Galacturonic Acid Content Research Articles

Elucidation of pineapple softening based on cell wall polysaccharides degradation during storage

The degradation of cell wall polysaccharides in pineapple fruit during softening was investigated in the present study. Two pectin fractions and two hemicellulose fractions were extracted from the cell wall materials of ‘Comte de Paris’ pineapple fruit at five softening stages, and their compositional changes were subsequently analyzed. The process of softening of the fruit corresponded to an increase in the water-soluble pectin (WSP) and 1 M KOH-soluble hemicellulose (HC1) fractions, and a decrease in the acid-soluble pectin (ASP) fraction, which suggested the solubilization and conversion of cellular wall components. However, the content of 4 M KOH-soluble hemicellulose (HC2) decreased and then returned to the initial level. Furthermore, WSP, ASP, and HC1 showed an increment in the content of low molecular weight polymers while a decline in the high molecular weight polymers throughout softening, and not significant change in the contents of different molecular polymers of HC2 was observed. Moreover, the galacturonic acid (GalA) content in the main chain of WSP was maintained at a relatively constant level, but the major branch monosaccharide galactose (Gal) in WSP decreased. Different from WSP, the molar percentages of Gal and GalA in ASP decreased. The Gal or Arabinose (Ara) in HC1 exhibited a gradual decline while the molar percentages of xylose (Xyl) and glucose (Glu) in the main chain increased. These suggested that the main chain of ASP degraded while the branched chains of ASP, WSP and HC1 depolymerized during pineapple softening. Overall, fruit softening of ‘Comte de Paris’ pineapple was found to be the result of differential modification of pectin and hemicellulose.

Grape pomace high-methoxyl pectin: A new prebiotic stabilizer for low-fat synbiotic yogurt gels – Optimization and characterization

High-methoxyl pectin (HMP, 72.5 % esterification degree and galacturonic acid content of 67.9 %) was extracted from grape pomace using a sequential ultrasound-microwave extraction. The extracted HMP was used to develop low-fat synbiotic set yogurts containing probiotic cells. Higher grape pomace pectin (GPP) concentrations (0.5–2 %) increased the probiotic bacterial population of Lactobacillus acidophilus LA-5 and Bifidobacterium bifidum BB-12. Higher cell viability was observed for L. acidophilus LA-5 compared to B. bifidum BB-12. A response surface optimization showed that the presence of 8.08 Log CFU mL−1L. acidophilus LA-5 and 1.88 % HMP experimentally resulted in the best probiotic viability (10.83 ± 0.11 Log CFU mL−1), overall acceptability (8.03 ± 0.06), and pH (4.25 ± 0.05) values. Compared to pectin-free probiotic yogurts, the optimal yogurt gels presented higher probiotic survivability, lower syneresis, and superior storage-dependent sensory attributes during 21 days of storage. However, a 14-day storage period was generally deemed suitable. The GPP-containing yogurt compared to the pectin-free sample exhibited higher colloidal stability with a larger particle size (433.8 nm vs. 272.5 nm) and lower zeta potential (−20.4 mV vs. −10.6 mV). Field emission-scanning electron (FE-SEM) and fluorescent (FLM) microscopy images confirmed a denser microstructure for GPP-enriched yogurts. The chemical interactions in the yogurt were not affected by enriching with GPP as investigated by FTIR, whereas the steady and dynamic rheological properties were significantly improved. GPP-enriched yogurt had a firmer gel structure with a larger linear region and lower G′ compared to the control, indicating a semi-solid state. The GPP as a multi-functional prebiotic ingredient would be promising in designing healthier food products.

Can Enzymatic Modified Pectin in Mediterranean Fruits Be Therapeutic Against Stomach Cancer?

ABSTRACTThe aim of this study was to evaluate the cytotoxic effects of enzymatically modified pectin products derived from grapefruit, jujube, and kumquat on the MKN‐45 gastric cancer cell line in vitro. FTIR analysis revealed that the spectra of the pectins produced were comparable to those of commercial pectin and included the characteristic peaks identified in the literature. The galacturonic acid content was measured as 612 mg/g in grapefruit pectin, 544 mg/g in jujube pectin, and 704 mg/g in kumquat pectin. DSC analysis indicated that all pectin samples and their modifications exhibited one endothermic peak and one exothermic peak. Cytotoxicity assessments revealed that the enzymatically modified grapefruit pectin demonstrated significant cytotoxic effects across all tested concentrations, with 0.075 mg/mL being the most effective. For kumquat pectin, all tested concentrations showed cytotoxic properties, with 0.3, 0.15, and 0.075 mg/mL being the most effective. In the case of jujube pectin, cytotoxic effects were observed at all concentrations except for 1.2 mg/mL.

