Physicochemical and functional properties of Cucurbita maxima pumpkin pectin and commercial citrus and apple pectins: A comparative evaluation

Structural characterization and prebiotic activity of rhamnogalacturonan-I rich pumpkin pectic polysaccharide extracted by alkaline solution

The present study aimed to investigate the structural and physicochemical characteristics of alkali-extracted pectic polysaccharide (AkPP) and to evaluate its prebiotic effects. AkPP was obtained from pumpkin pulp using an alkaline extraction method. AkPP, which had a molecular weight (Mw) of mainly 13.67 kDa and an esterification degree of 9.60%, was composed mainly of galacturonic acid (GalA), rhamnose (Rha), galactose, and arabinose. The ratio of the homogalacturonan (HG) region to the rhamnogalacturonan-I (RG-I) region in AkPP was 48.74:43.62. In the nuclear magnetic resonance spectrum, the signals indicating α-1,4-linked D-GalA, α-1,2-linked L-Rha, α-1,2,4-linked L-Rha residues were well resolved, demonstrating the presence of the HG and RG-I regions in its molecular structure. Collectively, AkPP was low methoxyl pectin rich in the RG-I region with short side chains and had a low Mw. Thermal analysis revealed that AkPP had good thermal stability. Compared to inulin, AkPP more effectively promoted the proliferation of Lactobacillus acidophilus, Lacticaseibacillus rhamnosus GG, Lacticaseibacillus casei, and Lacticaseibacillus paracasei and the production of lactic, acetic, and propionic acids. This study presents the unique structural features of AkPP and provides a scientific basis for further investigation of the potential of AkPP as a promising prebiotic.

Pumpkin seed oil: a comprehensive review of extraction methods, nutritional constituents, and health benefits

Pumpkin seed oil (PSO), a rich source of nutrients, is extracted from the seeds of different pumpkin varieties for food and medicines. This article aims to provide an evidence-based review of the literature and to explore the extraction technologies, nutritional properties, and biological activity of PSO. From previous literature, PSO contains a large proportion of unsaturated fatty acids, with linoleic acid as the main component, and an amount of tocopherol, phytosterol, and phenolic acids. Some differences in the yield, composition, and physicochemical properties of PSO can be associated with the pumpkin's cultivars and the extraction methods. Some novel technologies involved in supercritical fluid extraction, enzyme-assisted aqueous extraction, and ultrasound-assisted extraction have been replacing the conventional technologies gradually as promising methods for the safe, non-polluting, and effective recovery of PSO. This healthy vegetable oil was reported by several in vitro and in vivo studies to have potential protective roles in oxidative stress, inflammation, cancer, and cardiovascular diseases. © 2023 Society of Chemical Industry.

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.

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

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

A critical review of RG-I pectin: sources, extraction methods, structure, and applications

In recent years, RG-I pectin isolated by low-temperature alkaline extraction methods has attracted the attention of a large number of researchers due to its huge health benefits. However, studies on other applications of RG-I pectin are still lacking. In this study, we summarized the sources (e.g. potato pulp, sugar beet pulp, okra, apple pomace, citrus peel, pumpkin, grapefruit, ginseng, etc.), extraction methods, fine structure and applications of RG-I pectin in physiological activities (e.g. anti-cancer, anti-inflammatory, anti-obesity, anti-oxidation, immune regulation, prebiotics, etc.), emulsions, gels, etc. These neutral sugar side chains not only endow RG-I pectin with various physiological activities but the entanglement and cross-linking of these side chains also endow RG-I pectin with excellent emulsifying and gelling properties. We believe that this review can not only provide a comprehensive reading for new workers interested in RG-I pectin, but also provide a valuable reference for future research directions of RG-I pectin.

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.

