Physicochemical properties of pectin from Malus domestica ‘Fălticeni’ apple pomace as affected by non-conventional extraction techniques

Efficient extraction of pectin from spaghetti squash (Cucurbita pepo L. subsp. pepo) peel by electron beam irradiation combined with ultrasound: Structural characterization and functional properties

This study investigated the effects of acid extraction, electron beam irradiation (EBI) extraction, ultrasound extraction, and combined EBI and ultrasound extraction on the yield, structure, and functional properties of pectin from spaghetti squash (Cucurbita pepo L. subsp. pepo) peel. The established extraction kinetics model indicated that the combined EBI and ultrasound extraction exhibited a synergistic effect, resulting in a pectin yield (13.50 %) higher than that obtained from acid extraction (6.55 %), EBI extraction (10.91 %), and ultrasound extraction (7.56 %). The pectin produced through the combined method (EUSP) demonstrated a low degree of esterification (DE) (34.77 %) and molecular weight (Mw) of 83 kDa. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses revealed that EBI and ultrasound significantly disrupted the internal structure of the pectin. Rheological analysis indicated that the combined treatment reduced the viscosity characteristics of the pectin solution. EUSP exhibited good thermodynamic properties, emulsifying characteristics, antioxidant activities, and prebiotic activity. These findings provide a theoretical basis for the combined EBI and ultrasound extraction of pectin and offer insights for the efficient utilization of spaghetti squash peel and the application of pectin in the food industry.

Sustainable microwave-based eutectic mixture assisted purification of low-methoxy pectin and its role as an edible emulsifier in carrot jam preparation

An optimized microwave-assisted low methoxyl pectin extraction procedure was described. Six task specific deep eutectic solvents (TDES) were used in the extraction of pectin from bilimbi (LMABP) and pomelo peels (LMCGP). Response surface methodology-based optimization of the parameters like feed-to-solvent ratio, extraction time, and microwave power level results in 72.94 % (w/w) LMABP and 79.3 % (w/w) of LMCGP respectively. Fourier transform infrared (FTIR) analysis shows 20.93 % (w/w) and 20 % (w/w) degree of esterification for LMABP and LMCGP respectively. The stability, particle size, and pH of the extracts were found to be -5.554 mV, 1923 nm, and 2.95 for LMABP, and - 2.34 mV, 3320 nm, and 2.55 for LMCGP respectively. Additionally, the LMP extracts were successfully employed in the preparation of carrot jam with better stability, texture, and lower sugar content. This investigation highlights the synergetic effectiveness of microwave-assisted DES extraction for sustainable LMP extraction.

Preparation and structure-function relationships of homogalacturonan-rich and rhamnogalacturonan-I rich pectin: A review

Pectin has multiple functions and is widely used in the food industry. It is an acidic heteropolysaccharide found in most plants, mainly consisting of two regions: homogalacturonan (HG) and rhamnogalacturonan-I (RG-I). HG and RG-I rich pectin have unique structures and functional properties, which can be obtained through specific preparation methods. Some emerging physics assisted preparation strategies are more advantageous for preparing specific structures with higher purity and efficiency than traditional preparation methods. HG and RG-I rich pectin have unique processing and functional properties, but sometimes a proper ratio of HG and RG-I pectin may have better effects than individuals. Therefore, it is speculated that there may be some synergistic effects between the two pectin structures. A comprehensive understanding of the preparation, structure, and functional relationship of HG and RG-I rich pectin is crucial for the efficient preparation of pectin with targeted functions.

Extraction of pectin from watermelon rinds using sequential ultrasound-microwave technique: Optimization using RSM and ANN modeling and characterization

This study aimed to optimize pectin extraction from watermelon (Citrullus lanatus) rind using sequential ultrasound-microwave assisted extraction (UMAE) with artificial neural network (ANN) and response surface methodology (RSM). The effects of pH, sonication time, microwave power, and irradiation time on pectin yield were evaluated. The ANN model showed higher precision in predicting yield compared to the RSM model. The optimal yield was 32.11 % under the conditions of pH 2.01, sonication time 54.23 min, microwave power 900 watts, and irradiation time 6.34 min. This study evaluated the effects of different extraction techniques, including ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and microwave-ultrasound-assisted extraction (MUAE), on pectin yield and their physicochemical properties under optimal UMAE conditions. The highest pectin yield was achieved with UMAE, followed by MUAE, MAE, and UAE. The Fourier transform infrared spectroscopy (FTIR) analysis confirmed the presence of homogalacturonan, galacturonic acid backbone, and methyl esters in the extracted pectin. The viscosity study revealed that the pectin solution showed pseudoplastic behavior at 0.2 % w/v. All extracted pectin in different methods had high-methoxy content ranging from 7.68 ± 0.56 % to 11.96 ± 1.29 % and a degree of esterification between 56.55 ± 0.68 % and 63.43 ± 1.54 %. However, UMAE showed significantly lower energy consumption and CO2 emissions, suggesting it as a sustainable approach for pectin extraction from watermelon rind.

Sustainable pectin extraction from Riang husk using ultrasound-assisted extraction with deep eutectic solvents and its potential in antipollution products

With increasing concerns about air pollution and its adverse effects on health, particularly in Thailand, the demand for antipollution products has risen significantly. Parkia timoriana (DC.) Merr., commonly known as Riang, has emerged as a promising source for developing antipollution products due to its characteristics. This study investigates the use of ultrasound-assisted extraction (UAE) combined with deep eutectic solvents (DESs) as a sustainable and efficient method for optimizing pectin extraction from Riang husks through the evaluation of a central composite design (CCD), and the structural, functional, and rheological characteristics of the extracted pectin. The antioxidant activity and protective effects against PM2.5-induced cellular damage of this method were also evaluated. The condition that exhibited the highest yield were found to be a liquid-to-solid ratio of 40 mL/g, 35 % amplitude (ultrasonic power of 28.11 W), and 60 min of extraction time. The extracted pectin was primarily composed of monosaccharides, including galacturonic acid (53.74 %), arabinose (23.97 %), galactose (12.36 %), and rhamnose (6.81 %). The degree of esterification (DE) was 73.41 %, classifying it as high methoxyl pectin. Functionally, the pectin demonstrated a solubility of 53 %, a water holding capacity of 3.88 g water/g pectin, an oil holding capacity of 3.30 g oil/g pectin, and a swelling capacity of 11.77 mL/g. Rheological analysis showed shear-thinning behavior across all pH gel forms. Furthermore, Riang husk pectin exhibited antioxidant activity, measured at 0.26 ± 0.02 mmol Trolox equivalents/g, and demonstrated cytoprotective effects against hydrogen peroxide-induced oxidative stress. It also attenuated damage caused by PM2.5 in HaCaT cells. The current study highlights UAE combined with DESs as a sustainable and effective method for obtaining high-quality pectin, contributing to the development of antipollution products and supporting sustainability goals.

