Search Results (160)

Conventional thermal pasteurization is widely applied to ensure the safety of fruit juices, although its impact on bioactive compounds and functional properties may vary according to cultivar. This study evaluated the effects of conventional pasteurization on physicochemical parameters, bioactive composition, antioxidant capacity, and enzyme inhibitory activities of juices obtained from five Sicilian Citrus grandis cultivars (Todarii, Maxima, Pyriformis, Chadock, and Terracciani). Total polyphenols, flavonoids, and carotenoids were quantified, while flavanone profiles were characterized by means of HPLC analysis. Antioxidant activity was assessed using DPPH, ABTS, FRAP, and β-carotene bleaching assays, and in vitro inhibitory activities against α-amylase, α-glucosidase, and pancreatic lipase were determined. Pasteurization led to cultivar-dependent reductions in total polyphenols (up to ~40%), flavonoids (up to ~45%), and carotenoids (up to ~25%), accompanied by decreased radical scavenging capacity and reducing power. Naringin was identified as the predominant flavanone, with thermal processing inducing both degradation and release phenomena depending on the cultivar. Fresh juices exhibited stronger enzyme inhibitory activities, particularly against α-amylase and α-glucosidase. Multivariate analysis discriminated against fresh and pasteurized juices, identifying phenolics as the main contributors to antioxidant capacity. Despite bioactive reductions, functional quality was partially preserved, supporting targeted cultivar selection for optimized industrial processing. Full article

Citrus fruits are susceptible to ‘Huanglongbing’, leading to widespread antibiotic use during planting. Additionally, to enhance economic efficiency, plant growth regulators (PGRs) are also applied to citrus fruits. To rapidly screen for antibiotics and plant growth regulators in citrus fruits, a method was developed for the simultaneous detection of exogenous contaminants in mandarin, orange, pomelo, and lemon using QuEChERS combined with liquid chromatography–quadrupole/orbitrap mass spectrometry. By comparing the responses or recoveries of compounds under different conditions, the optimal extraction and purification were determined. The method was used to verify the methodological parameters for four citrus fruits. The results showed that the detection limits for 10 antibiotics and 53 plant growth regulators in the four citrus fruits ranged from 1 to 50 μg/kg, and the limits of quantitation ranged from 1 to 80 μg/kg. And the coefficient of determination (R²) was ≥ 0.99. The recovery of all compounds was between 60% and 120%, and the relative standard deviation (RSD) was less than 20%. The method was applied to the 42 real samples, and a total of nine compounds were detected at concentrations ranging from 0.002 to 0.852 mg/kg. The results demonstrated that the method was simple, sensitive, accurate, and reliable, making it suitable for detecting antibiotics and plant growth regulators in citrus fruits. Full article

Contarinia citri Barnes is a major pest of Citrus grandis ‘Tomentosa’, damaging flowers, including abnormal development with lantern-like morphology, and substantially reducing yield. However, the molecular mechanisms underlying this abnormal development remain unclear. Structural and anatomical observations combined with transcriptome analyses of normal and lantern-like flowers were performed to elucidate host regulatory pathways in response to C. citri. Infestation increased levels of salicylic acid, indole-3-acetic acid, and cis-zeatin, as well as chlorophyll and total flavonoid accumulation in petals. Simultaneously, an increased number of transverse petal cell layers led to petal thickening and lantern-like flower formation. Transcriptome sequencing identified 5601 differentially expressed genes. C. citri induced genes associated with increased petal cell number and enhanced photosynthesis and amino acid synthesis, likely providing nutrients for larvae. Most genes in the jasmonic acid, salicylic acid, and mitogen-activated protein kinase signaling pathways were up-regulated, promoting the synthesis of resistance-related compounds, including terpenoids, flavonoids, lignin, and wax, thereby enhancing petal resistance to C. citri. These findings elucidate plant–insect interactions and provide a new framework for understanding insect-induced plant developmental reprogramming, while identifying potential targets for breeding resistant C. grandis ‘Tomentosa’ varieties and developing novel C. citri control strategies. Full article

