Maturation Process, Nutritional Profile, Bioactivities and Utilisation in Food Products of Red Pitaya Fruits: A Review

Physical-Chemical Characterization of Fruit Harvested at Different Maturity Stages of Grafted Yellow Pitahaya (Selenicereus megalanthus Haw.)

The physicochemical properties of fruits at different maturity stages using grafting technology are of great importance since grafting can alter the nutritional and functional parameters of the fruit. In this study, grafted yellow pitahaya (Selenicereus megalanthus Haw.) fruit, grown on live tutors, was evaluated from stages 0 to 5. The following response variables were recorded: fruit weight, diameter, and length; pulp weight with seed and peel; color; firmness; total soluble solids content; titratable acidity; pH; total flavonoid content; total polyphenol content; and antioxidant activity determined using FRAP and ABTS. The results show that fruits harvested from grafted plants have better physical characteristics such as fruit weight, diameter, and length. However, the total soluble solids content and titratable acidity were similar in fruits from grafted and ungrafted plants. The highest content of total polyphenols, flavonoids, and antioxidant activity determined by ABTS and FRAP were found in fruits at maturity stage 0, and the content decreased as the fruits ripened. A positive correlation was found between the total polyphenol content, total flavonoid content, and antioxidant capacity with protein content. The S. megalanthus grafting technique is a promising technology for sustainable production because it reduces pesticide use by combatting soil pathogens and not modifying fruit quality.

Fates of bioactive compounds and antioxidant activities of red pitaya pulp upon in vitro gastrointestinal digestion

Health benefit effects of bioactive compounds depend on their bioavailabilities, which could vary according to factors including food matrix and digestion environment. To understand the "bioaccessible" health benefit of red pitay pulp, the INFOGEST static in vitro simulation of gastrointestinal (GI) digestion model and targeted metabolomics method were applied to unravel the fates of bioactive compounds in the whole food of red pitaya pulp during GI digestion. The antioxidant activity as one of the health benefit indices was also assessed to compare the changes in bioactive properties of red pitaya pulp. Results showed that, after GI digestion, total phenolic and flavonoid content increased by 84% and 4.55 folds, respectively. But total betacyanin content decreased. All the detected phenolic acids increased during the GI process, and lots of new phenolic compounds were produced. The overall chemical antioxidant capacity of red pitaya pulp increased after GI digestion. Correlation analysis results indicated that flavonoids and ferulic acid were probably the primary sources of the antioxidant capacity of the red pitaya pulp and its digests. Moreover, the cytoprotective effects against H2O2-induced oxidative damage varied among gastric cell, enterocyte and hepatocyte. The GI digests of red pitaya pulp could better alleviate the H2O2-induced oxidative stress in cells by preventing the increase of reactive oxygen species (ROS), inhibiting the production of malondialdehyde (MDA), increasing the production of glutathione (GSH), and promoting the activities of catalase (CAT) and superoxide dismutase (SOD). These findings can be used as a basis for future studies in the design and production of functional ingredients/foods.

Genetic Analyses of Flower, Fruit, and Stem Traits of Intergeneric Hybrids Between 'Honghuagqinglong' and 'Heilong' Pitayas

Pitaya is renowned for its delicious taste, high nutritional value, and economic as well as ornamental appeal. Breeding new pitaya varieties can boost economic returns by appealing to consumers with diverse morphological traits. However, the genetic basis underlying key traits in intergeneric hybrids of pitaya has yet to be fully understood. This study investigates the genetic dynamics in flower, fruit, and stem traits, including segregation patterns and a mixed inheritance model for major and polygenic traits, in an intergeneric hybridization between 'Honghuagqinglong' (HHQL) (Hylocereus stenopterus) and 'Heilong' (HL) (Selenicereus grandiflorus). The study identified normal or skewed, normal distribution patterns in seven floral, fifteen fruit, and five stem traits, indicating their quantitative nature governed by multiple genes. Specifically, flower size and color exhibited a hereditary bias towards 'HL' characteristics, while 'HHQL' significantly influenced the coloration of fruit peel and pulp. Fruit weight and total soluble solids (TSS) content decreased, whereas stem traits exhibited broader and thicker dimensions with fewer thorns. This study offers valuable insights into genetic variation and the influence of major genes on flower, fruit, and stem traits between 'HHQL' and 'HL' intergeneric hybrids, providing a useful reference for parental selection in pitaya breeding programs.

