Pistachio green hull pectin: Optimization of microwave-assisted extraction and evaluation of its physicochemical, structural and functional properties

Optimization of subcritical water extraction for pectin extraction from cocoa pod husks using the response surface methodology

This study optimized subcritical water extraction (SWE) conditions to maximize pectin yield from cocoa pod husk (CPH) and compared the characteristics of CPH pectin extracted through SWE with those of CPH pectin obtained through conventional extraction (CE) with citric acid. The Box-Behnken experimental design was employed to optimize SWE and examine the influence of process parameters, including temperature (100 °C-120 °C), extraction time (10-30 min), and solid:liquid ratio (SLR) (1:30-2:30 g/mL), on pectin yield. The maximum pectin yield of 6.58% was obtained under the optimal extraction conditions of 120 °C for 10 min with 1:15 g/mL SLR and closely corresponded with the predicted value of 7.29%. Compared with CE, SWE generated a higher yield and resulted in a higher degree of esterification, methoxyl content, and anhydrouronic acid value but a lower equivalent weight. The extracted pectin was pure, had low-methoxyl content, and similar melting and degradation temperatures.

Effect of high-pressure-homogenisation on the interaction between pomegranate peel pectin fractions and anthocyanins in acidic environment

In this study, changes in the basic composition and structural characterisation of water-soluble pectin (WSP), homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) from pomegranate peel were investigated after high-pressure-homogenisation (HPH) at 50 MPa and 300 MPa. The interactions between three pectin and anthocyanin (ACN) complex were also studied. The three pectin fractions were mainly composed of galacturonic acid (34.95%-87.69%), all with low degrees of methyl-esterification ≤41.20%. HPH at 300 MPa increased the binding ratios of ACN to three pectin fractions by 34.22%-34.59%. Changes in the structural characterisation results of pectin confirmed that the depolymerisation and breakdown of the side chains of pectin after HPH promoted electrostatic interactions, hydrogen bond and hydrophobic interaction between pectin and ACN. Correspondingly, the thermal and storage stabilities of ACN in the complex was boosted after HPH at 300 MPa. This study provides insights into the interaction between pectin and ACN under HPH.

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.

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

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

Valorization of pistachio industrial waste: Simultaneous recovery of pectin and phenolics, and their application in low-phenylalanine cookies for phenylketonuria

This study introduces a sustainable approach to simultaneously produce pectin and phenolic compounds from pistachio industrial waste and applies them in the formulation of low-phenylalanine cookies. The co-optimization process was performed using the microwave-assisted technique and a Box-Behnken design, considering four variables and two responses: pectin yield and total phenolic content (TPC). The co-optimized condition (microwave power of 700 W, irradiation time of 210 s, pH level of 1.02, and LSR of 20 mL/g) resulted in a pectin yield of 15.85 % and a TPC of 10.12 %. The pectin obtained under co-optimized condition was evaluated for its physicochemical, structural, and thermal properties and the phenolic extract for its antiradical activity. Characterization of the pectin sample revealed a high degree of esterification (44.21 %) and a galacturonic acid-rich composition (69.55 %). The average molecular weight of the pectin was determined to be 640.236 kDa. FTIR and 1H NMR spectroscopies confirmed the structure of pectin, with an amorphous nature and high thermal stability observed through XRD and DSC analysis. Additionally, the extract exhibited significant antiradical activity comparable to butylated hydroxyanisole and ascorbic acid. The isolated ingredients were used to formulate low-protein, low-phenylalanine cookies for phenylketonuria patients. The addition of 0.5 % pectin and 1 mL/g extract led to increased moisture content (from 9.05 to 12.89 %) and specific volume (from 7.28 to 9.90 mL/g), decreased hardness (from 19.44 to 10.39 N × 102), and improved antioxidant properties (from 5.15 % to 44.60 % inhibition) of the cookies. Importantly, there was no significant increase observed in the phenylalanine content of the samples with pectin and extract addition. Furthermore, sensory evaluation scores demonstrated significantly higher scores for taste, odor, texture, and overall acceptability in cookies enriched with 0.5 % pectin and 1 mL/g extract, with scores of 4.53, 3.93, 4.40, and 4.60, respectively.

