White Pitaya Research Articles

Nutrition, phytochemical profiling, in vitro biological activities, and in silico studies of South Chinese white pitaya (Hylocereus undatus)

BackgroundWhite pitaya, a popular tropical fruit, is known for its high nutritional value. It is commercially cultivated worldwide for its potential use in the food and pharmaceutical industries. This study aims to assess the nutritional and phytochemical contents and biological potential of the South Chinese White Pitaya (SCWP) peel, flesh, and seed extracts. MethodsExtract fractions with increasing polarity (ethyl acetate < acetone < ethanol < methanol < aqueous) were prepared. Antibacterial potential was tested against multidrug-resistant (MDR) bacteria, and antioxidant activity was determined using, 2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assays, and cytotoxic activity against human keratinocyte cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Pharmacological screening and molecular docking simulations were conducted to identify potential antibacterial compounds with druggable characteristics. Molecular dynamics simulation (MDS) was employed to validate the binding stability of the promising ligand-protein complexes. ResultsAll parts of the fruit exhibited a substantial amount of crucial nutrients (minerals, sugars, proteins, vitamins, and fatty acids). The ethanol (ET) and acetone (AC) fractions of all samples demonstrated notable inhibitory effects against tested MDR bacteria, with MIC50 ranges of 74–925 μg/mL. Both ET and AC fractions also displayed remarkable antioxidant activity, with MIC50 ranges of 3–39 μg/mL. Cytotoxicity assays on HaCaT cells revealed no adverse effects from the crude extract fractions. LC-MS/MS analyses identified a diverse array of compounds, known and unknown, with antibacterial and antioxidant activities. Molecular docking simulations and pharmacological property screening highlighted two active compounds, baicalein (BCN) and lenticin (LTN), showing strong binding affinity with selected target proteins and adhering to pharmacological parameters. MDS indicated a stable interaction between the ligands (BCN and LTN) and the receptor proteins over a 100-ns simulation period. ConclusionOur study provides essential information on the nutritional profile and pharmacological potential of the peel, flesh, and seeds of SCWP. Furthermore, our findings contribute to the identification of novel antioxidants and antibacterial agents that could be capable of overcoming the resistance barrier posed by MDR bacteria.

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.

Nanocomposite based on green synthesis of gold nanoparticles decorated with functionalized multi-walled carbon nanotubes for the electrochemical determination of hydroxychloroquine

In this study, a selective and sensitive electrochemical approach for determining hydroxychloroquine (HCQ) was proposed. A novel nanocomposite based on gold nanoparticles synthesized by green synthesis in an extract of white pitaya (Hylocereus undatus) (AuNP-Ext) decorated with functionalized multi-walled carbon nanotubes (f-MWCNTs) was presented. AuNP-Ext was characterized by ultraviolet-visible spectroscopy and the f-MWCNTs/AuNP-Ext nanocomposite by transmission electron microscopy. The nanocomposite was used to modify a glassy carbon electrode (GCE). Using the f-MWCNT-AuNP-Ext/GCE sensor, an irreversible oxidation peak at +0.74 V vs. Ag/AgCl was verified by HCQ. The calibration plot was studied in two linear ranges, from 0.03 to 3.5 µmol/L and from 3.5 to 17.0 µmol/L, with a limit of detection of 0.0093 µmol/L and a limit of quantification of 0.031 µmol/L, regarding the first linear range. The proposed sensor was successfully applied to the determination of HCQ in pharmaceutical and clinical samples without any special purification, separation or pre-treatment steps. The accuracy was verified by UV-Vis spectrometry, and this revealed that the proposed method was accurate and precise, as evidenced by F- and t-tests.

