Pectin extraction from common fig skin by different methods: The physicochemical, rheological, functional, and structural evaluations

Effect of Organic Acid-Aided Extraction on Characteristics and Functional Properties of Pectin from Cannabis sativa L

The extraction of cannabinoids from the inflorescence and leaves of Cannabis sativa L. is gaining interest from researchers, in addition to addressing the under-utilization of the by-products in the stems and roots of the trees. The present study investigated the recovery of pectin from the left-over parts of hemp tress using an eco-friendly method with the aid of organic acids. Different cannabis cultivars-Chalotte's Angels (CHA) and Hang-Krarog (HKR)-were used as plant materials. The stems of both cannabis cultivars contained more pectin than the roots, and tartaric acid-aided extraction provided higher yields than from citric acid. Extracting the acid solution affected some characteristics, thereby differentiating the functional properties of the derived pectin. Extraction using tartaric acid provided pectin with a higher galacturonic acid content, whereas pectin with a higher methylation degree could be prepared using citric acid. The pectin samples extracted from the stems of CHA (P-CHA) and HKR (P-HKR) had low methoxyl pectin. P-CHA had better free radical scavenging capability, whereas P-HKR showed more potent reducibility. Considering the functional properties, P-CHA showed greater emulsion formability and foaming activity, whereas P-HKR possessed a better thickening effect. The present work suggests the feasible utilization of P-CHA and P-HKR as food additives with bioactivity.

Differences in physicochemical properties of pectin extracted from pomelo peel with different extraction techniques

In order to obtain high yield pomelo peel pectin with better physicochemical properties, four pectin extraction methods, including hot acid extraction (HAE), microwave-assisted extraction (MAE), ultrasound-assisted extraction, and enzymatic assisted extraction (EAE) were compared. MAE led to the highest pectin yield (20.43%), and the lowest pectin recovery was found for EAE (11.94%). The physicochemical properties of pomelo peel pectin obtained by different methods were also significantly different. Pectin samples obtained by MAE had the highest methoxyl content (8.35%), galacturonic acid content (71.36%), and showed a higher apparent viscosity, thermal and emulsion stability. The pectin extracted by EAE showed the highest total phenolic content (12.86%) and lowest particle size (843.69 nm), showing higher DPPH and ABTS scavenging activities than other extract methods. The pectin extracted by HAE had the highest particle size (966.12 nm) and degree of esterification (55.67%). However, Fourier-transform infrared spectroscopy showed that no significant difference occurred among the different methods in the chemical structure of the extracted pectin. This study provides a theoretical basis for the industrial production of pomelo peel pectin.

Structural and flow rheological properties of pumpkin pectic polysaccharide extracted by citric acid

The present study aimed to investigate the structural and physicochemical characteristics of acid-extracted pumpkin pectic polysaccharide (AcPP) and to evaluate their flow rheological properties. AcPP was extracted from pumpkin pulp using the citric acid extraction method. The physicochemical and structural properties were analyzed by chemical methods and instrumental analyses. The obtained results showed that AcPP consisted predominantly of GalA (85.99 %) and small amounts of Rha, Gal, and Ara, with the ratio of HG/RG-I being 81.39/16.75. In addition, AcPP had medium DE (45.34 %) and contained four macromolecular populations with different Mw of 106.03 (main), 10.15, 4.99, and 2.90 kDa. The NMR analysis further confirmed that AcPP contained a linear backbone consisting of α-1,4-linked GalA residues, some of which were partially methyl-esterified. Furthermore, AcPP was amorphous in nature and had favorable thermal stability. The effects of extrinsic factors on the flow rheological properties of AcPP were evaluated. In particular, the high concentrations of CaCl2 (8 mM) and MgCl2 (10 mM) were effective in enhancing the viscosity and non-Newtonian shear-thinning behavior of the AcPP solution. This study elucidates the unique molecular structure of AcPP and suggests the potential of AcPP as a rheology modifier in low-viscous and mineral-reinforced beverages.