Nutritional Value and Therapeutic Benefits of Dragon Fruit: A Comprehensive Review with Implications for Establishing Australian Industry Standards

Dragon fruit, which is native to northern South America and Mexico, has become a significant crop in tropical and subtropical regions worldwide, including Vietnam, China, and Australia. The fruit (Hylocereus spp.) is rich in various bioactive phytochemical compounds, including phenolic acids, flavonoids, and pigments such as betalains and anthocyanins, which contribute to its antioxidant, anti-inflammatory, and anti-microbial properties. This comprehensive review introduces the origin, classification, and global production of dragon fruit, with a particular focus on its bioactive phytochemicals and therapeutic potential. Additionally, it critically evaluates the current industry standards for fresh dragon fruit production across key producing countries. While these standards primarily focus on quality, classification, and grading criteria, they lack focus on parameters related to the fruit's bioactive content. The absence of established quality standards for fresh produce in the Australian dragon fruit industry presents a unique opportunity to develop guidelines that align with both international benchmarks and the therapeutic potential of the fruit. By addressing this gap, this review can potentially help Australia to position its dragon fruit industry to achieve greater consistency, competitiveness, and consumer appeal. As the demand for functional foods continues to rise, aligning Australian production practices with global standards becomes critical to meeting domestic market expectations. This review provides a comprehensive understanding of dragon fruit's nutritional and therapeutic significance and highlights its potential role in establishing a robust standard for the Australian dragon fruit industry. A review of global industry standards reveled that Australian standard could incorporate classifications of dragon fruits, including external factors like appearance, size, and defect tolerance. Future research is needed to prioritize understanding of the impact of cultivation practices and environmental factors on the bioactive composition of dragon fruit, enabling the development of best practices for growers. Additionally, further studies are needed to evaluate the therapeutic effects of these bioactive properties through clinical trials, particularly their potential in preventing chronic diseases. The advancement of analytical methods for quantifying bioactive compounds will provide deeper insights into their health benefits and support the establishment of bioactive-oriented industry standards. Moreover, investigations of post-harvest handling and processing techniques could optimize the preservation of these valuable compounds, enhancing dragon fruit's role as a functional food.

Phytochemicals and Functional Properties of Pitaya Juice Powders

BACKGROUND

Crassulacean acid metabolism plants, such as Stenocereus spp., are climate warming-resilient crops used as food and for by-products elaboration in arid and semi-arid agroecosystems. A few studies on secondary metabolites have been conducted in pitayo fruit (PF), but there are no reports of these compounds in juice powders (JP) with (JPS) or without seeds (JPWS). This study was devoted to characterizing the juice powders (JPS and JPWS) of five pitayas with different flesh colors with regard to some phytochemical and functional attributes.

METHODS

The study was conducted with a completely random design with factorial arrangement in treatments (PF × JP).

RESULTS

Differences among pitayas were related to peel and flesh color attributes. Except for soluble dietary fiber, the remainder of the non-digestible carbohydrates were greater in JPS than in JPWS of all pitayas. Phenols and flavonoids were found to be the highest in the JPWS of all pitayas, whereas total saponins were the highest in JPS of the 'Pink' pitaya. The JPWS of the 'Yellow' and 'Reddish-Purple' pitayas had the highest content of betaxanthins and indicaxanthins, respectively. Antioxidant capacity was the highest in JPS of 'Reddish-Purple' and 'Pink' pitayas.

CONCLUSIONS

Except for some phenolic compounds, the study suggests that pitayas' JPS would benefit human health when freshly consumed or as elaborated by-products.

Lacticaseibacillus casei- and Bifidobacterium breve-fermented red pitaya promotes beneficial microbial proliferation in the colon

