Quantitation of triacylglycerols from plant oils using charged aerosol detection with gradient compensation

Fabrication of immobilized lipases for efficient preparation of 1,3-dioleoyl-2-palmitoylglycerol

This study aims to fabricate immobilized lipases for efficient preparation of 1,3-dioleoyl-2-palmitoyl-glycerol (OPO) through acidolysis of glycerol tripalmitate (PPP). Twelve (three types) supports and five lipases were studied carefully. Among them, the immobilized Thermomyces lanuginosa lipase (TLL) samples exhibited overall better performance than that of other immobilized lipases. Particularly, organic groups functionalized SBA-15 (R-SBA-15) supported TLL (TLL@R-SBA-15) samples gave PPP conversion from 97.70 to 99.00 % and OPO content from 59.52 to 64.73 %. After optimization, PPP conversion up to 99.07 %, OPO content 73.15 % and sn-2 palmitic acid content 90.09 % were obtained with TLL@C₁₈H₃₇-SBA-15 as catalyst. Moreover, TLL@C₁₈H₃₇-SBA-15 exhibited better acidolysis performance from 50 °C than that from 60 to 80 °C, which helped inhibit acyl migration. In addition, after 5 cycles of reuse, TLL@C₁₈H₃₇-SBA-15 retained 81.04 % (based on OPO content) and 98.88 % (based on sn-2 palmitic acid content) of its initial activity, indicating it had an attractive prospect in future applications.

Accurate quantification of TAGs to identify adulteration of edible oils by ultra-high performance liquid chromatography-quadrupole-time of flight-tandem mass spectrometry

Edible oils play important roles in biological functions, and triacylglycerols (TAGs) in edible oils are complex mixtures. This makes accurate TAGs quantitation quite difficult that bring economically motivated food adulteration. Herein, we demonstrated a strategy for accurate quantification of TAGs in edible oils, which could be applied in identification of olive oil adulteration. The results showed that the proposed strategy could significantly improve the accuracy of TAG content determination, reduce the relative error of fatty acids (FAs) content determination, and present a wider accurate quantitative range than that of gas chromatography-flame ionization detection. Most important, this strategy coupled with principal component analysis could be used to identify adulteration of high-priced olive oil with cheaper soybean oils, rapeseed oils or camellia oils at a lower concentration of 2%. These findings indicated that the proposed strategy could be regarded as a potential method for edible oils quality and authenticity analysis.

Quality analysis of hawthorn leaves (the leaves of Crataegus pinnatifida Bge. var major N.E.Br) in different harvest time

INTRODUCTION

Harvest time plays an important role on the quality of medicinal plants. The leaves of Crataegus pinnatifida Bge. var major N.E.Br (hawthorn leaves) could be harvested in summer and autumn according to the Pharmacopoeia of the People's Republic of China (Pharmacopoeia). However, little is known about the difference of the chemical constituents in hawthorn leaves with the harvest seasonal variations.

OBJECTIVE

The chemical constituents of hawthorn leaves in different months were comprehensively analysed to determine the best harvest time.

METHODS

Initially, the chemical information of the hawthorn leaves were obtained by ultra-high-performance liquid chromatography and quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS). Subsequently, principal component analysis (PCA) was applied to compare the chemical compositions of hawthorn leaves harvested in different months. Then, an absolute quantitation method was established using high-performance liquid chromatography-charged aerosol detector (HPLC-CAD) to determine the contents of five compounds and clarify the changes of these components with the harvest seasonal variations. Meanwhile, a semi-quantitative method by integrating HPLC-CAD with inverse gradient compensation was also established and verified.

RESULTS

Fifty-eight compounds were identified through UHPLC-Q-TOF-MS. PCA revealed that the harvest season of hawthorn leaves had a significant effect on the chemical compositions. The contents of five components were relatively high in autumn. Other four main components without reference standards were further analysed through the semi-quantitative method, which also showed a high content in autumn.