Analysis of yeast diversity during spontaneous fermentation of red and white pitaya

Yeast communities during spontaneous fermentation of red and white pitaya were characterised and compared to provide a reference for the isolation of pitaya yeast strains. Using Illumina MiSeq high-throughput sequencing technology, we investigated the composition and diversities of yeast communities during five stages of spontaneous fermentation (1, 3, 5, 7, and 15 d), and the results showed 584,055 and 699,120 valid sequences from red and white pitaya, respectively. The sequences were classified into 86 and 42 operational taxonomic units, then assigned to 69 species in 49 genera (red pitaya) and 37 species in 32 genera (white pitaya). Taxonomic composition and diversity analysis results showed high yeast diversity during the early stage of spontaneous fermentation (RF1) for red pitaya, and during the middle stage (WF5) for white pitaya fermentation. The dominant yeast species was unclassified_o_Saccharomycetales in red pitaya, and Clavispora opuntiae in white pitaya, and these species showed opposite trends during red and white pitaya fermentation. One-way ANOVA showed highly significant differences in unclassified_o_Saccharomycetales (p ≤ 0.01) in red pitaya, and in Clavispora opuntiae (p ≤ 0.001) in white pitaya across the five spontaneous fermentation stages. In addition, phylogenetic analysis revealed that unclassified_o_Saccharomycetales and Clavispora opuntiae were positioned farthest from other yeast species. Overall, yeast community diversity during spontaneous fermentation was higher in red rather than white pitaya.

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.

Применение ферментов при выработке фруктового сока: обзор

Enzymatic treatment is a common method of fruit juice production that facilitates juice extraction from plant cells. The choice of enzyme depends on the fruit composition. Pectinase and cellulase are the most popular enzymes while amylase remains less wide-spread. For some raw materials, enzymatic procedures are more efficient than mechanical comminution or thermal processing. The fruit juice industry uses enzymes for streamlining. Enzymes maximize juice extraction from raw materials and improve such processes as pressing, solid settling, and solid removal. Juices that underwent enzymatic treatment are clear and, as a result, more aesthetically appealing to consumers.&#x0D; The review covered the most recent and influential publications on the enzyme treatment of fruit juices (2000–2021). The list of enzymes included pectinase, cellulase, and amylase. The research included the factors that affect the juice fermentation process, i.e., hydromodule, enzyme concentration, incubation time, temperature, and enzyme combination. The methods included data extraction, data analysis, and data compilation, as well as literature search and screening.&#x0D; The review focuses on the effects that individual parameters have on specific responses, e.g., yield, viscosity, total soluble solids, acidity, turbidity, clarity, pigment concentration, phenolic content, color, and solids. A greater enzyme concentration, incubation time, and temperature decrease the viscosity of juice and turbidity but cause color changes. If used in different combinations and at different concentrations, enzymes boost the production of bael pulp, banana, sapodilla, durian, pawpaw, grape, white pitaya, and water melon juices. A longer incubation period improves the production of bael pulp, citron, date, and pawpaw juices. However, higher incubation temperatures seem to have no positive effect on the juice yield. Cellulases, pectinases, amylases, and their combinations are able to produce more fruit juice of higher quality with a more favorable time-temperature combination of incubation.&#x0D; The optimal enzyme concentration, incubation time, and temperature can increase the juice yield. Therefore, enzymatic treatment is an effective method that ensures favorable properties of the finished product.

Analysis of Bioactive Components and Antioxidant Capacities of Some Tropical Fruits Adapted to the Mediterranean Region

