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

Identification of Key Genes Controlling Sugar and Organic Acid Accumulation in Wampee Fruit (Clausena lansium) via Genome Assembly and Genome-wide Association Analysis

Wampee (Clausena lansium) is an economically significant subtropical fruit tree widely cultivated in Southern China. To provide high-quality genomic resources for C. lansium, we report a chromosome-level genome sequence for the "JinFeng" cultivar. The 297.1 Mb C. lansium genome contained nine chromosomes with a scaffold N50 of 29.2 Mb and encoded 23,468 protein-coding genes. Selective sweep analysis between sweet and sour C. lansium varieties and genome-wide association analysis identified 14 candidate genes putatively involved in sugar and acid accumulation. ClERF061, encoding an ethylene response factor, and ClSWEET7, encoding a Sugars Will Eventually be Exported Transporters (SWEET) family protein, were proposed as key regulators of the sweet and sour tastes of the wampee fruit. ClERF061 and ClSWEET7 overexpression in tomatoes increased the total sugar and acid content in fruits. ClSWEET7 promoter activation by ClERF061 was confirmed via Nicotiana benthamiana transient expression. Our study provides valuable genomic resources for C. lansium genetics and breeding.

Cytotoxicity and antibacterial susceptibility assessment of a newly developed pectin-chitosan polyelectrolyte composite for dental implants

Biopolymers such as chitosan and pectin are currently attracting significant attention because of their unique properties, which are valuable in the food industry and pharmaceutical applications. These properties include non-toxicity, compatibility with biological systems, natural decomposition ability, and structural adaptability. The objective of this study was to assess the performance of two different ratios of pectin-chitosan polyelectrolyte composite (PCPC) after applying them as a coating to commercially pure titanium (CpTi) substrates using electrospraying. The PCPC was studied in ratios of 1:2 and 1:3, while the control group consisted of CpTi substrates without any coating. The pull-off adhesion strength, cytotoxicity, and antibacterial susceptibility tests were utilized to evaluate the PCPC coatings. In order to determine whether the composite coating was the result of physical blending or chemical bonding, the topographic surface parameters were studied using Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). PCPC (1:3) had the highest average cell viability of 93.42, 89.88, and 86.85% after 24, 48, and 72 h, respectively, as determined by the cytotoxicity assay, when compared to the other groups. According to the Kirby-Bauer disk diffusion method for testing antibacterial susceptibility, PCPC (1:3) showed the highest average diameter of the zone of inhibition, measuring 14.88, 14.43, and 11.03 mm after 24, 48, and 72 h of incubation, respectively. This difference was highly significant compared to Group 3 at all three time periods. PCPC (1:3) exhibited a significantly higher mean pull-off adhesion strength (521.6 psi) compared to PCPC (1:2), which revealed 419.5 psi. PCPC (1:3) coated substrates exhibited better surface roughness parameters compared to other groups based on the findings of the AFM. The FTIR measurement indicated that both PCPC groups exhibited a purely physical blending in the composite coating. Based on the extent of these successful in vitro experiments, PCPC (1:3) demonstrates its potential as an effective coating layer. Therefore, the findings of this study pave the way for using newly developed PCPC after electrospraying coating on CpTi for dental implants.

Characterization of Functional Ingredients Extracted with Ethanol Solvents from Ponkan (Citrus reticulata) By-Products Using the Microwave Vacuum Drying Method Combined with Ultrasound-Assisted Extraction