The Physicochemical Properties and Antioxidant Activities of the Hawthorn Pectin Extracted Using Ultra-High Pressure Assisted Acid Extraction (UPAAE)

This study aims to investigate the positive effects of ultra-high pressure assisted acid extraction (UPAAE) on both physicochemical properties and antioxidant activities of hawthorn pectin. The basic indicators, structure characterization, and antioxidant activities were measured, which could indicate the disadvantages and advantages among traditional water extraction (WE), acid extraction (AE), and UPAAE. The results show that the hawthorn pectin of UPAAE has a decrease in esterification degree, protein content, and total polyphenols, but has an increase in total galacturonic acid aldehyde compared to the hawthorn pectin of AE. In the Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM) analyses, the hawthorn of UPAAE has typical pectin absorption peaks in the FT-IR spectrum and a distinct layered structure in the SEM surface image. The ion chromatography profiles show that the molar ratio of galacturonic acid to arabinose in the hawthorn pectin of UPAAE increases and 5.50 μg/mg ribose appears compared to the pectin of AE and WE. The high performance gel permeation chromatography (HPGPC) profile indicates that the molecular weight distribution of hawthorn pectin of UPAAE is more concentrated and has the highest molecular weight compared to the pectin of the other two extraction methods. In the vitro antioxidant activity analysis, the pectin of UPAAE exhibits the highest scavenging rate against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals (93.70%), which is close to the scavenging rate of vitamin C (96.30%). These findings demonstrated that UPAAE is a more efficient and environmentally friendly method for pectin extraction from hawthorn. It is also an effective way to enhance its antioxidant activity, which has great application prospects in the food industries.

Extraction of high methoxyl pectin from unripe waste Ponkan mandarine (Citrus reticulata Blanco cv. Ponkan) with an eco-friendly solvent

The aqueous batch extraction of pectin from unripe Ponkan mandarin was evaluated for potential application in the food industry. A small central composite design with 4 variables (temperature, volume to mass ratio, pH, and mean particle size) and 3 levels was applied for pectin extraction optimization. Also, the kinetic of the pectin yield extraction was investigated at temperatures 70-90 °C, stirring rate of 100-700 rpm, ultrasound pretreatment system, and modeling using four mathematical models. The pectin extraction process was evaluated by yield of pectin and esterification degree. FTIR, TGA, and DTA were performed to evaluate the quality of pectin obtained. The small central composite design demonstrated that temperature and volume to mass ratio were significant variables, and the highest yield of pectin extraction was 11.62 % obtained at temperature and volume to molar ratio of 81.9 °C and 33.9 v/w %, respectively. Besides, the esterification degree showed higher than 70 % for all extraction conditions, suggesting high methoxyl pectin. The kinetics showed the stirring rate and the ultrasound pretreatment did not cause any significant alteration, while high temperatures proved to be beneficial to the rate and the yield of the pectin extraction. The best fit was provided by Fick's law, suggesting the extraction process is limited by internal mass transfer. FTIR showed the functional groups expected for pectin, and TGA and DTA indicated that the pectin obtained is proper for most food products, as only above 200 °C the pectin should degrade.

Effects of Lactobacillus plantarum FM 17 fermentation on jackfruit polysaccharides: Physicochemical, structural, and bioactive properties

Fermentation is a novel technology for modifying polysaccharides in fruits and improving their bioactivities. In this work, we introduced Lactobacillus plantarum FM 17 to ferment jackfruit pulp and subsequently purified polysaccharides from unfermented (JP) and fermented jackfruit pulp (JP-F). Furthermore, the physicochemical, structural, and bioactive properties of JP and JP-F were investigated. Results showed fermentation dropped the glucuronic acid, molecular weight, and particle size of JP-F by 15.62 %, 23.92 %, and 39.43 %, respectively, compared with those of JP. JP-F showed higher solubility than JP but lower apparent viscosity and thermal stability. Additionally, FT-IR spectra and X-ray diffraction analysis showed that fermentation did not alter the different types of glycosidic bonds and the fundamental polysaccharide structure. Moreover, JP-F exhibited stronger DPPH and ABTS free radical scavenging properties than JP and stronger stimulation on macrophage secretion of NO and IL-6 in RAW 264.7 cells. Therefore, using L. plantarum FM 17 for fermentation can alter physical and chemical properties of jackfruit pulp polysaccharides, enhancing their bioactivities.