Türkiye sahip olduğu ekolojik özellikleri sebebiyle birçok bitki türüne ev sahipliği yapmaktadır. Bununla birlikte Türkiye’nin farklı iklimsel özelliklere sahip olan farklı bölgelerinde yeni meyve türlerinin adaptasyon çalışmaları her geçen gün artmaktadır. Bu çalışmanın amacı Akdeniz Bölgesine adapte edilen Mango (Mangifera indica L.), beyaz (Hylocereus undatus Britton &amp; Rose) ve kırmızı pitaya (Hylocereus lemairei (Hook.) Britton &amp; Rose), guava (Psidium guajava L.) ve bölgede yaygın olarak yetişen mart inciri (Opuntia ficus-indica (L.) Mill.) meyvelerinin etinde toplam fenolik madde, toplam flavanoid madde, toplam askorbik asit ve antioksidan kapasitenin (ABTS, DPPH) belirlenmesidir. En yüksek toplam fenolik madde ve toplam flavanoid madde içeriği sırasıyla guava (80.1 mg 100g-1) ve mart inciri (4.68 mg 100g-1) meyvelerinde; en düşük mango (45.4 mg 100g-1) ve beyaz pitaya (0.95 mg 100g-1) meyvelerinde tespit edilmiştir. Kırmızı pitaya meyve etinde renk maddelerinin de içerisinde yer aldığı toplam flavanoid madde içeriği beyaz pitaya meyvelerinden daha yüksek bulunmuştur. Toplam askorbik asit içeriği en yüksek olan meyve mart inciri meyvesidir (5.38 mg 100g-1). ABTS ve DPPH radikal süpürücü aktiviteler ise guava meyvesinde en yüksek bulunurken, mart inciri meyvesinde en düşük olarak belirlenmiştir.

A novel fluorescent probe based on white pitaya peel‐derived carbon dots for highly selective and sensitive determination of sulfaquinoxaline in food

SummaryA fluorescent probe based on carbon dots (CDs) for the detection of sulfoquinoxaline (SQX) in food was studied. White pitaya peel‐derived carbon dots (WCDs) were synthesised by hydrothermal method. The obtained WCDs exhibit excellent fluorescence response towards SQX due to the inner filter effect (IFE) and aggregation‐caused quenching(ACQ), which cause the fluorescence to be quenched. The prepared fluorescent probe has a good linear relationship, and the detection limit of SQX is 24.5 μg L−1. The practicability of the fluorescent probe was further validated in milk, honey, eggs, carp, pork, chicken, beef and pork liver, and the recoveries of SQX range from 93.38% to 103.86%. The fluorescent probe based on WCDs has high selectivity, specificity, sensitivity, reliability and good reproducibility for the detection of SQX.

Screening of multifunctional fruit carbon dots for fluorescent labeling and sensing in living immune cells and zebrafishes.

Nine kinds of carbon dots (CDs) were synthesized by using fruits with different varieties as carbon sources; meanwhile, the fluorescence characteristics, quantum yield, and response ability to different metal ions and free radicals were systematically studied. These CDs showed similar excitation and emission spectral ranges (λex ≈ 345nm, λem ≈ 435nm), but very different fluorescence quantum yield (QY), in which orange and cantaloupe CDs have the highest QY around 0.25 and green plum CDs showed the lowest quantum yield around 0.1. Interestingly, the fluorescence of all of these CDs can be significantly quenched by hydroxyl radical (•OH) and iron ion (Fe3+); however, these CDs showed very different response characteristics to other metal ions (e.g., Co2+, Ni2+, Cu2+, Ce3+, Mn2+, Ag+, and Fe2+). Through in-depth analysis, we found some interesting patterns of the influence of carbon sources on the fluorescence characteristics of CDs. Finally, by using white pitaya CDs as fluorescence probe, we realized sensing of Fe3+ and •OH with limits of detection (LOD) of 19.4μM and 0.7μM, respectively. Moreover, the CDs were also capable for sensitive detection in immune cells and even in zebrafishes. Our work can provide valuable guidance for the rational design of functional CDs for biological applications.