Towards Valorization of Food-Waste-Derived Pectin: Recent Advances on Their Characterization and Application

Pectin, a natural biopolymer, can be extracted from food waste biomass, adding value to raw materials. Currently, commercial pectin is mostly extracted from citrus peels (85.5%) and apple pomace (14.0%), with a small segment from sugar beet pulp (0.5%). However, driven by high market demand (expected to reach 2.12 billion by 2030), alternative agro-industrial waste is gaining attention as potential pectin sources. This review summarizes the recent advances in characterizing pectin from both conventional and emerging food waste sources. The focus is the chemical properties that affect their applications, such as the degree of esterification, the neutral sugars' composition, the molecular weight, the galacturonic acid content, and technological-functional properties. The review also highlights recent updates in nutraceutical and food applications, considering the potential use of pectin as an encapsulating agent for intestinal targeting, a sustainable biopolymer for food packaging, and a functional and emulsifying agent in low-calorie products. It is clear from the considered literature that further studies are needed concerning the complexity of the pectin structure extracted from emerging food waste raw materials, in order to elucidate their most suitable commercial application.

Functional Characterization and Toxicity of Pectin from Red Chilto Fruit Waste (Peels)

BACKGROUND

Food and agricultural wastes constitute a rich source of functional ingredients for the food, pharmaceutical, and cosmetic industries. In this context, by-products from the red variety of Solanum betaceum fruits (chilto) from Northwestern Argentina are suitable sources for pectin extraction.

METHODS

In this study, pectin from the peels of red chilto fruits was extracted and characterized.

RESULTS

The recovery yield of red chilto peel pectin was about 24%, and it was co-extracted with 40.0 mg phenolic compounds, 6.5 mg anthocyanins, and 4.7 g proteins per 100 g of pectin. The pectin obtained from red chilto showed proper technological functionality displaying water and oil holding capacities of 4.2 and 2.0%, respectively, an emulsifying capacity of 83%, emulsion stability of 87.5%, foaming capacity of 21.1%, and foaming stability of 79.1%. The pectin displayed antioxidant activity with the ability to scavenge ABTS radical, superoxide anion, and H₂O₂. The polysaccharide exhibited in vitro hypoglycemic potential and inhibited the α-amylase enzyme, retarded glucose diffusion, and improved the cellular uptake of glucose in a Saccharomyces cerevisiae model. The extract was non-toxic on acute toxicity tests.

CONCLUSIONS

Red chilto pectin showed potential as a new and safe functional ingredient for the design of foods, health products, and cosmetics.

Comparison between Ultrasound- and Microwave-Assisted Extraction Methods to Determine Phenolic Compounds in Barley (Hordeum vulgare L.)

Barley (Hordeum vulgare L.) is one of the major cereal crops worldwide. It is grown not only to be used as fodder but also for human consumption. Barley grains are a great source of phenolic compounds, which are particularly interesting for their health-promoting antioxidant properties, among other benefits. Two extraction methods, namely ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE), have been optimized and compared by using Box-Behnken design (BBD) to determine both the antioxidant power and the phenolic compound levels of the extracts. Three variables have been assessed based on these designs: solvent composition (% MeOH in water), temperature (°C), and sample-to-solvent ratio (mg sample mL^-1 solvent). The solvent composition used and the interaction between the solvent and the temperature were the most significant variables in terms of recovery of phenolic compounds and antioxidant capacity of the extracts. Short extraction times, a high precision level, and good recoveries have been confirmed for both methods. Moreover, they were successfully applied to several samples. Significant differences regarding the level of phenolic compounds and antioxidant power were revealed when analyzing three different barley varieties. Specifically, the amounts of phenolic compounds ranged from 1.08 to 1.81 mg gallic acid equivalent g^-1 barley, while their antioxidant capacity ranged from 1.35 to 2.06 mg Trolox equivalent g^-1 barley, depending on the barley variety. Finally, MAE was found to be slightly more efficient than UAE, presenting higher levels of phenolic compounds in the extracts.

Identification of Polyphenolic Compounds Responsible for Antioxidant, Anti-Candida Activities and Nutritional Properties in Different Pistachio (Pistacia vera L.) Hull Cultivars

The use of by-products from the agri-food industry is a promising approach for production of value-added, polyphenol-rich dietary supplements or natural pharmaceutical preparations. During pistachio nut processing, a great amount of husk is removed, leaving large biomass for potential re-use. The present study compares antiglycative, antioxidant, and antifungal activities as well as nutritional values of 12 genotypes belonging to four pistachio cultivars. Antioxidant activity was measured using DPPH and ABTS assays. Antiglycative activity was evaluated as inhibition of advanced glycation end product (AGE) formation in the bovine serum albumin/methylglyoxal model. HPLC analysis was performed to determine the major phenolic compounds. Cyanidin-3-O-galactoside (120.81-181.94 mg/100 g DW), gallic acid (27.89-45.25), catechin (7.2-11.01), and eriodictyol-7-O-glucoside (7.23-16.02) were the major components. Among genotypes, the highest total flavonol content (14.8 mg quercetin equivalents/g DW) and total phenolic content (262 mg tannic acid equivalent/g DW) were in KAL1 (Kaleghouchi) and FAN2 (Fandoghi), respectively. The highest antioxidant (EC₅₀ = 375 μg/mL) and anti-glycative activities were obtained for Fan1. Furthermore, potent inhibitory activity against Candida species was recorded with MIC values of 3.12-12.5 µg/mL. The oil content ranged from 5.4% in Fan2 to 7.6% in Akb1. The nutritional parameters of the tested cultivars were highly variable: crude protein (9.8-15.8%), ADF (acid detergent fiber 11.9-18.2%), NDF (neutral detergent fiber, 14.8-25.6%), and condensed tannins (1.74-2.86%). Finally, cyanidin-3-O-galactoside was considered an effective compound responsible for antioxidant and anti-glycative activities.