Characterization of a low-methoxyl pectin extracted from red radish (Raphanus sativus L.) pomace and its gelation induced by NaCl

There is an increasing demand for obtaining pectin from new sources. Red radish (Raphanus sativus L.) pomace pectin extracted by alkali was low-methoxyl pectin with esterification degree of 10.17 %, galacturonic acid content of 69.71 % (wt), and average molar weight of 78.59 kDa. The pectin primarily consisted of rhamnogalacturonan I and homogalacturonan domains. The predominant monosaccharides of the pectin were galacturonic acid (46.32 mol%), arabinose (16.03 mol%), galactose (10.46 mol%), and rhamnose (10.28 mol%), respectively. The red radish pomace pectin solution exhibited a shear-thinning behavior. NaCl could induce gelation of red radish pomace pectin, and the gel properties of red radish pomace pectin were considerably affected by the NaCl concentration. As the NaCl concentration (0.25-0.50 mol/L) increased, the rate of gelation accelerated, and the time to gelation point appeared earlier. There was an optimal NaCl concentration (0.50 mol/L) for the pectin to form a gel with the greatest solid-like properties, gel hardness (33.84 g) and water-holding capacity (62.41 %). Gelation force analysis indicated gel formation mainly caused by electrostatic shielding effect of Na+ and hydrogen bonding. This research could facilitate the applications of the red radish pomace pectin in the realm of edible hydrocolloids.

Pectin-rich dragon fruit peel extracts: An environmentally friendly emulsifier of natural origin

Pectin extraction is generally an energy-intensive industrial process, while on the other hand their extraction methods vary from different sources. Starting with that perspective, pectin (WSP) containing ultra-low degree of methylation (31.08 ± 1.27%) from dragon fruit peel (DFP) was extracted by using pure water at room temperature. WSP, dominant in DFP (17.13 ± 1.01%), showed both a high molecular weight and a wide molecular weight distribution, while the yield of the rest acid-soluble pectin (HAP) from DFP residue was only 5.22 ± 0.76%. Furthermore, WSP can stabilize emulsions over a wide range of concentrations and oil phases, especially HIPE. Therefore, the hypothesis was verified that the pectin-rich extract from dragon fruit peel with excellent emulsifying properties could be simply extracted by pure water. This environmentally-friendly and energy-saving extraction method provides a new insight to increase the additional value of dragon fruit peel produced in food processing.

Recent Advances in the Extraction of Pectin from Various Sources and Industrial Applications

Pectin is a structural polysaccharide present in plants that primarily consists of galacturonic acid units. This Review discusses the chemistry of pectin, including its composition and molecular weight. Pectin is conventionally extracted from agricultural waste (fruit and vegetable peels) using an acidic or basic aqueous medium at high temperatures. These processes are time- and energy-consuming and also result in severe environmental problems due to the production of acidic effluents and equipment corrosion. As pectin usage is increasing in food industries for developing different products and it is also used as an excipient in pharmaceutical products, better extraction procedures are required to maximize the yield and purity. The Review encompasses various alternate green approaches for the extraction of pectin, including traditional acid extraction and various emerging technologies such as deep eutectic solvent-based extraction, enzyme-assisted extraction, subcritical fluid extraction, ultrasound-assisted extraction, and microwave-based extraction, and evaluates the yield and physicochemical characteristics of the extracted pectin. This work aims to provide a platform for attracting more thorough research focused on the engineering of novel and more efficient green methods for the extraction of pectin and its utilization for various biotechnological purposes.

Characterization of soluble dietary fiber from citrus peels (Citrus unshiu), and its antioxidant capacity and beneficial regulating effect on gut microbiota

This study aimed to evaluate the physicochemical, structural and functional properties of soluble dietary fiber extracted from citrus peels (Citrus unshiu) by ultrasound-assisted alkaline extraction. Unpurified soluble dietary fiber (CSDF) was compared with purified soluble dietary fiber (PSDF) in terms of composition, molecular weight, physicochemical properties, antioxidant activity, and intestinal regulatory capacity. Results showed that the molecular weight of soluble dietary fiber was >15 kDa, which showed good shear thinning characteristics and belonged to non-Newtonian fluid. The soluble dietary fiber showed good thermal stability under 200 °C. The contents of total sugar, arabinose and sulfate in PSDF were higher than those in CSDF. At the same concentration, PSDF showed stronger free radical scavenging ability. In fermentation model experiments, PSDF promoted the production of propionic acid and increased the abundance of Bacteroides. These findings suggested that soluble dietary fiber extracted by the ultrasound-assisted alkaline extraction has good antioxidant capacity and promotes intestinal health. It has broad development space in the field of functional food ingredients.