CONCLUSIONS

This work emphasised the effect of harvest time on the chemical constituents of hawthorn leaves and autumn is recommended to ensure the quality.

Determination of Glycerophospholipids in Biological Material Using High-Performance Liquid Chromatography with Charged Aerosol Detector HPLC-CAD-A New Approach for Isolation and Quantification

The method of using high-performance liquid chromatography with a charged aerosol detector method (HPLC-CAD) was developed for the separation and determination of phospholipids isolated from cell membranes. The established cell lines—normal and neoplastic prostate cells and normal skin fibroblasts and melanoma cells—were selected for the study. Chromatographic separation was performed in the diol stationary phase using a gradient elution based on a mixture of n-hexane, isopropanol and water with the addition of triethylamine and acetic acid as buffer additives. Taking the elements of the Folch and Bligh–Dyer methods, an improved procedure for lipid isolation from biological material was devised. Ultrasound-assisted extraction included three extraction steps and changed the composition of the extraction solvent, which led to higher recovery of the tested phospholipids. This method was validated by assessing the analytical range, precision, intermediate precision and accuracy. The analytical range was adjusted to the expected concentrations in cell extracts of various origins (from 40 µg/mL for PS up to 10 mg/mL for PC). Both precision and intermediate precision were at a similar level and ranged from 3.5% to 9.0%. The recovery for all determined phospholipids was found to be between 95% and 110%. The robustness of the method in terms of the use of equivalent columns was also confirmed. Due to the curvilinear response of CAD, the quantification was based on an internal standard method combined with a power function transformation of the normalized peak areas, allowing the linearization of the signal with an R² greater than 0.996. The developed method was applied for the isolation and determination of glycerophospholipids from cell membranes, showing that the profile of the tested substances was characteristic of various types of cells. This method can be used to assess changes in metabolism between normal cells and neoplastic cells or cells with certain pathologies or genetic changes.

Regio- and Stereospecific Analysis of Triacylglycerols—A Brief Overview of the Challenges and the Achievements

The efforts to reveal, in detail, the molecular and intramolecular structures of one of the main lipid classes, namely, triacyl-sn-glycerols, which are now known to affect their specific and important role in all living organisms, are briefly overviewed. Some milestones of significance in the gradual but continuous development and improvement of the analytical methodology to identify the triacylglycerol regio- and stereoisomers in complex lipid samples are traced throughout the years: the use of chromatography based on different separation principles; the improvements in the chromatographic technique; the development and use of different detection techniques; the attempts to simplify and automatize the analysis without losing the accuracy of identification. The spectacular recent achievements of two- and multidimensional methods used as tools in lipidomics are presented.

HRMS Detector for the New HILIC CBD Method Development in Hemp Seed Oil

The cannabis analysis has gained new importance worldwide due to the rapid expansion of the hemp global market. Many reverse phase high performance liquid chromatography (HPLC) methods have been developed to analyze cannabidiol (CBD) and its analogues due to the nice fit with their log P values at around 6. However, when CBD was blended with hemp seed oil in consumer, cosmetic, and food industries, the high content of triacylglycerides (TAGs) from hemp seed oil were retained and accumulated inside C₁₈ columns with the common mobile phases and caused a column pressure increase and ghost peaks after continuous sample injections. Coupled with the chemical profile from high resolution mass spectrometry (HRMS) detection, a novel hydrophilic interaction liquid chromatography (HILIC) CBD quantitation method was developed, specifically for CBD blended hemp seed oil materials, which can overcome the matrix buildup in reverse phase columns. The zwitterionic (ZIC)-cHILIC column containing a dense water layer on the stationary phase surface provided a stable partitioning separation mechanism to separate the CBD from TAGs in hemp seed oil. This water layer favors the sustaining NH₄F buffer ions, which can maximize the salting-out action and help reduce the adsorptive interaction between TAGs and stationary phase sulfobetaine materials. The high percentage of acetonitrile (99%) contributed to method sensitivity and reduced instrument maintenance time. The method was developed and validated for the first time. It has been successfully applied to quantify CBD content in hemp seed oil samples, thus demonstrating it to be a useful tool for both quality control and safety assurance in CBD hemp seed oil raw materials and related products.