The effect of biochar amendment on Cd accumulation in Bidens pilosa L: Changing Cd subcellular distribution, cell wall polysaccharide Cd-binding capacity and composition

Biochar can reduce Cd uptake by plants, thereby reducing its biotoxicity, but the mechanisms involved at the subcellular level have not been thoroughly elucidated. In this work, we explored the effect of maize straw biochar on Cd accumulation by Bidens pilosa L. and its mechanism at subcellular levels. After 90 days of potting experiment, the subcellular fractions were extracted by differential centrifugation, and the polysaccharide fractions of root cell walls were extracted by leaching centrifugation, and then the Cd content of each fraction was determined. Results showed that Cd was preferentially distributed in cell walls of three organs. Additionally, biochar addition resulted in a greater distribution of Cd from cell wall to soluble fractions and organelles in stems. These results suggested that cell wall immobilization and intracellular compartmentalization were critical detoxification mechanisms tackling Cd stress with biochar addition of Bidens pilosa L. Pectin was the main sink where Cd was stored. And galacturonic acid content in pectin occupied the highest ratio among the three polysaccharide fractions. After biochar addition, in hemicellulose the change of Cd content was consistent with the change of galacturonic acid content. These results suggested that the galacturonic acid in hemicellulose played an important role in Cd binding. Biochar addition reduced the bioavailability of soil Cd and improved the growth environment, thus inducing Bidens pilosa L. to change the composition of root cell wall in response to Cd stress.

Impacts of microwaves on the pectin extraction from apple pomace: Technological properties in structuring of hydrogels

The valorization of by-products eliminates the risks of economic barriers and reduces the overall amount of pollution and the carbon footprint of the products. In this context, conventional heating extraction (CE) and microwave-assisted extraction (MAE) were compared to extract pectin from apple pomace. The effects of temperature on MAE were evaluated based on the resulting properties obtained in subsequent pectin hydrogels. A pectin yield of 10.6 ± 0.3% was obtained by MAE with 5 min extraction, while CE showed a yield of 9.5 ± 0.3% after 2 h. The pectin extracted by both methods had a low methoxyl content, indicating a low degree of esterification. The galacturonic acid content was greater than 60% for most samples. Zeta potential analysis indicated the ability of the pectin to form stable gels. According to the X-ray diffractograms, increasing the extraction temperature led to a decrease in the crystallinity of the pectin structure. Rheological tests showed increased storage modulus as the temperature increased by MAE from 80 to 100 °C for the pectin-based hydrogel. The water holding capacity was greater than 50% for all hydrogels. Furthermore, an analysis of electrical consumption and energy costs highlighted the economic advantage of using microwave heating technology to extract pectin.

Valorisation of Blackcurrant Pomace by Extraction of Pectin-Rich Fractions: Structural Characterization and Evaluation as Multifunctional Cosmetic Ingredient

Blackcurrant pomace is a widely available waste stream derived from the industrial production of juice rich in pectin and unextracted polyphenols. Since pectin, an emerging class of gastrointestinal prebiotics, is also a common cosmetic ingredient, the aim of this work was to evaluate blackcurrant pomace as a source of pectin-rich fractions suitable for application in prebiotic cosmetics. Hereby, this raw material was valorised by sequential extraction of acid-soluble (by citric acid, CAP) and Ca-bound (by ammonium oxalate, AOPP) pectic polysaccharides. Both fractions had favourable physicochemical features and a similar degree of methyl-esterification between low- and high-methoxyl pectin (approx. 50%), but CAP had significantly higher galacturonic acid content (72.3%), branching, and purity. Regardless of that, both had very high oil (18.96 mL/g for CAP and 19.32 mL/g for AOPP) and water (9.97 mL/g for CAP and 7.32 mL/g for AOPP)-holding capacities and excellent emulsifying properties, making them promising cosmetic ingredients. The polyphenol content was 10 times higher in CAP, while corresponding antioxidant activity was 3-fold higher. Finally, the influence of varying CAP and AOPP concentrations on common skin pathogen, Staphylococcus aureus, and beneficial skin bacteria, Staphylococcus epidermidis, was examined. The results show significant prebiotic potential of two pectic fractions since they were capable of selectively stimulating S. epidermidis, while S. aureus growth was inhibited, whereas CAP demonstrated a particularly high capacity of up to 2.2, even with methicillin-resistant S. aureus.

