Pitaya Peel Research Articles

Effects of Pitaya Peel Supplementation on Nutritional Quality, Overall Sensory Acceptance, In Vitro Glycemic Index, and Antioxidant Release from Fiber-Enriched Cookies

Pitaya peel is a by-product of fruit processing. In this study, the effects of pitaya peel supplementation in the cookie recipe on the nutritional quality, in vitro glycemic index, and antioxidant release from the enriched fiber cookies were investigated. The higher the ratio of pitaya peel powder (PPP) in the recipe, the greater the dietary fiber, betacyanin and phenolic contents, and antioxidant activities of the product. Cookies supplemented with 10–25% PPP were classified as having a low glycemic index, ranging from 51.9 to 45.7 in relation to glucose reference. The release of betacyanins, phenolics, and antioxidant activities from the cookie samples was recorded at the salivary, gastric, intestinal, and colon steps during in vitro sequential digestion, and the gastric digestion showed the highest release of antioxidant content and activity. The increased PPP ratio in the cookie recipe improved the antioxidant activities of the aqueous fractions at the four digestive steps. Statement. This study has a preprint entitled “Effects of the ratio of pitaya peel powder on the product quality, predicted glycemic index, and antioxidant release during in vitro sequential digestion” (DOI: https://doi.org/10.21203/rs.3.rs-2322871/v1). This preprint was posted on the research square website on December 5th, 2022.

ANTI-BACTERIAL, CYTOTOXICITY, AND ANTIOXIDANT PROPERTIES OF THE ISOLATED FLAVONOIDS EXTRACT FROM WHITE DRAGON FRUIT (HYLOCEREUS UNDATUS) PEELS AND FLESH

The presence of flavonoids in white pitaya’s flesh and peel was confirmed using the Thin Layer Chromatography Screening method. Flavonoid was extracted using solvent fractionation and then subjected to the three assays. Using the Kirby-Bauer method, better antibacterial activity against E. coli was found using 100% peel extract, partially active at 10.28 mm. The flesh flavonoid extract was inactive against both E. coli and S. aureus at concentrations of 100%, 75%, and 50%. The flavonoid peel and flesh have the potential as anticancer agents since they are active, toxic, and potent, with LC50 of less than 1000 ppm in Brine Shrimp Lethality Assay. Using a UV VIS spectrophotometer at 517 nm, both the flesh flavonoid extract and the peel flavonoid extract have antioxidant potential. However, the flesh with a percent Radical Scavenging Activity close to the catechin control is a better antioxidant. This study proved that the peel and flesh of White Pitaya, particularly its flavonoid, have medical benefits, can be a potential source of income for farmers, and decrease waste in the environment.

NiO nanocrystal anchored on pitaya peel-derived carbon laminated mesoporous composites for the electrocatalytic oxidation of ethanol

Direct ethanol fuel cell (DEFC) is a kind of energy conversion device with potential application prospect. The development of non-precious metal-based catalysts with high activity and stability is of great necessary for ethanol oxidation reaction (EOR). Here, the laminated composites with hollow structure were synthesized by a simple strategy, which consists of NiO nanocrystals anchored on pitaya peel-derived carbon (PPC). The electrochemical tests show that the optimal electrocatalyst (NiO@PPC-600) exhibits excellent catalytic activity for EOR with the current density (j) of 231.8 mA cm-2 (1.6 V vs. RHE) under alkaline conditions. Furthermore, the j retention rate (83.0%) of NiO@PPC-600 exceeds that (16.4%) of Pt/C in the long-term 12 h EOR test. The superior properties of the NiO@PPC-600 are mainly ascribed to its mesoporous structure that facilitates electrolyte and electron transfer and the PPC substrate that avoids the shedding of NiO nanocrystals, it has moderate lattice defects and graphitization, minimal contact resistance and Tafel slope. The work provides a simple route to prepare a high-efficient electrocatalyst for EOR, and the reuse of biomass pitaya peel (PP) is realized.

