Methods of extraction of pectin from various agrowaste compounds.
With the advent of science and technology, agro-industrial wastes are converted into various value-added products to meet the demands of increasing population. In recent years, natural polymers have evoked tremendous interest due to easy conversion into value-added products. Apart from various natural polymers, pectin occupied a prominent place due to diverse pharmaceutical and therapeutic applications. Excess utilisation of pectin, the gap between production and demand is widening. To fulfil this gap various techniques are adopted for obtaining high yield pectin from various agro-industrial wastes. This chapter will be focusing on extraction and purification of pectin from various agro-industrial wastes, considered as main environmental pollutants.
Pectins are complex branched polysaccharides present in the primary cell wall of plants . It is a highly valued food ingredient commonly used as a gelling agent and stabilizer . It is usually extracted by chemical or enzymatic methods from fruits . Pectin is considered as the most complex macromolecule in nature, since it can be composed of up to 17 different monosaccharides containing more than 20 different linkages .
Pectins are enriched with repeated units of methyl ester galacturonic acid . They form chemically stable and physically strong skeletal tissues of plants when combined with proteins and other polysaccharides . They are usually produced in the initial stages of primary cell wall growth and make one third of the cell wall in both monocots and dicots . Pectin is significantly reduced or absent in non-extendable secondary cell walls and is the only major class of plant polysaccharide largely limited to primary cell walls . Pectin imparts strength and flexibility to the cell wall, apart from number of fundamental biological functions such as signalling, cell proliferation, differentiation, cell adhesion and maintaining turgor pressure of cell . Pectins are involved in regulating mobility of water and plant fluids through the rapidly growing parts . It also influences the texture of fruit and vegetables . Apple pomace and orange peel are the two major sources of commercial pectin due to the poor gelling behaviour of pectin from other sources .
Pectin is one of the most important polysaccharides due to its increasing demand in the global market, reaching a total production capacity of around 45–50 Million tonnes per annum. While the demand in 2011 was approximately 140–160 Million tonnes per annum, earning the interest of industry in this complex polysaccharide processing . Pectins have received considerable attention as a high fibre diet that benefits health by reducing cholesterol and, serum glucose levels and acting as anticancer agents . Pectins have shown promising results as drug carriers for oral drug delivery and are widely used for various bio-medical applications . In addition, pectin has been described as an emerging prebiotic with the ability to modulate colon microbiota . Considering above properties and applications, pectin has gained immense priority in the global biopolymer market with great potential and opportunities for future developments.
2. Structure and properties of pectin
One of the most abundant macromolecules present in the primary cell wall of the plants is pectin; their presence is detected in the matrix as well as in the middle lamellae . Pectin is highly rich with galacturonic acid (GalA), that forms the backbone of three more domains found along with pectin that are homogalacturonan (HGA), rhamnogalacturonan-I (RG-I) and rhamnogalacturonan-II (RG-II) . About 70% of pectin is mainly composed of galacturonic acid (GA) . Pectin is made of three polysaccharides that are covalently linked together, thus forming pectin networks in the cell wall matrix and the middle lamellae [15, 16].
Homogalacturonan (HG) takes up about 60–65% of the total pectin [3, 17], with a backbone of alpha-1,4-linked GalA residues, these GalA residues are methyl esterified which has an important role in the physical properties of pectin . The presence of HG is seen to be present in approximately 100 GalA residues, but there are cases when its detected interspersed within other pectin polysaccharide . On the other hand rhamnogalacturonan-I (RG-I) backbone which contributes 20–35% of pectin is composed of repeated and alternating groups of l-rhamnosyl and d-galacturonosyl residues . There can be as many repeats as 300 of this disaccharide in case of sycamore cells, which are cultured in suspension [3, 16, 19]. The rhamnosyl residues have side chains of sugars which are mainly consisting of either galactosyl or arabinosyl residues . The GalA residue of RGI unlike HGA are mostly not methyl esterified .
Rhamnogalacturonan-II (RG-II) is one of the highly conserved and complex structure which consist of distinct regions within HG, which makes up about 10% of the pectin , they have side chains of four different types with a particular sugar residue like aceric acid, apiose-3-deoxy-lyxo-2-heptulosaric acid, and 3-deoxy-manno-2-octulosonic acid. The HG residues along with nine of the GalA residues are attached to these side chains [3, 5]. There are other substituted HG residues that make up pectin such as xylogalacturonan and apiogalacturonan whose expression is restriction. Even a minor mutation in R-II structure can lead to defects in the plant growth like dwarfism, thus suggesting its importance for normal growth of plant . RG-I being highly branched in nature thus, called as the hairy region of pectin on the other hand HGA domain are known as the smooth region . It is generally believed and noticed that there is covalent linkage within the pectin polysaccharides and pectin degrading enzymes are needed to separate and isolate HG, RG-I and RG-II from each other [21, 22]. Due to their similarity in HG and RG-II backbone structure composing of 1-4-linked alpha-D-GalA residues, they are likely to be linked covalently but there are no reports of RG-I to be covalently linked with HG .
