-water emulsions prepared with 2% (w/w) of different APP samples were shear thinning and viscosity was 2–20 times higher in pectin added emulsions. Inhibition of lipid digestibility measured in a multiple stage in vitro model showed that APP and modified APP with higher DE significantly reduced lipid digestibility by 25%. The results contribute to the design of higher fat foods and putative higher consumer acceptability. The addition of pectin with certain structural characteristics, can reduce the degree of lipid digestibility, that may help mitigate public health problems such as obesity.

The effect of degree of esterification of pectin on the interaction between pectin and wheat gluten protein

Pectins with different degree of esterification (DE) (37, 46, 58, 63 and 73%) were prepared by alkali method and the effect of the DE on the interaction between pectin and wheat gluten protein was investigated in the present study. The results showed that low-ester pectin increased the water holding capacity (WHC) and viscoelasticity of gluten protein. The low-ester pectin promoted the conversion of sulfhydryl groups (-SH) to disulfide bonds (-S-S-). Compared with control gluten protein, the -S-S- content of gluten protein added with low-ester pectin significantly increased from 18.82 to 21.65 μmol/g, indicating that the gluten network structure was strengthened. Compared with high-ester pectin, low-ester pectin increased β-sheet content by 18.48%, suggesting that the stability of gluten protein was enhanced. In addition, intrinsic fluorescence spectra showed that the maximum intrinsic fluorescence intensity (Imax) of gluten protein added with low-ester pectin decreased from 826.53 to 630.47. Meanwhile, the surface hydrophobicity (H0) of gluten protein added with low-ester pectin decreased from 497.33 to 419.82. These results showed that low-ester pectin interacted more easily with gluten protein than high-ester pectin and formed some aggregates. Moreover, SEM and mercury intrusion results indicated that the low-ester pectin (DE-46%) was beneficial to maintaining the gluten network structure. These results will provide a theoretical basis for the application of pectin in wheat flour products.

Physicochemical characteristics and functional properties of high methoxyl pectin with different degree of esterification

Moderate alkali de-esterification can change the physicochemical characteristics and thus the functional properties of high methoxyl pectin (HMP). The results revealed that de-esterification could increase negative charges (Zeta potential from −21 to −31 mV), decrease molecular weight (from 448 to 136 kDa) and apparent viscosity of HMP. Homogalacturonan (HG) content decreased (from 62% to 49%) while rhamnogalacturonan Ⅰ (RG-Ⅰ) content increased (from 32% to 46%) after de-esterification. The group characteristics of HMP with different degree of esterification (DE) were similar and no obvious impact was made on degree of crystallinity by alkali de-esterification. A conformation transition of HMP molecule implied by Congo red test were occurred as the DE decreased. With the decrease of DE, the molecular structure of HMP became shorter and smaller, and the entanglement was weaker. The de-esterification caused slight decrease of thermal stability. Alkali de-esterification would weaken the gel property and the emulsifying ability of HMP.

Effect of the degree of esterification of disperse dyes on the dyeing properties of polyethylene terephthalate in supercritical carbon dioxide

The reason of color differences caused by different degree of esterification disperse dyes were investigated by disperse orange 30, disperse red 167:1, disperse blue 79:1 with different degree of esterification. The results showed that the changes of light absorbance abilities and melting points caused by ester groups had no obvious correlation with the color differences caused by ester groups. The changes in the solubilities and affinities caused by the ester groups were the fundamental reason for the changes in the dyeing properties of disperse orange 30, disperse red 167:1 and disperse blue 79:1. As a joint result of the decrease in solubilities and affinities, the dye sorption in polyethylene terephthalate of unesterified disperse orange 30, unesterified disperse red 167:1 and unesterified disperse blue 79:1 were reduced by 37.7%, 83.6% and 54.6%, respectively, compared with those of the corresponding completely esterified dyes.

