Total Volatiles Research Articles

Economic analysis of volatile characteristics of Haematococcus pluvialis and the effect of roasting temperature on the profile of volatiles and chemical components

Haematococcus pluvialis, an excellent natural source of astaxanthin, is also enriched with protein, PUFA, carbohydrates. However, the off-flavour of H. pluvialis powder has limited its direct application in food products. The characteristic odour diversity of algae depends on the composition and relative concentration of volatile organic compounds (VOCs). The present study sought to characterize the chemical profile of VOCs of H. pluvialis powders to improve its odour and promote its direct application in functional food and feed products. Additionally, the roasting treatment was applied to improve the flavour, and the effect of roasting temperature on VOCs, nutritional components, and antioxidant activity was investigated. A total of 401 VOCs were identified, with esters being the major class of VOCs, accounting for 63.108% of the total volatiles. Esters, ketone, and aldehydes were the major VOCs contributing to the odour of H. pluvialis powders. After roasting for 30 min at different temperatures, most volatiles were increased, except for esters. Several important flavour VOCs, such as β-ionone, geranylacetone, β-cyclocitral, and nonanal derived from carotenoids and fatty acids, were increased with the increase of the roasting temperatures, exhibiting pleasant odours, such as violet-like, fruity, and fresh odours. The biochemical components, pigments, and antioxidant activity were destroyed with varying degrees during roasting. Additionally, the thermal treatment process accelerated the degradation and oxidation of pigment, proteins, and lipids. Furthermore, the Maillard reaction significantly reduced proteins and carbohydrates. The degradation of pigments and fatty acids resulted in the formation of volatile compounds. Finally, 100–120 °C was considered as an appropriate roasting temperature to improve the flavour of H. pluvialis without interfering with the nutrients.

Effects of secondary fermentation of four in-bottle Saccharomyces cerevisiae strains on sparkling cider sensory quality

In this study, the first fermentation of Fuji apple juice was carried out using Saccharomyces cerevisiae WLS21 and continued a second fermentation using S. cerevisiae HYJ1, HYJ2, PE2, and Y41 in sealed bottles after adjusting the sugar level. The physicochemical indexes, aromas, and sensory characteristics of four sparkling ciders were analyzed. The results revealed that HYJ2 produced the highest amount of ethanol and Y41 had the highest pressure in the bottle at the end of fermentation. Y41 produced the highest citric and succinic acids and HYJ1 produced higher fumaric acid and total volatiles. HYJ1 cider had an obvious herbaceous odor, and Y41 cider had a fruity character. Sixty-seven volatiles were detected from four sparkling ciders (55 fermentative and 12 non-fermentative aromas). Esters (EEFAs and HAAs) were the main volatile aroma family produced during secondary fermentation, and terpenes contributed the most to fruity odor. Based on univariate (ANOVA) and multivariate analysis of variance (PLS-DA) screening of four cider significant variables, 13 volatiles with variable predictive importance (VIP)≥1 were identified. PLSR analysis revealed that 2-methylbutyl acetate, ethyl heptanoate, 2-methyl-1-butanol, nonanal, 2-nonanone, β-damascenone, and linalool were potential volatile markers for OAV>1.

Free Amino Acids and Volatile Aroma Compounds in Watermelon Rind, Flesh, and Three Rind-Flesh Juices.

Watermelon rind is treated as agricultural waste, causing biomass loss and environmental issues. This study aimed to identify free amino acids and volatiles in watermelon rind, flesh, and rind-flesh juice blends with ratios of 10%, 20%, and 30%. Among the 16 free amino acids quantified, watermelon rind alone contained higher total amino acids (165 mg/100 g fresh weight) compared to flesh alone (146 mg/100 g). The rind had significantly higher (1.5×) and dominant amounts of citrulline and arginine (61.4 and 53.8 mg/100 g, respectively) than flesh. The rind, however, contained significantly lower amounts of essential amino acids. Volatile analysis showed that watermelon rind total volatiles (peak area) comprised only 15% of the flesh volatiles. Of the 126 volatiles identified, the rind alone contained 77 compounds; 56 of these presented in all five samples. Aldehydes and alcohols were most prevalent, accounting for >80% of the total volatiles in all samples. Nine-carbon aldehyde and alcohol compounds dominated both the flesh and rind, though the rind lacked the diversity of other aldehydes, alcohols, ketones, terpenes, terpenoids, esters and lactones that were more abundant in the watermelon flesh. Watermelon rind was characterized by the major aroma compounds above their thresholds, including 17 aldehydes and six unsaturated nine-carbon alcohols. This study demonstrated the potential for rind as a food or beverage supplement due to its key features such as concentrated citrulline and arginine, relatively low odor intensity, and valuable volatiles associated with fresh, green, cucumber-like aromas.