3. Properties of pectin
Pectin precipitates as a solid gel on treating with a dehydrating agent like alcohol. They are extremely sensitive to dehydration and get effected by any other hydrophilic colloids as well, thus they are known to be insoluble in most of the bio-colloids. The negative charge of pectin depends on the number of free carboxyl group that is mainly responsible for its precipitation .
Based on solubility pectins are of two types i.e., water soluble and water insoluble. Factors affecting the solubility of pectin are pH, temperature, nature of the solute and concentration of the solute [6, 13]. Pectin attains stability at a pH of 4 . The solubility of pectin also depends on its composition like monovalent cation of pectin are soluble in water whereas di or trivalent are insoluble in water.
One of the most interesting properties of pectin is its ability to form gel in the presence of either acid or calcium or sugar, this enables them to be used in many food industries . Hydrogen bonding and hydrophobic interactions between polymer chains stabilizes the pectin polymer .
4. Extraction and purification of pectin from agrowaste
Pectin is a high molecular weight polysaccharide that is present in almost all plants and help in maintaining the integrity of cell structure. Pectin is used in food industries to increase the viscosity of food products such as beverages, jams and jellies. It also has implications in pharmaceutical industry, especially in drug formulations, as an excipient due to its characteristics in release kinetics. Due to increased demand for pectin in food, pharmaceutical and therapeutic applications, thus, require efficient extraction processes. In order to increase the yield of pectin, various extraction methods have been adapted to obtain insoluble pectin present in the middle lamellae of plant cells, one of them being heating in acidic medium that makes insoluble pectin as soluble. Ripening of fruits also converts insoluble pectin into soluble pectin. Pectin can be extracted from various kinds of fruits, but the most commercial form of pectin is extracted from the peels of citrus fruits by alcohol precipitation [9, 25]. Citrus fruits contain 0.5–3.5% pectin which is largely present in the peel of fruits .
Pectin has been isolated from various plants such as apple , citrus peel, carrots , sugar beet pulp [29, 30], sunflower heads , papaya  and oranges . The most commonly used method for extracting pectin from plant tissue is by heating the plant sample in acidified water. The addition of extra chelating agents such as EDTA to the extraction mixture helps in easy release of pectin from cell wall. Care should be taken not to perform a long period of direct heating as it may lead to the thermal degradation of the polymer. Extraction process of pectin is carried out under reflux using acidified water at 97°C for 30 min. The hot acid extract was then filtered using a cheese cloth to remove the pulp. The filtrate was then cooled to 4°C and precipitated using double the volume of ethanol. The solvent precipitate mixture is then mixed till the pectin floats and removed by using cheese cloth followed by drying .
Pectin is also extracted from dried sugar beet pulp after treating with acidified medium followed by purification through alcohol precipitation. Xin Huang et al., slightly modified the traditional method, where the sample was diluted with deionized water and was made acidic (pH −1.2) by using HCl. The sample was then heated to 90°C for 3 h and cooled to 40°C (pH −4.5) with 25 g/100 g ammonia. The mixture was then filtered using a Buchner funnel and pectin was precipitated using ethanol . The ethanol is removed by squeezing with nylon cloth and washed several times followed by drying.
The carrot pomace is also used for pectin extraction by treating with hot aqueous citric acid solution adjusted to the desired pH. The pectin yield was maximum at the following optimum conditions: pH −1.3; temperature 90°C; heating time 79.8 min. Under these conditions, the extraction yield of carrot pomace pectin was found to be 16.0%. The extract mixture was then allowed to cool, filtered and precipitated by using ethanol in the ratio 2:1 . Dried papaya peel can be used in pectin extraction where the majority of the lipids, and soluble pigments are removed by treating with ethanol and acetone. It is repeatedly homogenised with 95% ethanol and filtered until the filtrate becomes clear. The final filtration was done with the residue homogenised in acetone and dried overnight to obtain the alcohol insoluble residue (AIR). The majority of the pectin in the papaya AIR is present as chelator soluble pectin (CSP) followed by sodium carbonate soluble pectin (SSP) and water-soluble pectin (WSP). The WSP fraction is first obtained from the AIR by boiling it in water and filtering it. The remaining residue is treated with 0.05 M cyclohexane trans-1,2-diamine tetra-acetic acid (CDTA) in 0.1 M potassium acetate (pH 6.5) for 6 h at 28°C and filtered to give the CSP fraction. The residue is then treated with 0.05 M sodium carbonate solution having 0.02 M NaBH4 for 16 h at 4°C, and subsequently for 6 h at 28°C. The solution when filtered gives the SSP fraction of the AIR .