Optimization and characterization of physicochemical, morphological, structural, thermal, and rheological properties of microwave-assisted extracted pectin from Dillenia indica fruit

Microwave-assisted extraction of pectin from Dillenia indica (DI) fruit was optimized using Box-Behnken design to maximize yield and quality. Parameters such as solid:solvent (1:10-1:30), microwave power (200-600 W), and extraction time (4-10 min) were varied to determine the optimal conditions. Through experimentation, the optimized extraction parameters were identified as 1:23.66 solid:solvent, 400 W microwave power, and 7 min of extraction time, under which the predicted yield and equivalent weight were 19.68 % and 915.93, respectively. The optimized conditions were validated experimentally (yield:19.4 ± 0.35 %) and equivalent weight:914.57 ± 0.62), showing close agreement with predicted values. Physicochemical properties of the extracted pectin were determined, revealing an effective pore radius of 0.263 ± 0.005 mm and a swelling index order of: water(1) > pH 6(0.7) > HCl(0.3). Moisture content was measured as 7.23 ± 0.25 %, while ash content was found to be 2.23 ± 0.25 %. Further analysis included the determination of methoxyl value, anhydrouronic acid content, degree of esterification, and protein content, which were 9.61 ± 0.31 %, 73.56 ± 1.86 %, 74.15 ± 0.28 %, and 1.16 ± 0.16 %, respectively. Monosaccharide composition revealed presence of neutral sugars, glucose, arabinose and rhamnose and molecular weight was 71,489 g/mol. Morphological characteristics, assessed using scanning electron microscopy, showed a rough, irregular surface of DI fruit pectin. Fourier-transform infrared spectroscopy (FTIR) indicated similarity to standard high methoxyl pectin, while nuclear magnetic resonance (NMR) confirmed characteristic functional groups. Thermal behaviour, determined via differential scanning calorimetry (DSC), exhibited endothermic and exothermic transitions at 83.6 °C and 260.027 °C, respectively. Rheological and functional properties revealed DI fruit pectin solution as a non-Newtonian fluid with shear thinning behaviour, forming weak gels and that its emulsion capacity increased with increase in pectin concentration. Overall, this study provides a comprehensive characterization of microwave-assisted extracted pectin from Dillenia indica fruit, offering insights into its potential applications in food industries.

Citrus Wastes as Source of Pectin and Bioactive Compounds Extracted via One-Pot Microwave Process: An In Situ Path to Modulated Property Control

In this paper, citrus pomace was used as a source of pectin and polyphenols extracted in one pot solution by microwave-assisted extraction (MAE) and conventional extraction (CE) methods. MAE parameters were optimized to maximize yield and adjust in situ final physicochemical properties of extracted pectins, such as the methylation degree (DM), significantly influencing pectin functionality and application. Citric acid (CA) and acetic acid (Hac) were employed as solvents to mitigate pectin degradation. Extracted pectins were structurally (GPC and FTIR-ATR), morphologically (SEM), and thermally (TGA) characterized. From the reaction batch, the bioactive compounds (AOs) were separated and recovered, and their yield and antioxidant activities were evaluated with a DPPH assay. Moreover, by strategically selecting pH and solvents, this research enabled precise control over the final properties of pectin. The various characterization techniques employed show that the extraction conditions significantly influence the physicochemical and morphological properties of the material. Molecular weight (Mw) values range from 218 kDa to 567 kDa, surface morphology varies from compact/aggregated structures to three-dimensional network-like formations, and the DM spans from 34% (low DM) to 83% (high DM). This highlights a novel approach for predicting and tailoring in situ characteristics of extracted pectin to meet specific application requirements.

Pectin: Structural Characteristics, ADME Profiles, and Their Interrelationship

Pectin, a plant-derived polysaccharide, is highly valued for its gelling, thickening, and stabilizing properties, with extensive applications in the food and pharmaceutical industries. This review provides a comprehensive analysis of pectin's structure, categorized by its degree of methyl esterification (DM) and key components, including homogalacturonan (HG) and rhamnogalacturonans (RG-I and RG-II). The influence of diverse extraction methods, such as subcritical water and microwave-assisted techniques, on its structure and functionality is critically examined. Furthermore, the review investigates the absorption, distribution, metabolism, and excretion (ADME) profiles of pectin, emphasizing how structural factors like molecular weight, DM, and neutral sugars impact bioavailability and interactions with gut microbiota. Notably, this review highlights emerging research methodologies, offering novel insights into pectin's pharmacokinetics. By addressing these interrelationships, the review underscores pectin's potential applications in functional foods, personalized nutrition, and targeted therapeutics and identifies key knowledge gaps for future research.

The Use of Different Cell Wall Degrading Enzymes for Pectin Extraction from Carrot Pomace, in Comparison to and in Combination with an Acid Extraction

The effect of different cell wall degrading enzymes, cellulase (C) and hemicellulase (HC), during the enzyme-assisted extraction (EAE) of pectin from carrot pomace was investigated. The EAE with C and a heat treatment resulted in a pectin yield, purity, and molecular structure comparable to an acid extraction (AE), except for a slightly lower molar mass and a slightly higher degree of methylesterification. The addition of HC had a negligible influence on the pectin yield and structure and mainly resulted in more hemicellulose co-extraction. Overall, the AE still resulted in the highest pectin yield, but, despite the much milder extraction conditions, the optimal EAE process resulted in 80% of the pectin yield of the AE. Additionally, this study investigated an EAE with C in combination with an AE, and both combination treatments, i.e., EAE as pretreatment or as an additional treatment, resulted in a significant increase in the pectin yield (up to 72%), while minor structural differences were observed in the extracted pectin. Overall, it can be concluded that the EAE process can be used as a more environmentally friendly alternative for the AE or that EAE can be used in combination with an AE to improve the efficiency of the extraction process.

Pectin obtention from agroindustrial wastes of Malus domestica using green solvents (citric acid and natural deep eutectic solvents). Chemical, thermal, and rheological characterization

The use of green solvents, citric acid (CA), and natural deep eutectic solvents (NADES) for the obtention of pectin from wastes (pulp and peel) of Malus domestica was studied. The NADES used comprised citric acid-glucose-water (N1) or lactic acid-glucose-water (N2). The fractions rich in pectin obtained after exposure to NADES showed lower yield (≈4 g/100 g CA vs. ≈ 11 g/100 g CA), equal to or lower degree of methoxylation (53-71 mol/100 mol CA vs. 73 mol/100 mol CA), equal to or greater content of uronic acid (50-63 g/100 g CA vs. 51 g/100 g CA) than those isolated with CA, and the ones obtained from peel were the most thermally stable. These pectins showed greater linearity, shorter branch lengths, and lower arabinose content than those obtained with CA. The neutral sugars present in the highest concentration in all the isolated fractions were arabinose, xylose, galactose, and rhamnose. Glucose was also detected, probably due to contamination with starch. Their aqueous solutions showed pseudoplastic behavior. The effect of ultrasound assistance was preliminarily evaluated in the production of pectic fractions using N2, observing higher yields (13-18 g/100 g), in general, a higher concentration of uronic acid and a higher degree of methoxylation when compared with the extraction without US. They also showed greater arabinose content (less degradative treatment), lower glucose content (increased purity), and higher rhamnogalacturonan I (RG-I) content. It is known that RG-I is linked to pectin bioactivity and rheological behavior. The green solvent techniques assayed allowed obtaining fractions rich in uronic acid with different chemical, thermochemical, and rheological characteristics. In the case of isolation with NADES, the yield was low, but preliminary tests with ultrasound assistance showed that it is possible to overcome this limitation.