Exploring the effect of utilising organic acid solutions in ultrasound-assisted extraction of pectin from apple pomace, and its potential for biomedical purposes

Biomass resulting from food production represents valuable material to recover different biomolecules. In our study, we used apple pomace to obtain pectin, which is traditionally extracted using mineral acids. Our hypothesis consisted of carrying out extractions with organic acids, assisted by ultrasound, by varying processing parameters including time, temperature, and type of acid. The analytical determinations of galacturonic acid content, methoxylation and esterification degree, ζ-potential and extraction yield were used as pectin quality indicators. Pectins extracted using treatment conditions with better performance were assessed biologically in vitro for their potential to be used in biomedical applications. Overall, the extracted pectin presented a galacturonic acid content, methoxylation and esterification degree ranged from 19.7 to 67%, 26.8-41.4% and 58-65.2% respectively, and were negatively charged (-24.1 to -13.2 mV). It was found that factors of time and temperature greatly influenced the response variables excepting the esterification degree, while the acid type influenced the ζ-potential, methoxylation and esterification degrees. Additionally, it was seen that the longer extraction time (50 min) and higher temperature (50 °C) exhibited the better extraction yield (∼10.9%). Finally, the selected pectin showed high cytocompatibility up to 500 μg/mL of concentration when seeded with Neonatal Normal Human Dermal Fibroblasts.

Supramolecular structure of banana peel pectin and its transformations during extraction by acidic methods

In this study, the approaches to describe the mesh structure in the homogalacturonate domains of pectin and the effect of the native structure violations on the stabilization effectiveness of the oil-in-water emulsion were demonstrated. Pectin with a native structure was isolated from banana peel by enzymolysis of insoluble dietary fibres. This pectin was compared with pectins, which were isolated using hydrochloric and citric acids. The properties of pectins were analyzed taking into account the ratio of galacturonate units in nonsubstituted, methoxylated and calcium-pectate forms. The content of calcium-pectate units determines the density of inter-molecular crosslinking formation. The simulation results reflect the structure of rigid "egg-box" crosslinking blocks and flexible segments formed in native pectin mainly by methoxylated links. Hydrochloric acid extraction is accompanied by the destruction of the crosslinking blocks and depolymerization of pectin. Citric acid partially demineralizes the crosslinking blocks contributing to the release of macromolecular chains that do not have calcium-pectate units. The granulometric data indicates that the individual macromolecules take the thermodynamically stable form of a statistical tangle. Such conformation is an ideal basis for the formation of "host-guest" microcontainers having a hydrophilic shell and a hydrophobic core with an oil-soluble functional substance.

Determination of the Major By-Products of Citrus hystrix Peel and Their Characteristics in the Context of Utilization in the Industry

Kaffir lime (Citrus hystrix) is a popular citrus in Southeast Asia. Despite the growing interest in the peel of the fruit, the leaves are the most frequently used part of the fruit. The aim of the study was to determine the main by-products of the peel, such as pectins, minerals, essential oil, and bioactive compounds, and to evaluate the possibility of using them in various branches of industry. In the study of the essential oil obtained by hydrodistillation performed using the TGA chromatography technique (GC-MS), sabinene (31.93%), β-pinene (26%), and limonene (19%) were selected as the most abundant volatile compounds. Nine microelements (Fe, Zn, Cu, Mn, Co, Ni, Cr, Mo, and V), four macroelements (Mg, Ca, K, and Na), and seven ballast substances (Cd, Hg, Pb, Al, V, Sr, and Pt) were also determined using the microwave plasma-atomic emission spectrometry technique (MP-AES). In the case of microelements, iron 32.72 ± 0.39 mg/kg DW (dry weight) had the highest concentration. In the case of macroelements, the calcium content was 9416 ± 34 mg/kg DW. Optimization of the pectin extraction was also performed by selecting citric acid and obtaining a yield of 7.6–17.6% for acid extraction and 9.9–28.2% for ultrasound-assisted extraction (UAE), depending on the temperature used. The obtained pectins were characterized by the degree of methylation, galacturonic acid content, 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, and DSC (differential scanning calorimetry) analysis. Among bioactive compounds, the contents of polyphenols (22.63 ± 2.12 mg GAE/g DW), flavonoids (2.72 ± 0.25 mg CE/g DW, vitamin C (2.43 ± 0.19 mg Asc), xantoproteins + carotenes (53.8 ± 4.24 ug), anthocyanins (24.8 ± 1.8 mg CGE/kg DW), and chlorophylls A and B (188.5 ± 8.1, 60.4 ± 3.23 µg/g DW) were evaluated. Antioxidant capacity using (cupric ion-reducing antioxidant capacity) CUPRAC and DPPH assays was also provided with the results of 76.98 ± 8.1, and 12.01 ± 1.02 µmol TE/g DW, respectively.