Agro-industrial wastes can be used as the raw material for the production of industrial low and high methoxy pectin. The alcohol insoluble material (AIM) produced from dried agrowaste by boiling it with 3 volumes of ethanol for 25 min and continuous washing with 70% ethanol to remove impurities such as pigments, free sugars, etc. Sunflower heads also act as potential sources for pectin extraction. The heads are washed by hot distilled water through a mesh or cheese cloth and the pectin was precipitated by addition of 1 M nitric acid at 1:5 acid:filtrate ratio . The mixture was maintained for 1 h at 5°C and was washed six times in ethanol solvent at 1:2 gel:solvent ratio to remove the impurities and to increase pH by removing the acid . The washed pectin gel can be dried in a vacuum oven at 55°C for 16 h. The dried pectin flakes are ground into a powder for further use (Table 1).
|Material||Extraction process||Pectin (%)||References|
|Cacao pod husk (
|Mangosteen rind (
|Durian rind (
|Orange peels (
|Lemon peels (
|Dragon fruit peels (
|Banana-stem, leaf, peel (
|Orange peel||Alcohol precipitation||7.9|||
|Aqueous acid extraction alcohol precipitation||4.53|||
|Cocoa peel||Microwave assisted||42.3|||
|Apple Pomace||Acid extraction||12.9–20.9|||
|Lime-peel and pulp||Microwave assisted extraction under pressure||8–17.9|||
|Watermelon rind||Acid and enzymatic extraction|||
|Orange peels||Acid extraction||5.4–26.3|||
|Sweet potato peels||Acid extraction||2.59–5.08|||
|Orange peel||Ultrasound assisted||20.92|||
|Orange peels (
|Kaffir lime peel (
||Chemical and acid extraction||61.8|||
|Orange peel (
|Orange peel||Water-based extraction||2.2|||
|Sweet potato peel (
|Tomato waste||Ultrasound assisted||15.1–35.7|||
|Pumpkin peels||Soxhlet extraction||6.8–7.7|||
|Lemon pomace||Acid extraction||10.3–13.1|||
|Jackfruit waste (
||Acid and chemical extraction||12–15|||
|Lemon peel wastes||Aqueous extraction|||
|Citric waste||Acid extraction||78|||
|Apple peel waste (
||Acid and chemical extraction||1.21|||
|Horse eye bean peel (
|Banana peel||Acid extraction||11.31|||
|Mango peel||Acid extraction||18.5|||
|Grapefruit peel||Alcohol extraction||25|||
|Saba banana peel (
|Passion fruit peels||Acid extraction||2.25–14.6|||
|Citrus peel||Acid extraction||25.5|||
|Pumpkin waste (
|Mango peel||Acid extraction||20.8|||
|Jackfruit wastes (
||Optimised acid extraction||38.42|||
|Orange peel||Acid extraction||7.3–52.9|||
|Jackfruit waste (
||Chemical and acid extraction||8.9–15.1|||
Large amounts of fruit wastes that are being generated can be disposed effectively by manufacturing beneficial by-products like pectin. Pectin is used to increase foaming power of gases, as agglutinator, as filler in pharmaceutical preparations and also in food industry. The use of pectin for different purposes depends on its characters like acetyl value, degree of esterification, uronic acid content and methoxyl content, etc. . The amount of anhydrouronic acid gives the purity of pectin which is not less than 65% for pectin that is used commercially .
5.1 Qualitative tests
Colour reader can be used to measure the colour of extracted pectin by placing lens of reader on sample powder. The colour of the extracted samples can be compared with that of commercial pectin. Solubility of pectin in different solvents is measured i.e., solubility in cold and, hot water and alkali like NaOH.
5.2 Quantitative tests
Acetyl content and equivalent weight of pectin can be estimated using NaOH whereas methoxyl content can be estimated by saponification and titration. Degree of esterification can be calculated from methoxyl content and anhydrouronic acid content. After acid hydrolysis, sugar separation can be achieved by thin layer chromatography. Intrinsic viscosity of pectin is measured by dissolving pectin in water and by preparation of solutions of various concentrations [27, 32, 60].
Pectin being a great inert, biodegradable and biocompatible complex, is widely used in various fields such as in textiles, food industries as gelling agents, pharmaceuticals and other products as well . Pectin are used as biomaterials in gene delivery , application in oral drug delivery , as edible coating for food packaging , biomass yield and bio refinery [21, 22]. It also has applications in tissue engineering as scaffolds , in paper and textile industries for the preparation of ultracentrifugation membrane .
6.1 As food product
From the very early period of time, pectin had become one of the major natural constituents of human food, and they have been widely used as a gelling agent for jams and jellies. In jam processing, fruits are cooked properly in order to release juice and pectin which converts the proto-pectin into soluble pectin . Pectins are also used as a substitute of sugar in jams that are made without sugar, using LM (low methoxy) pectin due to its stability in acidic condition. Pectin is widely used for making instant jellies for bakery production these are made with the use of HM (high methoxy) pectin that are thermally stable, the only difference between HM and LM pectin is the amount of pectin in the formula, LM requires a higher amount than that of HM . Other food products like artificial cherries , are used to make different kinds of gel puddings that is made of pectin present in the fruit syrup and cold milk . Edible coating of food material is also made of pectin . Pectin is used in beverages as a beverage clouding agent like in diabetic soft drinks . Pectins are also used in the fruit preparation of yogurt to make it more soft and to obtain the partial gel texture .