Novel bio-based, time-temperature dependent colorimetric ink and film containing colorants from the red pitaya (Hylocereus costaricensis)

Natural colorimetric indicators are environmentally friendly and safe alternatives to those based on synthetic materials. However, low stability limits the use of many natural colorants in commercial settings, especially at high temperatures. This study demonstrates the application of betalains extracted from the peel of red pitaya (Hylocereus costaricensis) as natural colorants in diagnostic packaging materials. Extracted betalain pigment (BP) and dye (BD) were applied to BP-based screen-printing ink (BPi) and BD-based film (BDf), respectively. The color transitions of BPi and BDf were observed at high temperatures as a function of time. BPi could be screen printed with good appearance properties. BD could be applied homogeneously to a methylcellulose thin film. Both BPi and BDf exhibited a color change from the initial pink to orange and yellow, respectively, depending on temperature and storage time. At 180 ̊C, a complete change in color was observed for both BPi (7.5 wt% BP) and BDf (7.0 pphr of BD) with ∆E of 22.03 (50 min) and 23.95 (6 min), respectively. The activation energy (Ea) of BPi and BDf were 25.8474 and 63.6420 kJ mol−1, respectively. Therefore, BPi and BDf are promising bio-based materials for the development of time-temperature dependent materials.

Betacyanins obtained from alternative novel sources as natural food colorant additives: incorporated in savory and sweet food products.

The aim of this study was to assess the performance and stability of betacyanin compounds present in enriched extracts of red-fleshed pitaya peels (Hylocereus costaricensis) and the flowers of Amaranthus caudatus; they were evaluated as natural food colorants in tagliatelle pasta and meringue cookies. The recovered natural extracts showed promising stability, maintaining a deep pink color over a storage time of 14 days, without deeply changing the chemical composition. A number of factors were assessed, including the microbial load, texture, color, nutritional value, and contents of organic acids, fatty acids, and even free sugars of the products. Some significant interactions between the type of colorant and storage time contributed to the changes in some analyzed parameters, as can be observed from the results for organic and fatty acids in the tagliatelle pasta and meringue cookies. Another significant achievement was the reduction in the microbial load during the storage time, which strengthens the antibacterial power of these natural extracts.

Development of shrimp freshness monitoring labels based on betacyanins-rich red pitaya peel and cassava starch

Development of shrimp freshness monitoring labels based on betacyanins-rich red pitaya peel and cassava starch

Partition of bioactive components from red pitaya fruit (Hylocereus polyrhizus) peels into different fractions using supercritical fluid fractionation technology

The pitaya peel powder was mixed with 50% ethanol solution at a ratio of 1:10 (w/v) for 24 h to obtain the pitaya peel ethanol extract (E). The extract was further fractionated with supercritical carbon dioxide (SC–CO2) under the operating conditions: temperature 40 °C and pressure of 30, 25, 20 or 10 MPa into R, F1, F2 or F3 fractions, respectively. Our results confirmed SC-CO2 fractionation significantly influenced the distribution of phenolic compounds, polysaccharides and betalains in fractions and thus affected their physico-chemical properties. Bioactive compounds majorly distributed in F1; consequently, DPPH and ABTS radicals scavenging activities of F1 are higher than those of other fractions. The IC50 values of DPPH and ABTS scavenging ability were 0.78 mg/mL and 0.69 mg/mL for F1 fraction, respectively. Linear structure model analysis showed that the scavenging activities of the both free radicals were positively related to phenolic compounds and polysaccharide components. The strong red-orange color spectrum of E was simultaneously fractionated into the red-orange color F1, the bright red color of F2 and F3 and the vivid orange color of R.