Cucurbita maxima Seeds Reduce Anxiety and Depression and Improve Memory

The current study was planned to assess the neuropharmacological benefits of the Cucurbita maxima seed. These seeds have been conventionally used for the nutritional as well as amelioration of various diseases. However, there was a need to provide a pharmacological basis for such use. Four central nervous system-related functions, that is, anxiety, depression, memory, and motor coordination, were evaluated, and the levels of brain biogenic amines were also assessed. Anxiety was evaluated through selected experimental models, such as light and dark apparatus, elevated plus maze, head dip, and open field test. The head dip test was mainly used to assess exploratory behavior. Depression was assessed by two animal models, that is, the forced swim test and tail suspension test. Memory and learning ability were assessed by the passive avoidance test, stationary rod apparatus, and Morris's water maze test. Motor skilled learning was assessed by stationary rod and rotarod apparatus. Reversed phase high-pressure liquid chromatography was used to determine biogenic amine levels. Results reveal that C. maxima exhibited anxiolytic and antidepressant effects with memory improvement. There was a reduction in the weight of the animal following chronic administration. Furthermore, no remarkable effects were observed on motor coordination. Norepinephrine was found elevated, which may be linked to its antidepressant effects. These biological effects of C. maxima may be due to the presence of secondary metabolites, such as cucurbitacin, beta-sitosterol, polyphenolic compounds, citrulline, kaempferol, arginine, β-carotene, quercetin, and other antioxidants. The outcomes of the present study authenticate that the chronic use of C. maxima seeds reduces the intensity of neurological problems like anxiety and depression.

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.

Assessment of the ‘taro-like’ aroma of pumpkin fruit (Cucurbita moschata D.) via E-nose, GC–MS and GC-O analysis

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E-nose and GC–MS could distinguish the different pumpkin based on aroma profiles and volatile compounds.

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It’s the first time to study the key volatile compound associated with ‘taro-like’ aroma of pumpkin fruit.

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2-Acetyl-1-pyrroline is the key contributor to the ‘taro-like’ aroma of pumpkin fruit.

‘Taro-like’ aroma is a pleasant flavor and value-added trait in pumpkin species imparted by unknown key volatile compounds. In this study, we used the electronic nose (E-nose), gas chromatography-mass spectrometry (GC–MS), and GC-Olfactometry (GC-O) to study the aroma profile, volatile compounds, and key contributors, respectively. By E-nose and GC–MS, we found significant differences in the aroma profiles and volatile compounds between fruits from five samples with/without ‘taro-like’ aroma. According to the analysis of differential volatile compounds obtained from GC–MS and the GC-O analysis of the sample with ‘taro-like’ aroma, we found that 2-acetyl-1-pyrroline representing the ‘taro’ odor was only identified in the sample with ‘taro-like’ aroma. Therefore, we conclude that 2-acetyl-1-pyrroline is the key contributor to the 'taro-like' aroma. Moreover, the relationship between 2-acetyl-1-pyrroline and ‘taro-like’ aroma was further verified via other pumpkin samples. Our results provide a theoretical basis for understanding the aroma characteristics of pumpkin fruit.

Comparison of characterization and antioxidant activity of different citrus peel pectins

Pectins obtained from citrus peel of different cultivars and growth regions were compared based on physicochemical properties and antioxidant activity in vitro. The physicochemical features were elucidated using Fourier transform infrared (FT-IR), molecular weight distribution, monosaccharide composition, thermal behaviors and flow behaviors. Results showed that the different cultivars and growing areas have significant effects on the properties of citrus peel pectins (CPPs). Citrus peel pectins extracted by acetic acid were highly heterogeneous polysaccharides with broad molecular weight distributions and had high proportions of the RG-I domain. Among the 10 kinds of citrus peel pectins, Shatangju (CPP-6) and Xuecheng (CPP-7) own superior antioxidant biological activity and Dahongpao (CPP-3) and Buzhihuo (CPP-9) had excellent functional properties (thermal stability and viscosity). According to the correlation analysis, molecular weight, galacturonic acid content and degree of methyl-esterification were beneficial to increase the thermal stability and viscosity of citrus peel pectins, while the rhamnose content, rhamnogalacturonan I region and lower molecular weight can improve citrus peel pectins antioxidant activity. Our findings suggest that CPP-6 and CPP-7 may be useful as a potential natural antioxidant in pharmaceutical and cosmetic industries. Meanwhile, CPP-3 has great application potential in high temperature food and CPP-9 can be used as a thickener or stabilizer in the food industry.