Red pitaya has been demonstrated to strongly inhibit α-glucosidase activity; however, the impact of red pitaya fermentation by probiotic bacteria on α-glucosidase inhibition remains unclear. In this study, six strains of lactic acid bacteria (Lactiplantibacillus plantarum, Lacticaseibacillus rhamnosus, Lactobacillus bulgaricus, Lacticaseibacillus casei, Lactobacillus acidophilus and Streptococcus thermophilus) and one strain of Bifidobacterium breve were utilized for the fermentation of red pitaya pulp. The α-glucosidase and α-amylase inhibition rates of red pitaya pulp were significantly greater after fermentation by Bifidobacterium breve and Lacticaseibacillus casei than by the other abovementioned strains. The LC group exhibited an α-glucosidase inhibition rate of 99%, with an α-amylase inhibition rate of 89.91%. In contrast, the BB group exhibited an α-glucosidase inhibition rate of 95.28%, accompanied by an α-amylase inhibition rate of 95.28%. Moreover, red pitaya pulp fermented with Bifidobacterium breve and Lacticaseibacillus casei produced a notable quantity of oligosaccharides, which was more than three times greater than that in the other groups. Furthermore, 16S rRNA high-throughput sequencing analysis was conducted to assess alterations in the composition of the gut microbiota. This revealed an increase in the abundance of Lactobacillus and Faecalibacterium in the pulp fermented by Bifidobacterium breve and Lacticaseibacillus casei, whereas the abundance of Sutterella decreased. Further analysis at the species level revealed that Bifidobacterium longum, Faecalibacterium prausnitzii, and Lactobacillus zeae were the dominant strains present during colonic fermentation. These results indicate a beneficial health trend associated with probiotic bacterial fermentation of red pitaya pulp, which is highly important for the development of functional products.

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.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-024-05940-2.

HPLC-ESI/MS-MS metabolic profiling of white pitaya fruit and cytotoxic potential against cervical cancer: Comparative studies, synergistic effects, and molecular mechanistic approaches

Natural approach became a high demand for the prevention and treatment of such diseases for their proven safety and efficacy. This study is aimed to perform comparative phytochemical analysis of white pitaya (Hylocereus undatus) peel, pulp and seed extracts via determination of total flavonoid content, phenolic content, and antioxidant capacity, coupled with HPLC-ESI/MS-MS analysis. Further, we evaluated the synergistic cytotoxic potential with Cisplatin against cervical cancer cells with investigation of underlying mechanism. The highest content of phenolics and antioxidants were found in both seed and peel extracts. The HPLC-ESI/MS-MS revealed identification of flavonoids, phenolic acids, anthocyanin glycosides, lignans, stilbenes, and coumarins. The cytotoxicity effects were evaluated by MTT assay against prostate, breast and cervical (HeLa) and Vero cell lines. The seed and peel extracts showed remarkable cytotoxic effect against all tested cell lines. Moreover, the selectivity index confirmed high selectivity of pitaya extracts to cancer cells and safety on normal cells. The combined therapy with Cisplatin effectively enhanced its efficacy and optimized the treatment outcomes, through the apoptotic ability of pitaya extracts in HeLa cells, as evaluated by flow cytometry. Besides, RT-PCR and western blotting analysis showed downregulation of Bcl-2 and overexpression of P53, BAX among HeLa cells treated with pitaya extracts, which eventually activated apoptosis process. Thus, pitaya extract could be used as adjuvant therapy with cisplatin for treatment of cervical cancer. Furthermore, in-vivo extensive studies on the seed and peel extracts, and their compounds are recommended to gain more clarification about the required dose, and side effects.

Comparative analysis of nutrient composition and antioxidant activity in three dragon fruit cultivars