6.2 Biomedical application
6.2.1 Pectin as films
The blending of the natural and synthetic polymers is one of the promising areas of development, this gives new polymeric material with better durability and resistance. Materials like sponge, hydrogels, encapsulating drugs etc. are produced by polymer films . Due to development and discovery of natural polymers scientist have started to form bio-based material rather than synthetic one due to its physiochemical properties like biodegradability, this shift is mainly caused due to the environmental issues and concern regarding the heavy use of plastic . Films of pectin are used to encapsulate and thicken food, and in pharmaceuticals . Hoagland et al. made pectin films with glycerol and lactic acid to prevent fungal contamination on the laminated films . The similar kind of products were made by Fisherman et al., where an edible pectin blend film were plasticized with glycerol, they also suggested that the glass transition at about 50°C was large in case of pectin films, which indicates that the films were fairly flexible at room temperature . Liu et al., made different varieties of biofilms one each with pectin, fish skin gelatin and soybean flour protein which in turn resulted in a composite film that showed an increase in stiffness as well as the strength, whereas decrease in water solubility and water vapour transmission rate when compared to the film that was made with pectin alone. They thus suggested that the tensile strength can be improved by crosslinking the films with methanol or glutaraldehyde . A bio-reactive substance for tissue regeneration was developed by Liu et al., which was composed of pectin or PGLA matrix, which demonstrated that pectin was able to carry signals to molecules, further they suggested that the pectin also helped in the adhesion of the cell and promotes cell proliferation . Some researches have reported the use of pectin membranes as a wound dressing material .
6.2.2 Drug delivery
In recent years, biomedical application especially in case of drug delivery system, the use of natural polymers is preferred over the other types due to their inert nature and its biocompatibility. Pectin as the natural polymer is a new developed interest for drug delivery application due to its properties of gel formation in acidic condition, its mucoadhesiveness and its ability to dissolve in basic environment . These properties of pectin are applied in different ways such as the mucoadhesiveness helps in targeting and controlling the drug delivery especially in the nasal and gastric environment, where as its ability to dissolve in basic condition helps in the release of colon related drugs and the formation of gel helps in increasing the contact time of drug in gastric condition [35, 36]. Recent studies have shown the use of LM pectin for nasal drug delivery due to its mucoadhesive property they have a tendency to bind to the mucin with the help of hydrogen bond . Its use in the production of fentanyl (painkiller) has also been seen that help in treating cancer pain which needs rapid drug release [83, 84]. An alternative for smoking cessation are the nasal pectin containing nicotine . As pectin have resistance towards proteases and amylases it has been highly preferred as an encapsulating nanoparticle for drug delivery as most of the proteins are easily degraded by our digestive enzymes and thus to protect these drugs the use of pectin as an outer cover that cannot be degraded in the gastrointestinal tract are preferred for colon and oral drugs . Studies have shown that pectin is able to inhibit cancer metastasis and primary tumour growth in many animal related cancer [87, 88]. Gal-3 is one of the important factors controlling cancer progression and metastasis, and pectin has the ability to recognise these Gal3 components . In a study, citrus pectin was used to target Gal3 that could inhibit the metastatic successfully [87, 90].
6.2.3 As gene delivery and nanoparticles
The treatment of any genetic disorder is called gene therapy as it deals with the defected genes that are responsible for the disorder; these are treated by replacing the defective gene, silencing the unwanted gene expression or by substituting missing genes and these are carried out with the help of viral or non-viral vectors . The use of non-viral vectors is preferred over viral due many reasons like biocompatibility, minimal toxicity and immunogenic reactions of our body . These non-viral vectors are made of polymers of polycationic, chitosan or even pectin. It has been observed that the use of carbohydrate mediated products have better binding capacity, to facilitate the uptake by target cell [91, 92, 93]. Pectins were found to be suitable as a coating substance for b-PEI [94, 95]. Opanasopit et al. has also observed the formation of pectin nanoparticle which in turn helps to entrap the DNA for transfection . Katav et al., modified pectin with the help of three different amine groups and these complexes were able to bind with plasmid DNA and there efficiency to transfect or their potential as a non-viral gene delivery carrier was compared and suggested that modified pectin has a promising role in gene delivery . Similar type of study was conducted by Opanaopit et al., where pectin ability as a nanoparticle for gene delivery were studied and the study suggested the potential use of pectin as delivery vector to be safe . Pectin has also been used as wound dressing material in the form of pectin-chitosan based nanoparticles. It has the ability to create an acidic environment in which the bacteria cannot grow. Burapapadh et al. developed a pectin based nanoparticle to improve and enhance the drug dissolution of ITZ (Itraconazole) .
6.2.4 Pectin-based scaffolds
Scaffolds are 3-D biomaterials that are porous in nature and are designed to be applied in various fields, few of its basic functions are to promote cell adhesion, to allow enough nutrients and gases transportation and mainly for tissue engineering . Tissue engineering mainly involves the use of biocompatible scaffolds materials to act as a support matrix or to be used as a substrate for delivery of some compounds. There has been a great research going on to promote tissue reconstructions. Coimbra et al., prepared pectin based scaffolds to be used for bone tissue engineering . Similar study was performed by Munarin et al., who examined the use of pectin as injectable biomaterial for bone tissue engineering . Ninan et al. were also able to fabricate biopolymer scaffold of pectin and other compounds using the technique of lyophilisation, thus suggested the use of pectin as ideal polymeric matrix for tissue engineering [73, 100, 101].