Recent progress in pectin extraction and their applications in developing films and coatings for sustainable food packaging: A review

Perishable foods like fruits and vegetables, meat, fish, and dairy products have short shelf-life that causes significant postharvest losses, which poses a major challenge for food supply chains. Biopolymers have been extensively studied as sustainable alternatives to synthetic plastics, and pectin is one such biopolymer that has been used for packaging and preservation of foods. Pectin is obtained from abundantly available low-cost sources such as agricultural or food processing wastes and by products. This review is a complete account of pectin extraction from agro-wastes, development of pectin-based composite films and coatings, their characterizations, and their applications in food packaging and preservation. Compared to conventional chemical extraction, supercritical water, ultrasound, and microwave assisted extractions are a few examples of modern and more efficient pectin extraction processes that generate almost no hazardous effluents, and thus, such extraction techniques are more environment friendly. Pectin-based films and coatings can be functionalized with natural active agents such as essential oils and other phytochemicals to improve their moisture barrier, antimicrobial and antioxidant properties. Application of pectin-based active films and coatings effectively improved shelf-life of fresh cut-fruits, vegetables, meat, fish, poultry, milk, and other food perishable products.

Influences of Ultrasonic Treatments on the Structure and Antioxidant Properties of Sugar Beet Pectin

The objective of this study was to explore the structural changes and oxidation resistance of ultrasonic degradation products of sugar beet pectin (SBP). The changes in the structures and antioxidant activity between SBP and its degradation products were compared. As the ultrasonic treatment time increased, the content of α-D-1,4-galacturonic acid (GalA) also increased, to 68.28%. In addition, the neutral sugar (NS) content, esterification degree (DE), particle size, intrinsic viscosity and viscosity-average molecular weight (M_V) of the modified SBP decreased. Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) were used to study the degradation of the SBP structure after ultrasonication. After ultrasonic treatment, the DPPH and ABTS free radical scavenging activities of the modified SBP reached 67.84% and 54.67% at the concentration of 4 mg/mL, respectively, and the thermal stability of modified SBP was also improved. All of the results indicate that the ultrasonic technology is an environmentally friendly, simple, and effective strategy to improve the antioxidant capacity of SBP.

Roles of physical fields in the extraction of pectin from plant food wastes and byproducts: A systematic review

Pectin is a naturally occurring hydrocolloid found in the cell wall and middle lamella of many plants and has numerous functional applications in food and other related industries. The type of extraction methods used in production has a strong influence on the structural or physicochemical properties of the resultant pectin and the potential application or market value of the produced pectin. Many conventional extraction methods are well-established and commercially well adopted. However, the increased demand for pectin due to limitations of the existing methods in terms of efficiency and influence on end product quality has been renewed in developing novel techniques or procedures that help to alleviate these problems. In this review paper, a series of strategies involving the application of physical fields, such as acoustic, electromagnetic, electric and mechanical one, are reviewed for potential opportunities to improve the yield and quality attributes of pectin extracted from plant food wastes and byproducts. The extraction mechanism, processing equipment, key operating parameters as well as advantages and disadvantages of each method are systematically reviewed, and findings and conclusions on the potential applications of each method are described. Moreover, the challenges and future directions of physical field assisted extraction (PFAE) of pectin are also discussed to facilitate a better understanding of the complex mechanism in PFAE and optimizing operational parameters. This review may also provide specific theoretical information and practical applications to improve the design and scale up PFAE of pectin.