Rheological and Microstructural Properties of Acidified Milk Drink Stabilized with Butternut Squash Pulp Hydrocolloids (BSPHs)

In this study, hydrocolloids from butternut squash pulp (BSPH) have been employed as stabilizers for the development of acidified milk drinks to evaluate their physicochemical, rheological, and microstructural properties. BSPH was obtained in the alkaline medium (yield of 630 mg of hydrocolloids/100 g of pulp), presenting 79.97 ± 0.240% carbohydrate and non-Newtonian-type shear thinning. Four acidified milk drinks (AMDs) were obtained with 0.25, 0.50, and 1.00% BSPHs and a control sample without BSPHs. The addition of BSPHs did not alter the proximal composition of AMDs with similar proximal values; also, the samples present typical behavior of non-Newtonian-fluid-type shear thinning adjusted to the Carreau-Yasuda model. Storage (G') and loss (G″) moduli values were slightly dependent on the frequency in most of the studied systems. Then, the addition of BSPHs retained their uniform internal structure and contributed to the stabilization of the products.

Effects of Oat Complex High-Fiber Formula Powder on the Composition of Intestinal Microbiota and Enzyme Activities in Mice Induced by a High-Fat Diet

Using oat-corn-konjac extruded mixed powder, oat bran micro powder, skim milk powder, Pueraria whole powder, and pumpkin powder as raw materials, a formula powder with high dietary fiber was prepared, and its effect on obesity in mice with a high-fat diet was investigated. After 7 days of adaptive feeding, the mice were divided into blank group, high-fat diet group, formula powder + high-fat diet group, and weight-loss drug + high-fat diet group. After 8 weeks of treatment, the body weight of mice were observed and measured to determine the composition of tract flora, liver leptin content, insulin content, and activities of AMP-activated protein kinase (AMPK), lipoprotein lipase (LPL), fatty acid synthetase (FAS), sterol-regulatory element-binding proteins (SREBPs), and acetyl CoA carboxylase 1 (ACC1). The results indicated that treatment with the formula powder could reduce the body weight of mice and increase the abundance of Bifidobacterium, Akkermansia, and Romboutsia compared to the group given a high-fat diet. Moreover, the leptin and insulin contents of the experimental group decreased from 5.67 μg/L to 0.12 μg/L and from 12.71 μg/L to 7.13 μg/L, respectively, compared to the control group, which was not significantly different from the blank group (P > 0.05). Also, the activities of AMPK and LPL increased, and the activities of FAS, SREBPs, and ACC1 were significantly decreased (P < 0.05). Some pathogenic bacteria were significantly positively correlated with leptin and FAS and significantly negatively correlated with LPL. Some beneficial bacteria were positively correlated with LPL. Therefore, the formula powder used in this study could reduce the body weight of mice, increase the abundance of some beneficial bacteria in the colonic intestinal microbiota, and improve the activities of enzymes related to lipid metabolism in the liver. This study provides a theoretical reference for the pathway by which high-fiber diet improves liver and intestinal metabolic abnormalities.

The Influence of Extraction Conditions on the Yield and Physico-Chemical Parameters of Pectin from Grape Pomace

Grape pomace is one of the most abundant by-products generated from the wine industry. This by-product is a complex substrate consisted of polysaccharides, proanthocyanidins, acid pectic substances, structural proteins, lignin, and polyphenols. In an effort to valorize this material, the present study focused on the influence of extraction conditions on the yield and physico-chemical parameters of pectin. The following conditions, such as grape pomace variety (Fetească Neagră and Rară Neagră), acid type (citric, sulfuric, and nitric), particle size intervals (<125 µm, ≥125−<200 µm and ≥200−<300 µm), temperature (70, 80 and 90 °C), pH (1, 2 and 3), and extraction time (1, 2, and 3 h) were established in order to optimize the extraction of pectin. The results showed that acid type, particle size intervals, temperature, time, and pH had a significant influence on the yield and physico-chemical parameters of pectin extracted from grape pomace. According to the obtained results, the highest yield, galacturonic acid content, degree of esterification, methoxyl content, molecular, and equivalent weight of pectin were acquired for the extraction with citric acid at pH 2, particle size interval of ≥125−<200 µm, and temperature of 90 °C for 3 h. FT-IR analysis confirmed the presence of functional groups in the fingerprint region of identification for polysaccharide in the extracted pectin.