Pectin is one of the most extensively studied natural biodegradable polymer. In spite of its availability in a large number of plant species, commercial sources of pectin are very limited. There is, therefore, a need to explore other sources of pectin or modify the existing sources to obtain pectin of desired quality attributes. Current knowledge of the molecular basis of pectin has helped us to understand some aspects of this complex polysaccharide. Extensive studies must be carried out to find out more about the biological pathways to devise various efficient means of pectin extraction that are scalable and can be commercialized. The large variety of applications as well as the increasing number of studies on pectin suggests that the potential of pectin as novel and versatile biomaterial will be even more significant in the future. As the research and development continues in pectin-based products, we expect to see many innovative and exciting applications.
The authors would like to thank Fr. Jobi, Head of the Department of Life Sciences, for providing laboratory facilities and supporting this work.
Conflict of interest
The authors would like to declare that there was no conflict of interest in this work.
Bonnin E, Garnier C, Ralet MC. Pectin-modifying enzymes and pectin-derived materials: Applications and impacts. Applied Microbiology and Biotechnology. 2014; 98(2):519-532
Willats WG, Knox JP, Mikkelsen JD.Pectin: New insights into an old polymer are starting to gel. Trends in Food Science and Technology. 2006; 17(3):97-104
Munarin F, Tanzi MC, Petrini P. Advances in biomedical applications of pectin gels. International Journal of Biological Macromolecules. 2012; 51(4):681-689
Voragen AGJ, Coenen GJ, Verhoef RP, Schols HA. Pectin, a versatile polysaccharide present in plant cell walls. Structural Chemistry. 2009; 20(2):263-275
Liu L. Pectin composite matrices for biomedical applications. Biomaterials. 2004; 25(16):3201-3210
Thakur BR, Singh RK, Handa AK, Rao MA. Chemistry and uses of pectin—A review. Critical Reviews in Food Science and Nutrition. 1997; 37(1):47-73
Willats WGT, McCartney L, Mackie W, Knox JP. In: Carpita NC, Campbell M, Tierney M, editors. Pectin: Cell Biology and Prospects for Functional Analysis in Plant Cell Walls. Dordrecht: Springer Netherlands; 2001. pp. 9-27
Ciriminna R, Chavarria N. Pectin: A new perspective from the biorefinery standpoint. Biofuels, Bioproducts and Biorefining. 2015; 9(4):368-377
Jarvis MC. Structure and properties of pectin gels in plant cell walls. Plant, Cell & Environment. 1984; 7(3):153-164
Valdes A, Burgos N, Jimenez A, Garrigos M. Natural pectin polysaccharides as edible coatings. Coatings. 2015; 5(4):865-886
Mishra RK, Banthia AK, Majeed ABA. Pectin based formulations for biomedical applications: A review. Asian Journal of Pharmaceutical and Clinical Research. 2012; 5(4):1-6
Pacheco MT, Villamiel M, Moreno R, Moreno FJ. Structural and rheological properties of pectins extracted from industrial sugar beet by-products. Molecules. 2019; 24(3):392
Mohnen D. Biosynthesis of pectins and galactomannans. Comprehensive Natural Products Chemistry. 1999; 3(3):497-527
Mohnen D. Pectin structure and biosynthesis. Current Opinion in Plant Biology. 2008; 11(3):266-277
McNeil M, Darvill AG, Albersheim P. The structural polymers of the primary cell walls of dicots. In: Herz W, Grisebach H, Kirby GW, editors.Progress in the Chemistry of Organic Natural Products. Vol 37. New York: Springer-Verlag; 1979. pp. 191-249
Schols H, Voragen A. Complex pectins: Structure elucidation using enzymes. Pectins and Pectinases. 1996; 14:3-19
Oneill M, Albersheim P, Daevill A. The pectic polysaccharides of primary cell walls. Methods in Plant Biochemistry. 1990; 2:415-441
Harris PJ, Smith BG. Plant cell walls and cell-wall polysaccharides: Structures, properties and uses in food products. International Journal of Food Science and Technology. 2006; 41(2):129-143
McNeil M, Darvill AG, Albersheim P. Structure of plant cell walls: X. Rhamnogalacturonan I, a structurally complex pectic polysaccharide in the walls of suspension-cultured sycamore cells. Plant Physiology. 1980; 66(6):1128-1134
Kravtchenko T, Arnould I, Voragen A, Pilnik W. Improvement of the selective depolymerization of pectic substances by chemical β-elimination in aqueous solution. Carbohydrate Polymers. 1992; 19(4):237-242
Ishii T, Matsunaga T. Pectic polysaccharide rhamnogalacturonan II is covalently linked to homogalacturonan. Phytochemistry. 2001; 57(6):969-974