Postharvest lignification of juice sacs in Meizhou pomelo is a major physiological disorder that compromises fruit quality and limits sustainable industry development. Through a comprehensive three-year field study, we investigated the effects of key factors—soil organic matter, storage temperature, and tree age—on fruit lignification, and evaluated the efficacy of ten plant growth regulators (PGRs) and their combinations in mitigating granulation. Our results demonstrated that soil rich in organic matter and exchangeable calcium significantly reduced the granulation index. Constant storage at 15 °C effectively suppressed weight loss and lignification compared to fluctuating ambient temperatures. Among the tested PGRs, 28-Homobrassinolide (28-homo-BR), 28-Epihomobrassinolide (28-epi-BR), 24-Epibrassinolide (24-epi-BR), and 14-Hydroxybrassinosteroid (14-hydro-BR) exhibited the most pronounced effects in alleviating granulation. Two superior PGR combinations were subsequently identified, which functioned by synergistically downregulating the activities of key phenylpropanoid pathway enzymes—phenylalanine ammonia-lyase, 4-coumarate: CoA ligase, cinnamyl alcohol dehydrogenase, and peroxidase. This downregulation likely contributed to reduced lignin biosynthesis and accumulation. Metabolomic profiling further revealed an accumulation of phenylpropanoid precursors, including ferulic acid and p-coumaric acid, in lignified juice sacs, indicating that the overactivation of this pathway is a key metabolic feature associated with lignification. This finding provides critical evidence for the potential mechanism whereby PGRs suppress lignification, thus offering both mechanistic insights and practical strategies for controlling lignification in pomelo and other citrus fruits. Full article

The granulation of pomelo (Citrus maxima) juice sacs severely compromises fruit quality and is closely associated with lignin accumulation, a process catalyzed by peroxidases (PODs). Analysis of ‘Sanhong’ pomelo juice sacs collected 175–215 days after flowering revealed that bound peroxidase (BPOD) activity paralleled changes in lignin content, suggesting a potential role for BPOD in lignin biosynthesis. A total of 71 CmPOD genes were identified in the pomelo genome through integrated HMMER and BLAST analyses. Among them, CmPOD52 was selected for functional characterization based on its alkaline peroxidase properties, absence of a CE domain, predicted extracellular localization, and gradually increasing expression pattern revealed by RT-qPCR. Its transient overexpression in ‘Sanhong’ pomelo juice sacs for 36 h increased BPOD activity 2.06-fold (p < 0.01) compared to the empty vector control, indicating that CmPOD52 may be a BPOD gene. The recombinant CmPOD52 protein was expressed in a prokaryotic system, purified, and used in enzymatic assays with sinapyl alcohol as the substrate. The recombinant CmPOD52 protein, assayed at 272 nm with controls (substrate-only blank and heat-inactivated protein), showed an activity of 13.67 ± 0.9 U. The experimental group showed new products, identified by mass spectrometry as sinapyl alcohol dimers, thus suggesting that the recombinant protein catalyzes the dehydrogenation and polymerization of sinapyl alcohol monomers. This study identified CmPOD52, a gene potentially involved in lignin polymerization in pomelo juice sacs, offering a key candidate for further in vivo validation. Full article

Instance segmentation in agricultural robotics requires a balance between real-time performance and accuracy. This study proposes a lightweight pomelo image segmentation method based on the YOLOv8n-seg model integrated with the RepGhost module. A pomelo dataset consisting of 5076 samples was constructed through systematic image acquisition, annotation, and data augmentation. The RepGhost architecture was incorporated into the C2f module of the YOLOv8-seg backbone network to enhance feature reuse capabilities while reducing computational complexity. Experimental results demonstrate that the YOLOv8-seg-RepGhost model enhances efficiency without compromising accuracy: parameter count is reduced by 16.5% (from 3.41 M to 2.84 M), computational load decreases by 14.8% (from 12.8 GFLOPs to 10.9 GFLOPs), and inference time is shortened by 6.3% (to 15 ms). The model maintains excellent detection performance with bounding box mAP50 at 97.75% and mask mAP50 at 97.51%. The research achieves both high segmentation efficiency and detection accuracy, offering core support for developing visual systems in harvesting robots and providing an effective solution for deep learning-based fruit target recognition and automated harvesting applications. Full article