Physical field-assisted deep eutectic solvent processing: A green and water-saving extraction and separation technology

Extraction of organic and bioactive compounds from plant materials with the traditional organic solvents aided by water or oil bath heating is not sustainable, because it consumes a lot of energy, time, water/oil, solvents, and results in lower yield. This review discusses deep eutectic solvent (DES) as a green solvent, physical field technology (PFT) as a water-saving and green technology, and how the coupling of PFT (ultrasound [US], microwave [MW], infrared [IR]) to DES will improve the yield and quality of protein, polysaccharides, polyphenols, pectin, and terpenoids extracted from plant materials. Ultrasonication increases DES extraction efficiency via cavitation dislodgement and pores creation. IR coupling to DES enhances the extraction yield of polyphenols and the antioxidant and antiradical activity. MW improves DES extraction yield, reduces energy consumption, operational cost, and compound degradation, and is inferred to be the greenest technology.

Transformation of agricultural wastes into functional oligosaccharides using enzymes and emerging technologies

INTRODUCTION

Pectin-oligosaccharides (POS) serve diverse purposes as a food ingredient, antimicrobial and biostimulant in plants, and their functionality is linked to the degree of esterification. Grape and broccoli wastes emerge as environmentally friendly alternatives to obtaining pectin, serving as a sustainable source to producing POS. For example, microwaves have proven to be an effective and sustainable method to extract polysaccharides from plant matrices.

OBJECTIVE

This work aims to use grape and broccoli wastes as alternative sources for obtaining pectin by microwave-assisted extraction and biotransformation into POS, which possess biological properties.

MATERIAL AND METHODS

The extraction conditions were identified at a power of 400 W, 300 s for the extraction of pectin from grape pomace and broccoli waste. Biotransformation of pectins into POS, using commercial enzyme preparations (Viscozyme L and Pectinase). Characterisation was carried out by Fourier-transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy.

RESULTS

Physicochemical analysis indicated grape pomace and broccoli waste pectins had galacturonic acid content of 63.81 ± 1.67 and 40.83 ± 2.85 mg 100 mg-1, low degree of esterification of 34.89% and 16.22%, respectively. Biotransformation of pectins into POS resulted in a 20% hydrolysis rate. The main enzymatic activity was polygalacturonase for the degradation of the main structure of the pectin.

CONCLUSION

Production of POS from agro-industrial wastes by emerging technologies, such as the combined use of microwave-assisted extraction and enzymatic processes, represents an alternative method for the generation of bioactive compounds with distinctive properties suitable for different applications of interest.

An in-depth review: Unraveling the extraction, structure, bio-functionalities, target molecules, and applications of pectic polysaccharides

Pectic polysaccharides have long been a challenging subject of research in the field of macromolecular science, given their complex structures and wide range of biological effects. However, the extensive exploration of pectic polysaccharides has been limited due to the intricacy of their structures. In this comprehensive review, we aim to provide a thorough summary of the existing knowledge on pectic polysaccharides, with a particular focus on aspects such as classification, extraction methodologies, structural analysis, elucidation of biological activities, and exploration of target molecules and signaling pathways. By conducting a comprehensive analysis of existing literature and research achievements, we strive to establish a comprehensive and systematic framework that can serve as a reference and guide for further investigations into pectic polysaccharides. Furthermore, this review delves into the applications of pectic polysaccharides beyond their fundamental attributes and characteristics, exploring their potential in fields such as materials, food, and pharmaceuticals. We pay special attention to the promising opportunities for pectic polysaccharides in the pharmaceutical domain and provide an overview of related drug development research. The aim of this review is to facilitate a holistic understanding of pectic polysaccharides by incorporating multifaceted research, providing valuable insights for further in-depth investigations into this significant polymer.

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.

Sustainable Jam with Apple Pomace: Gelling, Rheology, and Composition Analysis

Fruit juice processing can generate significant waste, but efficiently repurposing some of its byproducts not only reduces environmental impact but also adds value, thereby enhancing sustainability in the food industry. This work assesses the use of hydrocolloids in jam preparation and the influence of time and temperature on gelation in the presence of apple pomace. The effects of different processing conditions were analyzed using response surface methodology. Viscosity, elastic modulus (G'), viscous modulus (G″), and firmness were measured. Results indicated that both time and temperature significantly improved rheological and textural properties. The optimal conditions (35.6 min and 84.2 °C) yielded a viscosity of 3.66 × 10⁴ ± 4.49 × 102 Pa·s and a G' at 1 Hz of 2596 ± 128 Pa. The final product exhibited the desirable texture, was free of added sugars, had low lipid content, and retained its bioactive compounds. Applying apple pomace in the formulation allows a more efficient hydrocolloid system, promotes a circular economy, and combats food waste.

Polysaccharides from fruit and vegetable wastes and their food applications: A review

Fruit and vegetables are a great source of nutrients and have numerous health benefits. The fruit and vegetable industry produces enormous amounts of waste such as peels, seeds, and stems. The amount of this waste production has increased, causing economic and environmental problems. Fruit and vegetable wastes (FVWs) have the potential to be recovered and used to produce high-value goods. Furthermore, FVWs have a large variety and quantity of polysaccharides, which makes them interesting to study for potential industrial use. Currently, the investigations on extracting polysaccharides from FVWs and examining how they affect human health are increasing. The present review focuses on polysaccharides from FVWs such as starch, pectin, cellulose, and inulin, and their various biological activities such as anti-inflammatory, anti-tumor, anti-diabetic, antioxidant, and antimicrobial. Additionally, applications as packaging material, gelling agent, emulsifier, prebiotic, and fat replacer of polysaccharides from FVWs in the food industry have been viewed in detail. As a result, FVWs can be reused as the source of polysaccharides, reducing environmental pollution and enabling sustainable green development. Further investigation of the biological activities of polysaccharides from FVWs on human health is of great importance for using these polysaccharides in food applications.

Cocoa by-products: A comprehensive review on potential uses, waste management, and emerging green technologies for cocoa pod husk utilization

Cocoa is considered to be one of the most significant agricultural commodities globally, alongside Palm Oil and Rubber. Cocoa is the primary ingredient in the manufacturing of chocolate, a globally popular food product. Approximately 30 % of cocoa, specifically cocoa nibs, are used as the primary constituent in chocolate production., while the other portion is either discarded in landfills as compost or repurposed as animal feed. Cocoa by-products consist of cocoa pod husk (CPH), cocoa shell, and pulp, of which about 70 % of the fruit is composed of CPH. CPH is a renewable resource rich in dietary fiber, lignin, and bioactive antioxidants like polyphenols that are being underutilized. CPH has the potential to be used as a source of pectin, dietary fibre, antibacterial properties, encapsulation material, xylitol as a sugar substitute, a fragrance compound, and in skin care applications. Several methods can be used to manage CPH waste using green technology and then transformed into valuable commodities, including pectin sources. Innovations in extraction procedures for the production of functional compounds can be utilized to increase yields and enhance existing uses. This review focuses on the physicochemical of CPH, its potential use, waste management, and green technology of cocoa by-products, particularly CPH pectin, in order to provide information for its development.