Preventive Effect of Pectic Oligosaccharides on Acute Colitis Model Mice: Modulating Epithelial Barrier, Gut Microbiota and Treg/Th17 Balance

Pectin as dietary fiber supplements has shown emerging potential in clinical ulcerative colitis (UC) adjuvant therapy. In this study, the preventive and prebiotic effect of enzymatic-degraded pectic oligosaccharides (POS) was...

Analgesic and anti-inflammatory effects and safety profile of Cucurbita maxima and Cucumis sativus seeds

The premise of the pharmacology of natural product is to explore benefits of natural resources for the mankind. Medicines extracted from natural resources are considered as primary source for drug discovery. Thus, the current study was designed to evaluate the safety profile and explore the analgesic and anti-inflammatory activity of ethanol extract of Cucurbita maxima (C. maxima) and Cucumis sativus (C. sativus) seeds. These seeds are edible, good in taste and have been used for several therapeutic purposes. Acute toxicity of the seeds was evaluated by Lorke’s method while Eddy’s hot plate and tail immersion methods were used to assess analgesic activity in mice. Anti-inflammatory activity was evaluated by rat hind paw edema method. The seed extracts of C. maxima and C. sativus were found to be safe and showed significant analgesic and anti-inflammatory activity in comparison with the control group. The therapeutic effects of these extracts were almost comparable to aspirin and brufen. Therefore, the seeds can be used as effective analgesic and anti-inflammatory agents.

Potentials of Antitussive Traditional Persian Functional Foods for COVID-19 Therapy†

Coronavirus disease 2019 is a worldwide pandemic resulting in a severe acute respiratory syndrome. Remdesivir is the only FDA-approved drug for hospitalized patients older than age 12. It shows the necessity of finding new therapeutic strategies. Functional foods (FFs) could have co-therapeutic and protective effects against COVID-19 infection. Traditional Persian medicine (TPM), one of the safest and most popular schools of medicine for hundreds of years, has recommended potential FF candidates to manage such a global pandemic. To reveal the potential of TPM in terms of antitussive FFs, traditional Persian pharmacopoeia "Qarabadin-e-Salehi" was searched using the keywords "Soaal" and "Sorfeh." Also, a search of MEDLINE, PubMed Central, Google Scholar, and Science Direct was performed for the relevant literature published from the inception up to March 2021. A combination of search terms including "cough, antitussive, antioxidant, anti-inflammation, antiviral, COVID-19, mucoactive, mucolytic, expectorant, and mucoregulatory" was also applied. The potential mechanism of action in SARS-CoV-2 infection was discussed. Twelve TPM FFs were found including Laooqs, Morabbas, a Saviq, a soup, and a syrup. They are combinations of two to seven ingredients. Natural compounds of mentioned formulations have the main pharmacological mechanisms including antiviral, anti-inflammatory, antioxidant, antihistamine, bronchodilator, immunomodulatory, and mucoactive effects as well as central or peripheral antitussive activities. FFs are cost-effective, easily accessible, and safe options for both treatment and prevention of COVID-19. They might have positive psychological effects along with their pharmacological effects and nutritional virtues. They could also manage persistent respiratory discomforts after recovery from COVID-19.

Hypotensive and Hepatoprotective Properties of the Polysaccharide-Stabilized Foaming Composition Containing Hydrolysate of Whey Proteins

Whey protein hydrolysates (WPHs) are one of the most promising sources of biofunctional peptides with such beneficial properties as antioxidant, antihypertensive, anti-inflammatory and others. WPHs also could be used as foaming agents for aerated products (e.g., milk shake type drinks). However, WPH alone has a bitter taste and foamed WPH should be stabilized by additional ingredients. Here, we present a composition including WPH and three polysaccharides-pumpkin pectin, sodium alginate and ι-carrageenan-used as foam stabilizers. Polysaccharide content was selected according to foaming, organoleptic antioxidant and angiotensin-I-converting enzyme inhibitory characteristics of the resulted composition. Further, the hypotensive, antioxidant and hepatoprotective properties of the composition were proved by in vivo tests performed in spontaneously hypertensive rats and Wistar rats with CCl₄-induced hepatic injury.