Eco-friendly simultaneous extraction of pectins and phenolics from passion fruit (Passiflora edulis Sims) peel: Process optimization, physicochemical properties, and antioxidant activity

The objective of this study was to simultaneously extract passion fruit (Passiflora edulis) peel pectins and phenolics using deep eutectic solvents, to evaluate their physicochemical properties and antioxidant activity. By taking L-proline: citric acid (Pro-CA) as the optimal solvent, the effect of extraction parameters on the yields of extracted passion fruit peel pectins (PFPP) and total phenolic content (TPC) was. and the highest TPC (9.68 mg GAE/g DW) were attained under 90 °C, extraction solvent pH = 2, extraction time of 120 min and L/S ratio of 20 mL/g. In addition, Pro-CA-extracted pectins (Pro-CA-PFPP) and HCl-extracted pectins (HCl-PFPP) were subjected to high performance gel permeation chromatography (HPGPC), Fourier transform infrared spectroscopy (FT-IR), thermogram analysis (TG/DTG) and rheological measurements. Results verified that the Mw and thermal stability of Pro-CA-PFPP were higher than those of HCl-PFPP. The PFPP solutions featured a non-Newtonian behavior, and compared with commercially pectin solution, PFPP solution exhibited a stronger antioxidant activity. Additionally, passion fruit peel extract (PFPE) exhibited stronger antioxidant effects than PFPP. The results of ultra-performance liquid chromatography hybrid triple quadrupole-linear ion trap mass spectrometry (UPLC-Qtrap-MS) and high performance liquid chromatography (HPLC) analysis showed that (-)-epigallocatechin, gallic acid, epicatechin, kaempferol-3-O-rutin and myricetin were the main phenolic compounds in PFPE and PFPP. Our results suggest that Pro-CA can be considered as an eco-friendly solvent for high-efficient extraction of high-value compounds from agricultural by-products.

Structural characteristics and gel properties of pectin from citrus physiological premature fruit drop

This study is the first to extract and characterize pectin from citrus physiological premature fruit drop. The extraction yield of pectin reached 4.4 % by acid hydrolysis method. The degree of methoxy-esterification (DM) of citrus physiological premature fruit drop pectin (CPDP) was 15.27 %, indicating it was low-methoxylated pectin (LMP). The monosaccharide composition and molar mass test results showed CPDP was a highly branched macromolecular polysaccharide (β: 0.02, Mw: 2.006 × 10⁵ g/mol) with rich rhamnogalacturonan I domain (50.40 %) and long arabinose and galactose side chain (32.02 %). Based on the fact that CPDP is LMP, Ca²⁺ was used to induce CPDP to form gels. Textural and rheological tests showed that the gel strength and storage modulus of CPDP were higher than commercial citrus pectin (CP) used in this paper due to the lower DM and rich neutral sugar side chains of CPDP. Scanning electron microscope (SEM) results showed CPDP had stable gel network structure.

Development and Characterization of Yellow Passion Fruit Peel Flour (Passiflora edulis f. flavicarpa)

In this study, the peels of the yellow passion fruit (Passiflora edulis f. flavicarpa) were used to develop a flour that was evaluated in terms of its physicochemical, microscopic, colorimetric, and granulometric characteristics, its total phenolic compound and carotenoid contents, and its antioxidant capacity. Fourier Transform Infrared (FTIR) spectroscopy measurements were employed to investigate the constituent functional groups, compounds' chemical profiles were assessed by Paper Spray Mass Spectrometry (PS-MS), and the compound's chemical profiles were evaluated by Ultra-Performance Liquid Chromatography (UPLC). This flour presented a light color, heterogeneous granulometry, high carbohydrate, carotenoid, and total phenolic compound contents with high antioxidant capacity. Scanning Electron Microscopy (SEM) showed a particulate flour, which is supposed to contribute to its compactness. FTIR demonstrated the presence of functional groups corresponding to cellulose, hemicellulose, and lignin, constituents of insoluble dietary fiber. The PS-MS analysis suggested the presence of 22 substances, covering diverse component classes such as organic, fatty, and phenolic acids, flavonoids, sugars, quinones, phenylpropanoid glycerides terpenes, and amino acids. This research demonstrated the potential of using Passion Fruit Peel Flour (PFPF) as an ingredient for food products. The advantages of using PFPF comprise the reduction of agro-industrial waste, contribution to the development of a sustainable food system, and increment of food products' functional profile. Moreover, its high content of several bioactive compounds can benefit consumers' health.