Dragon fruit has significant economic value in many countries due to has excellent nutritional content, health advantages, and adaptability to different climates, making it an important crop in the global fruit industry. This study aimed to gather comprehensive nutritional data on three dragon fruit cultivars by analysing the levels of micronutrients, fibre, carbohydrates, antioxidants, vitamins, and minerals in their pulps. Uniform dragon fruit samples underwent thorough analysis for proximate composition, mineral content, pigments, antioxidants, and vitamin C, with statistical methods used to assess significant differences among the parameters studied. The proximate composition analysis revealed significant differences among the three dragon fruit cultivars. Among the proximate components, protein (0.40 ± 0.02 g/100 g), moisture (91.33 ± 0.88%), crude fibre (0.32 ± 0.07 g/100 g), and ash (1.27 ± 0.09 g/100 g) were more abundant in Hylocereus costaricensis than in Hylocereus undatus and Hylocereus megalanthus. On the other hand, Hylocereus undatus had higher carbohydrate (17.02 ± 0.63 g/100 g) and energy (69.74 ± 2.44 kcal/100 g) contents. K (7.23 ± 0.35 mg/100 g), Ca (1.61 ± 0.13 mg/100 g), Fe (1.84 ± 0.05 mg/100 g), and Zn (0.37 ± 0.034 mg/100 g) are highly abundant in H. costaricensis. Additionally, Hylocereus costaricensis had the highest anthocyanin content (120.15 ± 3.29 mg/g FW) and total carotenoid content (72.51 ± 1.62 mg/g FW), along with the highest vitamin C content (8.92 ± 0.13 mg/g FW) and total soluble phenolic content (572.48 ± 20.77 mg/100 g). Its remarkable antioxidant activity was further highlighted by the lowest SC50 value (13.50 ± 0.4 mg/mL) for its DPPH radical scavenging capacity. The total soluble sugar content was highest in Hylocereus megalanthus (8.72 ± 0.30 g/100 g FW). Hierarchical clustering analysis revealed distinct trait and genotype associations; among the studied cultivars, Hylocereus costaricensis demonstrated superior performance across multiple traits. Correlation analysis indicated significant positive correlations among several traits, while principal component analysis highlighted the contribution of each trait to overall variance, with PC1 explaining 73.95% of the total variance. This study highlights the nutritional variations among dragon fruit cultivars, with Hylocereus costaricensis showing superior performance, guiding dietary planning and functional food development.

Optimizing germination: comparative assessment of various growth media on dragon fruit germination and early growth

Dragon fruit (Selenicereus undatus), known for its captivating appearance and remarkable nutritional profile, has garnered considerable attention in recent years. Despite its popularity, there's a dearth of research on optimal conditions for seed germination and early growth stages such as seedling shoot length, which are crucial for optimal crop yield. This study aims to bridge this gap by evaluating various growing media's performance on dragon fruit germination and early growth stages. Dragon fruit seeds were obtained from local markets in Pakistan and evaluated in five different growing media: cocopeat, peat moss, sand, vermiculite, and compost. Germination parameters were observed for 45 days, including seed germination percentage, mean germination time, and mean daily germination percentage, among others while early growth was monitored for 240 days. Statistical analysis was conducted using ANOVA and Tukey's HSD test. Significant differences were found among the growing media regarding germination percentage, mean germination time, and mean daily germination. Vermiculite exhibited the highest germination rate (93.33%), while compost showed the least (70%). Peat moss and sand media facilitated rapid germination, while compost showed slower rates. Stem length was significantly influenced by the growth media, with compost supporting the longest stems. Vermiculite emerged as the most effective medium for dragon fruit seed germination, while compost showed slower but steady growth. These findings provide valuable insights for optimizing dragon fruit cultivation, aiding commercial growers and enthusiasts in achieving higher yields and quality. Further research could explore additional factors influencing dragon fruit growth and development.

Integrated metabolic profiles and microbial communities to reveal the beneficial effect of red pitaya on early constipation

Pitaya is a well-known fruit widely cultivated in tropical and subtropical tropical regions, and is characterized by its flesh colour into red, white, and yellow pitaya. Red pitaya has dark red flesh and is the preferred choice among consumers due to its superior taste compared to other varieties. Red pitaya has been known to cause diarrhoea, and studies have reported that pitaya does this by drawing moisture into the intestines, resulting in defecation. However, the exact mechanism of action is still unclear. In this study, mass spectrometry was employed to identify small molecular compounds in red pitaya powder, and a loperamide hydrochloride-induced early constipation mouse model was used to assess the efficacy of red pitaya. 16S rDNA and non-targeted metabolomics techniques were used to systematically reveal the regulatory characteristics of the intestinal flora and to identify the intestinal metabolites associated with constipation. The results showed that 44 novel small molecular compounds were identified from red pitaya powder, including a variety of phenolic acids and flavonoids. Pathological results showed that administration of red pitaya powder at a high dose (1000 mg kg-1) significantly ameliorated the abnormal expansion of intestinal goblet cells observed in the early stages of constipation. In addition, early constipation increased metabolites such as serotonin and 5-hydroxytryptophol, which were normalized following the ingestion of red pitaya powder. Furthermore, Erysipelatoclostridium, Parasutterella, and other abnormal gut microbiota associated with early constipation returned to healthy levels after the ingestion of red pitaya powder. Finally, significant correlations were observed between the expression of 33 different serum metabolites and the abundance of eight kinds of intestinal flora. Consequently, red pitaya holds potential as a safe food supplement for the prevention or amelioration of early-stage constipation.