Novel films of pectin extracted from ambarella fruit peel and jackfruit seed slimy sheath: Effect of ionic crosslinking on the properties of pectin film

Here, we prepared ionically crosslinked films using pectin extracted from agro-wastes, specifically ambarella peels (AFP) and jackfruit seed slimy sheath (JFS). Physiochemical properties of pectins, including moisture content, molecular weight (Mw), degree of esterification (DE), and galacturonic acid (GA), were analyzed. Optimal extraction was determined, i.e., citric acid concentration 0.3 M, time 60 min, solid/liquid ratio 1:25, and temperature 90 °C for AFP or 85 °C for JFS. Pectin yields under these conditions were 29.67 % ± 0.35 % and 29.93 ± 0.49 %, respectively. AFP pectin revealed Mw, DE, and GA values of 533.20 kDa, 67.08 % ± 0.68 %, and 75.39 ± 0.82 %, while JFS pectin exhibited values of 859.94 kDa, 63.04 % ± 0.47 %, and 78.63 % ± 0.71 %, respectively. The pectin films crosslinked with Ca2+, Cu2+, Fe3+, or Zn2+ exhibited enhanced tensile strength and Young's modulus, along with reduced elongation at break, moisture content, water solubility, water vapor permeability, and oxygen permeability. Structural analyses indicated metal ions were effectively crosslinked with carboxyl groups of pectin. Notably, the Cu2+-crosslinked film demonstrated superior water resistance, mechanical properties, and exhibited the highest antioxidant and antibacterial activities among all tested films. Therefore, the pectin films represent a promising avenue to produce eco-friendly food packaging materials with excellent properties.

A methyl esterase from Bifidobacterium longum subsp. longum reshapes the prebiotic properties of apple pectin by triggering differential modulatory capacity in faecal cultures

Pectin structures have received increasing attention as emergent prebiotics due to their capacity to promote beneficial intestinal bacteria. Yet the collective activity of gut bacterial communities to cooperatively metabolize structural variants of this substrate remains largely unknown. Herein, the characterization of a pectin methylesterase, BpeM, from Bifidobacterium longum subsp. longum, is reported. The purified enzyme was able to remove methyl groups from highly methoxylated apple pectin, and the mathematical modelling of its activity enabled to tightly control the reaction conditions to achieve predefined final degrees of methyl-esterification in the resultant pectin. Demethylated pectin, generated by BpeM, exhibited differential fermentation patterns by gut microbial communities in in vitro mixed faecal cultures, promoting a stronger increase of bacterial genera associated with beneficial effects including Lactobacillus, Bifidobacterium and Collinsella. Our findings demonstrate that controlled pectin demethylation by the action of a B. longum esterase selectively modifies its prebiotic fermentation pattern, producing substrates that promote targeted bacterial groups more efficiently. This opens new possibilities to exploit biotechnological applications of enzymes from gut commensals to programme prebiotic properties.

Evaluation of citrus pectin extraction methods: Synergistic enhancement of pectin's antioxidant capacity and gel properties through combined use of organic acids, ultrasonication, and microwaves

The biological potency of pectin is intricately intertwined with its intricate molecular architecture. The fine structure of pectin is influenced by the extraction method, while the specific impact of these methods on the fine structure and the affected attributes thereof remains enigmatic. This study delves into the profound analysis of eight distinct extraction methods influence on the structure and biological activity of citrus peel pectin. The findings demonstrate that citric acid ultrasound-assisted microwave extraction yields pectin (PectinCA-US/MV) with higher viscosity and a dense, rigid chain. Pectin extracted with acetic acid ultrasound (PectinAA-US) and citric acid ultrasound (PectinCA-US) exhibits elevated galacturonic acid (GalA) levels and reduced D-galactose (Gal) content, enhancing antioxidant activity. Eight pectin-chitosan (CS) hydrogels, especially PectinCA-US/MV-CS, demonstrate commendable thermal stability, rheological properties, self-healing capability, and swelling behavior. This study characterizes citrus peel pectin properties from different extraction methods, laying a foundation for its application in food, pharmaceuticals, and industry.

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.

Hot-air drying vs. lyophilization of sugar beet flakes for efficient pectin recovery and influence of extraction conditions on pectin physicochemical properties

This study assessed the influence of drying pretreatment and extraction conditions (type of acid and particle size of plant material) on the yield and physicochemical properties of pectin from sugar beet flakes resulted as by-product of sugar beet processing in the sugar industry. The results indicated that the drying conditions (hot-air drying and lyophilization) affected the extraction yield, the chemical composition of pectin, its color, degree of methylation and acetylation, molecular weight, and its rheological and emulsifying properties. The best results for pectin yield (16.20%), galacturonic acid content (91.19 g/100 g), degree of methylation and acetylation (66.93 and 23.87%), and molecular weight (3.89 × 105 g/mol) were obtained when sugar beet flakes were pretreated by hot-air drying, and the extraction was made with citric acid using plant material with particle sizes of 125-200 μm. This pectin also had high emulsion activity (51.42%) and emulsion stability (88.03%). The FT-IR spectra were similar, while pectin thermal behavior was affected by the drying pretreatment and extraction conditions. The results of this study showed that from this by-product of the sugar industry it can be extracted high quality pectin with rheological and emulsifying properties that are superior to commercial citrus and apple pectin.

Properties of lime peel pectin as mainly influenced by ethanol and protein-based purification methods

BACKGROUND

Lime peel, obtained from juice factory waste, is considered as a source of pectin. Lime peel pectin samples, extracted by three extraction procedures of 90 °C heating for 120 min, 90 °C heating for 90 min and then 32 min of ultrasound, and 80 °C heating for 60 min and then 22 min of ultrasound, and purified by two methods using ethanol and sodium caseinate (SC), were prepared and characterized.

RESULTS

The results showed that the purification method significantly affected the lime pectin samples properties. Pectin samples purified with SC had a transparent and film-like appearance, whereas the ethanol-purified pectin samples showed an amorphous and opaque appearance. Pectin samples purified with ethanol showed higher extraction recovery (approximately 20%), whereas the lowest pectin yield was observed for the purification with SC (approximately 10%). Although SC purification did not enhance the pectin yield, it diminished the level of 'non-pectin' components and resulted in purer pectin. The bands at 1045-1076 cm-1 , relating to neutral sugars, had higher intensities in ethanol-purified pectin samples, indicating their higher sugar contents. Also the samples purified with SC exhibited more thermal stability, probably as a result of the presence of protein in their structure.

CONCLUSION

In the present study, under the same or varying extraction conditions, the most important element distinguishing pectins in terms of appearance, physicochemical, thermal and Fourier transform infrared characteristics was the type of purification method. Purification with SC may result in pectins with more non-esterified galacturonic acids from the homogalacturonan fraction. © 2023 Society of Chemical Industry.