Anti-diabetic effect of modified 'Guanximiyou' pummelo peel pectin on type 2 diabetic mice via gut microbiota

This study aimed to investigate the mechanisms of nature and modified 'Guanximiyou' pummelo peel pectin (GGP and MGGP) in alleviating T2DM through in vitro and in vivo. After modification, pectin was transformed from high methoxy pectin (HMP) to low methoxy pectin (LMP), and the content of galacturonic acid was increased. These made MGGP have stronger antioxidant capacity and better inhibition effect on corn starch digestion in vitro. In vivo experiments have shown that both GGP and MGGP inhibited the development of diabetes after 4 weeks of ingestion. However, MGGP can more effectively reduce blood glucose and regulate lipid metabolism, and has significant antioxidant capacity and the ability to promote SCFAs secretion. In addition, 16S rRNA analysis showed that MGGP changed the composition of intestinal microbiota in diabetic mice, decreased the abundance of Proteobacteria, and increased the relative abundance of Akkermansia, Lactobacillus, Oscillospirales and Ruminococcaceae. The phenotypes of the gut microbiome also changed accordingly, indicating that MGGP can inhibit the growth of pathogenic bacteria, alleviate intestinal functional metabolic disorders and reverse the potential risk of related complications. Altogether, our findings demonstrate that MGGP, as a dietary polysaccharide, may inhibit the development of diabetes by reversing the imbalance of gut microbiota.

Current Technologies and Uses for Fruit and Vegetable Wastes in a Sustainable System: A Review

The fruit and vegetable industry produces millions of tons of residues, which can cause large economic losses. Fruit and vegetable wastes and by-products contain a large number of bioactive substances with functional ingredients that have antioxidant, antibacterial, and other properties. Current technologies can utilize fruit and vegetable waste and by-products as ingredients, food bioactive compounds, and biofuels. Traditional and commercial utilization in the food industry includes such technologies as microwave-assisted extraction (MAE), supercritical fluid extraction (SFE), ultrasonic-assisted extraction (UAE), and high hydrostatic pressure technique (HHP). Biorefinery methods for converting fruit and vegetable wastes into biofuels, such as anaerobic digestion (AD), fermentation, incineration, pyrolysis and gasification, and hydrothermal carbonization, are described. This study provides strategies for the processing of fruit and vegetable wastes using eco-friendly technologies and lays a foundation for the utilization of fruit and vegetable loss/waste and by-products in a sustainable system.

Microwave-assisted valorization and characterization of Citrus limetta peel waste into pectin as a perspective food additive

Machine learning techniques were employed to evaluate the effect of process parameters viz. microwave power (100 W, 300 W, 600 W); pH (1, 1.5, 2); and microwave time (the 60 s, 120 s, 180 s) on the pectin yield from Citrus limetta peel. A fourth-order polynomial function of 66.60 scales was used by the Support Vector Regression (SVR) model at an epsilon (ε) value of 0.003. The co-efficient of determination (R2) and root mean square error-values for training data and test data were 0.984; 0.77 and 0.993; 0.66 respectively. At optimized conditions, microwave power 600 W, pH 1, and time 180 s the best yield of 32.75% was obtained. The integrity of pectin skeletal was confirmed with FTIR and 1H NMR spectrums. The physicochemical analysis revealed that CLP is a high-methoxyl pectin (HMP) with a 63.20 ± 0.88% degree of esterification, 798.45 ± 26.15 equivalent weight, 8.06 ± 0.62% methoxyl content, 67.93 ± 3.36 AUA content, 6.27 ± 0.27 g water/g pectin WHC, 2.68 ± 0.20 g oil/g pectin OHC, low moisture, ash and protein content of 6.85 ± 0.10%, 3.87 ± 0.10% and 2.61 ± 0.06% respectively, which can be utilized as a food additive. Therefore, pectin extraction from Citrus limetta peel using a greener technique like MAE is an eco-friendly, time-saving approach to transform waste into a versatile food additive.

Physicochemical and functional properties of pectin extracted from the edible portions of jackfruit at different stages of maturity

BACKGROUND

The physicochemical and functional properties of pectin (JFP) extracted from edible portions (including pericarp and seed) of raw jackfruit (an underutilized tropical fruit) at four different maturity stages (referred to as stages I, II, III, and IV) were characterized in terms of extraction yields, chemical composition, molecular weight, and antioxidant properties to evaluate its potential use in foods.