Structure analysis of a non-esterified homogalacturonan isolated from Portulaca oleracea L. and its adjuvant effect in OVA-immunized mice

We isolated and purified a pectin from Portulaca oleracea L. (P. oleracea), and analysed its structure by high-performance size exclusion chromatography (HPSEC), high-performance liquid chromatography (HPLC), gas chromatograph-mass spectrometer (GC-MS), fourier transform infrared spectroscopy (FT-IR), and ¹H, ¹³C nuclear magnetic resonance spectroscopy (NMR). The data indicated that this pectin (designated as POPW-HG) was a linear non-esterified homogalacturonan, which is unique in plants; its molecular weight was around 41.2 kDa. Meanwhile, POPW-HG as an adjuvant was evaluated in the mice immunized with OVA subcutaneously. OVA-specific antibody titres from the sera of immunized mice were tested by ELISA. It showed that POPW-HG significantly enhanced OVA-specific antibody titres (IgG, IgG1, and IgG2b) (p < 0.05) in a dose-dependent manner in the OVA-immunized mice, preliminarily indicating POPW-HG could increase an antibody response, Th1 and Th2 immune response. In addition, the ratio of IgG1/IgG2b suggested POPW-HG induced a Th2-biased response in the OVA-immunized mice. The results demonstrated POPW-HG could be a potential adjuvant candidate in vaccines.

Antioxidant potential of family Cucurbitaceae with special emphasis on Cucurbita genus: A key to alleviate oxidative stress-mediated disorders

Oxidative stress is the imbalance between reactive oxygen species (ROS) production, and accumulation and the ability of a biological system to clear these reactive products. This imbalance leads to cell and tissue damage causing several disorders in human body, such as neurodegeneration, metabolic problems, cardiovascular diseases, and cancer. Cucurbitaceae family consists of about 100 genera and 1,000 species of plants including mostly tropical, annual or perennial, monoecious, and dioecious herbs. The plants from Cucurbita species are rich sources of phytochemicals and act as a rich source of antioxidants. The most important phytochemicals present in the cucurbits are cucurbitacins, saponins, carotenoids, phytosterols, and polyphenols. These bioactive phyto-constituents are responsible for the pharmacological effects including antioxidant, antitumor, antidiabetic, hepatoprotective, antimicrobial, anti-obesity, diuretic, anti-ulcer activity, and antigenotoxic. A wide number of in vitro and in vivo studies have ascribed these health-promoting effects of Cucurbita genus. Results of clinical trials suggest that Cucurbita provides health benefits for diabetic patients, patients with benign prostate hyperplasia, infertile women, postmenopausal women, and stress urinary incontinence in women. The intend of the present review is to focus on the protective role of Cucurbita spp. phytochemicals on oxidative stress-related disorders on the basis of preclinical and human studies. The review will also give insights on the in vitro and in vivo antioxidant potential of the Cucurbitaceae family as a whole.

Evaluation of the physicochemical properties of pectin extracted from Musa paradisiaca banana peels at different pH conditions in the formation of nanoparticles

Colombia is one of the major producers and exporters of banana Musa paradisiaca. Its consumption is high then its agro-industrial wastes are important source to extract pectin. In the present study, inorganic acids (nitric acid and hydrochloride acid) and organic acids (citric acid and acetic acid) were evaluated to extract pectin from banana peels at pH 2 and 3, through acid hydrolysis during 1h at the temperature of 85 °C. The extraction yield, degree of esterification (DE) and intrinsic viscosity of the pectin were characterized. Nitric acid (NA) allowed to obtain higher extraction yield (54 ± 10%) and citric acid (CA) allowed to obtain higher DE (76.7 ± 2%). Additionally, the effect of polymer concentration and degree esterification, low degree of esterification (LDE, 33.1%) and high degree of esterification (HDE, 76.7%) were evaluated in the pectin nanoparticles formation. The pectin with HDE formed stable nanoparticles with a particle size of 255 ± 11 nm and the zeta potential value of -45 ± 3 mV, independently of the polymer concentration. Morphology analysis showed aggregated of the pectin nanoparticles.

Pectin limits epithelial barrier disruption by Citrobacter rodentium through anti-microbial effects

SCOPE

C. rodentium is the murine equivalent of Enteropathogenic Escherichia. coli (EPEC) and Enterohemorrhagic Escherichia coli (EHEC) which induce damage to the intestinal epithelial barrier that results in diarrhea and intestinal inflammation. Dietary fibre intake can be an effective approach to limit epithelial damage by these enteric pathogens. Therefore, the protective effect of dietary fibre pectin against dysfunction of epithelial barrier integrity upon C. rodentium infection was investigated.