Pectin-derived oligosaccharides (POS) are emerging as promising functional prebiotics with growing industrial interest. This study reports a synergistic fungal pectinolytic biocatalytic system comprising endopolygalacturonase (EndoPG) and pectin methylesterase (PET11) from Aspergillus aculeatinus BCC 17849 for the controlled depolymerization of pomelo (Citrus maxima) albedo pectin. PET11-mediated demethylation increased substrate accessibility, thereby enhancing EndoPG-catalyzed hydrolysis and resulting in higher POS yields than those obtained with single-enzyme systems. The highest production of short-chain POS, comprising GalA, di-GalA, and tri-GalA (681 mg/g substrate), was achieved at an EndoPG:PET11 dosage ratio of 15:5. The resulting POS fraction significantly promoted the growth of five probiotic strains, including Lactobacilli and Bifidobacteria species, and enhanced probiotic adherence to intestinal epithelial cells. In particular, Lactobacillus acidophilus TBRC 5030 exhibited the highest adhesion level (35.24 ± 6.43%) in the presence of 2.0 mg/mL POS. Overall, this work demonstrated that enzyme-assisted demethylation coupled with targeted endo-hydrolysis enables effective tailoring of POS chain length, providing a promising biocatalytic strategy for pectin valorization into prebiotic ingredients. Full article

Cerebral ischemic reperfusion injury (CIRI) induces irreversible neurological dysfunction with high morbidity and mortality, yet effective clinical interventions remain limited. This study focused on ferroptosis in CIRI and explored the neuroprotective components and mechanisms of Pomelo peel essential oil (PPEO)—a product derived from Guangxi’s characteristic Shatian pomelo. Sprague-Dawley rats were used to establish two CIRI models: focal CIRI via Middle Cerebral Artery Occlusion (MCAO) and global CIRI via Cardiac Arrest/Cardiopulmonary Resuscitation (CA/CPR). Analyses were conducted using metabolomics, transcriptomics, histopathological staining, biochemical assays, RT-qPCR, Western blotting (WB), and molecular docking. Metabolomic results showed altered lipid-related metabolites in both models, predominantly unsaturated fatty acids and components of the arachidonic acid (AA) metabolic pathway. Transcriptomic analysis revealed significant upregulation of PTGS1/2 in the MCAO model. Nootkatone and β-pinene improved neuronal morphology, increased glutathione peroxidase 4 (GPX4) levels, and enhanced neurological scores. Notably, Nootkatone exhibited strong binding affinity to ALOX15, and reduced lipid metabolic disturbances in the CA/CPR model. AA metabolism varies with CIRI severity: it is inflammation-driven in focal CIRI and ferroptosis-associated in global CIRI. As a key component of PPEO, Nootkatone antagonizes ferroptosis via the ACSL4-LPCAT3-ALOX15 axis, offering a novel therapeutic target for global CIRI after CA/CPR. Full article

It is essential to introduce new cultivars to diversify the pomelo industry in China. This paper compared the agronomic and environmental performances of new Tabtim Siam (TS) and Xishi (XS) pomelos with the local cultivars (Red-fleshed Sweet (RS) and Shatian (ST)) in Dabu County. We have generally evaluated the phenological, physiological, fruit quality, stress resistance, and storage characteristics. Findings indicated that TS and XS grew up well, and the phenological stages were adjusted to the local conditions. They had a high pollen viability and equivalent photosynthetic capacity. XS and TS had the highest yield and good fruit quality in terms of higher edible rates, more juice rate, and balanced sugar–acid content. Both the introduced cultivars had greater cold resistance compared with the control with lower semi-lethal temperatures. Polyethylene film at low temperatures to preserve the quality of storage was effective. Compared with RS and ST, TS and XS had a higher price in the market economically. The use of molecular markers (SCoT and SRAP) was able to discriminate all cultivars, which proved genetic uniqueness. In summary, TS and XS have potential to be grown in the Meizhou area and provide high quality, good adaptability, and greater market potential. Full article