RESULT

The JFP yield increased from 9.7% to 21.5% with fruit maturity, accompanied by an increase in the galacturonic acid content (50.1%, 57.1%, 63.6%, and 65.2%) for stages I-IV respectively. The molecular weight increased from 147 kDa in stage I to 169 kDa in stage III, but decreased to 114 kDa in stage IV, probably due to cell-wall degradation during maturation. The JFP was of the high methoxyl type and the degree of esterification increased from 65% to 87% with fruit maturity. The functional properties of JFP were similar to or better than those reported for commercial apple pectin, thus highlighting its potential as a food additive. Although the phenolics and flavonoids content of JFP decreased with fruit maturity, their antioxidant capacity increased, which may be correlated with the increased content of galacturonic acid upon fruit development. Gels prepared from JFP showed viscoelastic behavior. Depending on the maturity stage in which they were obtained, different gelation behavior was seen.

CONCLUSION

The study confirmed the potential of pectin extracted from edible parts of jackfruit as a promising source of high-quality gelling pectin with antioxidant properties, for food applications. © 2022 Society of Chemical Industry.

Extraction and characterization of pectin from watermelon rind using acetic acid

In this work, watermelon rind was used for extraction of pectin with acetic acid solution. The effects of pH, temperature and extraction time on the pectin yield were investigated. Response surface based on Box-Behnken model was employed to optimize the extraction parameters. The model shows an optimum pectin yield of 18.21%, which is in agreement with the value confirmed through experiment (18.20%). The moisture content, ash content, degree of esterification, degree of methylation, equivalent weight, methoxy content, and anhydrouronic acid of the extracted pectin were determined. The values of the moisture content, ash content, degree of esterification, degree of methylation, equivalent weight, methoxy content, anhydrouronic acid are 8.42%, 5.1%, 57.30%, 23.5%, 983.9 mg/mol, 7.3% and 72.36%, respectively. The results show watermelon peel can be an alternative source for pectin production with reasonable pectin yield and pectin quality.

Microwave-assisted extraction of polysaccharide from Cinnamomum cassia with anti-hyperpigmentation properties: Optimization and characterization studies

The anti-hyperpigmentation effect and tyrosinase inhibitory mechanism of cinnamon polysaccharides have not been reported. The current study focused on the extraction of polysaccharides from Cinnamomum cassia bark using microwave-assisted approach and optimization of the extraction process (i.e., microwave power, irradiation time and buffer-to-sample ratio) by Box-Behnken design to obtain a high yield of polysaccharides with high sun protection factor (SPF), anti-hyperpigmentation and antioxidant activities. The extracted pectic-polysaccharides had low molecular weight and degree of esterification. The optimal extraction process had polysaccharides characterized by (a) monophenolase inhibitory activity = 97.5 %; (b) diphenolase inhibitory activity = 99.4 %; (c) ferric reducing antioxidant power = 4.4 mM; (d) SPF = 6.1; (e) yield = 13.7 %. The SPF, tyrosinase inhibitory and antioxidant activities were primarily contributed by the polysaccharides. In conclusion, the polysaccharides from C. cassia could be an alternative therapeutic source for skin hyperpigmentation treatment.

Response surface methodology as a tool to optimize the extraction of bioactive compounds from plant sources

Response surface methodology (RSM) is a widely used mathematical and statistical technique for modeling and optimizing the process for the extraction of bioactive compounds. This review explains the optimization approach through the use of experimental design and empirical models for response prediction and the utilization of the desirability function for multiple response optimization. This paper also reviews recent studies on the application of RSM to optimize bioactive compound extraction processes such as conventional solvent extraction, microwave-assisted extraction, supercritical fluid extraction, and ultrasound-assisted extraction. Finally, the challenges associated with the use of RSM and the efforts made to improve RSM in the extraction process are also highlighted. Overall, this review informs many aspects of RSM that are occasionally ignored or insufficiently discussed with regard to the optimization of bioactive compound extraction processes, and it summarizes significant applications where RSM proved suitable. © 2022 Society of Chemical Industry.