Preharvest Elicitors as a Tool to Enhance Bioactive Compounds and Quality of Both Peel and Pulp of Yellow Pitahaya (Selenicereus megalanthus Haw.) at Harvest and during Postharvest Storage

Yellow pitahaya is a tropical fruit that has gained popularity in recent years. Natural elicitors are compounds that can stimulate the resistance and quality of fruits. The objective of this study was to evaluate the effects of natural elicitors, methyl salicylate (MeSa), methyl jasmonate (JaMe), salicylic acid (SA) and oxalic acid (OA) at concentrations of 0.1 mM (MeSa and JaMe) and 5 mM (SA and OA), applied to the yellow pitahaya fruits under greenhouse conditions. After full blossom, four applications were made with a frequency of 15 days. At the time of harvest and after storage, the following variables were evaluated: firmness (whole fruit), total soluble solids (TSS), total acidity (TA), phenolics and carotenoids (in the pulp), while phenolics, carotenoids, macronutrients and micronutrients were determined in the peel. The results showed MeSa advanced the fruit maturation, according to higher TSS, lower TA and firmness than MeJa-treated fruits, for which a delayed ripening process was shown. All treatments induced a higher polyphenolic concentration during storage. Regarding the alternative use of the peel as a by-product, the application of natural elicitors significantly increased the content of polyphenols, carotenoids, macronutrients and micronutrients in the peel, especially MeSa, which can be used as a bioactive compound in the food industry. In conclusion, the results indicate that natural elicitors can be an alternative to improve the quality and shelf life of yellow pitahaya fruits.

How Rhizosphere Microbial Assemblage Is Influenced by Dragon Fruits with White and Red Flesh

The synthesis of betalain using microorganisms is an innovative developmental technology, and the excavation of microorganisms closely related to betalain can provide certain theoretical and technical support to this technology. In this study, the characteristics of soil microbial community structures and their functions in the rhizospheres of white-fleshed dragon fruit (Hylocereus undatus) and red-fleshed dragon fruit (Hylocereus polyrhizus) were analyzed. The results show that the soil bacterial and fungal compositions in the rhizospheres were shaped differently between H. undatus and H. polyrhizus. Bacterial genera such as Kribbella and TM7a were the unique dominant soil bacterial genera in the rhizospheres of H. undatus, whereas Bradyrhizobium was the unique dominant soil bacterial genus in the rhizospheres of H. polyrhizus. Additionally, Myrothecium was the unique dominant soil fungal genus in the rhizospheres of H. polyrhizus, whereas Apiotrichum and Arachniotus were the unique dominant soil fungal genera in the rhizospheres of H. undatus. Moreover, TM7a, Novibacillus, Cupriavidus, Mesorhizobium, Trechispora, Madurella, Cercophora, and Polyschema were significantly enriched in the rhizospheres of H. undatus, whereas Penicillium, Blastobotrys, Phialemonium, Marasmius, and Pseudogymnoascus were significantly enriched in the rhizospheres of H. polyrhizus. Furthermore, the relative abundances of Ascomycota and Penicillium were significantly higher in the rhizospheres of H. polyrhizus than in those of H. undatus.

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.

Enhancing betacyanin stability: Comparison of dragon fruit (Hylocereus polyrhizus) pulp and peel powders through encapsulation technology during storage

Betacyanin can be found in the peel or pulp of dragon fruit. As a natural pigment, betacyanin is unstable, so it requires encapsulation technology to maintain its quality. The stability of encapsulated betacyanin from dragon fruit peel compared to dragon fruit pulp has yet to be discovered. This study aims to compare the stability of encapsulated betacyanin (with maltodextrin and gum Arabic) from dragon fruit peel and pulp dried with vacuum drying. Dragon fruit peel extraction utilized a 50% aqueous ethanol solvent, while pulp juice extraction was performed. The ratio of dragon fruit extract to coating materials was set at 1:3 (solid/solid). Research shows that dragon fruit juice powder had higher stability and phytochemical concentrations than the ethanol extract of dragon fruit peel powder during 30 days of storage. Despite similar color stability (similar range value of ΔE), the color from dragon fruit juice powder more closely resembled the natural fruit, albeit with weaker antioxidant activity than the peel powder. Betacyanin concentration in juice powder was notably higher (82.56-156.82 μg/g) than in the ethanol extract of dragon fruit peel powder (52.51-75.12 μg/g). A combination of maltodextrin and Arabic gum (1:1) as coating materials demonstrated the highest concentrations of total phenolic and total betacyanin (81.15-95.87 mg/g and 121.91-156.82 μg/g, respectively) during the storage period. These findings contribute to our comprehension of betacyanin stability and functionality, facilitating precise applications in industrial processing environments based on their source attributes.