Elucidation of the structural changes of hemicellulose and cellulose in sunflower seed during roasting.

This study evaluated the structural changes in hemicellulose and cellulose from sunflower seeds before and after roasting at 160°C, 190°C, and 220°C. Sugar composition, molecular weight, Fourier transform infrared spectrometry, thermogravimetric, and NMR analyses were utilized to determine the structural properties of these polysaccharides and detect the volatile compounds. The results showed that roasting destroyed the microstructure of these hemicelluloses and cellulose. Glucose and arabinose of hemicellulose were more easily degraded than other sugars during roasting. The galacturonic acid content increased from 7.8% to 46.66% after roasting. The hemicellulose obtained at 220°C had a backbone of D-xylose residues with a β-(1→4)-linkage. The molecular weight of cellulosic polysaccharides decreased with the increase of roasting temperature. The crystallinity increased from 28.92% to 31.86% revealing that mainly the amorphous regions of cellulosic polysaccharides were destroyed by roasting. After roasting, the volatile compounds of these polysaccharides were rich in furfural, which was produced by caramelization and the Maillard reaction, contributing to the characteristic aroma of roasted sunflower seeds. This study provides some information on the relationship between structural changes of polysaccharides and the formation of flavor during roasting sunflower seeds.

Unlocking the Potential of Food Waste: A Review of Multifunctional Pectins.

This review comprehensively explores the multifunctional applications of pectins derived from food waste and by-products, emphasizing their role as versatile biomaterials in the medical-related sectors. Pectins, known for their polyelectrolytic nature and ability to form hydrogels, influence the chemical composition, sensory properties, and overall acceptability of food and pharmaceutical products. The study presents an in-depth analysis of molecular parameters and structural features of pectins, such as the degree of esterification (DE), monosaccharide composition, galacturonic acid (GalA) content, and relative amounts of homogalacturonan (HG) and rhamnogalacturonan I (RG-I), which are critical for their technofunctional properties and biological activity. Emphasis is placed on pectins obtained from various waste sources, including fruits, vegetables, herbs, and nuts. The review also highlights the importance of structure-function relationships, especially with respect to the interfacial properties and rheological behavior of pectin solutions and gels. Biological applications, including antioxidant, immunomodulatory, anticancer, and antimicrobial activities, are also discussed, positioning pectins as promising biomaterials for various functional and therapeutic applications. Recalled pectins can also support the growth of probiotic bacteria, thus increasing the health benefits of the final product. This detailed review highlights the potential of using pectins from food waste to develop advanced and sustainable biopolymer-based products.

Identification of pectin acetylesterase genes in moso bamboo (Phyllostachys edulis) reveals PePAE6 involved in pectin accumulation of leaves

As an indispensable polysaccharide, pectin profoundly affects various aspects of plant growth and development. Pectin acetylesterase (PAE) adjusts the acetylation level of pectin, thereby affecting the properties of pectin and cell walls, particularly in tissues such as leaves, where primary cell walls are predominant and rich in pectin. However, the PAE family in bamboo remains unknown. In the present study, ten PAE genes (PePAE1-PePAE10) were identified and characterized in moso bamboo (Phyllostachys edulis). All PePAEs possessed unique conserved domains and motifs of plant PAEs. The expression patterns of PePAEs varied across different tissues and developmental stages, indicating the sub-functionalization of these genes. Notably, the expression level of PePAE6 displayed the most remarkable change during leaf growth and was co-expressed with multiple transcription factors. Using various experimental approaches, we found that PeWRKY-1 and PeWRKY-2 negatively regulated PePAE6 by binding to its promoter. Knockdown of PeWRKY-1 or PeWRKY-2 inversely increased expression of PePAE6. While knockdown of PePAE6 resulted in increased acetylation levels and reduced galacturonic acid (GalA) content in moso bamboo leaves. Furthermore, overexpression of PePAE6 in rice indirectly enhanced vegetative growth and photosynthetic capacity, with a reduction in pectin acetylation levels and an increase in GalA. Additionally, an in vitro pectin acetylesterase activity assay confirmed that PePAE6 catalyzed pectin deacetylation, releasing acetic acid as a byproduct. These findings provide valuable insights into the basic characteristics of PAE in bamboo and reveal that PePAE6 is a functional gene involved in pectin accumulation, which could be helpful in genetic engineering in bamboo breeding.