Strategic design of self-generated Ni-N-C hybrid sites in 3D network structures as counter electrodes in photovoltaics

The technical bottleneck of carbon materials as counter electrodes (CEs) lies in their limited electrical conductivity, extended ion diffusion paths, poor dispersion, and high contact resistance. Problem-oriented in-situ self-grown N-doped CNTs-coated Ni nanoparticles based on N-doped carbonaceous structures derived from pitaya peel (PC) are adopted to construct Ni-N-C hybrid 3D ionized network sites (Ni@NCNTs/PC-4) as CEs. Structural characterization, micromorphological and chemical composition analyses revealed the 3D network structure of Ni@NCNTs/PC-4 with abundant active sites. They effectively shorten the diffusion distance of I3− ions with a smaller charge transfer resistance (5.21 Ω) than that of PC (12.53 Ω). DSSCs based on Ni@NCNTs/PC-4 display good optoelectronic properties, in which the short-circuit current density (Jsc) is 13.27 mA/cm2, higher than those of Pt (11.66 mA/cm2) and PC (6.99 mA/cm2). The PCE value (5.13%) of DSSCs based on Ni@NCNTs/PC-4 is also higher than that of DSSCs based on PC (2.47%). Overall, this work provides a preliminary research and new ideas for further in-depth study of biomass-derived 3D structured-carbons that contribute to key electrodes in DSSCs.

Properties of pectin-based films from white-fleshed pitaya (Hylocereus undatus) peel waste as affected by montmorillonite

In this study, pectin was prepared from white-fleshed pitaya (Hylocereus undatus) peel waste to develop a novel biodegradable film, and the reinforcement effect of montmorillonite (MMT) on the films was investigated. The presence of MMT could lower the moisture sensitivity, which was reflected in the lowered moisture uptake capacity and water vapor permeability. The incorporation of MMT into the white-fleshed pitaya (Hylocereus undatus) peel pectin (WPPP) film improved the light-barrier property of WPPP films with the transmittance of ultraviolet and visible light reduced. The WPPP/MMT composite film might have a more compact structure and lower chain mobility, resulting in the improved tensile strength and decreased elongation at break when the content of MMT was 1–5 wt%. In addition, WPPP/MMT composite films demonstrated a higher thermal stability compared with the plain WPPP films. It was found that approximately 90% of the WPPP and WPPP/MMT films were degraded on the 15th days, suggesting their great biodegradability. The present study might demonstrate that pitaya peel waste pectin could become a novel film-forming polymer for edible or packaging films, and the incorporation of MMT was effective in improving the overall performance of films, as reflected by the enhanced tensile strength, thermal stability, and barrier properties to water vapor and ultraviolet as well as visible light, which might assist in the sustainable valorization of pitaya by-products.

Development and characterization of a novel active and intelligent film based on pectin and betacyanins from peel waste of pitaya (Hylocereus undatus)

In the present study, peel waste of pitaya (Hylocereus spp.) was used to develop a novel active and functional film. The film was developed with a combination of the white-fleshed pitaya peel pectin (WPPP) as a biopolymer and white-fleshed pitaya peel betacyanins (WPPB) as an active constituent, respectively. Furthermore, montmorillonite (MMT), a cheap and environmental-friendly silicate material, was introduced into film matrix as a filler to reduce the moisture sensitivity of the film. The effect of the incorporation of WPPB on the properties of WPPP/MMT films was investigated. The colorimetric response of WPPP/MMT/WPPB to pH and ammonia was examined, respectively. Moreover, WPPP/MMT/WPPB-2 was employed to monitor the freshness of shrimp. The color of the film changed from redness to reddish-brown, and further to brownness, echoing the shrimp turned from fresh to spoiled. Therefore, WPPP/MMT/WPPB-2 composite films showed promise for the applications in monitoring the freshness of shrimp.