Use of hydrogel in the irrigation management of white pitaya (Hylocereus undatus) seedlings: Biometrics and accumulation of organic and inorganic solutes

The initial development of pitayas may be limited by a few factors, among them, water deficit. Agricultural hydrogels can be used as an alternative to enhance the retention and availability of water and nutrients in the soil. Therefore, this study aimed to evaluate the influence of irrigation frequency and hydrogel doses on the development of white pitaya (Hylocereus undatus) seedlings to establish a time interval in days between irrigations that provides better seedling development and determine the hydrogel dose that provides a reduction of water consumption without damaging seedling development. The experimental design consisted of randomized blocks in a 4 x 4 factorial arrangement, in which the treatments corresponded to 4 hydrogel doses (0, 2, 4, and 6 g/plant of Biogel Hidro Plus) incorporated into the substrate and four irrigation frequencies (1, 3, 5, and 7 days of interval). The biometric characteristics, photosynthetic pigments, and organic and inorganic solutes of the plants were evaluated after 120 days. The use of daily irrigation negatively influenced the growth and biomass accumulation of the aerial part of the seedlings and, consequently, provided the lowest values of cladodes of the pitaya seedlings. Pitaya seedlings had greater development when using an irrigation frequency of around 3 days. The application of 6 g/plant of hydrogel provided the highest averages for accumulation of dry biomass, photosynthetic pigments, and organic and inorganic solutes at irrigation levels of 3.6, 4, and about 3.8 days of intervals, respectively. Hydrogel incorporation allowed increasing the interval between irrigations by 1 day without damages to the seedling development.

A PRIMARY APPROACH FOR SEPARATION AND CHARACTERIZATION OF α-AMYLASE FROM WHITE PITAYA (HYLOCEREUS UNDATUS) PEELS BY POLYMER/SALT TWO PHASE SYSTEM

α-Amylase was isolated from white pitaya peel with two phase system in aqueous media and then characterized. The effects of polyethylene glycol (PEG), PEG concentration, molecular weight, sodium citrate, and sodium chloride (NaCl) on yield and purification factor were studied. The highest purification factor (4.5) and yield (83%) were obtained in system PEG 6000 (14% w/w)-sodium citrate (18% w/w) with 6% (w/w) NaCl. The purified α-amylase molecular weight exhibited a band above 40 KDa by SDS-PAGE. α-Amylase showed optimum activity at pH of 6.0 and temperature of 55 °C. The activity of this enzyme was stable in the pH scope of 6-8 and temperature scope of 10-55 °C. Various metal ions were evaluated for amylase activation/inhibition effect. Na+ and Ca2+ were exhibited to have appropriate activating effect, where as Mn2+, Zn2+, Fe3+, Ni+, Ba+ and Cu2+ had inhibition effect. In addition, this enzyme showed remarkable stability in the existence of TritonX-100, SDS, sodium perborate, Tween 20 and Tween-80. In conclusion, this enzyme has high stability and activity at suitable temperature and pH, and in the existence of different surfactants and metal ions. This approach has a potential in progress of various industrial applications by introducing a method for applying new, low-cost, and biocompatible amylases source.

A PRIMARY APPROACH FOR SEPARATION AND CHARACTERIZATION OF α-AMYLASE FROM WHITE PITAYA (HYLOCEREUS UNDATUS) PEELS BY POLYMER/SALT TWO PHASE SYSTEM

α-Amylase was isolated from white pitaya peel with two phase system in aqueous media and then characterized. The effects of polyethylene glycol (PEG), PEG concentration, molecular weight, sodium citrate, and sodium chloride (NaCl) on yield and purification factor were studied. The highest purification factor (4.5) and yield (83%) were obtained in system PEG 6000 (14% w/w)-sodium citrate (18% w/w) with 6% (w/w) NaCl. The purified α-amylase molecular weight exhibited a band above 40 KDa by SDS-PAGE. α-Amylase showed optimum activity at pH of 6.0 and temperature of 55 °C. The activity of this enzyme was stable in the pH scope of 6-8 and temperature scope of 10-55 °C. Various metal ions were evaluated for amylase activation/inhibition effect. Na+ and Ca2+ were exhibited to have appropriate activating effect, where as Mn2+, Zn2+, Fe3+, Ni+, Ba+ and Cu2+ had inhibition effect. In addition, this enzyme showed remarkable stability in the existence of TritonX-100, SDS, sodium perborate, Tween 20 and Tween-80. In conclusion, this enzyme has high stability and activity at suitable temperature and pH, and in the existence of different surfactants and metal ions. This approach has a potential in progress of various industrial applications by introducing a method for applying new, low-cost, and biocompatible amylases source.