For this study, microwave vacuum drying (MVD) was combined with ultrasound-assisted extraction to compare the effects of different ethanol volumes on ponkan extract and to evaluate the total phenolic content (TPC), total flavonoid content (TFC), and total ascorbic acid content (TAAC). High-performance liquid chromatography with photodiode array detection (HPLC-PDA) was used to analyze the flavanone contents and antioxidant activity of ponkan (Citrus reticulata) peels. The experimental results showed that the TPC and TFC increase with ethanol volume. Ethanol extraction (75%) showed significant advantages by increasing the TPC to 17.48 mg GAE/g (DW) and the TFC to 2.96 mg QE/g (DW) of ponkan extract and also exhibited the highest antioxidant activity. The TAAC improved along with increased water content. Water extraction showed the highest content (13.07 mg VitC/100 g, DW). The hesperidin content analyzed by HPLC-PDA was 102.95-622.57 mg/100 g (DW), which was the highest among the flavanones. Then, the ethanol insoluble residue extracts were taken from the pectin with four different solvents, evaluating TPC, TFC, and antioxidant activity. The TPC, TFC, and antioxidant capacity of pectin are significantly lower than those of the peels. Combining MVD and 75% ethanol with ultrasound-assisted extraction in the pre-treatment process can effectively eliminate polyphenols, flavonoids, and other compounds, thus enabling the extraction of high-methoxyl pectin. The total dietary fiber (TDF) content of MVD ponkan by-products was 25.83%. Ponkan by-products have the potential for the future development of functional foods and supplements.

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.

Acidic Electrolyzed Water Maintains the Storage Quality of Postharvest Wampee Fruit by Activating the Disease Resistance

Harvested wampee fruit is susceptible to disease, resulting in postharvest losses. Acidic electrolyzed water (AEW), a safe and innovative sterilization technology, plays a role in enhancing disease resistance in harvested produce. In this study, the efficacy of AEW in delaying wampee disease development was assessed, along with its association with disease resistance metabolism. Wampee fruit was treated with AEW (pH 2.5) at different available chlorine concentrations (ACCs) (20, 40, 60, and 80 mg/L) and subsequently stored at 25 °C for 8 days. Results revealed that 40 mg/L ACC in AEW (pH 2.5) was most effective in improving the postharvest quality of wampee fruit. Compared with control wampee fruit, those treated with 40 mg/L ACC in AEW exhibited lower incidence of fruit disease, higher pericarp lignin content, and higher activities of pericarp disease resistance enzymes (DREs), such as cinnamate-4-hydroxylase, phenylalanine ammonia-lyase, chitinase, β-1,3-glucanase, polyphenol oxidase, 4-coumarate CoA ligase, and cinnamyl alcohol dehydrogenase. These results suggested that AEW elevated DRE activities, promoted lignin accumulation, and ultimately enhanced disease resistance, suppressed disease development, and improved storage quality in harvested wampee fruit. Consequently, AEW emerged as a safe technology to mitigate the disease development and enhance the storage quality of harvested wampee fruit.

Effect of hydrochloric acid and citric acid with ultrasound processing on characteristics of superfine-ground pectic polysaccharides from okra (Abelmoschus esculentus L.) peel

The structural properties and biological activities of okra pectic polysaccharides (OPs) were impacted by various extraction methods. Based on commonly grinding (40, 100 meshes) and superfine grinding okra powders, two extraction solvents (hydrochloric acid, HA; citric acid, CA) were used firstly. Next, the extraction yield, physical and chemical properties, molecular structure and functional properties of OPs were analyzed by non-ultrasonic treatment and ultrasound-assisted superfine grinding method. The outcomes demonstrated that the extraction yield of OPs rose as the particle size of the powder decreased. HA-OPs had higher molecular weight (Mw), apparent viscosity and emulsification ability than CA-OPs. CA-OPs had higher esterification degree (DE), solubility and total sugar content, and higher amounts of rhamnogalacturonan-I (RG-I) segments. Compared with OPs without ultrasound-assisted extraction, ultrasound-assisted superfine grinding extraction exhibited higher sugar content, antioxidant capacity, emulsification ability, lower Mw, DE and apparent viscosity. Finally, the correlation between structure and function of OPs was further quantified. The antioxidant capacity was positively correlated with RG-I content, and negatively correlated with DE and Mw. The emulsification ability was mainly positively correlated with the GlcA of OPs. This study provides a theoretical basis for the development of OPs foods with clear structure-function relationship, which would be instructive for the application of OPs in food and cosmetics.