Nitrogen doped biomass derived carbon dots as a fluorescence dual-mode sensing platform for detection of tetracyclines in biological and food samples

Nitrogen-doped carbon dots (N-CDs) were synthesized hydrothermally using abundantly accessible pitaya peel and 1,2-ethylenediamine as precursors. N-CDs exhibited favorable photostability, which can serve as a multifunctional nano-sensor for detection of three tetracycline antibiotics (TCs) based on fluorescence (FL) dual-mode sensing strategy. The FL intensity of N-CDs could be rapidly quenched by tetracycline (TC) and oxytetracycline (OTC) based on bandgap transition, inner filter effect (IFE), static quenching (SQ) and electrostatic interaction. While a new finding that FL of N-CDs demonstrated a remarkable enhancement in the presence of chlortetracycline (CTC) with the same detection mechanisms as TC and OTC, also including the aggregation-induced emission (AIE). Furthermore, an easily extensible fluorescence sensor array was developed based on multiple CDs for identifying multiple TCs in real samples. Therefore, the constructed N-CDs provides a new perspective for choosing extensive natural biomass to synthesize CDs, further developing a novel sensor to realize their versatile sensing application.

Comparative transcriptomic profiling in the pulp and peel of pitaya fruit uncovers the gene networks regulating pulp color formation.

Pitaya (genus Hylocereus) is a popular fruit. To develop pitaya fruit with greater marketability and high nutritional value, it is important to elucidate the roles of candidate genes and key metabolites that contribute to the coloration of the pitaya pulp and peel. By combining transcriptome and biochemical analyses, we compared and analyzed the dynamic changes in the peel and pulp of H. undatus (white pulp) and H. polyrhizus (red pulp) fruits at four key time points during ripening. Differential expression analysis and temporal analysis revealed the difference regulation in pathways of plant hormone signal transduction, phenylpropanoid biosynthesis, and betalain biosynthesis. Our results suggest that color formation of purple-red peel and pulp of pitaya is influenced by betalains. Increased tyrosine content and fluctuation in acylated betalain content may be responsible for pulp color formation, while some of the key genes in this network showed differential expression patterns during ripening between white pulp and red pulp fruits. The data and analysis results of this study provide theoretical basis for the red color formation mechanism of pitaya, which will facilitate future work to improve pitaya fruit physical appearance and marketability.

Propiedades estructurales, fisicoquímicas y emulsionantes de la pectina obtenida por extracción acuosa de la cascara de la pitaya roja (Hylocereus polyrhizus)

This work aimed to carry out a straightforward aqueous extraction of pectin from red pitaya peels (RPP), in a drive to promote the circular economy of the settlements where the fruit of this endemic species grows. The average pectin yield was 11.59 g/100 g dry basis, the degree of esterification was 60.35±1.35%, the galacturonic acid content was 54.36±1.03%, and the protein content of 5.86 ± 0.25%. The RPP pectin was analyzed in terms of physicochemical, functional, and structural features. The FTIR spectrum confirmed that the unveiled pectin structure was consistent with that reported for commercial pectins from different botanical sources. Pectin aqueous dispersions exhibited power-law shear thinning behaviour. Corn oil (10 mL) in 150 mL aqueous pectin solutions (0.12, 0.15, 0.30, 0.60 and 0.90%, w/v) emulsions exhibited increasing emulsifying activity and emulsifying stability with increased pectin concentration. The small It was concluded that the RPP pectin is an alternative potential new source of pectin for use in the formation and stabilization of oil-in-water food emulsions.

Pengaruh Jenis Pelarut dan Waktu Ekstraksi Pada Metode Microwave Assisted Extraction Terhadap Karakteristik Pewarna Ekstrak Kulit Buah Naga Kuning (Selenicereus megalanthus)


 
 
 This study aimed to determine the effect of the type of solvent and extraction time using the extraction method of Microwave Assisted Extraction (MAE) on the pigment characteristics of the yellow pitaya peel extract and to find the right type of solvent and extraction time to produce yellow pitaya peel extract with the best colorant characteristics. The research design used was a randomized block design with 2 factors. First factor was type of solvent (ethanol, ethyl acetate, and n-hexane). Second factor in extraction time of MAE (6,8, and 10 minutes). The treatment was repeated twice to get 18 experimental units. The data were analyzed statistically using the variance test and if the treatment had a significant effect to observed variables, it was continued with Duncan's Multiple Range Test. The results showed that the interaction of the type of solvent and extraction time had a very significant effect (P<0.01) on yield, total carotenoids, total suspended solids (TSS), L *, a *, b * values, total phenolic, antioxidant activity, and IC50. The best treatment was found in n-hexane and 10 minutes extraction time with characteristics yield 10.00%, total carotenoids 33.40 mg/g, total dissolved solids 19.54%, the brightness (L*) 41.25, redness (a*) 19.86, yellowness (b*) 53.87, total phenolic 3.09 mg GAE/g, antioxidant activity 65.97%, and IC50 777.773 ppm.
 