Non-aqueous reversed phase liquid chromatography with charged aerosol detection for quantitative lipid analysis with improved accuracy

There is a great need for efficient analysis of the composition of vegetable oils and fats, since it affects the physical and technical properties. However, due to the complex nature of these kind of samples, it is often difficult and costly. In the present study, we developed a Non-Aqueous Reversed-Phase HPLC method that can be used to separate and quantify different free fatty acids, fatty acid esters, monoacylglycerides, diacylglycerides and triacylglycerides, including regioisomers such as SOS/SSO and 1,2- and 1,3-diolein. Two 25 cm Nucleodur C18 Isis columns in series, sub-ambient column temperature and a mobile phase gradient composed of acetonitrile, acetic acid, isopropanol and heptane were used for the separation. The lipids were detected and quantified using a charged aerosol detector and it was found that the peak shape highly affected the detector response as well as the response uniformity, even when inverse gradient compensation was employed. Thus, calibration and determination of response factors were necessary for reliable quantification. A correlation between response factors and peak width at half peak height was found and used for quantification of non-calibrated components. A quantification approach was suggested including an appropriate selection of calibrated components, depending on sample composition and the accuracy required. It was shown in a complex oil sample that the reduced calibration approach, using only 6 instead of 33 calibrated components, resulted in virtually the same composition, but yielded a more accurate result compared to using relative area that neglects response factors. The method validation showed good reproducibility and accuracy, making it an excellent tool for extensive analysis of complex lipid mixtures.

Analysis of mono-, di-, triacylglycerols, and fatty acids in food emulsifiers by high-performance liquid chromatography–mass spectrometry

Mono- and diacylglycerols (MG/DG) of fatty acids (FA), known as emulsifiers of the type E 471, are food additives used to adjust techno-functional properties of various foodstuffs. These emulsifiers, however, are not defined single compounds but comprise, in addition to MG and DG, other constituents such as FA, triacylglycerols (TG), and glycerol. Although the emulsifiers’ compositions affect techno-functional properties of the food, knowledge of the composition is scarcely available, and the emulsifiers and their dosage are generally chosen empirically. Thus, a simple and rather inexpensive method for the simultaneous determination of FA, 1-MG, 2-MG, 1,2-DG, 1,3-DG, and TG by high-performance liquid chromatography–mass spectrometry including a straightforward quantitation strategy has been developed. Reversed-phase chromatography with gradient elution offered adequate separation of 29 considered analytes within 21 peaks, while mass-selective detection provided their unequivocal identification. The quantitation strategy based on calibration just with the C16:0 representatives of each lipid class and a corresponding response factor system has proven to provide reliable results. The determined concentrations of different mixtures comprising varying compositions and concentrations of C16:0, C18:0, and C18:1 components of each lipid class deviated < 20% (n = 351) from the respective target concentrations. Limits of decision were determined to 0.3–0.8 mg/L and limits of quantitation to 0.8–1.7 mg/L, expressed as C16:0 representatives. Application of the method to various E 471 emulsifiers provided detailed data on their chemical compositions, and calculated FA compositions matched very well those determined by common methods such as gas chromatography with flame ionization detection.

Authentication of the Geographical Origin of Margarines and Fat-Spread Products from Liquid Chromatographic UV-Absorption Fingerprints and Chemometrics

Fat-spread products are a stabilized emulsion of water and vegetable oils. The whole fat content can vary from 10 to 90% (w/w). There are different kinds, which are differently named, and their composition depends on the country in which they are produced or marketed. Thus, having analytical solutions to determine geographical origin is required. In this study, some multivariate classification methods are developed and optimised to differentiate fat-spread-related products from different geographical origins (Spain and Morocco), using as an analytical informative signal the instrumental fingerprints, acquired by liquid chromatography coupled with a diode array detector (HPLC-DAD) in both normal and reverse phase modes. No sample treatment was applied, and, prior to chromatographic analysis, only the samples were dissolved in n‑hexane. Soft independent modelling of class analogy (SIMCA) and partial least squares-discriminant analysis (PLS-DA) were used as classification methods. In addition, several classification strategies were applied, and performance of the classifications was evaluated applying proper classification metrics. Finally, 100% of samples were correctly classified applying PLS-DA with data collected in reverse phase.