Passion fruit peel-derived low-methoxyl pectin: De-esterification methods and application as a fat substitute in set yogurt

Passion fruit pectin, originally high methoxyl pectin, undergoes substantial conversion into low methoxyl pectin (LMP) through de-esterification. This de-esterification is significance for reducing the application of sugar in food, as calcium ions can replace excessive sugar during gel formation. In this study, LMPs derived from passion fruit pectin were prepared using four methods: low-temperature alkali, room temperature alkali, enzymatic, and dielectric barrier discharge plasma (DBD)-assisted enzyme (DBDE). The de-esterification conditions were optimized, leading to the selection of LMPs with a degree of esterification for the analysis of molecular weight, monosaccharide composition, and gel properties. The results revealed significant differences in the structure and properties of LMPs depending on the de-esterification method applied. The galacturonic acid content of LMPs significantly increased, with LMP from DBDE (LMP-DBDE) exhibiting the highest increase at 47.81 %. Additionally, the molecular weights of LMPs significantly decreased, with LMP-DBDE showing the smallest decrease. LMP-DBDE demonstrated higher apparent viscosity, thermal stability, and gel properties, facilitating the formation of gels. After 21 days of storage, 0.40 % LMP-DBDE yogurt showed no whey separation, significantly extending its shelf life. Therefore, LMP-DBDE exhibits potential as a fat substitute, combining the advantages of LMP with enhanced water-holding capacity, and presenting promising applications in low-fat dairy products.

Investigation of the Structural Properties and Antioxidant Potency of Pectic Polysaccharides Derived from Rohdea japonica (Thunb.) Roth.

This study investigated the structural composition and antioxidant properties of pectic polysaccharides extracted from Rohdea japonica (Thunb.) Roth. Pectins, which belong to a complex category of acidic polysaccharides, possess a wide range of biological effects stemming from their distinctive structural domains. The polysaccharides were extracted using water, and were subsequently purified through ion exchange and gel permeation chromatography. In order to elucidate their structural features, Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance techniques were applied. Two specific polysaccharides, WRJP-A2a and WRJP-A3b, with molecular weights of 42.7 kDa and 64.1 kDa, respectively, were identified to contain varying proportions of homogalacturonan, rhamnogalacturonan I, and rhamnogalacturonan II domains. Regarding antioxidant capacity, WRJP-A3b exhibited superior scavenging capabilities against DPPH, ABTS, and hydroxyl radicals, potentially attributed to its higher galacturonic acid content and abundance of homogalacturonan domains. These results enhance our comprehension of the structure-activity interplay of pectic polysaccharides sourced from Rohdea japonica (Thunb.) Roth and their potential utility in the healthcare and functional food sectors.

Physicochemical, structural and functional properties of pomelo peel pectin extracted by combination of pulsed electric field and cellulase hydrolysis

In this study, pectin extracted from pomelo peel was investigated using three different combination methods of pulsed electric field (PEF) and cellulase. Three action sequences were performed, including PEF treatment followed by enzymatic hydrolysis, enzymatic hydrolysis followed by PEF treatment, and enzymatic hydrolysis simultaneously treated by PEF. The three corresponding pectins were namely PEP, EPP and SP. The physiochemical, molecular structural and functional properties of the three pectins were determined. The results showed that PEP had excellent physiochemical properties, with the highest yield (12.08 %), total sugar (80.17 %) and total phenol content (38.20 %). The monosaccharide composition and FT-IR analysis indicated that the three pectins were similar. The molecular weights of PEP, EPP and SP were 51.13, 88.51 and 40.00 kDa, respectively. PEP showed the best gel properties, emulsification stability and antioxidant capacity among the three products, due to its high galacturonic acid and total phenol content, appropriate protein and low molecular weight. The mechanism of PEF-assisted cellulase hydrolysis of pomelo peel was also revealed by SEM analysis. These results suggested that PEF pretreatment was the best method, which not only improved the efficiency of enzymatic extraction, but also reduced resource waste and increased financial benefits.