Nakamura A, Furuta H, Maeda H.Structural studies by stepwise enzymatic degradation of the main backbone of soybean soluble polysaccharides consisting of galacturonan and rhamnogalacturonan. Bioscience, Biotechnology, and Biochemistry. 2002; 66(6):1301-1313
Ridley BL, Neill MA, Mohnen D. Pectins: Structure, biosynthesis, and oligogalacturonide-related signaling. Phytochemistry. 2001; 57(6):929-967
Bonner J. The chemistry and physiology of the pectins. The Botanical Review. 1936; 2(10):475-497
Norziah MH, Fang EO, Karim AA. Extraction and Characterization of Pectin from PomeloFruit Peels. In: Williams PA, editor. Gums and Stabilisers for the Food Industry. Vol 10. Cambridge, UK: The Royal Society of Chemistry; 2000. pp. 26-36
Mudgil D, Barak S. Composition, properties and health benefits of indigestible carbohydrate polymers as dietary fiber: A review. International Journal of Biological Macromolecules. 2013; 61:1-6
Canteri-schemin MH, Cristina H, Fertonani R, Waszczynskyj N. Extraction of pectin from apple pomace. Brazilian Archives of Biology and Technology. 2005; 48:259-266
Zafari F, Khodaiyan F, Kiani H, Hosseini SS. Pectin from carrot pomace: Extraction optimization and physicochemical properties of pectin from melon peel. International Journal of Biological Macromolecules. 2017; 98:709-716
Huang X, Li D, Wang L. Characterization of pectin extracted from sugar beet pulp under different drying conditions. Journal of Food Engineering. 2017; 211:1-6
Levigne S, Ralet MC, Thibault JF. Characterisation of pectins extracted from fresh sugar beet under different conditions using an experimental design. Carbohydrate Polymers. 2002; 49(2):145-153
Shi XQ , Chang KC, Schwarz JG, Wiesenborn DP, Shih MC. Optimizing pectin extraction from sunflower heads by alkaline washing. Bioresource Technology. 1997; 58:291-297
Koubala BB, Christiaens S, Kansci G, Van Loey AM, Hendrickx ME. Isolation and structural characterisation of papaya peel pectin. Food Research International. 2014; 55:215-221
Yeoh S, Shi J, Langrish T. Comparisons between different techniques for water-based extraction of pectin from orange peels. Desalination. 2008; 218(1):229-237
Yapo BM, Koffi KL. Extraction and characterization of gelling and emulsifying pectin fractions from cacao pod husk. Journal of Food and Nutrition Research. 2013; 1(4):46-51
Gan CY, Latiff AA. Extraction of antioxidant pectic-polysaccharide from mangosteen ( Garcinia mangostana) rind: Optimization using response surface methodology. Carbohydrate Polymers. 2011; 83(2):600-607
Wai WW, Alkarkhi AFM, Easa AM. Effect of extraction conditions on yield and degree of esterification of durian rind pectin: An experimental design. Food and Bioproducts Processing. 2010; 88(2):209-214
Bagde PP, Dhenge S, Bhivgade S. Extraction of pectin from orange peel and lemon peel. International Journal of Engineering Technology Science and Research. 2017; 4(3):1-7
Zaidel DNA, Rashida J, Hamidona NH, Salleha L, Kassim ASM. Ultrasound assisted extraction of pectin from dragon fruit peels. Chemical engineering transactions. 2017; 56:805-810
Bhavya DK, Suraksha R. Value added products from agriculture: Extraction of pectin from agro waste product Musa Acuminataand citrus fruit. Food and Industrial Microbiology. 2015; 3:6
Edima H, Biloa D, Enama T, Abossolo S, Mbofung C. Optimization of the extraction of pectin from Cucumis melo. British Journal of Applied Science & Technology. 2014; 4(35):4860-4877
Sarah M, Hanum F, Rizky M, Hisham MF. Microwave-assisted extraction of pectin from cocoa peel. Conference Series: Earth and Environmental Science. 2018; 122:012079
Fishman ML, Chau HK, Hoagland PD, Hotchkiss AT. Microwave-assisted extraction of lime pectin. Food Hydrocolloids. 2006; 20(8):1170-1177
Campbell M. Extraction of pectin from watermelon rind [thesis]. 2006. pp. 1-96
Kanse NG, Chirag S, Vishal S. Effects of operating parameters on extraction of pectin from orange peel’s. International Journal of Engineering Technology Science and Research. 2018; 5(4):981-987
Hamidon NH, Zaidel DNA. Effect of extraction conditions on pectin yield extracted from sweet potato peels residues using hydrochloric acid. Chemical Engineering Transactions. 2017; 56:979-984
Yousuf O, Singh A, Shahi NC, Kumar A, Verma AK. Ultrasound assisted extraction of pectin from orange peel. Bulletin of Environment, Pharmacology and Life Sciences. 2018; 7(12):48-54
Kanmani P. Extraction and analysis of pectin from citrus peels: Augmenting the yield from citrus limon using statistical experimental design. Iranica Journal of Energy and Environment. 2014; 5(3):303-312
Shaha RK. Optimized extraction condition and characterization of pectin from kaffir lime ( Citrus hystrix). Research Journal of Agriculture and Forestry Sciences. 2013; 1(2):1-11