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-β-D-galactose-6-O-a-L-rhamnose]-β-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.

Comparative Analysis of Physicochemical and Functional Properties of Pectin from Extracted Dragon Fruit Waste by Different Techniques

Dragon fruit peel, often discarded, is a valuable source of commercial pectin. This study investigates different extraction methods, including cold-water (CW), hot-water (HW), ultrasound (US), and novel enzyme extraction (xylanase: EZX), to extract pectins from dragon fruit peel and compare their characteristics. The pectin yield ranged from 10.93% to 20.22%, with significant variations in physicochemical properties across methods (p < 0.05). FTIR analysis revealed that extraction methods did not alter the primary structural configuration of the pectins. However, molecular weights (Mws) varied significantly, from 0.84 to 1.21 × 103 kDa, and the degree of esterification varied from 46.82% to 51.79% (p < 0.05). Monosaccharide analysis identified both homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) pectic configurations in all pectins, predominantly comprising galacturonic acid (77.21-83.12 %mol) and rhamnose (8.11-9.51 %mol), alongside minor side-chain sugars. These properties significantly influenced pectin functionalities. In the aqueous state, a higher Mw impacted viscosity and emulsification performance, while a lower Mw enhanced antioxidant activities and promoted the prebiotic function of pectin (Lactis brevies growth). This study highlights the impact of extraction methods on dragon fruit peel pectin functionalities and their structure-function relationship, providing valuable insights into predicting dragon fruit peel's potential as a food-grade ingredient in various products.

Improving red pitaya fruit quality by nano-selenium biofortification to enhance phenylpropanoid and betalain biosynthesis

Red pitaya, the representative tropical and subtropical fruit, is vulnerable to quality deterioration due to climate or agronomic measures. Nano-selenium (Nano-Se) has shown positive effects on crop biofortification in favour of reversing this situation. In this study, Se could be enriched efficiently in red pitayas via root and foliar application by Nano-Se, which induced higher phenolic acids (16.9-94.2%), total phenols (15.7%), total flavonoids (29.5%) and betacyanins (34.1%) accumulation in flesh. Richer antioxidative features including activities of SOD (25.2%), CAT (33.8%), POD (77.2%), and levels of AsA (25.7%) and DPPH (14.7%) were obtained in Nano-Se-treated pitayas as well as in their 4-8 days shelf-life. The non-targeted metabolomics indicated a boost in amino acids, resulting in the stimulation of phenylpropanoid and betalain biosynthesis. In conclusion, the mechanism of Nano-Se biofortification for red pitaya might be fortifying pigment, as well as the enzymatic and non-enzymatic antioxidant substances formation by regulating primary and secondary metabolism facilitated by Se accumulation.

Nutrition Value of Baked Meat Products Fortified with Lyophilized Dragon Fruit (Hylocereus undatus)

This study evaluates the nutritional value of a baked pork meat product containing lyophilized dragon fruit pulp. The selected nutritional properties of a baked pork meat product fortified with lyophilized Hylocereus undatus pulp in doses of 0.5%, 1.5%, 2.5%, and 4% were evaluated. For this assessment, changes in the basic chemical composition of the products, the content of calcium, magnesium, potassium, iron, and phosphorus, and the profile of fatty acids were considered. Additionally, characteristics typical for meat products, such as pH, water activity, oxidation-reduction potential or thiobarbituric acid reactive substances, and antioxidant properties of the product during 21 days of refrigerated storage, were assessed. The findings indicate that the use of higher doses of lyophilizate, i.e., in the amounts of 2.5% and 4%, significantly (p < 0.05) increases the nutritional value of meat products, leading to an increase in the concentration of essential minerals important for the proper functioning of the human body (calcium, magnesium, potassium, and iron). These changes occurred without affecting the basic chemical composition (except for an increase in the content of fat and carbohydrates in the sample with the addition of 4% lyophilizate). The introduction of the fortification treatment improved the fatty acid profile, resulting in an increase in the content of C14:0, C16:0, C20:0, and C20:5n3. In addition, in the variant with a 4% dosage, there was an increased content of C8:0, C10:0, C16:1n7, C18:0, C18:1n9C + C18:1n9t, and C18:2n6C + C18:2n6t, C18:3n3 (alpha), C20:1n15, and C20:1n9. In this particular variant, an increase in saturated-, monounsaturated-, and polyunsaturated fatty acids was also observed, which was associated with an increased level of TBARS in meat products. However, the increase in the dose of lyophilizate caused an increase in the antiradical effect of meat extracts. Based on the results obtained, it seems reasonable to use a plant additive in the form of lyophilized dragon fruit pulp in the amount of 4.0% in the production of pork meat products.