Synergistic gelling mechanism of RG-I rich citrus pectic polysaccharide at different esterification degree in calcium-induced gelation

RG-I rich pectic polysaccharide is common in fruit and vegetable and possesses health benefits. However, it is removed during commercial pectin production because of poor gelling properties. Synergistic gelation can improve rheological properties of RG-I pectic polysaccharide and expand its application in functional food hydrocolloids. In the study, RG-I rich pectic polysaccharides at different degree of esterification was extracted from citrus membrane by sequential mild acidic (0.4% HCl, 28 °C) and alkaline (0.6% NaOH, 32 °C) treatment. The pectic polysaccharide from acid water (PA) composes of 41% RG-I and 44% HG with DM of 45%, while the pectic polysaccharide from basic water (PB) composed of 63% RG-I and 19% HG with DM of 15%. PA/PB blend gel under CaCO3-glucono-δ-lactone system showed improved rheological properties compared with pure gels. Ca-bridges connected pectin aggregates and promoted the three-dimensional structure of PA/PB blend gels, while neutral sugar side-chains prompted hydrogen bonds and strengthened gel network.

The Impact of Esterification Degree and Source of Pectins on Complex Coacervation as a Tool to Mask the Bitterness of Potato Protein Isolates

There is an increasing interest in the food industry to use potato protein as an alternative plant protein. However, its bitter taste often limits the utilization in novel foods and beverages. Coacervation is a promising technique to mask bitterness of certain food compounds. In the present study, we aimed to reduce the degree of bitterness of potato protein by generating protein-pectin complexes based on coacervation. Potato protein isolate and pectins derived from various origins having different degree of esterification (DE) were initially mixed under acidic conditions to promote the formation of complexes. Single and complex biopolymers were then characterized in terms of surface charge, solubility, rheological and sensorial properties as a function of protein pectin ratio, pectin source, and the degree of esterification, respectively. The protein-pectin ratio and degree of esterification of pectins substantially influenced the interaction behaviour and phase separation of the protein-pectin mixtures. The bitterness score decreased with increasing surface charge and pectin concentration. Bitterness was strongly reduced for complexes formed with high DE citrus pectin at a protein pectin ratio 0.33. The complexes generated at this ratio were relatively stable based on visual observation and microscopic images. Our results might have significant implications for the utilization of potato proteins in beverage applications.

Enhancing the stability of oil-in-water emulsion using pectin-lactoferrin complexes

The present study investigated on the emulsifying properties of natural low-methoxyl pectin (LMP) extracted from Green Jelly Leaf (GJLP) in stabilising lactoferrin stabilised oil-in-water emulsions. The emulsion stability of GJLP was compared to commercial pectins with different degree of esterification (DE) i.e. high-methoxyl pectin (HMP) and LMP. The influence of pH, pectin types and concentration on the stability and physical properties of emulsions were evaluated by determining zeta potential value, particle size, microstructure, rheological properties and creaming stability. Different types of pectin exhibited different mechanisms in providing the emulsion stability and the pectin effective charge was strongly dependent on its DE and pH of the continuous phase. The mechanism of actions of pectin and lactoferrin in the system were pH dependent for low molecular weight pectin, however not for high molecular pectin such as GJLP. The results showed that the complexes formed by pectin and lactoferrin at the interface were not sufficient to maintain the emulsion stability. This study also showed the important of unabsorbed pectin molecules in continuous phase in providing the physical stability of emulsion. These molecules formed a thick multilayers surround oil droplets. In addition, the incorporation of 0.2% w/w of GJLP could produce a stable emulsion, suggesting the potential use of GJLP to improve the stability of lactoferrin stabilised oil-in-water emulsions.

Preparation of methyl alginate and its application in acidified milk drinks.