Structural diversity and physicochemical properties of polysaccharides isolated from pumpkin (Cucurbita moschata) by different methods

Natural polysaccharides were isolated and purified from Cucurbita moschata by hot water extraction and mild acid-base sequential extraction. Chemical and instrumental studies revealed that hot water-extracted and mild acid-extracted polysaccharides with molecular masses of 48 kDa and 85 kDa were both pectic polysaccharides with homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) domains, while mild acid-extracted polysaccharide was more dominated by branched RG-I with higher contents of galactose (10.59 %) and arabinose (8.08 %). Furthermore, mild acid-extracted polysaccharide exhibited better thickening and emulsifying properties, likely due to its larger molecular mass and higher branching degree. Mild base-extracted polysaccharide with a molecular mass of 18 kDa was a glucan-like polysaccharide. It showed the strongest thermostability and gel behavior among these pumpkin polysaccharides, likely attributed to its unique network structure stabilized by substantial intra/intermolecular hydrogen bonds. This study aimed to establish the structure-property relationships between these structurally diverse pumpkin polysaccharides from different extraction methods and provided theoretical foundations for their targeted application in foods.

Extraction optimization and characterization of pectin from sesame (Sesamum indicum L.) capsule as a new neglected by-product

BACKGROUND

With production of over 6 million tonnes a year of sesame, its capsules are considered to be an unutilized waste. In this study, extraction of pectin from this novel source was optimized using a green method, and the functional and physiochemical characteristics of the resultant pectin were compared to commercial pectin.

RESULTS

In this study, the sesame capsule pectin (SCP) extraction conditions were optimized to reach maximum yield, and the results showed that the maximum pectin extraction yield (138 g kg^-1 ) was obtained under optimal conditions (microwave power 700 W, irradiation time 5 min, pH 1.5, and liquid-to-solid ratio 41.8 (mL g^-1 ). The results showed that the pectin was low methoxyl type with a galacturonic acid content of 670 g kg^-1 . The extracted pectin had a high molecular weight (341 kDa) and surface charge (34.09 ± 1.88 mV) and exhibited 66% DPPH radical scavenging. The obtained results from ¹ H-nuclear magnetic resonance and Fourier transform infrared spectra validated the presence of pectin structure in the extracted sample.

CONCLUSION

Sesame capsule pectin, when compared to commercial pectin, demonstrated better functional properties in terms of emulsifying properties, oil holding capacity, foaming capacity and antioxidant activity. SCP showed similar properties in comparison to its commercial counterpart, which suggests that it could well be considered as a new and suitable source for pectin extraction. © 2022 Society of Chemical Industry.

An appealing review of industrial and nutraceutical applications of pistachio waste

Pistachio (Pistacia vera L.) is consumed in almost every part of the world enclosed in shells that are thrown out in baskets. Similarly, hulls separated from pistachio are discarded as waste in food processing industries. These waste materials contain functional constituents having immense industrial and nutraceutical applications. This review article summarizes the scientific investigations regarding the functional constituents and bioactive compounds in pistachio shells (PSs) and pistachio hulls (PHs). It also highlights the nutraceutical potential exhibited by functionally active compounds as well as their potential applications in various industries including nutraceutical, medicinal, and feed industries together with biosynthetic development of useful products and wastewater treatment. Pistachio waste (PW) comprising PS and PH is a rich source of various bioactive compounds. PS is full of lignin, cellulose, and hemicellulose. PH is an excellent source of carbohydrates (80.64 ± 0.98%) (including glucose, galactose, rhamnose, arabinose, xylose, mannose, galacturonic acid) as well as ash (6.32 ± 0.26%) and proteins (1.80 ± 0.28%) with small amounts of fats (0.04 ± 0.005%). Owing to its composition, PW can be beneficial in many nutraceuticals, including antioxidation, cytoprotection, anti-obesity, anti-diabetic, anti-melanogenesis, neuroprotection, anti-cancer, anti-mutagenesis, anti-inflammation, and anti-microbial. The waste materials have vast applications in the food industry, such as bio-preservation of oils and meat products, prevention of enzymatic browning in fruits, vegetables, and mushrooms, development of functional cereal and dairy products, production of food enzymes, emulsions, and manufacturing of biodegradable films for food packaging. The use of these waste products to develop and design novel functional foods with improved quality is important for both food industries and food sustainability.

Pectin-type polysaccharide from galangal: An efficient emulsifier to construct the emulsion-based delivery system for galangal flavonoids

Galangal is rich in flavonoids and polysaccharides but underutilized. In this study, galangal flavonoids and polysaccharides (GP-HN and GP-UN) were obtained by segmented extraction, used for chemical composition determination/structural characterization, and constructed for the emulsion delivery system. The results showed that galangin accounted for 71.45 % of total flavonoids. GP-HN and GP-UN were prepared by enzymatic-assisted high-temperature and ultrasonic extraction, which were low-molecular-weight pectin-type polysaccharides mainly constructed by galacturonic acid, galactose, and arabinose. GP-UN was the best emulsifier due to interfacial activities, emulsifying properties, interfacial resistance to bile salts displacement abilities, and anti-lipid digestion abilities of GPs. GP-UN emulsion could stably deliver flavonoids. This study presented a method for orderly reorganizing flavonoids and polysaccharides, guiding for utilization of whole bioactive components in galangal.

