Altitudinal variation of dragon fruit metabolite profiles as revealed by UPLC-MS/MS-based widely targeted metabolomics analysis.

BACKGROUND: Geographical factors affect the nutritional, therapeutic and commercial values of fruits. Dragon fruit (Hylocereus spp) is a popular fruit in Asia and a potential functional food with diverse pharmacological attributes. Although it is produced in various localities, the information related to the altitudinal variation of dragon fruit nutrients and active compounds is scarce. Hence, this study aimed to investigate the variations in metabolite profiles of H. polyrhizus (variety Jindu1) fruit pulps from three different altitudes of China, including Wangmo (WM, 650 m), Luodian (LD, 420 m), and Zhenning (ZN, 356 m). Jindu1 is the main cultivated pitaya variety in Guizhou province, China. RESULTS: The LC-MS (liquid chromatography-mass spectroscopy)-based widely targeted metabolic profiling identified 645 metabolites, of which flavonoids (22.64%), lipids (13.80%), phenolic acids (12.40%), amino acids and derivatives (10.39%), alkaloids (8.84%), and organic acids (8.37%) were dominant. Multivariate analyses unveiled that the metabolite profiles of the fruit differed regarding the altitude. Fruits from WM (highest altitude) were prime in quality, with higher levels of flavonoids, alkaloids, nucleotides and derivatives, amino acids and derivatives, and vitamins. Fruits from LD and ZN had the highest relative content of phenolic acids and terpenoids, respectively. We identified 69 significantly differentially accumulated metabolites across the pulps of the fruits from the three locations. KEGG analysis revealed that flavone and flavonol biosynthesis and isoflavonoid biosynthesis were the most differentially regulated. It was noteworthy that most active flavonoid compounds exhibited an increasing accumulation pattern along with the increase in altitude. Vitexin and isovitexin were the major differentially accumulated flavonoids. Furthermore, we identified two potential metabolic biomarkers (vitexin and kaempferol 3-O-[2-O-ß-D-galactose-6-O-a-L-rhamnose]-ß-D-glucoside) to discriminate between dragon fruits from different geographical origins. CONCLUSION: Our findings provide insights into metabolic changes in dragon fruits grown at different altitudes. Furthermore, they show that growing pitaya at high altitudes can produce fruit with higher levels of bioactive compounds, particularly flavonoids.

First Report of Colletotrichum aenigma Causing Anthracnose on Dragon Fruit in Korea.

Dragon fruit (Selenicereus undatus) is a valuable fruit crop in tropical and subtropical regions. It is renowned for its nutritional benefits, such as high sodium, potassium, and vitamin levels, and as a source of prebiotics and antioxidants (Balendres et al. 2019). In July 2023, anthracnose symptoms on stems were detected on dragon fruit plants in Jeju, South Korea. The typical anthracnose symptoms, such as sunken necrotic lesions (5-20 mm in diameter), were seen on the mature stems. The disease incidence ranged from 10% to 12% among the three surveyed greenhouses. To isolate the causative organism, infected stem samples were surface sterilized, cut into small pieces, and placed on potato dextrose agar (PDA). After two days of incubation at 24ºC, white hyphae appeared on the PDA around the plant tissues. Isolates CNU H23009 and CNU H23010 were purified from a single hypha under a stereoscope (e-Xtra Figure 1). Conidial morphology was examined from two-day-old fungal cultures grown on V8 juice agar. The conidia were transparent, aseptate, cylindrical to clavate, with a rounded apex and base, and measured 11.9 - 16.85 × 5.17 - 6.91 µm (mean = 15.28 × 5.93 µm, n = 30). No appressoria was observed. Morphological characteristics indicated the isolates were Colletotrichum sp. matching the description of the C. gloeosporioides species complex (Weir et al. 2012). To further identify the isolates, genomic DNA was extracted and the ribosomal internal transcribed spacer (ITS) region, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and actin (ACT) were amplified using ITS1/ITS4, GDF/GDR, and ACT-512F/ACT-783R, respectively (Weir et al. 2012). Based on phylogenetic analysis, the isolates clustered with C. aenigma (strains ICMP18608, ICMP18686, CSH2, and QSG1), with 71% bootstrap support, as determined using the maximum parsimony method in PAUP 4.0 (e-Xtra Figure 2). Based on morphological and molecular characteristics, isolates were identified as C. aenigma. Sequences of CNU H23009 and CNU H23010 were deposited in GenBank with accession numbers OR535144 and OR535145 for ITS, OR540725 and OR540726 for GAPDH, and OR540723 and OR540724 for ACT. The pathogenicity was tested on healthy dragon fruit stems using wound inoculation with mycelial plugs of the CNU H23009 isolate. Controls were inoculated with PDA plugs. The plants were covered with plastic bags to maintain humidity and incubated in a greenhouse at 25ºC. After two days, necrotic spots had developed on the inoculated tissues; after four days, black, irregular, and sunken necrotic lesions similar to those seen in the field were observed. No symptoms occurred in the controls. C. aenigma was re-isolated from the artificially inoculated plants and re-identified based on conidial morphology. The pathogenicity test was repeated three times with three replications for each treatment. Previous studies have reported that C. aenigma, C. gloeosoporioides, C. siamense, C. truncatum, and C. karsti cause anthracnose in dragon fruit. However, C. aenigma has been reported only in Thailand (Balendres et al. 2019; Meetum et al. 2015). To our knowledge, this is the first report of C. aenigma causing anthracnose in dragon fruit in Korea.