A series of methyl alginate with different degree of esterification (DE) were prepared with low cost, and its application in acidified milk drinks (AMDs) was investigated. The gel strength, molecular weight, solution apparent viscosity and optical rotation value of methyl alginate all decreased with the increase of DE. Methyl alginate with DE equal or larger than 60.7% was more effective in stabilizing AMDs than high-methoxyl pectin (HMP) under the same conditions, and the higher the DE, the better its stabilizing ability. The methyl alginate had better synergistic action for stabilizing AMDs with propylene glycol alginate (PGA) than HMP. The reason for this could be attributed to that methyl alginate and PGA had the same main chain structure, and the same levorotatory optical activity. The results indicated that the methyl alginate had a potential industry application prospect for stabilizing AMDs as an alternative to HMP.

Environmental stress stability of pectin-stabilized resveratrol liposomes with different degree of esterification

Based on the hydrogen bonding ability of polysaccharides and phospholipids and steric hindrance, nanoliposomes (LPs), pectin-coated resveratrol liposomes (LMP-LPs and HMP-LPs) with different esterification degrees (DE = 30%, 70%) were prepared. The entrapment efficiency was 78 ± 5%. The addition of pectin with different degree of esterification (DE = 0%, 30%, 70%) increased the particle size of liposomes from 102 nm to 122 nm and 140 nm and negative charge change from −13.63 mV to −20.96 mV and −30.11 mV respectively. This is mainly due to the adsorption of pectin on the liposome surface. Some environmental factors such as pH, ionic strength and temperature have a significant effect on the appearance, particle size and leakage rate of liposomes. Experiments have shown that the leakage rate of low-methoxy pectin-coated liposomes resveratrol is lower, and this work provides useful information on the use of low-methoxy pectin for controlling food release.

Formation of Polyelectrolyte Complex Colloid Particles between Chitosan and Pectin with Different Degree of Esterification

The effects of degree of esterification, pectin/chitosan ratio and pH on the formation of polyelectrolyte complex colloid particles between chitosan (CS) and pectin (PE) were investigated. Low methoxyl pectin (LPE) was achieved by de-esterifying high methoxyl pectin (HPE) with pectin methyl esterase. Turbidity titration and colorimetric method was used to determine the stability of complex colloid particles. The structure and morphology of complex particles were characterized by FTIR and TEM. When pectin solution was dropped into chitosan solution, complex colloidal dispersion was stable as PE/CS mass ratio was no more than 3:2. Colloidal particles of HPE-CS complex coagulated at larger ratio of PE/CS than LPE-CS. The maximum complex occurred at pH 6.1 for HPE-CS and pH 5.7 for LPE-CS, and decreasing pH leaded to the dissociation of complex particles. Electrostatic interactions between carboxyl groups on pectin and amino groups on chitosan were confirmed by FTIR. Colloidal particle sizes ranged from about 100 nm to 400 nm with spherical shape.

Chemical modification of citrus pectin: Structural, physical and rheologial implications

The present study aimed to investigate the physical, structural and rheological modifications caused by the chemical modification process of citrus pectin. Therefore, three commercial citrus pectins with different degree of esterification were chemically modified by sequential alkali and acidic hydrolytic process to produce modified citrus pectins (MCP) with special properties. The molar mass (Mw), degree of esterification (DE), monosaccharide composition, 13C NMR spectra, homogeneity, morphology (SEM) and rheological behavior of both native and modified citrus pectins (MCP) were investigated. The chemical modification reduced the acid uronic content (up to 28.3%) and molar mass (up to 29.98%), however, showed little influence on the degree of esterification of native pectins. Modified citrus pectins presented higher amounts of neutral monosaccharides, mainly galactose, arabinose and rhamnose, typical of the Ramnogalacturonana-I (RG-I) region. Rheological tests indicated that the native and modified citrus pectins presented pseudoplastic behavior, however, the MCP samples were less viscous, compared to the native ones. Modified samples presented better dissolution in water and less strong gels, with good stability during oscillatory shearing at 25°C. This study aims to better understand the implications that chemical modifications may impose on the structure of citrus pectins.

Synthesis and Application of a New Amphiphilic Antioxidant.