Pitaya as a New Alternative Crop for Iberian Peninsula: Biology and Edaphoclimatic Requirements

Pitaya is one of the fruit species whose demand has increased in recent years due to the numerous health benefits and lucrative price of the fruit and its by-products. In Europe, the Iberian Peninsula and other Mediterranean countries are the ones with favorable climatic conditions for its cultivation. This document describes much of the history of pitaya in the Iberian Peninsula and the difficulties related to its cultivation. A bibliographical survey was carried out on the culture of pitaya in the world, focusing on the edaphoclimatic requirements, and on the possibility of this becoming a consolidated crop in the Iberian Peninsula. The relatively low water requirement of pitaya makes this crop sustainable among crops that require irrigation. In addition, we provide a perspective for use and research of this emerging crop. There has been an exponential growth of scientific publications on pitaya in the last decade; however, much more needs to be researched to know how to increase productivity as well as the sensory quality of fruits in different regions. This sustainable crop is a good option to diversify fruit production in the Iberian Peninsula.

Anti-Inflammatory, Antioxidant, and Other Health Effects of Dragon Fruit and Potential Delivery Systems for Its Bioactive Compounds

Dragon fruit (Hylocereus genus) has the potential for the prevention of diseases associated with inflammatory and oxidative processes. We aimed to comprehensively review dragon fruit health effects, economic importance, and possible use in delivery systems. Pubmed, Embase, and Google Scholar were searched, and PRISMA (Preferred Reporting Items for a Systematic Review and Meta-Analysis) guidelines were followed. Studies have shown that pitaya can exert several benefits in conditions such as diabetes, dyslipidemia, metabolic syndrome, cardiovascular diseases, and cancer due to the presence of bioactive compounds that may include vitamins, potassium, betacyanin, p-coumaric acid, vanillic acid, and gallic acid. Moreover, pitaya has the potential to be used in food and nutraceutical products as functional ingredients, natural colorants, ecologically correct and active packaging, edible films, preparation of photoprotective products, and additives. Besides the importance of dragon fruit as a source of bioactive compounds, the bioavailability is low. The development of delivery systems such as gold nanoparticles with these compounds can be an alternative to reach target tissues.

A review on the gastrointestinal protective effects of tropical fruit polyphenols

Tropical fruits are popular because of their unique, delicious flavors and good nutritional value. Polyphenols are considered to be the main bioactive ingredients in tropical fruits, and these exert a series of beneficial effects on the human gastrointestinal tract that can enhance intestinal health and prevent intestinal diseases. Moreover, they are distinct from the polyphenols in fruits grown in other geographical zones. Thus, the comprehensive effects of polyphenols in tropical fruits on gut health warrant in-depth review. This article reviews, first, the biological characteristics of several representative tropical fruits, including mango, avocado, noni, cashew apple, passion fruit and lychee; second, the types and content of the main polyphenols in these tropical fruits; third, the effects of each of these fruit polyphenols on gastrointestinal health; and, fourth, the protective mechanism of polyphenols. Polyphenols and their metabolites play a crucial role in the regulation of the gut microbiota, increasing intestinal barrier function, reducing oxidative stress, inhibiting the secretion of inflammatory factors and regulating immune function. Thus, review highlights the value of tropical fruits, highlighting their significance for future research on their applications as functional foods that are oriented to gastrointestinal protection.