Green Extraction of Pectin from Sugar Beet Flakes and Its Application in Hydrogels and Cryogels

Sugar beet flakes, a by-product of the sugar industry, were used as a source for pectin extraction that was performed using conventional citric acid extraction (CE) and two non-conventional extraction techniques-microwave-assisted extraction (MAE) and pulsed ultrasound-assisted extraction (PUAE). The influence of extraction conditions was studied for each technique based on pectin yield and galacturonic acid content, and spectroscopic, chromatographic and colorimetric methods were used for pectin characterization. Better results for pectin yield were achieved through CE (20.80%), while higher galacturonic acid content was measured in pectin extracted using PUAE (88.53 g/100 g). Pectin extracted using PUAE also presented a higher degree of methylation and acetylation. A significant increase in the molecular weight of pectin was observed for the PUAE process (7.40 × 105 g/mol) by comparison with conventional extraction (1.18 × 105 g/mol). Hydrogels and cryogels prepared with pectin from sugar beet flakes also showed differences in physicochemical parameters determined by the method of pectin extraction. Hydrogels had higher bulk density values irrespective of the pectin extraction method, and overall lower values of the textural parameters. Cryogels prepared with pectin from CE showed higher values of the textural parameters of hardness, adhesiveness, cohesiveness, gumminess and chewiness, while gels obtained with pectin from MAE and PUAE had higher thermal stability. The results of this study prove that sugar beet flakes can be considered a potential source for pectin production, and the extracted pectin is suitable for obtaining hydrogels and cryogels with physicochemical parameters comparable to the commercial citrus and apple pectin available on the market.

Recent progress and treatment strategy of pectin polysaccharide based tissue engineering scaffolds in cancer therapy, wound healing and cartilage regeneration

Natural polymers and its mixtures in the form of films, sponges and hydrogels are playing a major role in tissue engineering and regenerative medicine. Hydrogels have been extensively investigated as standalone materials for drug delivery purposes as they enable effective encapsulation and sustained release of drugs. Biopolymers are widely utilised in the fabrication of hydrogels due to their safety, biocompatibility, low toxicity, and regulated breakdown by human enzymes. Among all the biopolymers, polysaccharide-based polymer is well suited to overcome the limitations of traditional wound dressing materials. Pectin is a polysaccharide which can be extracted from different plant sources and is used in various pharmaceutical and biomedical applications including cartilage regeneration. Pectin itself cannot be employed as scaffolds for tissue engineering since it decomposes quickly. This article discusses recent research and developments on pectin polysaccharide, including its types, origins, applications, and potential demands for use in AI-mediated scaffolds. It also covers the materials-design process, strategy for implementation to material selection and fabrication methods for evaluation. Finally, we discuss unmet requirements and current obstacles in the development of optimal materials for wound healing and bone-tissue regeneration, as well as emerging strategies in the field.

Comparative study on thermo-mechanical, structural and functional properties of pectin extracted from immature wasted apples and commercial pectin

Pectin yield of 22.22 ± 0.98 % (dry basis) was achieved from prematurely dropped Golden Delicious apples, having a light orange hue (hue value: 78.08 ± 0.04) and an overall color difference (ΔE) of 9.92 ± 0.01 compared to commercial pectin (CP). Extracted AP exhibited a lower equivalent weight (725.24 ± 29.73) and higher methoxy content (8.36 ± 0.28 %) in contrast to CP. However, a similar degree of esterification of 71.57 ± 0.79 and 70.55 ± 0.59 %, was observed in AP and CP respectively. Apple pectin demonstrated slight lower galacturonic acid (GalA) content of 68.10 ± 3.94 % in comparison to 72.31 ± 4.62 % of CP, which was further corroborated by reduced intensity in FTIR fingerprint region (912-1025 cm-1). Morphology revealed a sheet-like cloudy appearance indicating a significant presence of associated sugars whereas X-ray diffraction highlighted the highly amorphous nature of AP. AP and CP solutions (3-9 %) displayed a shear-thinning flow and viscoelastic behavior where the loss (G') moduli dominated over the storage moduli (G"). Owing to high degree of esterification, galacturonic acid content (>65 %) that aligns with commercial standards and viscoelastic behavior, the extracted AP holds promise for potential utilization in commercial applications. This study underscores the potential for sustainable utilization of prematurely dropped apples through pectin extraction, contributing to valorization of the wasted bioresource.

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.

Exploring apple pectic polysaccharides: Extraction, characterization, and biological activities - A comprehensive review

Apple (Malus domestica) is a popular and ancient fruit of the Myrtaceae family. Apple fruit is well-known for its great nutritional and phytochemical content consisted of beneficial compounds such as polyphenols, polysaccharides, sterols, and organic acids. Polysaccharides extracted from different parts of the apple fruit, including the peel, pomace, or the whole fruit, have been extensively studied. Researchers have investigated the structural characteristics of these polysaccharides, such as molecular weight, type of monosaccharide unit, type of linkage and its position and arrangement. Besides this, functional properties and physicochemical and of apple polysaccharides have also been studied, along with the effects of extraction procedures, storage, and processing on cell wall polysaccharides. Various extraction techniques, including hot water extraction, enzymatic extraction, and solvent-assisted extraction, have been studied. From the findings, it was evident that apple polysaccharides are mainly composed of (1 → 3), (1 → 6): α-β-glycosidic linkage. Moreover, the apple polysaccharides were demonstrated to exhibit antioxidant, hepatoprotective, anti-cancer, hypoilipidemic, and enzyme inhibitory properties in vitro and in vivo. The potential applications of apple polysaccharides in the food, cosmetic, pharmaceutical, nutraceutical industries have also been explored in the present review. Overall, the research on apple polysaccharides highlights their significant potential as a source of biologically active compounds with various health benefits and practical applications.

Recent insights into mechanism of modified bio-adsorbents for the remediation of environmental pollutants

Rapid industrialization has exacerbated the hazard to health and the environment. Wide spectrums of contaminants pose numerous risks, necessitating their disposal and treatment. There is a need for further remediation methods since pollutant residues cannot be entirely eradicated by traditional treatment techniques. Bio-adsorbents are gaining popularity due to their eco-friendly approach, broad applicability, and improved functional and surface characteristics. Adsorbents that have been modified have improved qualities that aid in their adsorptive nature. Adsorption, ion exchange, chelation, surface precipitation, microbial uptake, physical entrapment, biodegradation, redox reactions, and electrostatic interactions are some of the processes that participate in the removal mechanism of biosorbents. These processes can vary depending on the particular biosorbent and the type of pollutants being targeted. The systematic review focuses on the many modification approaches used to remove environmental contaminants. Different modification or activation strategies can be used depending on the type of bio-adsorbent and pollutant to be remediated. Physical activation procedures such as ultrasonication and pyrolysis are more commonly used to modify bio-adsorbents. Ultrasonication process improves the adsorption efficiency by 15-25%. Acid and alkali modified procedures are the most effective chemical activation strategies for adsorbent modification for pollution removal. Chemical modification increases the removal to around 95-99%. The biological technique involving microbial culture is an emerging field that needs to be investigated further for pollutant removal. A short evaluation of modified adsorbents with multi-pollutant adsorption capability that have been better eliminated throughout the adsorption process has been provided.