METHODS AND RESULTS

Pectins that structurally differed in the degree and distribution of methylesters were tested on barrier protective effects on epithelial cells against C. rodentium by measuring transepithelial electrical resistance and lucifer yellow fluxes. All three pectins protected the epithelial barrier from C. rodentium induced damage in a structure-independent manner. These barrier protective effects were also independent of pectin-induced TLR2 activation. Furthermore, the pectins induced anti-adhesive effects on C. rodentium by interacting with C. rodentium and not with epithelial cells. This may be explained by antimicrobial effects of pectins on C. rodentium and not on other enteric bacteria including Lactobacillus plantarum and E. coli. A competition ELISA for binding of C. rodentium to pectin supported this finding as it showed that pectin interacts strongly with C. rodentium, whereas it interacts weakly or not with L. plantarum or E. coli.

CONCLUSION

These findings demonstrate that pectin protects the epithelial barrier from C. rodentium induced damage by inducing anti-microbial effects.

Molecular mechanisms of plant adaptive responses to heavy metals stress

Heavy metals (HMs) are among the main environmental pollutants that can enter the soil, water bodies, and the atmosphere as a result of natural processes (weathering of rocks, volcanic activity), and also as a result of human activities (mining, metallurgical and chemical industries, transport, application of mineral fertilizers). Plants counteract the HMs stresses through morphological and physiological adaptations, which are imparted through well-coordinated molecular mechanisms. New approaches, which include transcriptomics, genomics, proteomics, and metabolomics analyses, have opened the paths to understand such complex networks. This review sheds light on molecular mechanisms included in plant adaptive and defense responses during metal stress. It is focused on the entry of HMs into plants, its transport and accumulation, effects on the main physiological processes, gene expressions included in plant adaptive and defense responses during HM stress. Analysis of new data allowed the authors to conclude that the most important mechanism of HM tolerance is extracellular and intracellular HM sequestration. Organic anions (malate, oxalate, etc.) provide extracellular sequestration of HM ions. Intracellular HM sequestration depends not only on a direct binding mechanism with different polymers (pectin, lignin, cellulose, hemicellulose, etc.) or organic anions but also on the action of cellular receptors and transmembrane transporters. We focused on the functioning chloroplasts, mitochondria, and the Golgi complex under HM stress. The currently known molecular mechanisms of plant tolerance to the toxic effects of HMs are analyzed.

Comparative Phytochemical, Antioxidant and Haemostatic Studies of Preparations from Selected Vegetables from Cucurbitaceae Family

The aim of this study was to provide detailed insight into the chemical composition and activity of five cucurbit vegetable preparations (pumpkin, zucchini, cucumber, white and yellow pattypan squash), each containing various phytochemical compounds with potential use against oxidative stress induced by the hydroxyl radical donors in human plasma in vitro. We studied the antiradical capacity of vegetable preparations using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method. As oxidative stress may induce changes in hemostasis, our aim included the determination of their effect on three selected hemostatic parameters of plasma, which are three coagulation times: PT (prothrombin time), APTT (activated partial thromboplastin time) and TT (thrombin time). However, none of used vegetable preparations changed APTT, PT or TT compared to the control. The phytochemical composition of the tested preparations was determined by UPLC-ESI-QTOF-MS. In our in vitro experiments, while all five tested preparations had antioxidant potential, the preparation from yellow pattypan squash showed the strongest potential. All cucurbit vegetable preparations inhibited lipid peroxidation. Only zucchini did not have an effect on protein carbonylation and only yellow pattypan squash inhibited thiol oxidation. The antioxidant activity of cucurbits appears to have triggered significant interest in multiple applications, including CVDs (cardiovascular diseases) associated with oxidative stress, which can be treated by supplementation based on these vegetables.