Pectin extracted from dragon fruit Peel: An exploration as a natural emulsifier

As a potential source of pectin, the peel of dragon fruit is a by-product of fruit processing and will bring considerable economic benefits. In this study, pectin (DFP) was extracted from dragon fruit peel by using a hot-acid method, and two commercial pectins were used as controls to correlate structural differences with physical and chemical properties through systematic evaluation. The galacturonic acid (GalA) content, degree of esterification (DM) and molecular weight (Mw) of DFP were 87.02 ± 0.89 %, 37.26 ± 1.37 % and 1181.75 ± 11.21 kDa, respectively. The FTIR and XRD analysis also confirmed that DFP is ultra-low methoxylated pectin and also contains characteristic functional groups naturally present in pectin. Compared to APA140 and LMP, DFP showed excellent emulsification at low concentrations. In particular, the extraordinary antioxidant activity of DFP may be attributed to polyphenols in free or bound form. Overall, DFP can be considered as a promising emulsifier and the results of the study provide an alternative to natural sources of emulsifiers in the food industry.

Physical Properties, α-Glucosidase Inhibitory Activity, and Digestive Stability of Four Purple Corn Cob Anthocyanin Complexes

In this study, pectin (PC), whey protein isolate (WPI), and chitosan (CS) were combined with purple corn cob anthocyanins (PCCA). Four complexes, PC-PCCA, WPI-PCCA, WPI-PC-PCCA, and CS-PC-PCCA were prepared to evaluate the improvement in the α-glucosidase inhibitory activity and digestive stability of PCCA. The encapsulation efficiency (EE), particle size, physical properties, and mode of action of the synthesized PCCA complexes were evaluated. Among them, CS-PC-PCCA had the highest EE (48.13 ± 2.73%) except for WPI-PC-PCCA; furthermore, it had a medium size (200-300 nm), the lowest hygroscopicity (10.23 ± 0.28%), lowest solubility (10.57 ± 1.26%), and highest zeta potential (28.20 ± 1.14). CS-PC-PCCA was multigranular and irregular in shape; x-ray diffraction showed that it was amorphous; and Fourier transform infrared spectroscopy confirmed that it was joined with PCCA through hydrogen bonds and electrostatic interactions. Compared with PCCA, the four complexes showed a higher α-glucosidase inhibition activity and digestive stability, except for WPI-PC-PCCA. Furthermore, CS-PC-PCCA exhibited the best α-glucosidase inhibition and simulated digestion stability.

Bioactive and health-promoting properties of enzymatic hydrolysates of legume proteins: a review

This study comprehensively reviewed the effect of controlled enzymatic hydrolysis on the bioactivity of pulse protein hydrolysates (PPHs). Proteolysis results in the partial structural unfolding of pulse proteins with an increase in buried hydrophobic groups of peptide sequences. The use of PPHs in a dose-dependent manner can enhance free radical scavenging and improve antioxidant activities regarding inhibition of lipid oxidation, ferric reducing power, metal ion chelation, and β-carotene bleaching inhibition. Ultrafiltered peptide fractions with low molecular weights imparted angiotensin-I converting enzyme (ACE) inhibitory effects during in vitro simulated gastrointestinal digestion and in vivo conditions. Ultrasonication, high-pressure pretreatments, and glycosylation as post-treatments can improve the antiradical, antioxidant, and ACE inhibitory activities of PPHs. The electrostatic attachment of pulse peptides to microbial cells can inhibit the growth and activity of bacteria and fungi. Bioactive pulse peptides can reduce serum cholesterol and triglycerides, and inhibit the formation of adipocyte lipid storage, allergenic factors, inflammatory markers, and arterial thrombus without cytotoxicity. The combination of germination and enzymatic hydrolysis can significantly increase the protein digestibility and bioavailability of essential amino acids. Moreover, the utilization and enrichment of bakery and meat products with functional PPHs ensure quality, safety, and health aspects of food products.

Physicochemical, structural, and functional properties of wampee (Clausena lansium (Lour.) Skeels) fruit peel pectin extracted with different organic acids

Effects of different extraction acids on physicochemical, structural, and functional properties of wampee fruit peel pectin (WFPP) were comparatively investigated. The hydrochloric acid extracted WFPP (HEP) exhibited the highest degrees of methylation (67.79%) and acetylation (86.29%) coupling with abundant monosaccharides and rhamnogalacturonan branches, but lowest molecular weight (5.58 × 10⁵ Da). The results of SEM, X-ray diffraction, and Fourier transform infrared spectroscopy analyses showed that acid types had little effect on the surface morphology of WFPP. However, compared to commercial citrus pectin (CCP), several specific absorbance peaks (1539, 1019, 920 cm^-1) were found in WFPPs, which corresponds to aromatic skeletal stretching, pyranose, and d-glucopyranosyl, respectively. Moreover, the rheological behavior revealed that WFPP solution was pseudoplastic fluid and affected by acid types. And the WFPPs exhibited higher emulsifying activity and emulsion stability than CCP. All these WFPPs presented well antioxidant activity and promoting probiotics ability, especially for HEP.