Structural characterization of a water-soluble acidic polysaccharide CSP-IV with potential anticoagulant activity from fruit pulp of Clausena lansium (Lour.) Skeels Guifei

Four main water-soluble wampee fruit pulp polysaccharides, named CSP-I, CSP-II, CSP-III and CSP-IV, were isolated from Clausena lansium (Lour.) Skeels Guifei, therein CSP-IV content was higher than the others. All components possess certain anticoagulant activity demonstrated by prolonged activated partial thromboplastin time, especially CSP-IV, which suggests that CSP-IV plays anticoagulant effect through disturbing intrinsic coagulation pathway. The wampee polysaccharide CSP-IV with Mw of 510.1 kDa was mainly composed of Gal, Ara and GalA. Backbone of CSP-IV contains Gal, Ara and GalA, two kinds of side chains contain one monosaccharide Gal or Ara, both branch on Gal residue of backbone. CSP-IV has no the conformation of triple helix demonstrated by Congo red test. These results showed that CSP-IV is an acidic polysaccharide with potential anticoagulant activity via targeting intrinsic coagulation pathway.

Extraction of Ampelopsis japonica polysaccharides using p-toluenesulfonic acid assisted n-butanol three-phase partitioning: Physicochemical, rheological characterization and antioxidant activity

Polysaccharides as the biopolymers are showing various structural and modulatory functions. Effective separation of carbohydrate structures is essential to understanding their function. In this study, we choose an efficient organic acid in combination with recyclable organic solvent three-phase partitioning technology for the simultaneous extraction of polysaccharides from Ampelopsis japonica (AJPs) to ensure the integrity of linear and branched polysaccharide. The monosaccharide composition, glycosidic linkage information, structural and physicochemical analyses and associations with antioxidant activities were extensively analyzed. Synergistic extraction was compared with the conventional hot water extraction method and the results showed that AJPs-HNP exhibited better elastic properties and excellent antioxidant activity. Correlation analysis confirmed that the antioxidant activity of AJPs was significantly correlated with relative molecular weight, uronic acid content and terminal glycoside linkage molar ratios. The collaborative processing has significantly improved the utilization potential of AJPs and provides a sound theoretical foundation for the effective extraction and separation of polysaccharides. Overall, this work provides systematic and comprehensive scientific information on the physicochemical, rheological and antioxidant properties of AJPs, revealing their potential as natural antioxidants in the functional food and pharmaceutical industries.

Extraction of pectins from renewable grapefruit (Citrus paradisi) peels using deep eutectic solvents and analysis of their structural and physicochemical properties

This study presents an innovative attempt to extract high-quality pectins from grapefruit (Citrus paradisi) peels by using deep eutectic solvents (DESs) as extraction agents. The maximum yield of betaine-citric acid (BC)-extracted pectin (BC-P) reached 36.47 % under the optimum process conditions: an L/S ratio of 25 mL/g, a pH of 2.0, and a temperature of 85 °C for 120 min. The yield of BC-P was significantly higher than HCl-extracted pectin (HCl-P, 8.76 %) under a pH of 2.0. In addition, the structural, physicochemical, and emulsifying properties of the purified pectins (BC-P and HCl-P) and commercial pectin (CP) were comparatively analyzed. Results showed that BC-P exhibited higher RG-I value, more arabinan side-chains, bigger Mw and Mn value than HCl-P. Moreover, the viscosity, G' and G'' of BC-P were significantly higher than those of HCl-P and CP. More importantly, BC-P demonstrated better emulsifying activity and stability compared to HCl-P and CP. When the concentration of BC-P was increased to 1.50 %, a stable emulsion containing a 50 % soybean oil fraction could be obtained. Our results confirmed that DESs can be considered as high-effective agents for pectin extraction. Pectins extracted from grapefruit peels can be as a promising natural emulsifiers that can be used in the food industry.