Sathish S, Gowthaman KA, Augustus H. Utilization of Punica granatumpeels for the extraction of pectin. Research Journal of Pharmacy and Technology. 2018; 11(2):613
Pandharipande S, Makode H. Separation of oil and pectin from orange peel and study of effect of pH of extracting medium on the yield of pectin. Journal of Engineering Research and Studies. 2012; 3(2):6-9
Aina VO. Extraction and characterization of pectin from peels of lemon ( Citrus limon), grape fruit ( Citrus paradisi) and sweet orange ( Citrus sinensis). British Journal of Pharmacology and Toxicology. 2012; 3(6):259-262
Liu Y, Shi J, Langrish T. Water-based extraction of pectin from flavedo and albedo of orange peels. Chemical Engineering Journal. 2006; 120(3):203-209
Grassino AN, Brncic M, Vikic D, Roca S, Dent M, Brncic CR. Ultrasound assisted extraction and characterization of pectin from tomato waste. Food Chemistry. 2016; 198:93-100
Hamed A, Elkhedir A, Mustafa S. Effect of Soxhlet method extraction on characterization of pectin of pumpkin peels. Journal of Experimental Food Chemistry. 2017; 3(1):1-3
Azad A, Ali M, Akter MS, Rahman MJ, Ahmed M. Isolation and characterization of pectin extracted from lemon pomace during ripening. Journal of Food and Nutrition Sciences. 2014; 2(2):30-35
Gomez B, Gullon B, Yanez R, Parajo JC, Alonso JL. Pectic oligosacharides from lemon peel wastes: Production, purification, and chemical characterization. Journal of Agricultural and Food Chemistry. 2013; 61(42):10043-10053
Gama B, Silva CDF, Da Silva LO, Abud A. Extraction and characterization of pectin from citric waste. Chemical Engineering Transactions. 2015; 44:259-264
Virk B, Sogi D. Extraction and characterization of pectin from apple ( Malus pumila Cv amri) peel waste. International Journal of Food Properties. 2004; 7(3):693-703
Ogunka-Nnoka CU, Atinlikou MF. Extraction and characterization of pectin from some selected non-citrus agricultural food wastes. Journal of Chemical and Pharmaceutical Research. 2016; 8:283-290
Girma E, Worku T. Extraction and characterization of pectin from selected fruit peel waste. International Journal of Scientific and Research Publications. 2016; 6(2):447-454
Castillo-Israel K, Baguio S, Diasanta M, Lizardo R, Dizon E, Mejico M. Extraction and characterization of pectin from Saba banana [ Musa’saba( Musa acuminata× Musa balbisiana)] peel wastes: A preliminary study. International Food Research Journal. 2015; 22(1):202-207
Liew SQ , Chin NL, Yusof YA. Extraction and characterization of pectin from passion fruit peels. Agriculture and Agricultural Science Procedia. 2014; 2:231-236
Panchami P, Gunasekaran S. Extraction and characterization of pectin from fruit waste. International Journal of Current Microbiology and Applied Sciences. 2017; 6(8):943-948
Sudhakar D, Maini S. Isolation and characterization of mango peel pectins. Journal of Food Processing and Preservation. 2000; 24(3):209-227
Sundarraj AA, Vasudevan RT, Sriramulu G. Optimized extraction and characterization of pectin from jackfruit ( Artocarpus integer) wastes using response surface methodology. International Journal of Biological Macromolecules. 2018; 106:698-703
Tamaki Y, Konishi T, Fukuta M, Tako M. Isolation and structural characterisation of pectin from endocarp of Citrus depressa. Food Chemistry. 2008; 107(1):352-361
Tiwari AK, Saha SN, Yadav VP, Upadhyay UK, Katiyar D, Mishra T. Extraction and characterization of pectin from orange peels. International Journal of Biotechnology and Biochemistry. 2017; 13(1):39-47
Madhav A, Pushpalatha P. Characterization of pectin extracted from different fruit wastes. Journal of Tropical Agriculture. 2006; 40:53-55
Khamsucharit P, Laohaphatanalert K, Gavinlertvatana P, Sriroth K, Sangseethong K. Characterization of pectin extracted from banana peels of different varieties. Food Science and Biotechnology. 2018; 27(3):623-629
Noreen A. Pectins functionalized biomaterials; a new viable approach for biomedical applications: A review. International Journal of Biological Macromolecules. 2017; 101:254-272
Katav T, Liu L, Traitel T, Goldbart R, Wolfson M, Kost J. Modified pectin-based carrier for gene delivery: Cellular barriers in gene delivery course. Journal of Controlled Release. 2008; 130(2):183-191
Sriamornsak P. Application of pectin in oral drug delivery. Expert Opinion on Drug Delivery. 2011; 8(8):1009-1023
Ninan N, Muthiah M, Park IK, Elain A, Thomas S, Grohens Y. Pectin/carboxymethyl cellulose/micro fibrillated cellulose composite scaffolds for tissue engineering. Carbohydrate Polymers. 2013; 98(1):877-885