Microwave-assisted acid extraction of high-methoxyl kinnow (Citrus reticulata) peels pectin: Process, techno-functionality, characterization and life cycle assessment

The present study assessed the efficacy of kinnow peel pectin-acetic acid extraction using microwave heating at 110 °C, pH 2.2 for 10 min with a 1:2 ratio supernatant to ethanol for higher yield. The kinnow peel was freeze dried and grinded to fine powder for pectin extraction. The microwave extracted (ME) kinnow pectin showed 833 mg equivalent weight, 7.44 % methoxyl content, 66.67 % degree of esterification, 63.15 % galacturonic acid content and evinced higher purity than commercial citrus pectin. ME kinnow pectin exhibited shear thinning behaviour while higher apparent viscosity (Pa. s) at 20 % concentration. The ME kinnow pectin showed characteristic functional groups and a less crystalline structure as deduced from FT-IR, SEM and XRD respectively, and a higher thermal decomposition analysed from TGA. Further, life cycle assessment (LCA) predicted that the ethanol and acetic acid were major contributors toward climate change in this study. ME kinnow pectin has the potential to be used as a commercial pectin in various food applications.

Structural characterization and mast cell stabilizing activity of Red-edge tea polysaccharide

The potential anti-allergic properties of tea have been demonstrated in studies supporting theanine and catechin. However, research on tea polysaccharides' anti-allergic properties has been limited. In this study, we extracted red-edge tea crude polysaccharide (RETPS) and evaluated its anti-allergic activity using the mast cell, passive cutaneous anaphylaxis, and passive systemic anaphylaxis models. We purified RETPS using the DEAE-52 cellulose column, analyzed its composition and structural characteristics, and compared the anti-allergic properties of different polysaccharide fractions. The purified components RETPS-3 and RETPS-4 displayed higher galacturonic acid content and lower molecular weight (106.61 kDa and 53.95 kDa, respectively) compared to RETPS (310.54 kDa). In addition, RETPS-3 and RETPS-4 demonstrated superior anti-allergic activity than RETPS in mice's passive cutaneous and systemic allergic reactions. Our findings provide evidence of the anti-allergic potential of tea polysaccharides and offer a theoretical foundation for developing tea polysaccharides as a functional anti-allergic food product.

Optimizing the microwave-assisted hydrothermal extraction of pectin from tangerine by-product and its physicochemical, structural, and functional properties

Microwave-assisted hydrothermal extraction (MAHE) was optimized using a Box-Behnken design (BBD) of the response surface methodology (RSM) for optimal recovery of pectin from tangerine peel (TPP). The effects of three factors (pH, irradiation time and temperature) on extraction yield (EY), galacturonic acid content (GAC) and degree of esterification (DE) of pectin were investigated. The optimal extraction conditions were as follows: pH 1.7, irradiation time 12 min and temperature 109 °C. Under these conditions, the EY, GAC and DE were 30.4, 72.3 and 45.2%, respectively. The low methoxyl content of MHAE (45.2%) compared to CE is confirmed by the 1H NMR and FTIR spectra, and the emulsifying activity is 57.65% and 50.56% for CE and MHAE, respectively. The total phenolic content (TPC) of pectin produced using MAHE is 41.2 mg GAE/g, thus indicating higher antioxidant properties compared to pectin produced with CE, which had a TPC of 38.4 mg GAE/g. In addition, the X-ray diffraction (XRD) and surface morphological analysis (SEM) results showed that TPP had a rough surface and crystalline structure. Overall, our findings show that TTP from MAHE can be used as a natural antioxidant ingredient in the functional food and pharmaceutical industries.

Analysis of Metoxyl and Galacturonate Contents from Pectin of Banana Peel Waste Combined with Sappan Wood

The production of banana plants (Musaceaea sp.) ranks first in agricultural output in Indonesia, but this is not balanced by the processing of waste from banana peels, which is a large amount. Therefore, an attempt is made to use banana peel waste as raw material for making pectin. Pectin is used as a functional component in the food industry because of its ability to form thin gels and stabilize proteins. Pectin is also used as a filler in the paper and textile industries, and as a thickener in the rubber industry. This research aims to determine the effect of extraction time and temperature on the quality of pectin from Kepok banana peels. The method used is extraction through Ultrasonic Assisted Solvent Extraction (UASE) in 40 kHz. Banana peels that had been dried and ground into powder were extracted with 0.1 N HCl at temperatures of 70 oC, 80 oC and 90 oC. The variables used in this extraction are variations in extraction time, namely 60 minutes and 80 minutes. The extracted solution is filtered and thickened to half the volume of the original filtrate by heating, then the pectin is thickened using acid ethanol. The pectin precipitate was washed using 96% alcohol until it was free of chloride and the precipitate was separated using a vacuum and then dried in an oven then to analysis of pectin using methoxyl and galacturonate as method to determine pectin quality form banana peel waste. The research results showed that the pectin quality was optimum at a temperature of 90 oC for 80 minutes with a methoxyl content of 4.12% (low methoxyl) and a galacturonic acid content of 79.96%.