α-amylase from white pitaya (Hylocereus undatus L.) peel: optimization of extraction using full factorial design

Introduction. Amylase is a significant enzyme with numerous commercial applications, which is largely used to convert starches into oligosaccharides. Extraction of amylase from plant by-products or cheap sources is cost-effective. Annually, pitaya fruit juice industry produces huge amounts of peels that could be utilized as an alternative source in enzyme production industry. The work aimed to examine and optimize extraction process.&#x0D; Study objects and methods. In this study, we investigated parameters of extraction to optimize the process, as well as activity of α-amylase from white pitaya fruit (Hylocereus undatus L.) peel. For this purpose, a two-level full factorial design was applied. Three variables, namely the pH of sodium phosphate buffer (X1, 4.5–7.5), mixing time (X2, 1–3 min), and a sample-to-buffer ratio (X3, 1:3–1:5), were used to identify significant effects and interactions within the samples.&#x0D; Results and discussion. The results demonstrated that the buffer pH had the most significant (P ≤ 0.05) effect on total amylase activity. Based on full factorial design analysis, we revealed the optimal conditions for amylase enzyme extraction ‒ pH of 6, mixing time of 2 min, and a sample-to-buffer ratio of 1:4. Lower and higher values influenced adversely on specific activity of amylase.&#x0D; Conclusion. Optimization increased the enzyme specific activity by a factor of 4.5. Thus, pitaya peel could be used in different industries as a rich natural α-amylase source.

Effects of UVC light‐emitting diodes on inactivation of Escherichia coli O157:H7 and quality attributes of fresh‐cut white pitaya

The work aimed to evaluate the effects of ultraviolet-C light-emitting diodes (UVC-LEDs) at 275 nm against Escherichia coli O157:H7 on fresh-cut white pitaya. Besides, the influences of UVC-LED treatments on the quality of fresh-cut white pitaya were also investigated. The distance between the UVC-LEDs and the surface of the pitaya pieces was approximately 5 cm. The inactivation behavior of E. coli O157:H7 on fresh-cut pitaya began almost instantaneously and then tailed off as the fluence increased. The quantities of E. coli O157:H7 inoculated on fresh-cut white pitaya were reduced by 2.21 lg10 CFU/g after UVC-LED treatment at 1200 mJ/cm2 (33 min). The Weibull plus tail model was satisfactorily fitted to estimate the reduction of E. coli O157:H7 on fresh-cut white pitaya, with the R2 and root mean square error (RMSE) reached 0.99 and 0.05, respectively. Physicochemical properties (pH, total soluble solids, and total phenolic content) and color parameters of fresh-cut pitaya did not change significantly after UVC-LED treatment. However, UVC-LED treatment at a higher fluence led to a small reduction of antioxidant properties. These results indicate that UVC-LEDs emitting at 275 nm may improve the microbiological safety and maintain the qualities of fresh-cut fruit. Moreover, the synergy of UVC-LEDs with other preservation methods would have a potential application in the fresh-cut fruit processing industry to present enhanced inactivation efficiency and to better maintain the nutritional and sensory qualities of fresh-cut fruits.