First Report of Gray Mold Caused by Botrytis cinerea on Dragon Fruit (Hylocereus undatus) in Mexico.

The dragon fruit is native of Mexico, and Puebla is the third-largest producing state (SIAP 2023). In June 2023, field sampling was conducted in El Paraíso, Atlixco (18° 49' 5.275" N, 98° 26' 52.353" W), Puebla, Mexico. The mean temperature and relative humidity were 20 °C and 75% for seven consecutive days. Dragon fruits cv. 'Delight' close to harvest with gray mold symptoms were found in a commercial area of 2 ha, with an incidence of 35 to 40% and an estimated severity of 75% on infected fruit. The symptoms included necrosis at the apex, which later spread throughout the fruit, along with a soft, black rot covered in abundant mycelium and sporulation. The fungus was isolated from 40 symptomatic fruits by disinfesting pieces of necrotic tissue with 3% NaClO for one minute, rinsing with sterile distilled water (SDW), plating on Petri dishes with potato dextrose agar, and incubating at 25 °C in the dark. One isolate was obtained from each diseased fruit by the hyphal-tip method. The colonies were initially white with a growth rate of 1.15-1.32 cm per day and turned gray after 10 days; the mycelium was dense and aerial. Spherical and irregular sclerotia were formed, measuring 0.9-1.4 × 0.6-1.1 mm (n = 100). Each Petri dish produced 56-278 sclerotia (n = 40) after 11 days; these were initially white and gradually turned dark brown. Brown to olive conidiophores were straight, septate, and branched, measuring 1075-1520 × 10-21 µm, with elliptical hyaline to light brown conidia of 6.6-11.5 × 5-8.1 µm (n=100). The isolates were tentatively identified as Botrytis cinerea based on morphological characteristics (Ellis 1971). Two representative isolates were chosen for molecular identification and genomic DNA was extracted by the CTAB protocol. The ITS region and the heat shock protein (HSP60), RNA polymerase binding II (RPB2) and glyceraldehyde 3-phosphate dehydrogenase (G3PDH) genes were sequenced (White et al. 1990; Staats et al. 2005). The sequences of a representative isolate (BcPh5) were deposited in GenBank (ITS-OR582337; HSP60-OR636622; RPB2-OR636623; and G3PDH-OR636621). BLAST analysis of the partial sequences of ITS (479 bp), HSP60 (1006 bp), RPB2 (1126 bp), and G3PDH (907 bp) showed 100% similarity to B. cinerea isolates (GenBank: KM840848, MH796663, MK919495, MF480679). Phylogenetic analysis confirmed that BcPh5 clustered with B. cinerea strains. Pathogenicity was confirmed by inoculating the non-wounded surface of 20 detached dragon fruits cv. 'Delight' using the BcPh5 isolate by depositing 20 µl of a 105 conidia/ml suspension with a sterile syringe. The fruits were placed on the rim of a plastic container and inserted in a moisture box with 2 cm of water at the bottom. The box was covered with a plastic sheet to maintain humidity. Control fruits were inoculated with SDW. The inoculated fruits became covered with abundant white to gray mycelium, and soft rot developed within eight days, while no symptoms were observed on the controls. The fungus was re-isolated from the inoculated fruits as described above, fulfilling Koch's postulates. The pathogenicity tests were repeated three times. Gray mold caused by B. cinerea was also recently reported in Mexico on pomegranate (Hernández et al. 2023) and rose apple (Isodoro et al. 2023). As far as we know, this is the first report of B. cinerea causing gray mold on dragon fruit in Mexico. This research is essential for designing integrated management strategies against gray mold on dragon fruits.

Neoscytalidium dimidiatum causing stem canker on Hylocereus megalanthus in China.