A new amphiphilic antioxidant (tannyl stearate) derived from reaction of tannic acid with stearic acid was synthesized in order to improve tannic acid solubility in lipid materials. This reaction gives many products having different degree of esterification (tannyl mono, di, tri, tetra, penta, hexa, hepta……stearate) which were separated using silica gel column chromatography and tentative identification was carried out using thin layer chromatography (TLC). The intrinsic viscosities (η) were used to differentiate between the different molecular weight of the produced esters1). Tannyl penta stearate is assumed to be the most suitable amphiphilic antioxidant derivative, where those derivatives with less degree of esterification would be less soluble in fat, and those of higher degree of esterification would exhaust more hydroxyl group that cause decreases of antioxidant activity. The structure of tannyl penta stearate was approved depending on its chemical analysis and spectral data (IR, H1 NMR,). The emulsification power of tannyl penta stearate was then determined according to method described by El-Sukkary et al.2), in order to prove its amphiphilic property. Then tannyl penta stearate was tested for its antioxidant and radical scavenging activities in three different manners, those are, lipid oxidation in sunflower oil using Rancimat, (DPPH) free radical scavenging and total antioxidant activity. {Pure tannic acid (T), butylhydroxyanisol (BHA) and butylhydroxytoluene (BHT) were used as reference antioxidant radical saving compounds}. Then tannyl penta stearate was added to sunflower oil, frying process was carried out and all physicochemical parameters of the oil were considered, and compared to other reference antioxidant in order to study the effect of this new antioxidant toward oil stability. Acute oral toxicity of the tannyl penta stearate was carried out using albino mice of 21-25 g body weight to determine its safety according to the method described by Goodman et al.3). Also liver and kidney functions of those mice were checked. Thus it could be concluded that the addition of tannyl penta stearate to frying oils offers a good protection against oxidation. The effectiveness of tannyl penta stearate as lipid antioxidant has been attributed mainly to its stability at high temperature. And according to acute lethal toxicity test tannyl penta stearate was found to be a safe compound that can be used as food additive.

Interfacial and emulsifying properties of citrus pectin: Interaction of pH, ionic strength and degree of esterification

The interfacial and emulsifying properties of citrus pectin of different degree of esterification (DE = 55, 70 and 84%) were investigated. Ionic strength and pH were varied in order to modify the polyelectrolyte behavior of citrus pectins. The smallest hydrodynamic radius, lowest charge and fastest adsorption kinetics were found for high DE and high ionic strength at low pH. The extent of the dilational interfacial elasticity correlated with the amount and ratio of hydrogen bonds and hydrophobic interactions. The measured droplet sizes were mostly influenced by the adsorption kinetics and the salt responsiveness of citrus pectin. The faster the adsorption kinetics the smaller the resulting droplet sizes. Sodium chloride induced microgel particle formation of pectins. These microgel particles were less effective in droplet stabilization so that demulsification due to strong coalescence occurred. It was possible to counterbalance this effect by increasing the hydrocolloid emulsifier concentration.

Preparation and characterization of nisin-loaded pectin-inulin particles as antimicrobials

Nisin is a known bacteriocin approved as a food additive for food preservation. To protect the bacteriocin from its interaction with food components, nisin-loaded pectin-inulin particles were prepared. For particles preparation, pectins with different degree of esterification were used. The combination of inulin with pectin increased the efficiency of nisin loading as compared with nisin-pectin particles. For all tested pectins in the pH range of 4.0–7.0 and in the range of nisin concentration of 0.1–1.0 mg/mL the loading efficiency was equal to 100%. The combination of inulin and pectin for particles preparation slightly but not significantly increased the antimicrobial activity of nisin comparing to nisin-pectin particles. The antimicrobial activity of nisin-loaded pectin-inulin particles was dependent on the degree of pectin esterification. The particles with low degree of pectin esterification or with not esterified pectic acid demonstrated the higher activity as compared with the particles of high degree of pectin esterification. Due to the high efficiency of nisin-loading and similar antimicrobial activity comparing to nisin-pectin particles, the combination of pectin and inulin has the perspectives for the antimicrobial particles preparation and their application in food industry.