‘Hainan Qingyou’ (Citrus maxima) Pomelo is one of the predominant local cultivars cultivated in Hainan Province, renowned for its high economic value and strong market competitiveness. However, during cultivation, it was observed that the fruit quality of ‘Hainan Qingyou’ grafted onto a ‘Sanhong’ interstock deteriorated, predominantly manifesting as vesicle granulation. This study was therefore conducted to investigate this phenomenon using ‘Sanhong’ Honey Pomelo as the interstock. Fruit quality indicators were measured, and pulp transcriptomic analysis was performed during the expansion and maturation stages. The results indicated that fruits grafted onto ‘Sanhong’ interstock (SHZ) exhibited increased peel thickness, yellower peel, reduced edible rate, higher pulp firmness, decreased total soluble solids (TSS), increased total acid content, and reduced total antioxidant capacity at maturity, all contributing to diminished fruit quality. Additionally, SHZ fruit accumulated higher lignin content in the pulp, leading to vesicle granulation, which severely compromised marketability. Transcriptomic analysis identified 42 structural genes involved in lignin biosynthesis in ‘Hainan Qingyou’ pulp, including 5 PAL, 2 C4H, 2 4CL, 6 CAD, 15 PER, 2 HCT, 1 C3′H, 1 CCoAOMT, 1 CCR, 1 COMT, 2 CSE, and 1 F5H genes. Most of these genes were highly expressed in SHZ fruit at maturity, with expression levels significantly higher than those in fruit grafted onto ‘Hainan Qingyou’ interstock (QYZ). The interstock also affected hormone signaling pathways. Weighted gene co-expression network analysis (WGCNA) identified transcription factors such as MYB, MIKC, ERF, and bZIP as key regulators involved in pulp lignin biosynthesis. This study provides insights into the effects of rootstocks on citrus fruit quality and offers valuable information for cultivar improvement in pomelo orchards. Full article

Wendan pomelo (Citrus maxima), valued for its unique quality and high nutritional value, is susceptible to postharvest decay caused by mechanical damage and fungal infection. This study developed a bio-based preservation strategy by incorporating Bacillus subtilis (B. subtilis) into a sodium alginate (SA)-based coating. An antagonistic B. subtilis strain, isolated from the pomelo growth environment, demonstrated effective inhibition against the pathogenic fungi P. digitatum and P. italicum. The B. subtilis/SA (2.0%) coating maintained high bacterial viability without adversely affecting the viscosity, gas barrier properties, or mechanical strength of the film. The application of the B. subtilis/SA coating significantly delayed fruit appearance deterioration, pulp softening, and decay in pomelo. Furthermore, the treatment enhanced flavonoid accumulation and increased the activity of antioxidant enzymes, thereby maintaining quality and extending storage life to 90 d. This study provides an effective bio-preservation strategy for the postharvest management of pomelo. Full article

Objectives: In response to the high prevalence of global obesity and associated metabolic diseases, this study aimed to investigate the effects of Pickering emulsions stabilized by cellulase-hydrolyzed pomelo peel insoluble dietary fiber (IDF), namely EPI and its octenyl succinic anhydride (OSA)-modified form (OSA-EPI), on alleviating high-fat diet (HFD)-induced metabolic disorders in mice. Methods: Male C57BL/6J mice were subjected to an HFD-induced obesity model. Biochemical index determination, histopathological examination, gut microbiota analysis, and short-chain fatty acids (SCFAs) analysis were used to study the potential efficacy of pomelo peel IDF-based emulsion (EPI and OSA-EPI) in alleviating obesity and related metabolic diseases. Results: The findings demonstrated that both emulsions effectively mitigated HFD-induced health impairments: reduced weight gain, improved blood glucose and lipid profiles, attenuated tissue steatosis and inflammation, and lowered oxidative stress. Furthermore, both EPI and OSA-EPI restored gut microbiota diversity, promoted the proliferation of beneficial bacterial taxa (e.g., Akkermansia), and inhibited the growth of harmful genera (e.g., Muribaculum, Faecalibaculum). These changes were accompanied by increased production of SCFAs. Conclusions: This study confirms that modified pomelo peel IDF can effectively exert the health intervention effect of IDF on obesity when used as an emulsion stabilizer, providing a robust scientific foundation for the application of emulsified dietary fibers in combating obesity and related metabolic disorders. Full article