Hylocereus megalanthus (syn. Selenecereus megalanthus), commonly known as Yanwo fruit (bird's nest fruit), is an important tropical fruit, which is popular and widely planted due to its high nutritional and economic value in southern China. In September 2022, a serious stem and fruit canker was observed on Ecuadorian variety of Yanwo fruit plant in a 0.2 ha orchard in Guangdong (N21°19'1.24" E110°7'28.49"). Almost all plants were infected and disease incidence of fruits and stems was about 80% and 90% respectively. Symptoms on the stem and fruits were small, circular or irregular, sunken, orangish brown spots that developed into cankers (Fig 1 A, B and C). Black pycnidia were embedded under the surface of the cankers at the initial stage, subsequently they became erumpent from the surface, and the infected parts rotted. Five symptomatic stems from five plants were collected, 0.2 cm2 tissues adjacent to cankers were surface sterilized and placed on potato dextrose agar (PDA) to incubate at 25 to 28 ℃. Fungal isolates each with similar morphology grew from 100% of the tissues. Colonies covered with aerial mycelium were grayish white, and then gradually turned to grayish black. Septate hyphae were hyaline to brown and constricted into arthroconidial chains. The arthroconidia were variously shaped and colored, orbicular to rectangular, hyaline to dark brown, thick-walled, and zero- to one- septate, averaging 7.7 × 3.6 µm (n>50) (Fig 1 D, E, F and G). To identify the fungus, the internal transcribed spacer region (ITS), translation elongation factor 1-alpha (tef1), beta-tubulin (tub2), histone H3 (his3) and chitin synthase (chs) gene of isolate ACCC 35488 and ACCC 35489 (Agricultural Culture Collection of China) were amplified and sequenced with primer pairs: ITS1/ITS4 (White et al. 1990), EF1-728F/EF2-rd (Carbone & Kohn 1999; O'Donnell et al.1998), TUB2Fd/ TUB4Rd（Aveskamp et al 2009）, CYLH3F/H3-1b (Crous et al. 2004) and CHS-79F/CHS-345R (Carbone & Kohn 1999) (ITS: OQ381102 and PP488350; tef1: OQ408545 and PP510454; tub2: OQ408546 and PP510455; his3: OQ408544 and PP510453; chs: OQ408543 and PP510452). Sequence Blastn results showed above 99% identical with those of Neoscytalidium dimidiatum ex-type strain CPC38666. Phylogenetic tree inferred from Maximum Likelihood analysis of the combined ITS, tub2 and tef1 sequences revealed two isolates clustered with N. dimidiatum (Fig 2). Pathogenicity was tested on healthy one-year-old cuttings and fruits of Ecuadorian variety at room temperature. Six sites were pin-pricked on each stem and fruit. Both wounded stems and fruits were inoculated with spore suspensions (106 spore/ml) and 6-mm fungal plugs respectively. Sterile water and agar were used as control. The test was repeated twice. Stems and fruits were enclosed in plastic boxes with 80% relative humidity. Symptoms described above were observed on inoculated stems and fruits at five days post inoculation (Fig 1 H and I). No symptoms developed on the controls. Neoscytaliudium dimidiatum was reisolated from the cankers with a frequency of 100% via morphological and molecular analysis. This is first report of stem and fruit canker caused by N. dimidiatum on H. megalanthus in China and this disease represents a serious risk of Yanwo fruit yield losses. This fungus is widespread occurring throughout the world causing diseases on a wide variety of plants. The finding will be helpful for its prevention and control.

Flexible SERS chips for rapid on-site detection of tricyclazole pesticide in agricultural products.

A flexible, ultrasensitive, and practical SERS chip is presented based on a paper/f-TiO2/Ag structure. The chip enhances the self-assembly of Ag nanoparticles on a cellulose fiber matrix, facilitated by smart functionalized TiO2 nanomaterials (f-TiO2). This design enables superior detection of the hazardous pesticide tricyclazole (TCZ) on crops using an advanced, simple, and efficient analytical method. Despite its straightforward fabrication process via a solvent immersion method, the intrinsic smart surface properties of the TiO2 bridging material - both hydrophilic and hydrophobic - enable the uniform and dense self-assembly of hydrophilic Ag nanoparticles (NPs) on the cellulose fiber paper substrate. This innovative design provides superior sensing efficiency for TCZ molecules with a detection limit reaching 2.1 × 10-9 M, a remarkable improvement compared to Paper/Ag substrates lacking f-TiO2 nanomaterials, which register at 10-5 M. This flexible SERS substrate also exhibits very high reliability as indicated by its excellent reproducibility and repeatability with relative standard deviations (RSD) of only 5.93% and 4.73%, respectively. Characterized by flexibility and a water-attractive yet non-soluble surface, the flexible Paper/f-TiO2/Ag chips offer the convenience of direct immersion into the analytical sample, facilitating seamless target molecule collection while circumventing interference signals. Termed the "dip and dry" technique, its advantages in field analysis are indisputable, boasting in situ deployment, simplicity, and high efficiency, while minimizing interference signals to negligible levels. Through the application of this advanced technique, we have successfully detected TCZ in two high-value crops, ST25 rice and dragon fruit, achieving excellent recovery values ranging from 90 to 128%. This underscores its immense potential in ensuring food quality and safety. As a proof of concept, flexible Paper/f-TiO2/Ag SERS chips, with a simple fabrication process, advanced analytical technique, and superior sensing efficiency, bring SERS one step closer to field applications beyond the laboratory.

YOLOv8-G: An Improved YOLOv8 Model for Major Disease Detection in Dragon Fruit Stems.