Iodine distribution and volatilization in contrasting forms of forest humus during a laboratory incubation experiment

Radionuclides 129I (t1/2 = 15.7 × 106 years) and 131I (t1/2 = 8.02 days) are both introduced into the environment as a result of nuclear human activities. Environmental transfer pathways and fluxes between and within ecosystems are essential information for risk assessment. In forest ecosystems, humus degradation over time could result in re-mobilization and then downward migration and/or volatilization of intercepted 129I. In order to estimate the scale of these processes, humus (mull and moder forms) sampled under deciduous and coniferous forests were spiked with 125I− (t1/2 = 59.4 days), as a surrogate for 129I, in order to study the evolution of its water-soluble and organic fractions as well as the volatilization rate during humus degradation at laboratory scale. To our knowledge, this is the first time that interactions between iodine and contrasting forms of forest humus have been investigated. The evolution of native stable iodine (127I) pools in unspiked humus was also studied.The nature of the humus’ organic matter appears to be a factor that impacts on the proportions of water-soluble and organic fractions of iodine and on their evolution. Iodine-125 was mainly organically bound (fraction for mulls and moders: ∼54–59 and 41–49%, respectively) and no clear evolution was observed within the 4-month incubation period. A large decrease in 125I water-solubility occurred, being more marked for mull (from ∼14–32 to 3–7%) than for moder (from ∼21–37 to 7–19%) humus. By contrast, a significant fraction was not extractible (∼38–43%) and varied in inverse proportion to the water-soluble fraction, suggesting a stabilization of iodine in humus after wet deposit. The nature of the humus organic matter also impacted on 125I volatilization. Although of the same order of magnitude, the total volatilization of 125I was higher for moders (∼0.039–0.323%) than for mulls (∼0.015–0.023%) within the 4-month incubation period. Volatilization rates for mulls were correlated with the water-soluble fraction, implying that volatilization of 125I could occur from the humus solution. Our results showed that humus is thus a zone of iodine accumulation by association with organic matter and that potential losses by lixiviation are significantly more important compared to volatilization.

Risk Contagion between Global Commodities from the Perspective of Volatility Spillover

Prices of oil and other commodities have fluctuated wildly since the outbreak of the COVID-19 pandemic. It is crucial to explore the causes of price fluctuations and understand the source and path of risk contagion to better mitigate systemic risk and maintain economic stability. The paper adopts the method of network topology to examine the path of risk contagion between China’s and foreign commodities, focusing on the dynamic evolution and transmission mechanism of risk contagion during the pandemic. This research found that among China’s commodities, energy, grain, and textiles are net recipients of risk contagion, while chemical products and metals are net risk exporters. Among international commodities, industries have positive risk spillover effects on metals and textiles. During the first phase of the pandemic, China’s commodities were the main exporters of risk contagion. However, international industries and metals became the main risk exporters and exerted risk spillover on China’s commodities in the second phase of the pandemic. Moreover, based on total volatility spillover index of commodities, the risk contagion among the commodities follows three paths: “interest rate → commodities → money supply”, “China’s economic expectation → commodities → foreign economic expectation”, and “commodities → consumer confidence”.

Time-frequency volatility spillovers across the international crude oil market and Chinese major energy futures markets: Evidence from COVID-19

This study investigates the impact of the recent COVID-19 pandemic on the time-frequency volatility spillovers across the international crude oil market and Chinese major energy futures markets. In addition to the Chinese crude oil market, six other major energy futures markets in China are also considered. Volatility spillover networks are constructed based on the generalized forecast error variance decomposition in the frequency domain. The results demonstrate that the outbreak of COVID-19 strengthened the total volatility spillover across these markets. Interestingly, the volatility spillovers from the international crude oil market to China's markets were found to be overall strong in the long term and to have increased substantially during the pandemic. However, the spillovers across the domestic markets were found to dominate in the short term, even with the occurrence of the pandemic and crude oil price turbulence. The findings suggest that policymakers and investors should be cautious about the diverse impacts of the pandemic at multiple scales.