Hybrid techniques of pre and assisted processing modify structural, physicochemical and functional characteristics of okra pectin: Controlled-temperature ultrasonic-assisted extraction from preparative dry powders and its field monitoring

Diversiform okra dry powders were prepared and controlled-temperature ultrasonic-assisted extraction (CTUAE) was then utilized to obtain okra pectin (OP) from the preparative powders. During processing of hybrid techniques, 6 types of dry powders were prepared through different drying technologies (hot air drying, HD; freeze-drying, FD) and meshes (60, 80, 120 meshes) at first. Next, the extraction yield, physicochemical and function characteristics, and molecular structure of OP were analyzed with or without CTUAE technique. Meanwhile, the time-frequency domains of acoustic fields during extraction process of OP were monitored to analyze the effects of ultrasonic fields. Results showed that OP main chains with less cracking by FD than that by HD; the yield, GalA, esterification degree (DE), M_w and viscosity of OP increased, but its particle size decreased. Water holding capacity (WHC) and oil holding capacity (OHC) of OP by HD were more prominent. Secondly, HD OP had dendritic rigid chains, while FD OP had flexible chains with multiple branches. For HD OP, as meshes of okra dry powders decreased, GalA, viscosity and emulsification ability decreased; while gel strength and thermal stability increased. For FD OP, the reduction of meshes improved thermal stability. Above all, CTUAE technique increased the yield and GalA, and decreased DE, M_w and particle size of OP. In terms of functional characteristics, the technique also improved gel strength, resilience and viscoelasticity, enhanced emulsifying stability, WHC and thermal stability, and reduced viscosity. Finally, the correlation between functional and structural characteristics of OP was quantified, and some suggestions were made for its application in food areas.

The Pulsed Electric Field Assisted-Extraction Enhanced the Yield and the Physicochemical Properties of Soluble Dietary Fiber From Orange Peel

The study aimed to investigate the effects of pulsed electric field (PEF)-assisted extraction on the yield, physicochemical properties, and structure of soluble dietary fiber (SDF) from orange peel. The results showed that the optinal parameters of PEF assisted extraction SDF was temperature of 45^oC with the electric field intensity of 6.0 kV/cm, pulses number of 30, and time of 20min and SDF treated with PEF showed the higher water solubility, water-holding and oil-holding capacity, swelling capacity, emulsifying activity, emulsion stability, foam stability and higher binding capacity for Pb²⁺, As³⁺, Cu²⁺, and higher which resulted from the higher viscosity due to PEF treatment. Compared with the untreated orange peel, the SDF obtained with PEF exhibited stronger antioxidant activities, which was due to its smaller molecular weight (189 vs. 512 kDa). In addition, scanning electron micrograph images demonstrated that the surface of PEF-SDF was rough and collapsed. Overall, it was suggested that PEF treatment could improve the physicochemical properties of SDF from the orange peel and would be the potential extraction technology with high efficiency.

High-Intensity Ultrasound-Assisted Extraction of Pectin from Mango Wastes at Different Maturity

Valorisation of food processing by-products is a welcome and developing area. The mango processing industry produces 40% to 60% of the fruit as solid waste, in which components of industrial interest, such as pectin, are lost. This study reports on energy-efficient high-intensity ultrasound-assisted extraction (HIUAE) to extract pectin from mango peels. The analysis considered the ripening stage of the fruit (0, 2, and 4), HIUAE frequency (37 kHz and 80 kHz), and extraction time (20 min, 25 min, and 30 min). Extractions of pectin from mango peels with HIUAE have been fairly studied. However, this work differs from those studies in including mango maturity grade as a factor. Pectin extraction yields ranged from 13% to 30%, with no influence (p > 0.05) of time, and the highest yields were obtained at the lowest maturity stage (0) and lowest frequency (37 kHz). This latest condition (37 kHz) also yielded pectin with the highest gel strength, purity, and quality. This work demonstrated that the mango maturity stage influenced pectin extraction yield. Ultrasound-assisted extraction of pectin from mango peels could be an efficient approach toward waste valorisation and extraction of pectin with high yield and good quality attributes for the food industry.