Betacyanins and Anthocyanins in Pulp and Peel of Red Pitaya (Hylocereus polyrhizus cv. Jindu), Inhibition of Oxidative Stress, Lipid Reducing, and Cytotoxic Effects

This study aimed to promote red pitaya fruit parts as alternate sources of nutraceuticals. The red pitaya of Chinese origin was determined for its in vitro efficacy, where the fruit extracts were evaluated based on the selected antioxidative properties, lipid-reducing capacity, and cytotoxicity. The betanin, total betacyanins, total anthocyanins, and DPPH radical scavenging activity of the red pitaya pulp and peel extracts were determined by spectrophotometric analyses. Cell culture assays were used to examine in vitro efficacy and cytotoxicity of the pitaya extracts. The result showed that red pitaya peel extract had a higher total betacyanins and total anthocyanins content than the pulp extract, but the peel extract had a lower DPPH radical scavenging effect than the pulp extract. The red pitaya extracts also had a protective effect in reducing oxidative stress, especially the peel extract. All fruit samples had a low anticancer potential except for betanin and anthocyanin standards. The protective effect of pitaya peel could be attributed to betacyanins and anthocyanins. Both pulp and peel extracts had a weak anticancer effect because these extracts contained polysaccharides and other phytochemicals that were not cytotoxic. As the peel extract of red pitaya was not cytotoxic, it is a potent source of betacyanins for reducing oxidative stress.

Identification of Allergens in White- and Red-Fleshed Pitaya (Selenicereus undatus and Selenicereus costaricensis) Seeds Using Bottom-Up Proteomics Coupled with Immunoinformatics

White-fleshed pitaya (Selenicereus undatus) and red-fleshed pitaya (Selenicereus costaricensis) are becoming increasingly popular because of their nutritional and medicinal benefits. However, in addition to their beneficial properties, allergy to pitaya fruits has occurred in daily life. In this study, we investigated the protein profile of pitaya fruit seeds and focused on the most reactive proteins against immunoglobulin E (IgE) in sera from allergic patients by immunoblotting. A protein band of approximately 20 kDa displayed a clear reaction with the serum IgE. The protein bands of interest were excised, in-gel digested, and analyzed using liquid chromatography–tandem mass spectrometry (LC–MS/MS), followed by data searching against a restricted database (Caryophyllales in UniProtKB) for protein identification. Immunoinformatic tools were used to predict protein allergenicity. The potential allergens included cupin_1 and heat shock protein 70 (HSP70) in white-fleshed pitaya seeds, and cupin_1, heat shock protein 70, and heat shock protein sti1-like in red-fleshed pitaya seeds are potential allergens. The expression of potential allergens was further verified at the transcriptional level in the species of S. undatus and S. costaricensis.

Nutritional Analysis of Red-Purple and White-Fleshed Pitaya (Hylocereus) Species

Pitaya is one of the most preferred and produced tropical fruit species recently introduced to the Mediterrranean region in Turkey. Due to its nutritional fruits with high economic value, the popularity of pitaya increases steadily in Turkey as an alternative crop. No detailed nutritional analysis has been undertaken in Turkey so far on fruits of the pitaya species. In this study, we determined and compared some nutritional parameters in fruit flesh of two pitaya (dragon fruit) species (Hylocereus polyrhizus: Siyam and Hylocereus undatus: Vietnam Jaina) grown in the Adana province located in the eastern Mediterranean region in Turkey. The individual sugars, antioxidant activity, total phenolic content, phenolic compounds and volatiles were determined for the first time in Turkey on two pitaya species. The results showed that total phenol content and antioxidant capacity are notably higher in red-fleshed fruits than white-fleshed ones and the predominant phenolic compound in fruits of both species was quercetin. The total sugar content and most of the phenolic compounds in fruits of two pitaya species were similar. A total of 51 volatile compounds were detected by using two Solid Phase Micro Extraction (SPME) fibers, coupled with Gas Chromatography Mass Spectrometry (GC-MS) techniques, and more volatile compounds were presented in the white-fleshed species. Total phenolic content (TPC) of the red-fleshed and white-fleshed pitaya species were 16.66 and 17.11 mg GAE/100 g FW (fresh weight). This study provides a first look at the biochemical comparison of red-fleshed and white-fleshed pitaya species introduced and cultivated in Turkey. The results also showed, for the first time, the biochemical content and the potential health benefit of Hylocereus grown in different agroecological conditions, providing important information for pitaya researchers and application perspective.