 

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.

Development of real-time intelligent films from red pitaya peel and its application in monitoring the freshness of pork.

Red pitaya peel (RPP) is a good source of polysaccharides, which can be used in the production of biodegradable material. Betacyanins in it possess antioxidant and pH-sensitive properties. However, RPP is commonly discarded during fruit processing. This study aimed to develop real-time intelligent film using RPP to evaluate pork freshness. Real-time intelligent films were developed with film-forming substrates (FFS) composed of 60-100% (w/w) RPP and 0-4% (v/w) glycerol in pH4.3 ~ 8.0. Rheology tests revealed that the FFS exhibited shear-thinning behavior. Fourier-transform infrared (FTIR) analysis showed that molecules in the RPP interacted with glycerol and formed hydrogen bonds. It showed that the film developed with FFS of 80% RPP and 2% (v/w) glycerol had strong molecular interaction, dense structure, and optimal tensile strength and elongation at break. Film with pH adjusted to 7.0 had greater sensitivity to ammonia than film that was prepared at an original pH of4.3, so this film was used to monitor freshness of pork. A visible change in the color of the film was observed during the spoiling process of pork, which correlated with the accumulated total volatile base nitrogen. Based on its sensitivity to ammonia, the film made of 80% (w/w) RPP and 2% (v/w) glycerol at pH7.0 was recommended for use in monitoring the freshness of protein-rich food. Our findings are of great significance for ensuring meat quality and safety and for reducing food waste. © 2022 Society of Chemical Industry.

Selective adsorption and recovery of scandium from red mud leachate by using phosphoric acid pre-treated pitaya peel biochar

In recent years, the global demand for scandium has increased due to its essential role in the high-technology industry. Red mud leachates constitute a significant source of scandium and an efficient and environmentally friendly approach that attracted considerable interest. In this study, H3PO4 activated biochar (P40s) is manufactured from pitaya peel (PP) as a novel material to be used for scandium adsorption and recovery from red mud leachates. The material was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption isotherms, X-ray photoelectron spectroscopy (XRF), zeta potential, and element analysis (such as C, H, O, N and P) to characterize adsorbents. The results indicated that the phosphorus-containing functional groups were successfully introduced to improve the physicochemical properties of biochar. The pseudo-second-order kinetic model and Freundlich isotherm fit experimental data, verifying that the scandium adsorption by activated biochar is dominated by chemisorption and belongs to multilayer sorption. The maximal adsorption capacity of 750 °C calcinated H3PO4 activated biochar (P40-750) was 20.77 mg/g. Notably, the adsorbent was better for selective recovery of Sc3+ from Al3+, Fe3+, Dy3+, Y3+ coexistence ions. The separation coefficients (SF) of scandium for aluminum, iron, dysprosium, and yttrium are 137.03, 27.04, 77.74, and 208.25 times respectively, at pH3. Importantly, scandium is efficiently extracted from the leaching solution of red mud with an 83% recovery rate. Meanwhile, P40-750 exhibited a stable scandium adsorption capacity after 5 adsorption/desorption cycles. Overall, P40-750 could be considered a low-cost and environment-friendly biosorbent for recovering scandium from red mud leaching solution.