Swenson H, Miers J, Schultz T, Owens H. Pectinate and pectate coatings. 2. Application to nuts and fruit products. Food Technology. 1953; 7(6):232-235
Colin D. Industrial pectins: Sources, production and applications. Carbohydrate Polymers. 1990; 12:79-99
El-Shamei Z, El-Zoghbi M. Producing of natural clouding agents from orange and lemon peels. Food/Nahrung (Food Nahrung). 1994; 38(2):158-166
Danielle BP, Alexandre CM, Eleni G. Pectin and pectinases: Production, characterization and industrial application of microbial pectinolytic enzymes. 2009; 3:9-18
Liu L, Finkenstadt V, Liu C, Jin T, Fishman M, Hicks K. Preparation of poly (lactic acid) and pectin composite films intended for applications in antimicrobial packaging. Journal of Applied Polymer Science. 2007; 106(2):801-810
Fishman M, Coffin D, Konstance R, Onwulata C. Extrusion of pectin/starch blends plasticized with glycerol. Carbohydrate Polymers. 2000; 41(4):317-325
Liu L, Liu CK, Fishman ML, Hicks KB. Composite films from pectin and fish skin gelatin or soybean flour protein. Journal of Agricultural and Food Chemistry. 2007; 55(6):2349-2355
Mishra RK, Majeed ABA, Banthia AK. Development and characterization of pectin/gelatin hydrogel membranes for wound dressing. International Journal of Plastics Technology. 2011; 15(1):82-95
Sriamornsak P, Wattanakorn N, Takeuchi H. Study on the mucoadhesion mechanism of pectin by atomic force microscopy and mucin-particle method. Carbohydrate Polymers. 2010; 79(1):54-59
Fisher A, Watling M, Smith A, Knight A. Pharmacokinetics and relative bioavailability of fentanyl pectin nasal spray 100-800 μg in healthy volunteers. International Journal of Clinical Pharmacology and Therapeutics. 2010; 48(12):860-867
Portenoy RK, Burton AW, Gabrail N, Taylor D. A multicenter, placebo-controlled, double-blind, multiple-crossover study of fentanyl pectin nasal spray (FPNS) in the treatment of breakthrough cancer pain. Pain. 2010; 151(3):617-624
Illum L. Nasal drug delivery composition containing nicotine. Patent; 1999. 1-14
Paharia A, Yadav AK, Rai G, Jain SK, Pancholi SS, Agrawal GP. Eudragit-coated pectin microspheres of 5-fluorouracil for colon targeting. AAPS PharmSciTech. 2007; 8(1):87-93
Glinsky VV, Raz A. Modified citrus pectin anti-metastatic properties: One bullet, multiple targets. Carbohydrate Research. 2009; 344(14):1788-1791
Pienta KJ. Inhibition of spontaneous metastasis in a rat prostate cancer model by oral administration of modified citrus pectin. Journal of the National Cancer Institute. 1995; 87(5):348-353
Kuwabara I, Liu FT. Galectin-3 promotes adhesion of human neutrophils to laminin. The Journal of Immunology. 1996; 156(10):3939-3944
Platt D, Raz A. Modulation of the lung colonization of B16-F1 melanoma cells by citrus pectin. Journal of the National Cancer Institute. 1992; 84(6):438-442
Ledley FD. Nonviral gene therapy: The promise of genes as pharmaceutical products. Human Gene Therapy. 1995; 6(9):1129-1144
Monsigny M, Midoux P, Mayer R, Roche AC. Glycotargeting: Influence of the sugar moiety on both the uptake and the intracellular trafficking of nucleic acid carried by glycosylated polymers. Bioscience Reports. 1999; 19(2):125-132
Brown MD, Schatzlein AG, Uchegbu IF. Gene delivery with synthetic (non viral) carriers. International Journal of Pharmaceutics. 2001; 229(1):1-21
Asnaghi MA. Trends in biomedical engineering: Focus on regenerative medicine. Journal of Applied Biomaterials & Biomechanics. 2011; 9(2):73-86
Wightman L. Different behavior of branched and linear polyethylenimine for gene delivery in vitro and in vivo. The Journal of Gene Medicine. 2001; 3(4):362-372
Opanasopit P, Apirakaramwong A, Ngawhirunpat T, Rojanarata T, Ruktanonchai U. Development and characterization of pectinate micro/nanoparticles for gene delivery. AAPS PharmSciTech. 2008; 9(1):67-74
Burapapadh K, Takeuchi H, Sriamornsak P. Development of pectin nanoparticles through mechanical homogenization for dissolution enhancement of itraconazole. Asian Journal of Pharmaceutical Sciences. 2016; 11(3):365-375
Coimbra P. Preparation and chemical and biological characterization of a pectin/chitosan polyelectrolyte complex scaffold for possible bone tissue engineering applications. International Journal of Biological Macromolecules. 2011; 48(1):112-118
Munarin F. Pectin-based injectable biomaterials for bone tissue engineering. Biomacromolecules. 2011; 12(3):568-577
Xiao C, Anderson CT. Roles of pectin in biomass yield and processing for biofuels. Frontiers in Plant Science. 2013; 4(67):1-7
Ludwig A. The use of mucoadhesive polymers in ocular drug delivery. Advanced Drug Delivery Reviews. 2005; 57(11):1595-1639