Dragon fruit stem disease significantly affects both the quality and yield of dragon fruit. Therefore, there is an urgent need for an efficient, high-precision intelligent detection method to address the challenge of disease detection. To address the limitations of traditional methods, including slow detection and weak micro-integration capability, this paper proposes an improved YOLOv8-G algorithm. The algorithm reduces computational redundancy by introducing the C2f-Faster module. The loss function was modified to the structured intersection over union (SIoU), and the coordinate attention (CA) and content-aware reorganization feature extraction (CARAFE) modules were incorporated. These enhancements increased the model's stability and improved its accuracy in recognizing small targets. Experimental results showed that the YOLOv8-G algorithm achieved a mean average precision (mAP) of 83.1% and mAP50:95 of 48.3%, representing improvements of 3.3% and 2.3%, respectively, compared to the original model. The model size and floating point operations per second (FLOPS) were reduced to 4.9 MB and 6.9 G, respectively, indicating reductions of 20% and 14.8%. The improved model achieves higher accuracy in disease detection while maintaining a lighter weight, serving as a valuable reference for researchers in the field of dragon fruit stem disease detection.

Enhancing productivity and sustainability of ravine lands through horti-silviculture and soil moisture conservation: A pathway to land degradation neutrality.

Ravine lands are the worst type of land degradation affecting soil quality and biodiversity. Crop production in such lands is impossible without adopting proper conservation measures. In-situ moisture conservation techniques could play an instrumental role in restoring ravine lands by improving soil moisture. We hypothesized that restoring ravine land through a combination of tree planting, fruit crop cultivation, and in-situ moisture conservation practice would result in significant improvements in productivity, profitability, and soil fertility. An experiment was conducted involving the combination of Malabar Neem (Melia dubia) and Dragon fruit (Hylocereus undatus) in conjunction with in-situ soil moisture conservation measures specifically involving half-moon structures (HM). The experiment was conducted under randomized block design (RBD) comprising eight treatments. These treatments include sole Melia cultivation (MD 3m × 3m), sole cultivation of dragon fruit (DF 3m × 3m), silviculture system (MDF-3m × 3m), horti-silviculture system with larger spacing (MDF-4m × 4m), sole Melia cultivation with in-situ moisture conservation (MDH-3m × 3m), sole Dragon fruit cultivation with in-situ moisture conservation (DFH-3m × 3m), horti-silviculture system of Melia and Dragon fruit with in-situ moisture conservation (MDFH-3m × 3m), and horti-silviculture system with larger spacing and in-situ moisture conservation (MDFH-4m × 4m). Each treatment was replicated thrice to evaluate their impact on productivity, profitability, soil fertility, and carbon sequestration for 8 years (2016-2023). The results revealed that the horti-silviculture system (MDFH-3 × 3 m) exhibited the highest total tree biomass and total carbon sequestration with an increase of 183.2% and 82.8% respectively, compared to sole Melia cultivation without HM and sole Melia with HM. Furthermore, sole Melia with HM augmented soil nutrients (N, P, K, and SOC) by 74.4%, 66.4%, 35.2%, and 78.3%, respectively, compared to control (no planting), with performance at par with MDFH-3 × 3 m. Similarly, sole Melia with HM enhanced SOC stock and SOC sequestration rate by 79.2% and 248% over control. However, it was found at par with MDFH-3 × 3 m. The horti-silviculture system (MDFH-3 × 3 m) consistently produced the highest fruit yield throughout the years surpassing other treatments. This treatment increased the average dragon fruit yield by 115.3% compared to sole dragon fruit without HM. Hence, the adoption of the horti-silviculture system (MDFH-3 × 3 m) could be a promising strategy for achieving enhanced environmental and economic benefits in ravine lands. Therefore, dragon fruit based horti-silviculture system (MDFH-3 × 3 m) could be recommended for restoration of ravine lands, improving land productivity, and mitigating impact of soil erosion particularly in Western India or similar agro-climatic regions of the world.

Pitahaya (Hylocereus ocamponis)-Peel and -Flesh Flour Obtained from Fruit Co-Products-Assessment of Chemical, Techno-Functional and In Vitro Antioxidant Properties.