Pistachio hull as an alternative pectin source: its extraction and use in oil in water emulsion system

In this study, pectin was extracted from the pistachio hull using two methods: conventional extraction and ultrasound-assisted extraction. Water and citric acid solution were tested separately as extraction solvents in both conventional and ultrasound methods. The highest yield (32.3 ± 1.44%) was obtained using a citric acid solution in the conventional extraction method. The pectin extracted with this method had 38.94 g acid per 100 g dry pectin extract. The galacturonic acid and ash contents were 65.81 ± 1.51 and 1.57 ± 0.03%, respectively. The pistachio hull pectin was under the low methoxy pectin group with a 19.29 ± 0.41% degree of esterification. The emulsifying property of the pectin extracted was investigated in an oil-in-water emulsion system at six different pectin concentrations (2, 4, 5, 6, 8, and 10% w/w) and at a fixed oil ratio (20% w/w). Emulsion performance was investigated in terms of emulsion stability, microstructural characteristics, droplet size, and rheological properties. The most stable emulsion was obtained at a 6% pectin concentration. The emulsifying activity index, emulsion stability index, droplet size, consistency index, and flow behavior index were 172.85 ± 0.59 m²/g, 158.28 ± 3.41 min, 6.08 ± 0.04 µm, 0.72 ± 0.001 Pa·sⁿ, and 0.752 ± 0.005 at this concentration, respectively.

Structure characterization and bioactivity of neutral polysaccharides from different sources of Polygonatum Mill

Polygonati rhizoma (PR), a traditional medical and edible product, is rich in polysaccharides and exhibits physiological activity, including antioxidant, hypoglycemic and hypolipidemic properties. Neutral polysaccharides have been reported to be one of the main active ingredients of Polygonatum, with many of these fractions being responsible for the biological activity. This behavior was shown to be closely connected to the chemical structure, monosaccharide composition, and glycosidic bond type. There are few reports on the chemical constituents of the neutral polysaccharides from different sources of PR. In this study, neutral polysaccharides of PR from four different regions of China (Chun'an (Zhejiang), Xixia (Henan), Danfeng (Shanxi), and Pan'an (Zhejiang)), named CAZJ, XXHN, DFSX, and PAZJ, respectively, were isolated by anion-exchange and gel-permeation chromatography. Structures of the four polysaccharides were investigated. The results showed that all of them were mainly glucose and mannose, while the monosaccharide composition and content of polysaccharides from different sources varied. The molecular weights of CAZJ, XXHN, DFSX, and PAZJ were 14.119, 22.352, 18.127, and 15.699 kDa, respectively. Infrared spectra illustrated the existence of α-glycosidic bond and β-glycosidic bond in the polysaccharides. CAZJ, XXHN, and DFSX possessed a pyranose ring structure, whereas PAZJ had a furanose ring structure. Congo red test indicated that XXHN, DFSX, and PAZJ had a triple-helix structure. X-ray diffraction showed that the polysaccharides consisted of crystalline and amorphous regions. All four polysaccharides exhibited different degrees of antioxidant and hypoglycemic activities with a dose-dependent manner in the 1.0-10.0 mg/mL concentration range. Correlation analysis revealed that the bioactivities of polysaccharides was significantly related to monosaccharide composition, uronic acid, and protein content. The results suggested that neutral polysaccharides could be used as potential natural antioxidants and hypoglycemic agents for functional and nutraceutical applications.

A Brief Review of Phenolic Compounds Identified from Plants: Their Extraction, Analysis, and Biological Activity

Phenolic compounds are the most abundant secondary metabolites in plants, showing a wide range of distinct biological activities, have received more and more attention in recent years. This review aims to gather and systematize available information on the phenolic compounds from plants by discussing different types of phenolic compounds, extraction, and analysis methods, with an emphasis on their potential biological activities. The research direction and problems that should be paid attention to in the future are also put forward to provide some references for the further study of phenolic compounds.

Rapid large-scale preparation of polysaccharides from jackfruit peel waste by high-speed countercurrent chromatography and their antioxidant and hypoglycemic activities

Polysaccharides with antioxidant and hypoglycemic activities were first isolated from jackfruit (Artocarpus heterophyllus Lam.) peel through the one-step high-speed countercurrent chromatography. The separation process was completed using the polymer two-phase aqueous system constituted by PEG1000-K₂ HPO₄ -KH₂ PO₄ -H₂ O (0.8:1.25:1.25:6.5, w/w). For every separation process, two main polysaccharides, namely, fraction-1 and fraction-2 (165 and 225 mg, respectively) were obtained from a 2.0 g crude sample. As suggested by high-performance gel permeation chromatography, jackfruit peel polysaccharides had the mean molecular weight values of 113.3 and 174.3 kDa, separately. Physicochemical analysis suggested that two polysaccharides were dominant in galacturonic acid, galactose, rhamnose, arabinose, glucose, mannose, as well as fucose, which were highly esterified. Biological activity analysis showed that fraction-1 exhibited stronger antioxidant activity in vitro and hypoglycemic activity in streptozotocin-induced diabetic mice compared with fraction-2. The results suggest that polysaccharide fraction-1 may be developed as a potential functional food supplement.

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

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