Utilisation of Pectins Extracted from Orange Peels by Non Conventional Methods in the Formation of Edible Films in the Presence of Herbal Infusions

Edible films of three high methoxy pectins (DE: 70–75%) in the presence of dittany and anise infusions were studied. Apart from a commercial one, two more pectins, selected by their yield and DE from preliminary experiments on pectin extraction from orange peels using ultrasound- and microwave-assisted extraction or a combination of both, were used. Extracted pectins were darker, less surface active and had lower [η] and absolute zeta values. All three pectin solutions were Newtonian. Furthermore, all films had statistically the same thickness (~40 μm) and moisture content (~25.2%). For the same herbal infusion, all pectins resulted in films with the same density (~1.01 and ~1.19 g/cm3 for dittany and anise films, respectively). Values of 2–4.65 N and 76.62–191.80 kPa, for maximum force and modulus, respectively, were reported. The commercial pectin film with anise was the stronger, whereas that with dittany, the stiffer. Total phenolics content (TPC) and antioxidant activity (SA) were also measured for films and film-forming solutions (FFS). TPC values ranged from 0.035 to 0.157 mg GAE/0.5 mL and SA from ~62 to 91%. Films had greater TPC but lower SA than their FFS. The presence of both pectin and herbal infusions were significant for our observations.

Characterization of Pectin from Grape Pomace: A Comparison of Conventional and Pulsed Ultrasound-Assisted Extraction Techniques

The yield, physicochemical and rheological parameters of grape pomace pectin (Fetească Neagră and Rară Neagră) obtained by conventional extraction (CE) were compared to those acquired by pulsed ultrasound-assisted extraction (PUAE). Extraction temperature (70–90 °C), pH (1–3) and time (1–3 h) were considered as independent variables for CE, while amplitude (20–100%), pH (1–3) and time (20–60 min) for PUAE. The optimal conditions for maximum yield and physicochemical parameters of pectin samples extracted by CE were temperature of 90 °C, pH 1.9 for 164 min (9.96% yield, 79.91 g/100 g of galacturonic acid (GalA) content, 81.28% of degree of esterification (DE) and 5.52 × 10⁴ g/mol of molecular weight (M_w) for Fetească Neagră (FN) pectin; 11.08% yield, 80.05 g/100 g of GalA content, 80.86% of DE and 5.59 × 10⁴ g/mol of M_w for Rară Neagră (RN) pectin), while for PUAE they were amplitude of 100%, pH 1.8 for 60 min (8.83% yield, 80.24 g/100 g of GalA content, 81.07% of DE and 4.19 × 10⁴ g/mol of M_w for FN pectin; 8.94% yield, 78.64 g/100 g of GalA content, 80.04% of DE and 4.23 × 10⁴ g/mol of M_w for RN pectin). The yield and physicochemical parameters of CE pectin were higher than PUAE pectin. The FT-IR spectra of pectin samples revealed the occurrence of polysaccharide compound, while rheology characteristics confirming its application in different food products.

Structural characterization, acute toxicity assessment and protective effects of selenylated apple pectin on dextran sulfate sodium-induced ulcerative colitis

This study was aimed at investigating the structural characterization, acute toxicity and protective effect of selenylated apple pectin on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice. Selenylated apple pectin was characterized by ion chromatography, NMR and SEC-RI-MALLS. The acute toxicity and protective effect of selenylated apple pectin against UC were investigated by gavage administration in mice. The organ state and coefficients, inflammatory cytokine (IL-6, IL-10 and TNF-α) contents in serum, GSH-Px activity and MPO content in colon tissues were also evaluated. The results indicated that selenylated apple pectin was non-toxic and contained 244.28 μg_selenium per g. The monosaccharide composition with different molar ratios, different relative molecular weights and a weakened signal peak (CH₂-O group) at 3-4 ppm were observed after selenylation. The selenylated apple pectin showed the protective effect against UC by down-regulating IL-6 and TNF-α contents and up-regulating the IL-10 content in serum, as well as increasing the GSH-Px activity and decreasing the MPO content in colon tissues. Moreover, DSS-induced alterations were effectively recovered by a high-dose sample. These findings provide evidence in support of selenylated apple pectin as a novel dietary selenium supplement for UC protection.