Low methyl-esterified pectin protects pancreatic β-cells against diabetes-induced oxidative and inflammatory stress via galectin-3

Insufficient intake of dietary fibers in Western societies is considered a major contributing factor in the high incidence rates of diabetes. The dietary fiber pectin has been suggested to be beneficial for management of both Diabetes Type 1 and Type 2, but mechanisms and effects of pectin on insulin producing pancreatic β-cells are unknown. Our study aimed to determine the effects of lemon pectins with different degree of methyl-esterification (DM) on β-cells under oxidative (streptozotocin) and inflammatory (cytokine) stress and to elucidate the underlying rescuing mechanisms, including effects on galectin-3. We found that specific pectins had rescuing effects on toxin and cytokine induced stress on β-cells but effects depended on the pectin concentration and DM-value. Protection was more pronounced with low DM5 pectin and was enhanced with higher pectin-concentrations. Our findings show that specific pectins might prevent diabetes by making insulin producing β-cells less susceptible for stress.

FTIR-ATR Spectroscopy Combined with Multivariate Regression Modeling as a Preliminary Approach for Carotenoids Determination in Cucurbita spp

Quantitative analysis of carotenoids has been extensively reported using UV-Vis spectrophotometry and chromatography, instrumental techniques that require complex extraction protocols with organic solvents. Fourier transform infrared spectroscopy (FTIR) is a potential alternative for simplifying the analysis of food constituents. In this work, the application of FTIR with attenuated total reflectance (ATR) was evaluated for the determination of total carotenoid content (TCC) in Cucurbita spp. samples. Sixty-three samples, belonging to different cultivars of butternut squash (C. moschata) and pumpkin (C. maxima), were selected and analyzed with FTIR- ATR (attenuated total reflectance). Three different preparation protocols for samples were followed: homogenization (A), freeze-drying (B), and solvent extraction (C). The recorded spectra were used to develop regression models by Partial Least Squares (PLS), using data from TCC, determined by UV-Vis spectrophotometry. The PLS regression model obtained with the FTIR data from the freeze-dried samples, using the spectral range 920–3000 cm−1, had the best figures of merit (R2CAL of 0.95, R2PRED of 0.93 and RPD of 3.78), being reliable for future application in agriculture. This approach for carotenoid determination in pumpkin and squash avoids the use of organic solvents. Moreover, these results are a rationale for further exploring this technique for the assessment of specific carotenoids in food matrices.

Whey Protein Hydrolysate and Pumpkin Pectin as Nutraceutical and Prebiotic Components in a Functional Mousse with Antihypertensive and Bifidogenic Properties

Systematical consumption of functional products has a significant positive effect on health and can reduce the risk of diseases. The aim of this study was to investigate the possibility of using whey protein hydrolysate (WPH) and pumpkin pectin as ingredients in a functional mousse, to evaluate the mousse’s antioxidant and hypotensive activities in vitro, and to evaluate the effect of the long-term intake of mousse samples on the progression of hypertension in spontaneously hypertensive rats (SHRs) and on the microbiome status in Wistar rats with antibiotic-induced dysbiosis. The experimental mousse’s in vitro antioxidant activity (oxygen radical absorbance capacity) increased by 1.2 times. The hypotensive (angiotensin-1-converting enzyme inhibitory) activity increased by 6 times in comparison with a commercial mousse. Moreover, the addition of pectin allowed the elimination of the bitter aftertaste of WPH. In vivo testing confirmed the hypotensive properties of the experimental mousse. The systolic blood pressure in SHRs decreased by 18 mmHg and diastolic blood pressure by 12 mmHg. The experimental mousse also showed a pronounced bifidogenic effect. The Bifidobacterium spp. population increased by 3.7 times in rats orally administered with the experimental mousse. The results of these studies confirm that WPH and pumpkin pectin are prospective ingredients for the development of functional mousses.

Rethinking the impact of RG-I mainly from fruits and vegetables on dietary health

Rhamnogalacturonan I (RG-I) pectin is composed of backbone of repeating disaccharide units →2)-α-L-Rhap-(1→4)-α-D-GalpA-(1→ and neutral sugar side-chains mainly consisting of arabinose and galactose having variable types of linkages. However, since traditional pectin extraction methods damages the RG-I structure, the characteristics and health effects of RG-I remains unclear. Recently, many studies have focused on RG-I, which is often more active than the homogalacturonan (HG) portion of pectic polysaccharides. In food products, RG-I is common to fruits and vegetables and possesses many health benefits. This timely and comprehensive review describes the many different facets of RG-I, including its dietary sources, history, metabolism and potential functionalities, all of which have been compiled to establish a platform for taking full advantage of the functional value of RG-I pectin.