Assessing over Time Performance of an eNose Composed of 16 Single-Type MOX Gas Sensors Applied to Classify Two Volatiles

This paper assesses the over time performance of a custom electronic nose (eNose) composed of an array of commercial low-cost and single-type miniature metal-oxide (MOX) semiconductor gas sensors. The eNose uses 16 BME680 versatile sensor devices, each including an embedded non-selective MOX gas sensor that was originally proposed to measure the total volatile organic compounds (TVOC) in the air. This custom eNose has been used previously to detect ethanol and acetone, obtaining initial promising classification results that worsened over time because of sensor drift. The current paper assesses the over time performance of different classification methods applied to process the information gathered from the eNose. The best classification results have been obtained when applying a linear discriminant analysis (LDA) to the normalized conductance of the sensing layer of the 16 MOX gas sensors available in the eNose. The LDA procedure by itself has reduced the influence of drift in the classification performance of this single-type eNose during an evaluation period of three months.

Dynamic spillover effects and portfolio strategies between crude oil, gold and Chinese stock markets related to new energy vehicle

This paper investigates the volatility spillover effects and the dynamic relationships among WTI crude oil, gold and the Chinese stock markets of new energy vehicle, environmental protection, new energy, coal & consumable fuels, high and new technology, by adopting the method of Diebold and Yilmaz (2012, 2014) based on TVP-VAR model. The results indicate that there exists a high interdependence among all analyzed assets, and the total volatility spillover has a sharp increase under the major crisis events. On average, WTI crude oil and gold are the net receivers of the systemic shocks, while all of the analyzed stock markets are the net transmitters of the systemic shocks. Besides, the Granger causality test shows that the volatility of each asset can Granger cause the total connectedness index. Finally, we also calculate optimal hedge ratios, portfolio weights and the corresponding hedging effectiveness based on DCC-GARCH-t copula model. The empirical results show WTI crude oil and gold are cheap hedging tools. When investing a small part in WTI crude oil and a large part in the analyzed stock markets, high hedging effectiveness could be achieved.

Characterization of the volatile profile from six different varieties of Chinese chives by HS-SPME/GC–MS coupled with E. NOSE

ObjectivesThe Chive chives cultivars Han Yu Zi Gen, Fu Jiu Bao F1, Shouguang Du Gen Hong, Xue Jiu, Jiu Xing 22, and Ma Lian Da Ye Bai Gen are recently evolved cultivars, and this would be the first study to characterize for agronomy, quality, volatile profile and E-Nose for aromatic and textural quality. MethodsThese cultivars were selected based on their suitability for aromatic and textural qualities that are desirable for food processing. The cultivars Han were analyzed for agronomy and quality indices by methods in general use in modern laboratories, while their volatile profile was studied by HS-SPME/GC–MS and E-nose analyses. ResultsThe cultivars varied for agronomy and quality indices (P < 0.05). The volatile profile showed that Esters, Heterocyclic polymers, Acids, Aldehydes, Hydrocarbons, Sulfides, Ketones, Ethers, Furfuryl derivatives, and Phenols were dominating compound groups. High total volatile contents (17.75 and 17.54 µg/g) were determined in Xue Jiu and Han Yu Zi Gen, respectively, more significant than Fu Jiu Bao F1, Ma Lian Da Ye Bai Gen, Jiu Xing 22, and Shouguang Du Gen Hong (12.22, 11.70, 10.19 and 9.53 µg/g), respectively. PCA showed that W5S and W2W were the farthest points of the first and second principal components, respectively, while W5S, W1S, W3C, W1C and W2W were main sensors classifying cultivars; where sensor W5S had larger contribution rate. ConclusionsIn this study, HS-SPME/GC–MS and E-nose methods accurately detected flavor differences among cultivars. These analyses further suggested that Xue Jiu and Han Yu Zi Gen possessed strong overall flavor characteristics; while Shouguang Du Gen Hong was the lightest in flavor characteristics. Hence it is for the general recommendation that Chinese chive cultivars Xue Jiu and Han Yu Zi Gen may be a choice of the food industry for appropriate utilization.