The aim of this work was to assess the chemical composition and physico-chemical, techno-functional, and in vitro antioxidant properties of flours obtained from the peel and flesh of pitahaya (Hylocereus ocamponis) to determine their potential for use as ingredients for food enrichment. The chemical composition, including total betalains, mineral content, and polyphenolic profile, was determined. The techno-functional properties (water holding, oil holding, and swelling capacities) were also evaluated. For the antioxidant capacity, four different methodologies, namely ferrous ion-chelating ability assay, ferric-reducing antioxidant power assay; 1,1-Diphenyl-2-picrylhydrazyl radical scavenging ability assay, and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical assay, were used. Pitahaya-peel flour had higher values for protein (6.72 g/100 g), ash (11.63 g/100 g), and dietary fiber 56.56 g/100 g) than pitahaya-flesh flour, with values of 6.06, 3.63, and 8.22 g/100 g for protein, ash, and dietary fiber, respectively. In the same way, pitahaya peel showed a higher content of minerals, betalains, and polyphenolic compounds than pitahaya-flesh flour, with potassium (4.43 g/100 g), catechin (25.85 mg/g), quercetin-3-rhamnoside (11.66 mg/g) and myricetrin (12.10 mg/g) as principal compounds found in the peel. Again, pitahaya-peel flour showed better techno-functional and antioxidant properties than pitahaya-flesh flour. The results obtained suggest that the flours obtained from the peel and pulp of pitahaya (H. ocamponis) constitute a potential material to be utilized as an ingredient in the food industry due to the high content of bioactive compounds such as betalains, phenolic acids, and flavonoids, with notable antioxidant capacity.

Supercritical extraction of betalains from the peel of different pitaya species.

BACKGROUND: Pitaya is a fruit with high consumer acceptance and health benefits. Pitaya peel is a waste product with potential in the food industry, as an antioxidant enrichment and natural colouring. Therefore, there is an interest in recovering its constituents and searching for pitaya species with greater potential. This work aimed to obtain bioactive extracts from the dried peel of pitaya fruits of the species Selenicereus monacanthus (Lem.), S. costaricensis W. and S. undatus H. using supercritical fluids at different pressures (100, 250 and 400 bar) and ethanol-water 15% v/v or ethanol 100% as co-solvents. The extraction yield, antioxidant activity, colour and total betalain content were evaluated. RESULTS: The extract obtained from S. monacanthus showed the highest extraction yield (49.6 g kg-1), followed by S. costaricensis (27.5 g kg-1) and S. undatus (17.7 g kg-1) at 400 bar and 35 °C using ethanol 15%, v/v. The antioxidant capacity was strongly influenced by pressure, favouring the obtaining of betalain-rich extracts at higher pressures, especially in the species S. costaricensis (0.6 g kg-1) and S. monacanthus (0.3 g kg-1). To improve the extraction of S. undatus (the most cultivated species), the procedure of subsequential extractions was applied. This procedure considerably increased the extraction yield, antioxidant activity and total content of betalains. The use of ethanol 100% provided more bioactive fractions and achieved a good separation of betalains. CONCLUSION: The supercritical extraction method can overcome the challenge of efficiently extracting compounds from pitaya peel, due to the presence of bioactive compounds of great polarity. © 2024 Society of Chemical Industry.

Uncovering Potentially Therapeutic Phytochemicals, In silico Analysis, and Biological Assessment of South-Chinese Red Dragon Fruit (Hylocereus polyrhizus).

Red dragon fruit is gaining popularity globally due to its nutritional value and bioactive components. The study aimed to assess the phytochemical, nutritional composition, antioxidant, antibacterial, and cytotoxic properties of extracts from the South Chinese red dragon fruit peel, flesh, and seeds. Extract fractions with increasing polarity (ethyl acetate

Comparative omics-based characterization, phylogeny and melatonin-mediated expression analyses of GDSL genes in pitaya (Selenicereus undatus L.) against multifactorial abiotic stresses.

The GDSL gene family plays diverse roles in plant growth and development. Despite its significance, the functions of the GDSL in the pitaya plant are still unknown. Pitaya (Selenicereus undatus L.) also called Hylocereus undatus (Hu), belongs to the family Cactaceae and is an important tropical plant that contains high dietary fibers and antioxidants. In the present investigation, we screened 91 HuGDSL genes in the pitaya genome by conducting a comprehensive computational analysis. The phylogenetic tree categorized HuGDSL genes into 9 distinct clades in combination with four other species. Further, 29 duplicate events were identified of which 12 were tandem, and 17 were segmental. The synteny analysis revealed that segmental duplication was more prominent than tandem duplication among these genes. The majority of duplicated gene pairs (95%) indicate their Ka/Ks ratios ranging from 0.1 to 0.3, which shows that maximum HuGDSL genes were under purifying selection pressure. The cis-acting element in the promotor region contains phytohormones such as auxin, gibberellin, jasmonic acid, and abscisic acid abundantly. Finally, the HuGDSL gene expression pattern under single and multiple stresses was analyzed via; RNA-seq. We select ten stress-responsive HuGDSL genes for RT-qPCR validation. After careful investigation, we identified five HuGDSL candidate genes (HuGDSL-1/3/55/59, and HuGDSL-78) based on RNA-seq, and RT-qPCR data that showed enhanced expression in stress and melatonin-applied seedlings. This study represents valuable insights into maintaining pitaya growth and development by preparing stress-resilient pitaya genotypes through modern biotechnological techniques. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-024-01506-w.

Red dragon fruit-soy protein isolate biofilm: UV-blocking, antioxidant & improved mechanical properties for sustainable food packaging.