Influence of the degree of esterification on the emulsifying performance of conjugates formed between whey protein isolate and citrus pectin

Conjugates were prepared from whey protein isolate (WPI) and pectins in a dry heating process (80 °C, 79% RH). Citrus pectins with different degree of esterification (DE) were employed: low methylesterified (LMCP, DE = 34%), high methylesterified (HMCP, DE = 72%), very high methylesterified (VHMCP, DE = 84%). SDS-PAGE of heat treated WPI-pectin samples showed typical patterns of conjugate formation with substances of Mw > 100 kDa being detected first after 6 h of reaction time. Fluorescence intensity measurements of conjugate solutions indicated a maximum for WPI-HMCP and WPI-VHMCP after 15–18 h of reaction time. However, the fluorescence intensity of WPI-LMCP solutions increased continuously reaching the highest values of the three mixtures. Zeta potential measurements of conjugate solutions exhibited the opposite behavior. A minimum was found for WPI-HMCP. The zeta potential of WPI-LMCP solutions decreased monotonously reaching values of around −50 mV. In emulsification experiments, a significant reduction of the emulsion's Sauter mean diameter d3,2 was found when conjugates were employed at pH 5.5 and 7. The smallest droplet sizes in the hundred nanometer range were obtained for WPI-LMCP conjugate emulsions. Linking fluorescence measurements of conjugate solutions to emulsion d3,2 revealed that 1.) the stabilizing mechanism of WPI-pectin conjugates is mostly steric, 2.) the conjugate yield is the main factor dominating emulsion droplet size and 3.) the conjugate yield is highest when low esterified pectin is used.

Thermogravimetric analysis of pectin gels

A weight loss and speed change occurring in gels of citrus and apple pectin of different degree of esterification and the effect of sodium citrate on the mass loss of low pectin gel are studied by thermographic technique constant heating rate. The dependence of the degree of weight change on temperature of gel of citrus and apple pectin with high and low degree of esterification is determined

Pectin-based pellets for crayfish aquaculture: structural and functional characteristics and effects on redclaw Cherax quadricarinatus performances

Pectin is a promising candidate to be employed as binder for manufacturing pellets for crayfish feeding. In this study, the gelling properties of different types of pectin and their effects on Cherax quadricarinatus performances have been analysed. Pectins with different degree of esterification from apple and citrus were screened to select those with the best gelling properties to be employed in pellet manufacturing. Three pectins were selected: low esterification degree apple pectin (LEAP), low esterification citrus pectin (LECP) and high esterification degree apple pectin (HEAP). Scanning electron microscopy analysis, nutrient leaching and water uptake indicated that LEAP showed the best aggregating properties, followed by LECP and HEAP pellets. Cherax quadricarinatus performances were affected by the pectin type, with redclaw fed LEAP pellets showing the highest (P < 0.05) growth rate and amylase activity (P < 0.05) in the gastrointestinal tract. Altogether these results indicate that LEAP can be considered an excellent binder for feed pellets due to its gelling properties and its efficacy to improve growth and stimulation of digestive enzyme activity.

Synthesis and Safety Evaluation of a New Enteric Coating Material

A series of styrene-maleic anhydride (SMA)-ethanol polymers with different degree of esterification (DE) were synthesized, they had different pH-sensitive values and could be used as enteric coating materials. SMA-ethanol (DE50%) was used as the model compound to evaluate the safety as an enteric coating material, the results of acute toxicity tests showed that there was no acute toxicity. The reaction condition such as catalysts, catalyst amount, reaction time and temperature were also evaluated, the results indicated that the triethylamine (TEA) was the optimal catalyst, when methyl ethyl ketone (MEK) was the solvent, the catalyst amount was 15-20%(molar percent), the reaction at 80 OC for 8h could gain the highest conversation.