Structural characterization of cell-wall polysaccharides purified from chayote (Sechium edule) fruit

Chayote (Sechium edule), an underutilized cucurbit vegetable crop, has gained attention as it exhibits health-promoting properties. However, the primary structure of chayote cell-wall polysaccharides has not been comprehensively studied. In this study, two cell-wall polysaccharides, CP-1 (41.1 KDa) and CP-2 (15.6 KDa), were extracted from chayote, and the structural analysis of CP-1 and CP-2 was carried out by monosaccharide composition analysis, Fourier transform infrared spectroscopy (FTIR), methylation analysis, and nuclear magnetic resonance spectroscopy (NMR). The results demonstrated that CP-1 was a galactan, and CP-2 was an anionic heteropolysaccharide composed of galacturonic acid, galactose, arabinose, rhamnose, glucose, glucuronic acid, mannose, and xylose in the molar ratio of 31.2:26.3:24.9:7.4:6.5:1.9:1.3:0.5. CP-2 has a backbone of → 4)-β-d-Galp-(1 → 3,6)-β-d-Galp-(1 → 3)-β-d-Galp-(1 → 4)-α-d-GalpA-(1→, with branches at O-6 of → 3,6)-β-d-Galp-(1→, consisting of α-l-Araf-(1 → 5)-α-l-Araf-(1 → 4)-β-d-Glcp-(1 →. Analysis of the structural and physicochemical properties confirmed the excellent application characteristics of CP-1 and CP-2. Hence, cell-wall polysaccharides of chayote could be used as new polysaccharides materials.

Evaluation of the Carbohydrate Composition of Crabapple Fruit Tissues Native to Northern Asia

A comprehensive comparative analysis of the carbohydrate composition (soluble sugars and pectins) of fruit tissues of Malus baccata, Malus mandshurica, Malus chamardabanica, and Malus sachalinensis, characteristic of the vast territory of Eastern Siberia and the Far East, was carried out. It was shown that a large part of the soluble carbohydrates of the studied species were represented by transport sugars-sorbitol and sucrose. These compounds also provided the main variability in the carbohydrate composition of fruits in the studied material. The polymers pectins and protopectins isolated from the studied fruits were highly methoxylated (up to 60-70%), and their content averaged about 6% of dry weight. The greatest length of pectin polymers was found in the fruit tissues of M. chamardabanica and M. sachalinensis. Data on elemental analysis of fractions of pectins and protopectins of all studied species showed the absence of potentially toxic concentrations of heavy metals. Of note is the rather high content of calcium in both polymer fractions of the four studied species, while its content in protopectin is significantly higher. In addition, in all cases, the presence of low-molecular-weight oligosaccharide molecules with a low-dispersed linear structure was revealed in the tissues of the fruits. It is worth noting that the high content of ascorbic acid was observed in the fruits of all studied species. In addition to being of fundamental interest, information about the carbohydrate composition of the wild Malus species can be useful for apple breeding when choosing sources of genes underlying useful traits.

Recent advances in polysaccharide biomodification by microbial fermentation: production, properties, bioactivities, and mechanisms

Polysaccharides are natural chemical compounds that are extensively employed in the food and pharmaceutical industries. They exhibit a wide range of physical and biological properties. These properties are commonly improved by using chemical and physical methods. However, with the advancement of biotechnology and increased demand for green, clean, and safe products, polysaccharide modification via microbial fermentation has gained importance in improving their physicochemical and biological activities. The physicochemical and structural characteristics, biological activity, and modification mechanisms of microbially fermented polysaccharides were reviewed and summarized in this study. Polysaccharide modifications were categorized and discussed in terms of strains and fermentation techniques. The effects of microbial fermentation on the physicochemical characteristics of polysaccharides were highlighted. The impact of modification of polysaccharides on their antioxidant, immune, hypoglycemic, and other activities, as well as probiotic digestive enhancement, were also discussed. Finally, we investigated a potential enzyme-based process for polysaccharide modification via microbial fermentation. Modification of polysaccharides via microbial fermentation has significant value and application potential.

Ultrasound- and Microwave-Assisted Extraction of Pectin from Apple Pomace and Its Effect on the Quality of Fruit Bars

The article investigates the process of pectin extraction using ultrasonic and microwave techniques from apple pomace generated during juice production in the context of circular bioeconomy. The extraction yield, equivalent mass, content of methoxyl groups, content of anhydrogalacturonic acid, and degree of esterification of pectin were investigated. These indicators varied depending on the parameters and extraction method. The resulting pectin displayed a co-extracted total polyphenol content (TPC) ranging from 2.16 to 13.05 mg GAE/g DW and a DPPH radical inhibition capacity of 4.32-18.86 μmol TE/g. It was found that the antioxidant activity of raw pectin is correlated with TPC and with the content of terminal groups released during the polysaccharide degradation process. The extracted pectin was used as a binding and coating agent for dried fruit bars. Evaluation of water activity (a_w), TPC and total flavonoid content (TFC), together with sensory and microbiological analyses of the fruit bars over a period of 360 days, revealed a protective effect of pectin: reducing moisture loss, minimizing the degradation of bioactive compounds during storage, and maintaining the potential antioxidant activity of the product.

Structural characteristics, functional properties, antioxidant and hypoglycemic activities of pectins from feijoa (Acca sellowiana) peel

The structure characteristics, functional properties, antioxidant and hypoglycemic activities of pectins extracted from feijoa peel with water (FP-W), acid (FP-A) and alkali (FP-B) were investigated. Results showed that the feijoa peel pectins (FPs) were mainly composed of galacturonic acid, arabinose, galactose and rhamnose. FP-W and FP-A had higher proportion of homogalacturonan domain, degree of esterification and molecular weight (for main component) than FP-B; FP-B owned the highest yield, protein and polyphenol contents. FP-W had a compact and smooth surface morphology unlike FP-A and FP-B. FP-W and FP-A had better thermal stability than FP-B. The rheological analysis suggested that the FPs exhibited pseudoplastic fluid behavior, and the elastic characteristics were dominant. Results showed that FP-W and FP-B had superior antioxidant and hypoglycemic activities than FP-A. According to correlation analysis, monosaccharide composition, sugar ratios and degree of acetylation were chief factors affecting the functional properties, antioxidant and hypoglycemic activities of the FPs.

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.

Research progress on extraction of active components from apple processing waste

Apple waste (APW) is the residual product after apple processing, including apple peel, apple core, apple seed, and other components. A large quantity of APW produced is abandoned annually, leading to serious resource waste and environmental pollution. APW is rich in natural active compounds, such as pectin, polyphenols, fatty acids, and dietary fiber, which has a good use value. This paper reviewed the current research on recovering active components from APW. The traditional extraction methods (acid, alkali, physical, enzyme, etc.) and the novel extraction methods (SWE, UAE, MAE, RFAE, etc.) for the recovery of pectin, polyphenols, apple seed oil, apple seed protein, and dietary fiber from APW were systematically summarized. The basic principles, advantages, and disadvantages of different extraction methods were introduced. The requirements of different extraction methods on extraction conditions and the effects of different extraction methods on the yield, quality, and functional activity of extracted products were analyzed. The challenges and future study direction of APW extraction have prospected. This paper aims to provide a reference for other researchers interested in APW extraction, improve the utilization rate of APW and extend the value chain of the apple industry.