In this study, an active biofilm was developed by incorporating red dragon fruit peel (RDF) extract into soy protein isolate (SPI) film matrix for sustainable food packaging. The addition of betalain-rich-RDF extract (1-7 wt%) significantly improved UV-blocking and antioxidant properties of the film compared to the control film. As wt% of RDF-extract increased, water vapor permeability, water solubility, and elongation at break decreased by 1.06 × 10-10 g m m-2 s-1 Pa-1, 34.25%, and 133.25%, respectively. On the other hand, Tensile strength increased significantly (P < 0.05) by 78.76%. FTIR results confirmed the intermolecular interaction between RDF extract and SPI through hydrogen bonding, while XRD result showed a decrease in the crystallinity degree of the film with RDF extract addition. However, no significant change in the TGA curve between extract-incorporated SPI films was observed. SEM analysis revealed that SPI B and SPI D films had a more compact and denser structure than the control film, while AFM analysis showed an increase in Ra and Rq values representing higher surface roughness of SPI D film. SPI D film also significantly (P < 0.05) decreased the weight loss and increased total soluble solids of freshly cut apples over 7-day storage period. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-024-05940-2.

Valorization of dragon fruit waste to value-added bioproducts and formulations: A review.

Owing to the increasing worldwide population explosion, managing waste generated from the food sector has become a cross-cutting issue globally, leading to environmental, economic, and social issues. Circular economy-inspired waste valorization approaches have been increasing steadily, generating new business opportunities developing valuable bioproducts using food waste, especially fruit wastes, that may have several applications in energy-food-pharma sectors. Dragon fruit waste is one such waste resource, which is rich in several value-added chemicals and oils, and can be a renewable resource to produce several value-added compounds of potential applications in different industries. Pretreatment and extraction processes in biorefineries are important strategies for recovering value-added biomolecules. There are different methods of valorization, including green extractions and biological conversion approaches. However, microbe-based conversion is one of the advanced technologies for valorizing dragon fruit waste into bioethanol, bioactive products, pharmaceuticals, and other valued products by reusing or recycling them. This state-of-the-art review briefly overviews the dragon fruit waste management strategies and advanced eco-friendly and cost-effective valorization technologies. Furthermore, various applications of different valuable bioactive components obtained from dragon fruit waste have been critically discussed concerning various industrial sectors. Several industrial sectors, such as food, pharmaceuticals, and biofuels, have been critically reviewed in detail.

Carboxylate-functionalized dragon fruit peel powder as an effective adsorbent for the removal of Rhodamine B (cationic dye) from aqueous solution: adsorption behavior and mechanism.

In this study, we used a simple and low-toxicity chemical treatment to make a carboxylate-functionalized dragon fruit peel powder (CF-DFPP) from dragon fruit peel to improve its capacity for adsorbing Rhodamine B (RhB) from an aqueous medium. Field Emission-Scanning Electron Microscopy/Energy-Dispersive X-ray (FE-SEM/EDX), point of zero charges (pHPZC), Brunauer-Emmett-Teller (BET), and Fourier Transform Infrared (FT-IR) analyses were performed to characterize the adsorbent materials. The adsorption performance and mechanism for the removal of RhB were examined. The kinetic, isotherm and thermodynamic parameters were employed to evaluate the adsorption mechanism. Compared to other models, the Langmuir isotherm and PSO kinetic models better defined the experimental data. CF-DFPP adsorbent exhibited a maximum adsorption efficiency of 228.7 mg/g at 298 K for RhB adsorption. Thermodynamic analysis revealed that the adsorption of RhB by CF-DFPP was spontaneous (ΔGo < 0) and exothermic (ΔHo < 0) nature of the process. Different eluting agents were used in desorption tests, and NaOH was revealed to have greater desorption efficiency (96.8%). Furthermore, regeneration examinations revealed that the biosorbent could effectively retain RhB, even after six adsorption/desorption cycles. These findings demonstrated that the CF-DFPP might be a novel material for removing RhB from an aqueous medium.

A Dragon Fruit Picking Detection Method Based on YOLOv7 and PSP-Ellipse.

Dragon fruit is one of the most popular fruits in China and Southeast Asia. It, however, is mainly picked manually, imposing high labor intensity on farmers. The hard branches and complex postures of dragon fruit make it difficult to achieve automated picking. For picking dragon fruits with diverse postures, this paper proposes a new dragon fruit detection method, not only to identify and locate the dragon fruit, but also to detect the endpoints that are at the head and root of the dragon fruit, which can provide more visual information for the dragon fruit picking robot. First, YOLOv7 is used to locate and classify the dragon fruit. Then, we propose a PSP-Ellipse method to further detect the endpoints of the dragon fruit, including dragon fruit segmentation via PSPNet, endpoints positioning via an ellipse fitting algorithm and endpoints classification via ResNet. To test the proposed method, some experiments are conducted. In dragon fruit detection, the precision, recall and average precision of YOLOv7 are 0.844, 0.924 and 0.932, respectively. YOLOv7 also performs better compared with some other models. In dragon fruit segmentation, the segmentation performance of PSPNet on dragon fruit is better than some other commonly used semantic segmentation models, with the segmentation precision, recall and mean intersection over union being 0.959, 0.943 and 0.906, respectively. In endpoints detection, the distance error and angle error of endpoints positioning based on ellipse fitting are 39.8 pixels and 4.3°, and the classification accuracy of endpoints based on ResNet is 0.92. The proposed PSP-Ellipse method makes a great improvement compared with two kinds of keypoint regression method based on ResNet and UNet. Orchard picking experiments verified that the method proposed in this paper is effective. The detection method proposed in this paper not only promotes the progress of the automatic picking of dragon fruit, but it also provides a reference for other fruit detection.