Preparation, physicochemical characteristics and bioactivity evaluation of pitaya peel extract/soy protein nanocomposite film containing zinc oxide nanoparticles by photocatalysis

Interactions between components in film-forming solution affected the physicochemical properties of active packaging. A series of soy protein isolate (SPI)-based nanocomposite films reinforced with zinc oxide nanoparticles and different pitaya peel extract (PPE) levels were fabricated by photocatalysis. Results showed that the tensile strength, oxygen and water vapor barrier properties, thermal stability and DPPH scavenging activity were substantially improved, but the elongation at break and transmittance decreased with the proportion of PPE increased due to the formation of a more compact film structure caused by the crosslinking of PPE and SPI, particularly at the SPI/PPE ratio of 1:2. However, excessive PPE was not conducive to the integrity and continuity of film structures. The SPI/PPE films had more favorable anti-bacterial activities against Staphylococcus aureus than Vibrio parahaemolyticus. Therefore, our finding suggested that photocatalytic SPI/PPE nanocomposite film is an interesting alternative to obtain materials with antimicrobial and antioxidant properties. Novelty impact statement Pitaya peel extract (PPE) was added into soy protein isolate (SPI)/ZnO film matrix through photocatalysis. Addition of PPE resulted in compact inner microstructures of the films. SPI-PPE conjugate greatly improved the antibacterial and antioxidant properties of the films.

Preparation of activated carbons from fruit residues for the removal of naproxen (NPX): Analytical interpretation via statistical physical model

In this work, physical statistical models were employed to provide reasonable information regarding the adsorption of naproxen onto different activated carbons. The activated carbons were prepared from different biomasses (pitaya peels, jabuticaba peels, or grape residues from the winery process) using ZnCl2 as an activator. All the adsorbents were characterized regarding their functional groups and morphological surfaces. The maximum capacity obtained for the activated carbons (at 328 K) was found to be: 167.0 mg g−1 for jabuticaba peels at pH 4; 158.81 mg g−1 for pitaya peels at pH 6.7; and last., grape residues the capacity was 176.0 mg g−1 at pH 7. The equilibrium data of the three adsorbents were well fitted to the monolayer with two energy sites adsorption model, assuming that NPX adsorption on the carbon surfaces occurs via two different functional groups. This statistical physics model calculated the number of NPX molecules bound on the surface and the saturated adsorption capacity for both functional groups at different temperatures. The obtained results indicate that the naproxen molecules can be adsorbed in a parallel and horizontal manner according to the material employed. The receptor density tends to increase with the temperature evolution, indicating that thermal energy and solubility play an important role in adsorption. Configurational entropy indicates similar thermodynamic behavior for all materials where higher disorder is found at the early stages of the adsorption, followed by and decrease a possible organization of the molecules on the surface. The Gibbs free energy shows that adsorption of naproxen is spontaneous in all cases and internal energy is proportional to the adsorption capacity indicating that the system releases energy as the adsorption occurs. Therefore, this article reports new findings to understand the adsorption mechanism of naproxen molecules on activated carbons prepared from lignocellulosic biomass.

Pitaya peel extract and lemon seed essential oil as effective sodium nitrite replacement in cured mutton

This study aimed to assess the effects of partial substitution of sodium nitrite with different combinations of pitaya peel (PP) and lemon seed essential oil (LSO) extract as antioxidants on the quality of cured mutton. The lipid oxidation, volatile basic nitrogen, sensory evaluation, and total viable count of cured mutton were determined. The results of the quality evaluation of cured mutton indicated that the L*, a*, and sensory evaluation values were significantly higher in the T9 group than in the T2 group (P < 0.05), and the pH, shear force, and lipid oxidation (TBARS value) were significantly lower in the T9 group (P < 0.05) than in the T2 group. The TBARS value, total volatile basic nitrogen, shear force, and total viable count were significantly lower in the T9 group than in the T7 and T8 groups (P < 0.05). In addition, the T2 group had the lowest values of total volatile basic nitrogen and total viable count compared with the other treatment groups. The results demonstrated that the application of LSO and PP extracts to replace nitrite partially could achieve the preservation of mutton and reduce the use of nitrite in the curing process.