Differentiation of avocados according to their botanical variety using liquid chromatographic fingerprinting and multivariate classification tree

BACKGROUND

The oil content, composition and marketing threshold value of an avocado depends on the cultivar hence, identifying the cultivar of the avocado fruit is desirable. However, analytical methods have not been reported with this aim.

RESULTS

A multivariate classification tree method was proposed to discriminate three commercial botanical varieties of avocado: Hass, Fuerte and Bacon, using high-performance liquid chromatography coupled to a charged aerosol detector (HPLC-CAD). Prior to the chromatographic analysis the avocados were lyophilized and then the oil fraction was extracted using a pressurized liquid extraction system. Normal and reverse phase liquid chromatography were applied in order to obtain the chromatographic fingerprint for each sample. Soft independent modelling of class analogies (SIMCA) and partial least-squares discriminant analysis (PLS-DA) were applied. Classification quality metrics were determined to evaluate the performance of the classification. Several strategies to develop the classification models were employed. Finally, the useful application of 'classification trees' methodology, which has been scarcely applied in the field of analytical food control, was evaluated to perform a multiclass classification.

CONCLUSION

Discrimination of the three botanical varieties was achieved. The best classification was obtained when the PLS-DA is applied on the normal-phase chromatographic fingerprints. Classification trees are showed to be useful tools that provide complementary information to single concatenated models showing different results from the same prediction sample set. © 2019 Society of Chemical Industry.

Triacylglycerol Composition of Breast Milk during Different Lactation Stages

Triacylglycerol (TAG) composition of breast milk plays an important role in improving digestion, absorption, and metabolism when consumed by infants. This study characterized the TAG profile of human colostrum, transitional, and mature milk samples from 103 women. Significant differences in the TAGs composition of breast milk fat from three lactation stages were observed. The TAGs with high molecular weight and unsaturated fatty acid (such as 1,3-olein-2-palmitin (OPO) and 1(3)-olein-2-palmitin-3(1)-linolein (OPL)) were enriched in colostrum, while the TAGs containing medium-chain fatty acids were more abundant in transitional and mature milk than that in colostrum. Of note, OPL was the most common TAG in breast milk of Chinese women while the most common TAG in breast milk of Western women was OPO. This data will promote the development of infant formulas in terms of the TAG composition more suitable for infants.

Quantification of Lipids: Model, Reality, and Compromise

Lipids are key molecules in various biological processes, thus their quantification is a crucial point in a lot of studies and should be taken into account in lipidomics development. This family is complex and presents a very large diversity of structures, so analyzing and quantifying all this diversity is a real challenge. In this review, the different techniques to analyze lipids will be presented: from nuclear magnetic resonance (NMR) to mass spectrometry (with and without chromatography) including universal detectors. First of all, the state of the art of quantification, with the definitions of terms and protocol standardization, will be presented with quantitative lipidomics in mind, and then technical considerations and limitations of analytical chemistry's tools, such as NMR, mass spectrometry and universal detectors, will be discussed, particularly in terms of absolute quantification.