Polysaccharide extracted from cultivated Sanghuangporous vaninii spores using three-phase partitioning with enzyme/ultrasound pretreatment: Physicochemical characteristics and its biological activity in vitro

Sanghuangporous vaninii, as a valuable dietary supplement and medicinal ingredient, contains abundant bioactive polysaccharides that have health-promoting effects. In the present study, four polysaccharides (SVSPs-C, SVSPs-E, SVSPs-U, and SVSPs-E/U) were extracted for the first time from S. vaninii spores by three-phase partitioning (TPP), enzyme pretreatment before TPP (E-TPP), ultrasonic pretreatment before TPP (U-TPP), and enzyme pretreatment followed by ultrasonic before TPP (E/U-TPP) methods, respectively. Their physicochemical characteristics and in vitro pharmacological functions were determined and compared. Results showed that four TPP-based extraction methods had remarkable impacts on the extraction yield, chemical properties, monosaccharide compositions, and molecular weights (Mw) of SVSPs. Specifically, SVSPs-E/U obtained by E/U-TPP showed the highest extraction yield (25.40 %), carbohydrate content (88.50 %), and the lowest protein content (0.86 %). The four SVSPs had high-Mw (183.8-329.1 kDa) and low-Mw (23.0-156.4 kDa) fractions and mainly consisted of galactose, glucose, and mannose with different contents. In vitro bioactivities assays indicated that SVSPs-E/U possessed stronger antioxidant, hypoglycemic, hypouricemic, immunostimulatory, and antitumor activities than those of SVSPs-C, SVSPs-E, and SVSPs-U. Therefore, our results provide an efficient and promising extraction technique for bioactive polysaccharides from S. vaninii spores, as well as SVSPs had the potential to be applied in functional food, pharmaceutical, and cosmetics fields.

Comprehensive evaluation of aroma and taste properties of different parts from the wampee fruit

Wampee is a tropical fruit having high medicinal value. To fully realize the fruit's potential, it is essential to reveal the flavor characteristics. In this study, a comprehensive analysis of the aroma and taste profiles of different parts from the wampee fruit was conducted. The aroma profile was analyzed by E-nose, and 67 volatile components were identified through HS-SPME-GC-MS. Among them, 11 were considered as crucial compounds. Additionally, 42 volatile components were identified by HS-GC-IMS, with 22 compounds showing a variable importance in projection scores greater than 1.0. Moreover, the taste profile and representative compounds were analyzed by E-tongue and HPLC, and 12 compounds were considered as important taste contributors based on taste activity value. These findings shed light on the various compounds responsible for the unique aroma and taste of the wampee fruit, providing theoretical foundation for exploring ways for its comprehensive utilization and development.

Spontaneous gelation behaviors and mechanism of Ficus awkeotsang Makino pectin

Ficus awkeotsang Makino (jelly fig) can produce edible gels by rubbing its seeds in water at room temperature in which pectin is considered as the main gelling component. However, the spontaneous gelation mechanism of Ficus awkeotsang Makino (jelly fig) pectin (JFSP) is still unclear. This study aimed to reveal the structure, physicochemical properties, and spontaneous gelation behaviors and mechanism of JFSP. JFSP was first obtained by water extraction and alcohol precipitation method, with a pectin yield of 13.25 ± 0.42 % (w/w), weight-average molar mass (Mw) of 111.26 kDa, and methoxylation degree (DM) of 26.8 %. Analysis of monosaccharide compositions showed that JFSP was composed of 87.8 % galactose acid, indicating a high percentage of galacturonic acid blocks. Measurement on the gelling capacity suggested that JFSP gels can be easily formed by simply dispersing the pectin in water at room temperature without adding any co-solutes or metal ions. Gelation force analysis indicated that hydrogen bonding, hydrophobic interactions, and electrostatic interactions were the main factors contributing to gel formation. At 1.0 % (w/v) of pectin concentration, JFSP gels exhibited relatively high gel hardness (72.75 ± 1.15 g) and good thermal and freeze-thawing stability. Overall, these findings highlight the potential application of JFSP as a promising commercial pectin resource.