Carbon (C), nitrogen (N) and phosphorus (P), and non-structural carbohydrates (NSCs) are basic nutrients and energy sources for flower development. In this study, the morphological traits, C, N, P, and NSC concentrations, and C:N:P ratios in pistil, stamen, and petal of C. maxima flower at three phenophases (BBCH54, BBCH59, and BBCH61) were comparatively analyzed. Morphology diverged markedly among the three phenophases, whereas relative water contents were stable. C, N, P, and NSC showed larger variations at three phenophases and parts in C. maxima flower. Maximal C:N, C:P, and N:P occurred in pistils, pistils, and petals at BBCH61, respectively. C:N:P stoichiometry was the most responsive to ontogeny, indicating development-specific elemental storage and biomass partitioning of C. maxima flowers. NSC contents (glucose, fructose, sucrose, starch) differed significantly among organs and phenophases, and peak NSC appeared in the pistils at the three phenophases. High correlations between NSCs and C:N:P ratios suggested coordinated resource allocation. Correlation analysis showed that significant differences occurred at three phenophases for the accumulation and allocation of C, N, P, and NSCs. Principal component analysis (PCA) ordinated samples along PC-1 (44.2%) and PC-2 (24.4%), cumulatively explaining 68.6% of variance, corroborating development- and organ-dependent divergence. These data elucidated the intricate regulatory dynamics of nutrient contents among the three parts during the flower development of C. maxima, providing a robust quantitative framework for targeted nutrient management strategies. Full article

Naringin and pectin were innovatively and sequentially extracted from naturally dropped fruit of pomelo (NDFP), optimizing yields via response surface methodology (RSM). Under optimized conditions, naringin was extracted first with 70% ethanol (70 °C, 110 min, SSR 15:1 v/w), followed by pectin extraction from the residue using pH 1.50 acetic acid (80 °C, 160 min, ratio 40:1 v/w) naringin yield reached 42.77% with 97.6% ± 0.31% HPLC purity, while pectin yield was 14.32%. Critically, the recovered pectin was identified as low-ester and exhibited significantly superior antioxidant activity compared to commercial pectin. This work establishes an efficient sequential extraction process valorizing waste pomelo drop, yielding high-purity naringin and antioxidant-rich, low-ester pectin. Full article

To solve the issue of environmental noise pollution and promote the resource recycling of waste pomelo peel, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) are used to systematically characterize the microstructure and chemical composition of waste pomelo peel. It was found that waste pomelo peel has a porous network structure, which is conducive to the improvement of sound absorption performance. Waste pomelo peel/polycaprolactone (PCL) sound-absorbing composites are prepared by the hot-pressing molding process, and the single-factor analysis method is adopted to explore the effects of seven factors (waste pomelo peel mass fraction, composite density, composite thickness, hot-pressing time, hot-pressing pressure, hot-pressing temperature, and thickness of rear air layer) on the sound absorption performance. Through process optimization, under the optimal conditions, the average sound absorption coefficient (SAC) of the composites reaches 0.54, the noise reduction coefficient (NRC) reaches 0.57, and the maximum SAC reaches 0.99, with the sound absorption performance reaching Grade III. This study not only provides a new idea for the preparation of porous sound-absorbing composites but also opens a new path for the high-value utilization of waste pomelo peel resources. Full article