Pectin from Fruit- and Berry-Juice Production by-Products: Determination of Physicochemical, Antioxidant and Rheological Properties

Plums (Prunus domestica); red currants (Ribes rubrum); black currants (Ribes nigrum); gooseberries (Ribes uva-crispa); sour cherries (Prunus cerasus); pumpkins (Cuccurbita spp.) are sources for valuable fruit- and berry-juice and cider production. This process leaves a large number of by-products (BP) in the form of pomace, which accounts for up to 80% of the raw material. This by-product represents a rich source of biologically active compounds, especially in the form of different pectic polysaccharides. The pectin extracted from commercial fruits such as citric fruits and apples has high medicinal properties, can be used as edible films and coatings, and is also useful in texture improvement and gel production in the food industry. However, many under-utilized fruits have received little attention regarding the extraction and characterization of their high/value pectin from their by-products. Moreover, the commercial extraction process involving strong acids and high temperature to obtain high-purity pectin leads to the loss of many bioactive components, and these lost components are often compensated for by the addition of synthetic antioxidants and colorants. The aim of the research is to extract pectin from juice production by-products with hot-water extraction using weak organic (0.1 N) citric acid, thus minimizing the impact on the environment. The yield of pectin (PY = 4.47-17.8% DM), galacturonic acid content (47.22-83.57 g 100^-1), ash content (1.42-2.88 g 100 g^-1), degree of esterification (DE = 45.16-64.06%), methoxyl content (ME = 4.27-8.13%), the total content of phenolic compounds (TPC = 2.076-4.668 µg mg^-1, GAE) and the antiradical scavenging activity of the pectin samples (DPPH method (0.56-37.29%)) were determined. Free and total phenolic acids were quantified by saponification using high-pressure liquid chromatography (HPLC). The pectin contained phenolic acids-benzoic (0.25-0.92 µg mg^-1), gallic (0.14-0.57 µg mg^-1), coumaric (0.04 µg mg^-1), and caffeic (0.03 µg mg^-1). The pectin extracts from by-products showed glucose and galactose (3.89-21.72 g 100 g^-1) as the main neutral sugar monosaccharides. Pectin analysis was performed using FT-IR, and the rheological properties of the pectin gels were determined. The quality of the obtained pectin from the fruit and berry by-products in terms of their high biological activity and high content of glucuronic acids indicated that the products have the potential to be used as natural ingredients in various food products and in pharmaceutical products.

Current progress in valorization of food processing waste and by-products for pectin extraction

Food processing waste and by-products such as peel of citrus fruit, melon, mango, pineapple, etc. and fruit pomace can be utilized for manufacturing of several high-value products. Valorization of these waste and by-products for extraction of pectin, can help offset growing environmental concerns, facilitate value-addition of by-products and their sustainable uses. Pectin has many applications in food industries such as gelling, thickening, stabilizing, and emulsifying agent, and as a dietary fibre. This review elaborates on various conventional and advanced, sustainable pectin extraction techniques, and paints a comparative picture between them considering extraction efficiency, quality, and functionality of the pectin. Conventional acid, alkali, and chelating agents-assisted extraction have been profusely used for pectin extraction, but advanced extraction technologies e.g., enzyme, microwave, supercritical water, ultrasonication, pulse electric field and high-pressure extraction are preferred due to less energy consumption, better quality product, higher yield, and minimal or no generation of harmful effluent.

Recent progress in pectin extraction, characterization, and pectin-based films for active food packaging applications: A review

Pectin is an abundant complex polysaccharide obtained from various plants. Safe, biodegradable, and edible pectin has been extensively utilized in the food industry as a gelling agent, thickener, and colloid stabilizer. Pectin can be extracted in a variety of ways, thus affecting its structure and properties. Pectin's excellent physicochemical properties make it suitable for many applications, including food packaging. Recently, pectin has been spotlighted as a promising biomaterial for manufacturing bio-based sustainable packaging films and coatings. Functional pectin-based composite films and coatings are useful for active food packaging applications. This review discusses pectin and its use in active food packaging applications. First, basic information and characteristics of pectin, such as the source, extraction method, and structural characteristics, were described. Then, various methods of pectin modification were discussed, and the following section briefly described pectin's physicochemical properties and applications in the food sector. Finally, the recent development of pectin-based food packaging films and coatings and their use in food packaging were comprehensively discussed.

Food and fruit waste valorisation for pectin recovery: Recent process technologies and future prospects

Pectin possesses a dual property of resistance and flexibility and thus has diverse commercial value which has generated research interest on this versatile biopolymer. Formulated products using pectin could be useful in food, pharma, foam, plasticiser and paper substitute industries. Pectin is structurally tailor-made for greater bioactivity and diverse applications. Sustainable biorefinery leaves greener footprints while producing high-value bioproducts like pectin. The essential oils and polyphenols obtained as byproducts from a pectin-based biorefinery are useful in cosmetics, toiletries and fragrance industries. Pectin can be extracted from organic sources following eco-friendly strategies, and the extraction techniques, structural alterations and the applications are continually being upgraded and standardized. Pectin has great applications in diverse areas, and its green synthesis is a welcome development. In future, growing industrial application of pectin is anticipated as research orients on biopolymers, biotechnologies and renewable source-based processes. As the world is gradually adopting greener strategies in sync with the global sustainable development goal, active involvement of policy makers and public participation are prime. Governance and policy framing are essential in the transition of the world economy towards circularity since green circular bioeconomy is ill-understood among the public in general and within the administrative circles in particular. Concerted efforts by researchers, investors, innovators, and policy and decision makers to integrate biorefinery technologies as loops within loop of biological structures and bioprocesses is suggested. The review focusses on generation of the different nature of food wastes including fruits and vegetables with cauterization of their components. It discusses the innovative extraction and biotransformation approaches for these waste conversions into value-added products at cost-effective and eco-friendly way. This article compiles numerous effective and efficient and green way pectin extraction techniques with their advantages with varying success in an integrated manner.

Sustainable utilization of Citrus limetta peel for obtaining pectin and its application in cookies as a fat replacer

In this study, a five-factorial central composite design was employed to optimize pectin extraction from novel source, through ultrasound-assisted extraction. A 35.58% yield was obtained under optimized conditions of pH 1.0, solid (g): liquid (mL) ratio 1:24, amplitude 84.2 Hz, duty cycle 23 s/30 s, and time 30 min. The equivalent weight, methoxyl content, anhydrouronic acid content, degree of esterification, water-holding capacity, and oil-holding capacity of the extracted pectin were 796.40 ± 2.07, 8.29 ± 0.38%, 71.32 ± 0.54%, 64.66 ± 2.08%, 8.04 ± 0.10 g water/g pectin, and 2.24 ± 030 g oil/g pectin, respectively. The chemical profile of the extracted pectin was assessed with FTIR and NMR analyses. The extracted pectin was utilized as a butter substitute in cookies. Up to 30% butter in cookies could be replaced with the extracted pectin without altering the sensory and physicochemical properties. Overall, results of presented work suggest that using waste-derived pectin as a fat substitute in cookies offers a sustainable and health-promoting approach for converting waste into wealth.