Health risk analysis from volatile organic compounds and fine particulate matter in the printing industry.

The association between the printing activity and the pollutant exposure of the workers was investigated in five consecutive working days, during 8 h work shift per day. Exposure concentrations of the total volatile organic compound and fine particulate matter were measured in the four voluntary printing factories in Thailand. Two types of the printing process, offset and digital printing, were compared. The 8 h average of particulate matter 2.5 in the field blank, Offset A, Offset B, Offset C printing and Digital printing D was 7.46, 21.51, 44.26, 77.92, and 42.08 µgm−3, respectively. The highest particulate matter level in the Offset printing C, 77.92 µgm−3 was due to the surrounded paper dust in the area. The 8 h average of total volatile organic compounds in field blank, Offset A, Offset B, Offset C printing and Digital printing D was 0.12, 2.68, 5.02, 21.86, and 0.67 ppm, respectively. The highest total volatile organic compound was 21.86 ppm in the Offset printing C because of the high production rate and the application of organic solvents in the cleanup process. Worker's exposure to total volatile organic compound and particulate matter 2.5 in the offset printings was higher than in the digital laser printing. From the health risk evaluation, the workers in offset printings were at risk from total volatile organic compound exposure, Hazard quotient > 1. However, workers exposed to particulate matter exposures were not at risk, Hazard quotient < 1.Graphic abstract

Forecasting risk measures using intraday and overnight information

Volatility forecasts are important for a number of practical financial decisions, such as those related to risk management. When working with high-frequency data from markets that operate during a reduced time, an approach to deal with the overnight return volatility is needed. In this context, we use heterogeneous autoregressions (HAR) to model the variation associated with the intraday activity, with distinct realized measures as regressors, and, to model the overnight returns, we use augmented GARCH type models. Then, we combine the HAR and GARCH models to generate forecasts for the total daily return volatility. In an empirical study, for returns on six international stock indices, we analyze the separate modeling approach in terms of its out-of-sample forecasting performance of daily volatility, Value-at-Risk and Expected Shortfall relative to standard models from the literature. In particular, the overall results are favorable for the separate modeling approach in comparison with some HAR models based on realized variance measures for the whole day and the standard GARCH model.

Impact of chitosan embedded with postbiotics from Pediococcus acidilactici against emerging foodborne pathogens in vacuum-packaged frankfurters during refrigerated storage

The objective of the study was to carry out characterization of postbiotics from Pediococcus acidilactici and to assess their efficacy (50% and 100%) in combination with chitosan (0.5 and 1%) against Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes on frankfurters during refrigerated storage for 35 days. High amounts of total phenolic content (1708.15 ± 93.28 mg GAE/L) and carboxylic acids, which comprised 74.89% of the total volatiles, were found in the postbiotics. On day 0, the postbiotic-chitosan combinations decreased the E. coli O157:H7, L. monocytogenes and S. Typhimurium counts ranging from 1.58 to 3.21 log10 compared to the control in frankfurters (P < 0.05). Total viable count and number of lactic acid bacteria were effectively reduced in all treatment groups (P < 0.05), and postbiotic and chitosan treatments did not cause any changes in pH and color of the frankfurters. In conclusion, postbiotic-chitosan combinations can be used to reduce the risks that might be associated with E. coli O157:H7, L. monocytogenes, and S. Typhimurium in frankfurters.