First Report of the Association of Zygocactus virus X with Dragon Fruit (Hylocereus spp.) plants from Telangana, India.

Dragon fruit (Hylocereus spp.) a member of the family Cactaceae, is widely cultivated throughout the world, includingspan style="font-family:'Times New Roman'; letter-spacing:0.05pt; color:#333333"> India. During 2020-2021 crop growing season, mosaic symptoms were observed on the cladodes of dragon fruit plants (Purple Pink cultivar: 1-2% disease incidence) grown at a farmer's field of Telangana, India (Fig. S1 a). The symptomatic cladodes (n= 4), observed under leaf-dip electron microscopy (Zuchmaan and Zellnig, 2009) at Indian Agricultural Research Institute, New Delhi, revealed the presence of flexuous rod- shaped virus-like particles (Fig S1 b). Virus particles were of 580 x 13 nm size, corresponding to the genus Potexvirus. For further confirmation, the total RNA isolated from symptomatic cladodes using a NucleoSpin RNA Plant Mini kit (Macherey-Nagel). Subsequently, a reverse transcription polymerase chain reaction (RT-PCR) was performed using the PrimeScript 1st strand cDNA Synthesis Kit (Takara Bio). The cDNA was further amplified with the primers specific to coat protein (CP) gene of four different species of the genus Potexvirus known to infect members of Cactaceae family. Four sets of primers were used for detection, viz., Cactus virus X (CVX) (F, 5'-ATGTCTACTACTGGAGTCCA-3'; R, 5'-CTACTCAGGGCCTGGGAGAA-3'); Pitaya virus X (PiVX) (F, 5'-ATGGCTACTCAAACAGCACAA-3'; R, 5'-CTACTCTGGGGAGGGAAG-3'); Schlumbergera virus X (SchVX) (F, 5'-ATGTCGACCACTCCATCTTC-3'; R, 5'-TTATTCAGGGGATGGTAGTA-3') and Zygocactus virus X (ZyVX) (F, 5'-ATGTCTAACACTGCAGGAGT-3'; R, TCATTC GGGACCCGGTAGGA-3') (Duarte et al., 2008; Janssen et al., 2021; Parameswari et al., 2021), by following the PCR profile (Park et al., 2018). The species-specific primers of CVX, PiVX and SchVX did not amplify any amplicon, whereas the primers specific to ZyVX at nucleotide position 5841-6521 from complete CP gene have resulted in amplification of expected size (~680 base pairs) from all the samples. The gel-purified RT-PCR products were cloned into a pDrive cloning vector (Qiagen, Germany) and sequenced bi-directionally using Sanger sequencing. The resultant sequences (681 nt) of the CP gene showed 98% (nucleotide) and 100% (amino acid) sequence similarity with the CP gene sequence (Accession No: KY581590) of ZyVX. Hence, one representative sequence was deposited to the NCBI GenBank database as ZyVX-DPC isolate (Accession number- OK415019). The Neighbour Joining Phylogenetic Tree constructed using MEGA6 software (Tamura et al. 2013) showed grouping of Indian ZyVX-DPC isolate with the previously reported ZyVX isolates from Korea, Taiwan, China and Germany (Fig. S1c). These results confirmed the association of ZyVX with the symptomatic cladodes of dragon fruit plants collected from Telangana, India. Earlier studies revealed that ZyVX is a member of the genus Potexvirus known to infect dragon fruit plants from Brazil and China (Duarte et al., 2008). In India until now, anthracnose disease (Colletotrichum siamense) and CVX from Hylocereus spp. were reported (Abirami et al., 2019; Parameswari et al., 2021). To the best of our knowledge, this is the first report of ZyVX infection on dragon fruit in India. The draon fruit, being vegetatively propagated and with increasing cultivable area in India (Abirami et al, 2019), the present study gains significance. Further studies on mode of virus transmission, estimation of crop yield losses, host range studies and finding out source of resistance are essential.

Elaboration and Characterization of Natural Deep Eutectic Solvents (NADESs): Application in the Extraction of Phenolic Compounds from pitaya.