Caracterização de filmes poliméricos com adição de polpa de pitaya vermelha (Hylocerus Polyrhizus)

A Pitaya é um fruto de cactos epífitos do gênero Hylocereus, podendo ser encontradas mais facilmente em território brasileiro em duas diferentes espécies: Pitaya Branca (Hylocereus undatus) casca vermelha e polpa branca e a pitaya vermelha (Hylocerus Polyrhizus) e polpa vermelha. O objetivo do trabalho foi confeccionar filmes poliméricos com adição de polpa de pitaya vermelha afim de detectar possíveis propriedades da polpa que ao serem inseridas nos filmes, dê ao mesmo características relevantes para futuras confecções de embalagens ativas. Foram confeccionadas três formulações distintas: a primeira formulação contendo somente quitosana 2% (em massa); a segunda formulação contendo quitosana 2% acrescido de 1mL de polpa; a terceira formulação contendo quitosana 2%, acrescida de 5mL de polpa. Afim de realizar a caracterização das três formulações de filmes, foram realizadas as seguintes análises: Espessura, Permeabilidade ao Vapor D’água (PVA), teor de umidade e solubilidade em água. Ao final, observou-se que a adição de diferentes concentrações de polpa alterou as características dos filmes biopoliméricos.

Constituent diversity of ethanol extracts from pitaya

AbstractPitaya is rich in nutrition and unique in function and contains vegetable albumin, anthocyanins, rich vitamins, and water soluble dietary fiber, which are rare in fruits and vegetables. However, researches mostly focused on pitaya cultivation, biological characteristics, fresh‐keeping, and lacked analyses about chemical composition of pitaya. Therefore, ethanol extraction and GC/MS were used to extract and identify the bioactive components in pulp and pericarp of red pitaya and white pitaya. The extracting results showed that percentages of ethanol extracts from pulp and pericarp of red pitaya were 14.5% and 12%, whereas those of white pitaya were 16% and 12%. The GC/MS results showed that different kinds of bioactive constituents were identified in fresh pericarp and pulp of red pitaya and white pitaya. In the four ethanol extracts, there are rich polysiloxane plant organosilicon with total contents of 10.09%, 24.21%, 25.77%, and 23.25%. Meanwhile, there are many heterocyclic substances, and the content of pericarp is much higher than that of pulp. The four ethanol extracts also contain some other bioactive ingredients, such as esters, hydrocarbons, alcohols, amides, halides, and fatty acids, which can be used as raw materials for biomedicine, advanced cosmetics, and skin care products.

Aqueous two-phase purification of α-Amylase from white pitaya ( Hylocereus undatus ) peel in polyethylene glycol /citrate system: Optimization by response surface methodology

Abstract α-Amylase is a significant enzyme with numerous commercial applications, which is largely used to convert starches into oligosaccharides. So, purification of α-Amylase from by products or cheap sources is of great importance due to its ease of production and industrially widespread applications. In the present study, α-amylase was purified from white pitaya peel in a system composed of two phase based on salt and polyethylene glycol. Furthermore, the impact of four independent variables, including (X1) polyethylene glycol molecular weight (4000–8000 g/mol), (X2) polyethylene glycol concentration (10–18% (w/w)), (X3) sodium citrate concentration (12–20% (w/w)), and (X4) NaCl (2–8% (w/w)), on partition coefficient (Y1), purification factor (Y2) and yield (Y3) of the purified enzyme was investigated using central composite design of response surface methodology. Results showed that optimum conditions for amylase purification were that, 14% (w/w) polyethylene glycol 6000 (g/mol), 16% (w/w) sodium citrate and 5% (w/v) NaCl; the partition coefficient, purification factor and amylase yield under the optimal conditions were 6.62%, 4.43% and 89.12%, respectively. Moreover, the experimental and predicted results were in considerable agreement, which established the reliability and validity of the proposed model. This study indicated that the citrate-based aqueous two-phase system provides a promising tool for effective purification of amylase at a low cost with a large loading capacity.