Changes in Visual and Olfactory Cues in Virus-Infected Host Plants Alter the Behavior of Bemisia tabaci

The cucurbit chlorotic yellows virus (CCYV) has caused serious damage to melon crops in many countries in recent years. This plant virus is exclusively transmitted by the whitefly Bemisia tabaci (Gennadius) in a semi-persistent mode. Previous studies have shown that both persistent and non-persistent viruses can affect the orientation and performance of insect vectors, through changing host phenotype or interacting with insect vectors directly to facilitate the spread of viruses. However, how CCYV affects host-plant selection by B. tabaci has not been reported. In this study, we investigated the visual and olfactory preferences of B. tabaci between healthy and CCYV-infected host plants Cucumis sativus (Cucurbitaceae). Volatile profiles of healthy and CCYV-infected C. sativus plants were analyzed using gas chromatography-mass spectrometry (GC-MS). In the choice assay, whiteflies preferred to settle on CCYV-infected C. sativus seedlings. However, the concentrations of total volatiles and terpenes in C. sativus plants decreased after CCYV infection. Interestingly, in the Y-tube assay and vision preference test, whitefly B. tabaci adults showed significant visual preference to CCYV-infected host but showed olfactory preference to healthy plants. These results indicated that CCYV infection in plants differently affected the visual and olfactory-mediated orientation behaviors of vector whiteflies and implied that visual cues could play a more important role than olfactory cues in whiteflies in locating CCYV-infected host plants.

The investment volatility-dampening role of foreign aid in poor sub-Saharan African countries

Sustained investment is required for economic growth. Investment however often experiences severe volatility in poor countries, making spending plans difficult to formulate, and diminishing growth potentials. Foreign aid serves as an important source of complementary financing for sustained investment. This paper thus studies the effect of aid inflows on total investment volatility in 19 heavily indebted poor sub-Saharan African countries over the period 1980–2018. Employing the cross-sectionally augmented distributed lag (CS-DL) estimation technique for long-run coefficients in dynamic heterogeneous panels with cross-sectional dependence along with bootstrap panel causality testing, we show that aid has an inverse relationship with investment volatility. We thus conclude that aid can be viewed as a dampening factor for investment volatility in poor countries. We also show that the ability of sudden reductions in aid inflows to trigger investment volatility is bigger than the ability of sudden increases in aid inflows to lower investment volatility.

Time-varying spillover effects and investment strategies between WTI crude oil, natural gas and Chinese stock markets related to belt and road initiative

This paper investigates the return volatility spillover effects and the dynamic relationships among WTI crude oil futures, Natural Gas futures, and the Chinese stock markets related to Belt and Road initiative employing the method of Diebold and Yilmaz (2012, 2014) based on TVP-VAR model and generalized forecast error variance decomposition. Our empirical results show that there exists a high interdependence among all analyzed assets, and the total volatility spillover has a sharp increase under the major crisis events. On average, WTI, GAS and the stock markets of FM, AGR and COM are the net receivers of systematic shocks, while the stock markets of EU, HSR and INF are the net transmitters of systematic shocks. Besides, we also calculate the hedge ratios, the optimal portfolio weights and the corresponding hedging effectiveness based on DCC-GARCH t-copula model. We find that WTI crude oil and Natural Gas futures are cheap hedging tools. When investing a small part in WTI crude oil future market and a large part in the analyzed stock markets, or investing a small part in the analyzed stock markets and a large part in Natural Gas future market, high hedging effectiveness could be achieved.

Rice-crayfish co-culture reduces ammonia volatilization and increases rice nitrogen uptake in central China

In recent years, rice-crayfish co-culture has been widely promoted as a newly emerging farming mode in China. The peripheral trench for crayfish farming and paddy field drainage in this farming mode can alter nitrogen (N) fertilizer deposition and ammonia (NH3) diffusion. However, the effect of the peripheral trench on NH3 volatilization remains unclear. We hypothesized that the peripheral trench under rice-crayfish co-culture (RC) can reduce total NH3 volatilization and enhance rice N uptake. Here, a field experiment was conducted to investigate the effect of different rice farming patterns [RC and rice monoculture (RM)] on NH3 volatilization and rice N uptake during the 2018–2019 rice growing seasons. NH3 volatilization from both the paddy field and the peripheral trench under RC was determined. Compared with RM, RC reduced the mean urease activity by 28.2–29.4% in the paddy field by promoting N fertilizer deposition into the peripheral trench. The decrease in urease activity finally reduced the total NH3 volatilization by 16.1–19.6% from both the paddy field and the peripheral trench. As a special drainage structure, the peripheral trench increased the rice N uptake by 16.7–18.3% under RC compared with that under RM by reducing NH3 volatilization.