In this paper, natural deep eutectic solvents (NADESs) with lactic acid, glycine, ammonium acetate, sodium acetate, and choline chloride were prepared with and without the addition of water. NADES formation was evaluated using FTIR and Raman, where hydrogen bonds were identified between the hydroxyl group of lactic acid and the amino and carboxyl groups of glycine. Acetate and ammonium ions were also identified as forming bonds with lactic acid. The addition of water did not cause changes in the vibrational modes of the FTIR and Raman spectra but contributed to a reduction in NADES viscosity and density. Viscosity ranged from 0.335 to 0.017 Pa s-1, and density ranged from 1.159 to 0.785 g mL-1. The best results for the extraction of phenolic compounds from pitaya (dragon fruit) were achieved with an organic solvent (450. 41 mg 100 g-1 dry bases-db) in comparison to NADESs lactic acid:glycine (193.18 mg 100 g-1 db) and lactic acid:ammonium acetate (186.08 mg 100 g-1 db). The antioxidant activity of the extracts obtained with the NADESs was not statistically different from that of the extract obtained with organic solvents.

Evaluation of a Novel Phosphorylated Red Dragon Fruit Peel Pectin for Enhancement of Thermal Stability and Functional Activity.

Red dragon fruit peel, as a fruit waste, is rich in plant-based nutritional pectins that can be applied as food additives. The present study aims to characterize a novel phosphorylated red dragon fruit peel pectin (PRDFP-P) and to explore its functional activities. The thermal analysis, morphology analysis, antibacterial, antioxidant and antitumor activities of PRDFP-P were evaluated. The results showed that the phosphorylated derivative PRDFP-P had typical phosphate groups. Compared with the native red dragon fruit peel pectin (PRDFP), PRDFP-P possessed superior thermal stability and exhibited significant inhibition effects on Escherichia coli and Staphylococcus aureus. Moreover, the phosphate groups on the derivative PRDFP-P chains remarkably enhanced the scavenging ability of hydroxyl radicals and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. In addition, PRDFP-P showed a significant inhibition effect on growth of human hepatic carcinoma cells (HepG2) and the IC50 value was determined to be 248.69 µg/mL (P < 0.05). Our results suggested that the phosphorylated derivative PRDFP-P might be potentially applied as stabilizing, thickening and gelling agents with functional activities in the food industry.

Effect of dragon fruit peel powder on quality and acceptability of fish nuggets stored in a solar cooler (5 ± 1 °C).

Fish nuggets were prepared with dragon fruit peel powder (1.0, 1.5 and 2.0% w/w) to evaluate its quality and improvement in shelf-life during 15 days storage in a prefabricated solar cooler (5 ± 1 °C). Antioxidative and antimicrobial effects of dragon fruit peel powder in fish model system were also evaluated during storage. Results showed that dragon fruit peel is a good source of dietary fibre (59.8%) and phenolic compounds [65.7 mg Gallic Acid Equivalent (GAE)/100 g of sample] and contained 6.03% protein, 6.14% fat and 4.34% ash. Use of dragon fruit peel powder significantly (p < 0.05) improved the emulsion stability and cooking yield and nuggets with peel powder had lower pH value than control. Fish nuggets with peel powder showed gradual decrease (p < 0.05) in hardness, springiness, cohesiveness, gumminess and chewiness with advancement of storage period. Nuggets with 1.5% dragon fruit peel showed better sensory attributes compared to the others. Dragon fruit peel powder significantly inhibited (p < 0.05) the lipid oxidation and microbial load in fish nuggets during the storage period. So, it can be concluded that dragon fruit peel powder may be used as antioxidant dietary fibre for improved quality and acceptability of fish nuggets in prefabricated solar cooler. 1.5% level of incorporation showed better results in terms of antioxidant activity and better shelf-life of the fish nuggets.

Water-in-Oil-in-Water Nanoemulsions Containing Temulawak (Curcuma xanthorriza Roxb) and Red Dragon Fruit (Hylocereus polyrhizus) Extracts.

Hydrophobic curcumin in temulawak extract and hydrophilic betacyanin in red dragon fruit extract are high-value bioactive compounds with extensive applications in functional food. In this study, these extracts were encapsulated in water-in-oil-in-water (w/o/w) nanoemulsions as a delivery system using a two-step high-energy emulsification method. PGPR and Span 20 were used as lipophilic emulsifiers for the primary w/o emulsion. The most stable w/o/w formulation with the least oil phase separation of 5% v/v consisted of w/o emulsion (15% w/w) and Tween 80 (1.5% w/w) as hydrophilic emulsifier. The formulation was characterized by a 189-nm mean droplet diameter, 0.16 polydispersity index, and -32 mV zeta potential. The freeze-thaw stability may be attributed to the combination of low w/o emulsion content and high Tween 80 concentration in the outer water phase of the w/o/w nanoemulsions used in this study. The IC50 values of the nanoemulsion and the red dragon fruit extract were similar. It means that the higher concentration of curcumin in the nanoemulsions and the lower IC50 value of temulawak extract ensured sufficient antioxidant activities of the w/o/w nanoemulsions.