Comprehensive Review of Phytochemical Profiles and Health-Promoting Effects of Different Portions of Wampee (Clausena lansium)

Clausena lansium, commonly known as wampee, is a subtropical fruit from the Rutaceae family characterized by its high nutrient content and numerous bioactive substances. This low-fat fruit is abundant in fiber, vitamins, minerals, and essential amino acids. Wampee has been found to contain several bioactive compounds, including essential oils, phenolic compounds, and alkaloids. These bioactive constituents provide numerous health-enhancing properties, such as antioxidant, neuroprotective, anticarcinogenic, anti-inflammatory, hepatoprotective, antidiabetic, and antimicrobial effects. The relationship between these compounds and their impacts on health has been explored in various studies. While the disease-prevention efficacy of C. lansium has been established, additional research is necessary to elucidate the precise mechanisms and metabolic pathways involved. This paper presents a comprehensive review of wampee, focusing on its bioactive compounds, the beneficial effects derived from its consumption, and the evidence supporting the development of wampee-based functional foods in future studies.

Versatile functionalization of pectic conjugate: From design to biomedical applications

Pectin exists extensively in nature and has attracted much attention in biological applications for its unique chemical and physical characteristics. Functionalized pectin, especially pectic conjugates, has given many possibilities for pectin to improve its properties and bioactivity as well as to deliver active molecules. To better exploit this strategy of pectic functionalization, this review presents in detail the structural modifications of pectin, different synthetic methods, and design strategies of pectic conjugates involving both traditional chemical and "green" approaches. Here, the research ideas and applications of pectic prodrugs as well as the development of preparation based on pectic conjugates are reviewed, with emphasis on crosslinking systems of functionalized pectin and nanosystems based on self-assembly techniques. We hope this review will provide comprehensive and valuable information for the functionalization and systematization of the pectic conjugate from synthesis to application.

Effect of acid hydrolysis on the structural and antioxidant characteristics of β-glucan extracted from Qingke (Tibetan hulless barley)

In this study, we explored the effect of acid hydrolysis on the molecular, structural, rheological, thermal, and antioxidant characteristics of Qingke β-glucan. The acid hydrolysis reduced the molecular weights of β-glucans from 510 to 155 KDa. The results of the structural analysis by nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction, and fourier transforms infrared (FTIR) spectroscopy indicated that acid hydrolysis did not change the primary functional groups of β-glucans. The rheological behavior of β-glucan without and with acid hydrolysis can be described as pseudoplastic and Newtonian, respectively. The DSC curves of the β-glucans with high molecular weights showed the highest transition temperature. The 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation scavenging activity and the reducing power of soluble β-glucans in Qingke showed a dose-dependent pattern. Meanwhile, the antioxidant activities of Qingke β-glucan of different molecular weights were similar. This study demostrated that the acid hydrolysis almost have no effect on antioxidant activity of Qingke β-glucans.

Synthesis and Evaluation of Antioxidant and Potential Prebiotic Activities of Acetylated and Butyrylated Fructo-Oligosaccharides

Fructo-oligosaccharides (FOS) have well-known bifidogenic effects as probiotics. In this study, esterification was adopted for FOS modification to produce better prebiotic properties. We synthesized and characterized acetylated fructo-oligosaccharides (Ac-FOS) and butyrylated fructo-oligosaccharides (Bu-FOS) as candidate prebiotics. Antioxidant activity and prebiotic esactiviti were evaluated as important indicators. We found, surprisingly, that butyrylation was an effective method in significantly improving the antioxidant activity of FOS. The fermentation products of feces from mice added to Ac-FOS and Bu-FOS, were investigated in vitro, including changes of pH values, short-chain fatty acids (SCFAs) production, and microbiota composition. Supplementation of Ac-FOS or Bu-FOS increased pH values and promoted the growth and activity of beneficial intestinal bacteria, such as Bifidobacteria and Lactobacillus. More importantly, the levels of prebiotic SCFAs were obviously elevated as detected by Gas Chromatography–Mass Spectrometry (GC-MS). Results suggest that Ac-FOS and Bu-FOS have great potential applications in SCFA delivery systems and gut microbiota regulation.