Fabrication and characterization of gelatin-EGCG-pectin ternary complex: formation mechanism, emulsion stability, and structure

BACKGROUND

Protein-polyphenol-polysaccharide ternary complex particles have better emulsion interfacial stability compared to protein-polysaccharide binary complexes. However, knowledge is scarce when it comes to the fabrication of protein-polyphenol-polysaccharide ternary complexes as interfacial stabilizers and the interactions between the three substances. In the present work, ternary complexes were prepared using gelatin, high methoxyl pectin, and epigallocatechin gallate (EGCG) as raw materials. The effect of different influencing factors on the formation process of ternary complexes was investigated by varying different parameters. physicochemical stability, emulsifying properties, and structural characteristics were analyzed.

RESULTS

The ternary complex had a smaller particle size (275 nm) and polydispersity index (0.112) when the mass concentration ratio of gelatin to high methoxyl pectin was 9:1, addition of EGCG was 0.05%, pH value was 3.0, and ionic strength was 10 mmol L^-1 . Meanwhile, the complex had the highest emulsifying stability index (691.75 min) and emulsifying activity index (22.96 m²  g^-1 ). Scanning electron microscopical observation demonstrated that the addition of EGCG promoted the dispersion of ternary complex more uniformly, and effectively reduced the agglomeration phenomenon. The discrepancy in fluorescence intensity suggested that interactions between EGCG and gelatin occurred, which altered the protein spatial conformation of gelatin. Fourier transform infrared spectroscopic analysis elucidated that hydrogen bond interaction was the primary non-covalent interaction between EGCG and gelatin-high methoxyl pectin binary complex.

CONCLUSION

The aforementioned results purposed to provide some theoretical reference and basis for the rational design of stable protein-polyphenol-polysaccharide ternary complexes. © 2022 Society of Chemical Industry.

Gelation behavior and mechanism of Nicandra physalodes (Linn.) Gaertn. seeds pectin induced by Glucono-delta-lactone

In this study, the physicochemical properties of pectin from Nicandra physalodes (Linn.) Gaertn. seeds (NPGSP) were analysed firstly, and the rheological behavior, microstructure and gelation mechanism of NPGSP gels induced by Glucono-delta-lactone (GDL) were investigated. The hardness of NPGSP gels was increased from 26.27 g to 226.77 g when increasing GDL concentration from 0 % (pH = 4.0) to 1.35 % (pH = 3.0), and the thermal stability was improved. The peak around 1617 cm^-1 was decreased as the adsorption peak of the free carboxyl groups was attenuated with addition of GDL. GDL increased the crystalline degree of NPGSP gels, and its microstructure exhibited more smaller spores. Molecular dynamics was performed on systems of pectin and gluconic acid (GDL hydrolysis product), indicating that inter-molecular hydrogen bonds and van der Waals forces were the main interactions to promote gels formation. Overall, NPGSP has the potential commercial value for developing as a thickener in food processing.

A Comparative Study of Pectin Green Extraction Methods from Apple Waste: Characterization and Functional Properties

Traditional methods of pectin extraction led to drop quality, yield, functional properties, and excessive time. The objective of our research is to produce high-quality pectin from apple pomace as food processing by-product. Four nonconventional methods of extraction (microwave, ultrasound, citric acid, and organic acid mixture (citric acid, ascorbic acid, and acetic acid)) were compared to conventional extraction of pectin in terms of yields, thermal behavior, functional groups, antioxidant activity, and functional properties. Citric acid extraction method gave the highest yield (22%) compared to other methods. The extraction of pectin by organic acid mixture maximized the galacturonic acid index to 87.58%;. Also, it was changed from structural into: compacted, multilaminated, and flaky surface compared to the other samples (more porous and hollow opening structural) as well as increased stability of pectin particles in colloids as a result of increasing the charge on particles to -59.42, beside its higher thermal stability of pectin behaviors, which reflected on improving all functional properties compared to the other methods. On the other side, microwave-extracted pectin had the highest antioxidant activity (3-4 times) compared to other extraction methods. In conclusion, extraction using organic acids, microwave, and ultrasonic led to improve the pectin quality and could be used in high-temperature food products, like bakery products.

Sustainable Approaches Using Green Technologies for Apple By-Product Valorisation as A New Perspective into the History of the Apple

The apple has been recognised as the most culturally important fruit crop in temperate land areas. Centuries of human exploitation and development led to the production of thousands of apple cultivars. Nowadays, the apple represents the third most widely cultivated fruit in the world. About 30% of the total production of apples is processed, being juice and cider the main resulting products. Regarding this procedure, a large quantity of apple by-product is generated, which tends to be undervalued, and commonly remains underutilised, landfilled, or incinerated. However, apple by-product is a proven source of bioactive compounds, namely dietary fibre, fatty acids, triterpenes, or polyphenols. Therefore, the application of green technologies should be considered in order to improve the functionality of apple by-product while promoting its use as the raw material of a novel product line. The present work provides a holistic view of the apple’s historical evolution, characterises apple by-product, and reviews the application of green technologies for improving its functionality. These sustainable procedures can enable the transformation of this perishable material into a novel ingredient opening up new prospects for the apple’s potential use and consumption.

Upgrading the Functional Potential of Apple Pomace in Value-Added Ingredients with Probiotics

Emerging customized designs to upgrade the functional potential of freeze-dried apple pomace was used in this study, in order to transform the industrial by-products into ingredients containing probiotics, for a better and healthier food composition. The freeze-dried apple pomace was analyzed for free and bounded phenolic contents, highlighting a significant level of caffeic acid (4978.00 ± 900.00 mg/100 g dry matter (DM)), trans-cinnamic acid (2144.20 ± 37.60 mg/100 g DM) and quercetin 3-β-D-glucoside (236.60 ± 3.12 mg/100 g DM). The pectin extraction yield was approximatively 24%, with a degree of esterification of 37.68 ± 1.74%, and a methoxyl content of 5.58 ± 0.88%. The freeze-dried apple pomace was added in a different ratio as a supplement to cultural medium of Loigolactobacillus bifermentans MIUG BL 16, suggesting a significant prebiotic effect (p < 0.05) at concentration between 1% and 2%. The apple pomace was used to design three freeze-dried ingredients containing probiotic, with a high level of polyphenolic content (6.38 ± 0.14 mg gallic acid equivalents/g DM) and antioxidant activity (42.25 ± 4.58 mMol Trolox/g DM) for the powder containing apple pomace ethanolic extract. When inulin was used as a prebiotic adjuvant, the obtained powder showed a 6 log/g DM viable cell count. The ingredients were added to fermented vegetable soy milk-based products, allowing us to improve the polyphenolic content, antioxidant activity and viable cell counts. The approach designed in this study allowed us to obtain ingredients suitable to add value to food, whereas premises to align with the current circular economy premises, by reintegrating the industrial waste as sources of high added value compounds, are also provided.