Growth and gas exchange in white pitaya under different concentrations of potassium and calcium

Agriculture in Brazil has improved at a fast pace in recent years, given the growing demand for quality and the need for new products. In this respect, white pitaya [Hylocereus undatus (Haw.) Britton & Rose] has become a feasible alternative for Northeast farmers. The limiting factors include a small amount of data on plant mineral nutrition and crop growth (phenology). Therefore, this study goal was to evaluate the effect of different concentrations of potassium (K) and calcium (Ca) on crop development and gas exchange in white pitaya grown in the coastal region of the state of Ceara, in Brazil. Sixteen treatments with three repetitions were organized in a completely randomized block design and a 4 × 4 factorial arrangement. Treatments consisted of various concentrations of K (0; 125; 250 and 375 mg dm-3) and Ca (0, 53, 106, and 159 mg dm-3). Biometric characteristics and gas exchange were determined after 270 and 240 days of treatment, respectively. For morphometric characteristics, the most significant nutrient combination was 250 mg dm-3 of K and 159 mg dm-3 of Ca. Net photosynthesis was higher at the dose of 125 mg dm-3 of K and 0 mg dm-3 of Ca. Our results indicate that, for the environmental conditions under which the test was conducted, an optimum nutrient combination for the analyzed variables was 250 mg dm-3 K and 159 mg dm-3 Ca.

High-Throughput Sequencing Analysis of Endophytic Bacteria Diversity in Fruits of White and Red Pitayas from Three Different Origins.

Pitaya contains various types of polyphenols, flavonoid and vitamins which are beneficial for health and it is among the most important commercial tropical fruits worldwide. Endophytic bacteria might be beneficial for plant growth and yield. However, bacterial diversity in pitaya is poorly characterized. In this study, fruits of white and red pitayas from three different origins (Thailand, Vietnam and China) were chosen for endophytic bacteria diversity investigation by using Illumina HiSeq second-generation high-throughput sequencing technology. Large number of endophytic bacteria were detected and 22 phyla, 56 classes, 81 orders, 122 families and 159 genera were identified. Endophytic bacteria diversity was uneven among pitaya fruits from different origins and bacteria structure was different between white pitaya group and red pitaya group. Phylum Bacteroidetes, classes Bacteroidia and Coriobacteriia, orders Bacteroidales and Coriobacteriales, families Prevotellaceae, Bacteroidaceae, Ruminococcaceae, Paraprevotellaceae, Rikenellaceae, Alcaligenaceae and Coriobacteriaceae, genera Prevotella, Bacteroides, Roseburia, Faecalibacterium and Sutterella were statistically significant different species (P < 0.05) between white and red pitayas. These findings might be useful for growth improvement, fruit preservation and processing of different pitaya species from different origins.

White Pitaya (Hylocereus undatus) Juice Attenuates Insulin Resistance and Hepatic Steatosis in Diet-Induced Obese Mice

Insulin resistance and hepatic steatosis are the most common complications of obesity. Pitaya is an important source of phytochemicals such as polyphenols, flavonoid and vitamin C which are related to its antioxidant activity. The present study was conducted to evaluate the influence of white pitaya juice (WPJ) on obesity-related metabolic disorders (e.g. insulin resistance and hepatic steatosis) in high-fat diet-fed mice. Forty-eight male C57BL/6J mice were assigned into four groups and fed low-fat diet with free access to water or WPJ, or fed high-fat diet with free access to water or WPJ for 14 weeks. Our results showed that administration of WPJ improved high-fat diet-induced insulin resistance, hepatic steatosis and adipose hypertrophy, but it exerted no influence on body weight gain in mice. Hepatic gene expression analysis indicated that WPJ supplement not only changed the expression profile of genes involved in lipid and cholesterol metabolism (Srebp1, HMGCoR, Cpt1b, HL, Insig1 and Insig2) but also significantly increased the expression levels of FGF21-related genes (Klb, FGFR2, Egr1 and cFos). In conclusion, WPJ protected from diet-induced hepatic steatosis and insulin resistance, which was associated with the improved FGF21 resistance and lipid metabolism.