Ethyl esters enhancement of Jinchuan pear wine studied by coculturing Saccharomyces bayanus with Torulaspora delbrueckii and their community and interaction characteristics

To enhance the fruity flavour of pear wine by coculturing Saccharomyces yeasts with non-Saccharomyces, the coculture patterns were optimised based on the effect of different strains on the physicochemical properties and metabolites, and the interaction relationship in the coculture fermentation was also studied. These results showed that total volatiles of S. bayanus were higher than those of S. cerevisiae, especially esters, acids and phenols. The contents of total volatiles and esters were enhanced by sequential inoculation. The effect of coculturing S. bayanus Y4 with T. delbrueckii Y7 or Pichia sp. was better than that of coculturing with them with S. cerevisiae Y1, enhancing the contents of phenylethanol, acetate and ethyl esters. Furthermore, the esters (mainly ethyl esters) content was increased by 53.30%, and the acids content was decreased by 32.82% when S. bayanus Y4 was cocultured with T. delbrueckii Y7 by sequential inoculation compared with S. bayanus Y4 single inoculation. Their coculture increased the α-diversity of the fungal community and changed the correlation network between the microbiota. Redundancy analysis showed that Torulaspora was closely correlated to ethyl hexanoate, ethyl decanoate and ethyl 9-decenoate, while Saccharomyces was associated with hexanoic acid and octanoic acid. PICRUSt2 prediction revealed that Torulaspora may utilize the fatty acids produced by Saccharomyces to synthesize fatty acid ethyl esters.

Content of mineral elements in different Artemisia argyi germplasms and their relationship with quality properties

To clarify the content characteristics of mineral elements in different Artemisia argyi germplasm resources and their relationship with the quality properties of Artemisiae Argyi Folium, this study measured the content of 10 mineral elements including nitrogen(N), phosphorus(P), potassium(K), calcium(Ca), magnesium(Mg), aluminum(Al), manganese(Mn), iron(Fe), copper(Cu), and zinc(Zn) in 100 Artemisia argyi germplasm samples. Besides, their relationship with the quality properties of Artemisiae Argyi Folium was explored by correlation analysis, path analysis, and cluster analysis. The results demonstrated that the variation coefficient of the 10 mineral elements in Artemisiae Argyi Folium ranged from 12.23% to 64.38%, and the genetic diversity index from 0.97 to 3.09. The genetic diversities of N, P, and Zn were obvious. As revealed by the correlation analysis, N, P, and K showed strong positive correlations with each other. Except that Mg and Al were negatively correlated, Ca, Mg, Al, Mn, Fe, Cu, and Zn were positively correlated. The correlation analysis of mineral elements with the quality properties of Artemisiae Argyi Folium proved the significant correlations of 17 pairs of characters. According to the path analysis, P, K, Ca, and Mn greatly affected the yield of Artemisiae Argyi Folium, P, K, and Mg the output rate of moxa, N, P, and K the content of total volatile oil, P and K the content of eucalyptol, and P, K, and Ca the content of eupatilin. The 100 germplasm samples were clustered into three groups. Specifically, in cluster Ⅰ, the enrichment capacity of P, K, and Mg elements was strong, and the comprehensive properties of mineral elements were better, implying good development potential. Ca, Mn, Fe, and Zn elements in cluster Ⅱ and N and Al in cluster Ⅲ displayed strong enrichment capacities. This study has provided new ideas for resource evaluation and variety breeding of A. argyi and also reference for fertilizer application.

The Thermal Decomposition Behavior of Pyrite-Pyrrhotite Mixtures in Nitrogen Atmosphere

To assess the thermal transformation process of common sulfide minerals in a nitrogen atmosphere, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, and thermogravimetric mass spectrometry are employed to define the influence of the pyrrhotite content in pyrite-pyrrhotite mixtures (mixed minerals). The results indicate that an increase in pyrrhotite content decreases the temperature of the maximum mass loss rate of mixed minerals and reduces its mass loss. The solid-phase transformation of the thermal decomposition of mixed minerals is accelerated because the apparent activation energy of pyrrhotite is lower than that of pyrite and mixed minerals. However, the pyrrhotite makes the mixed minerals easier to sinter and agglomerate, which reduces the total volatilization amount of the gas product, S2; thus, the rate of mass loss decreases.

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.