Almond hulls waste valorization towards sustainable agricultural development: Production of pectin, phenolics, pullulan, and single cell protein

This research aimed to valorize almond hulls based on a zero-waste strategy towards sustainable agricultural developments for the recovery and production of valuable compounds. For this purpose, the potential to produce four products, including pectin (AHP), phenolic compounds (AHPC), pullulan (PUL), and single-cell protein (SCP), was examined. The acidic extraction factors were optimized using a Box-Behnken design for the simultaneous extraction of AHP and AHPC, and the obtained results showed that the maximum AHP (26.32% w/w) and AHPC (6.97% w/w) yields were achieved at 90 °C, pH of 1.4, 58.65 min, and liquid-solid ratio (LSR) of 20.13 v/w as the optimum point. In the next step, the solid residues that remained from the AHP and AHPC extraction process (PESR) were treated with cellulase enzyme and ultrasound and were used for simultaneous microbial production of PUL (34.29-24.56 g/L) and biomass containing SCP (19.31-13.44% w/w). Furthermore, the obtained results showed that AHP was low methylated (26.40%), rich in galacturonic acid (67.88%), and high in molecular weight (595.299 kDa). Also, the investigations of structural properties of AHP and PUL confirmed the presence of chemical structures of these polysaccharides in the formed supernatants. In addition, the AHPC showed considerable antioxidant activity compared with ascorbic acid (ASC) and BHA.

Current emerging trends in antitumor activities of polysaccharides extracted by microwave- and ultrasound-assisted methods

This overview highlighted the in vitro and in vivo antitumor effects of polysaccharides extracted by ultrasound- and microwave-assisted solvent extraction methods. The polysaccharide fragments with stronger antiproliferation, antitumoral, and anticarcinoma effects can be identified through purification, fractionation, and bio-analytical assessments. Most of the extracted glucan-based polysaccharides in a dose-dependent manner inhibited the growth of human cancer cell types with cell death-associated morphological changes. Glucans, glucogalactans, and pectins without any cytotoxicity on normal cells showed the antitumor potential by the apoptosis induction and the inhibition of their tumorigenesis, metastasis, and transformation. There is a significantly high association among antiproliferative activities, structural features (e.g., molecular weight, monosaccharide compositions, and contents of sulfate, selenium, and uronic acid), and other bio-functionalities (e.g., antiradical and antioxidant) of isolated polysaccharides. The evaluation of structure-activity relationships of antitumor polysaccharides is an intriguing step forward to develop highly potent anticancer pharmaceuticals and foods without any side effects.

Recent advances in utilization of pectins in biomedical applications: a review focusing on molecular structure-directing health-promoting properties

The numerous health benefits of pectins justify their inclusion in human diets and biomedical products. This review provides an overview of pectin extraction and modification methods, their physico-chemical characteristics, health-promoting properties, and pharmaceutical/biomedical applications. Pectins, as readily available and versatile biomolecules, can be tailored to possess specific functionalities for food, pharmaceutical and biomedical applications, through judicious selection of appropriate extraction and modification technologies/processes based on green chemistry principles. Pectin's structural and physicochemical characteristics dictate their effects on digestion and bioavailability of nutrients, as well as health-promoting properties including anticancer, immunomodulatory, anti-inflammatory, intestinal microflora-regulating, immune barrier-strengthening, hypercholesterolemia-/arteriosclerosis-preventing, anti-diabetic, anti-obesity, antitussive, analgesic, anticoagulant, and wound healing effects. HG, RG-I, RG-II, molecular weight, side chain pattern, and degrees of methylation, acetylation, amidation and branching are critical structural elements responsible for optimizing these health benefits. The physicochemical characteristics, health functionalities, biocompatibility and biodegradability of pectins enable the construction of pectin-based composites with distinct properties for targeted applications in bioactive/drug delivery, edible films/coatings, nano-/micro-encapsulation, wound dressings and biological tissue engineering. Achieving beneficial synergies among the green extraction and modification processes during pectin production, and between pectin and other composite components in biomedical products, should be key foci for future research.