Preparation, physicochemical and functional characterization of pectic polysaccharides from fresh passion fruit peel by magnetic-induced electric field-assisted three-phase partitioning

In this study, we explored the use of magnetic-induced electric field (MIEF) treatment at various excitation voltages to assist three-phase partitioning (TPP) methods in extracting and separating pectic polysaccharides (PFPs) from the peel of fresh passion fruit (Passiflora edulis f. flavicarpa). The findings indicated that applying MIEF treatment prior to TPP separation significantly reduced the total sugar and galacturonic acid contents, as well as the degree of esterification of PFPs, with increasing excitation voltage. This treatment notably enhanced their yields and molecular weights. Although the MIEF treatment did not alter the monosaccharide composition of PFPs, it significantly modified their molar ratios of monosaccharides, thereby altering the backbone structure and neutral sugar side chains, which resulted in varied microstructures. Furthermore, especially at higher excitation voltages (≥300 V), the MIEF treatment improved the thermal stability, rheological, and emulsifying properties of PFPs. Consequently, our data suggest that the MIEF-assisted TPP method is a promising approach for the efficient and environmentally friendly preparation of pectic polysaccharides from plant materials.

The Effect of Different Extraction Conditions on the Physicochemical Properties of Novel High Methoxyl Pectin-like Polysaccharides from Green Bell Pepper (GBP)

Green peppers are massively produced all over the world; however, substantial quantities of peppers are wasted. Functional polysaccharides can be produced from pepper waste. A conventional acid extraction method was used to obtain pectin-like materials from green bell pepper (GBP). A 23 experimental design (two-level factorials with three factors: temperature, pH, and time) was used to study the relationship between the extraction conditions and the measured physicochemical properties. The extracted polysaccharides were further analysed regarding their physicochemical and functional properties. The yields were in the range of (11.6–20.7%) and the highest yield value was extracted at pH 1. The polysaccharides were classified as “pectin-like”, as the galacturonic acid content was lower than 65%. Glucose and galactose were the major neutral sugars, and their relative amounts were dependent on the extraction conditions. The degree of esterification (DE) of the pectin-like extracts was greater than 50% and they were therefore classified as high methoxyl regardless of the extraction conditions. Also, important levels of phenolic materials (32.3–52.9 mg GAE/g) and proteins (1.5–5.4%) were present in the extract and their amounts varied depending on the extraction conditions. The green bell pepper polysaccharides demonstrated antioxidant and emulsifying activities and could also be used adequately to stabilise oil/water emulsion systems. This finding shows that green bell pepper could be used as an alternative source of antioxidants and an emulsifier/stabilising agent, and furthermore, the extraction conditions could be fine-tunned to produce polysaccharides with the desired quality depending on their application.

Type of pectin affects the functionality of potato protein-pectin conjugates in emulsions

This study investigated the effect of the molecular structure of pectin on conjugate formation and its functionality in plant protein-based emulsions. For this purpose, high-methoxylated, low-methoxylated, amidated citrus pectin and their mixtures with potato protein were vacuum-dried at defined process conditions. The change in free amino groups, colour and molecular weight distribution assessed conjugation. The side reaction, such as pectin degradation, was monitored by the degree of methoxylation, galacturonic acid content and intrinsic viscosity. In addition, FT-IR and hydrophobicity measurements were performed to determine the changes in chemical structure due to the occurring reactions. The ζ-potential, solubility and oil droplet size reflected the functionality of the conjugated samples.The results confirm that, apart from the conjugation of protein and pectin, where the most significant decrease in free amino groups was obtained with an increasing degree of methoxylation or presence of amide groups, undesirable degradation of pectin occurring, resulting in a broad molecular weight distribution of the conjugate samples. The conjugate formation was the highest with amidated pectin. The FT-IR measurements confirmed the formation of Maillard conjugates. The FT-IR spectra showed a decrease in the intensity signals of amide I and amide II and the formation of new C–N bond maxima. In addition, the conjugation caused the shift of the protein's isoelectric point to the acidic environment, resulting in higher solubility and improved emulsion stability at the isoelectric point of the protein.Regarding emulsion stability, the conjugates with amidated pectin performed best and achieved the narrowest oil droplet size distribution over a wider pH range. Emulsion-stabilising properties of conjugates with high- and low-methoxylated pectin differed only slightly. To better understand the underlying mechanisms for emulsion stabilisation, future research will focus on the interfacial properties of the conjugates as determined by interfacial shear rheology and pendant drop analysis.

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.