Triacylglycerols in edible oils: Determination, characterization, quantitation, chemometric approach and evaluation of adulterations

Vegetable oils are a dietary source of lipids that constitute an essential component of a healthy diet. The commonly used vegetable oils differ significantly for their triacylglycerol (TAG) profile. TAGs represent the principal components of oils and may contain different fatty acids (FA) esterified with glycerol leading to several positional isomers. To differentiate individual TAGs species in edible oils, advanced analysis systems and innovative methods are therefore required. TAGs can be considered as good fingerprints for quality control and many studies have been performed to develop rapid and low cost analytical methods to determinate the authenticity, origin and eventually evidence frauds or adulterations. The present manuscript provides a general overview on the most common vegetable oils TAGs compositions and on the related analytical methodologies recently used. Finally, the chemometric applications developed to assess the authenticity, quality and botanical origin of various edible oils are discussed.

Optimization of Ultrasonic-assisted Extraction of Fatty Acids in Seeds of Brucea Javanica (L.) Merr. from Different Sources and Simultaneous Analysis Using High-Performance Liquid Chromatography with Charged Aerosol Detection

Our research aimed to optimize the oil extraction process and determine the fatty acids in Brucea javanica (L.) Merr. seeds. The extraction technology was optimized using response surface methodology. A Box-Behnken design was employed to investigate the effects of three independent variables on an ultrasonic-assisted extraction technique, namely, sonication time (X₁: 20–40 min), liquid–solid ratio (X₂: 16:1 mL/g–24:1 mL/g), and ethanol concentration (X₃: 90%–100%). The optimum conditions of sonication time, liquid–solid ratio, and ethanol concentration were 40 min, 24:1 mL/g, and 100%, respectively. The content of fatty acids and the oil yield were 14.64 mg/g and 16.87%, respectively, which match well with the predicted models. The optimum number of extraction times was eventually identified as two. A new rapid method for the qualitative and quantitative analysis of the fatty acids of B. javanica (L.) Merr. seed oil using HPLC with a charged aerosol detector was described. The fatty acid contents of 14 batches of B. javanica (L.) Merr. seed oil were determined, and the relevance and difference were analyzed by fingerprint analysis. The fingerprint has five common peaks, and the similarity was greater than 0.991. HPLC analysis represents a specialized and rational approach for the quality identification and comprehensive evaluation of B. javanica (L.) Merr. seed oils.

Determination of total ginsenosides in ginseng extracts using charged aerosol detection with post-column compensation of the gradient

AIM

Variation in structure-related components in plant products prompted the trend to establish methods, using multiple or total analog analysis, for their effective quality control. However, the general use of routine quality control is restricted by the limited availability of reference substances. Using an easily available single marker as a reference standard to determine multiple or total analogs should be a practical option.

METHOD

In this study, the Ultra-HPLC method was used for the baseline separation of the main components in ginseng extracts. Using a plant chemical component database, ginsenosides in ginseng extracts were identified by Ultra-HPLC-MS analysis. The charged aerosol detection (CAD) system with post-column compensation of the gradient generates a similar response for identical amounts of different analytes, and thus, the content of each ginsenoside in ginseng extracts was determined by comparing the analyte peak area with the reference standard (determination of total analogs by single marker, DTSM). The total ginsenoside content was determined by the summation of reference standard and other ginsenoside components.

RESULTS

The results showed that DTSM approaches were available for the determination of total ginsenosides in a high purity ginseng extract because of the removal of impurities. In contrast, DTSM approaches might be suitable for determination of multiple ginsenosides without interference from impurities in the crude ginseng extract.

CONCLUSION

Future practical studies similar to the present study should be conducted to verify that DTSM approaches based on CAD with post-column inverse gradient for uniform response are ideal for the quality control of plant products.

Enzymatic hydrolysis-based absolute quantification of triacylglycerols in plant oil by use of a single marker

Absolute quantification of triacylglycerols (TAGs) in plant oils is a challenge for analysts, because most of the necessary chemical standards are unavailable. In this study, a new method for absolute quantification analysis of multi-components by use of a single marker (AQAMS), using two crucial technologies, evaluation of the collection recovery without chemical standards and enzymatic hydrolysis, was used for determining the absolute content of TAGs in brucea javanica oil (BJO), using glycerol as the marker. The TAGs in BJO were initially characterized using ultrafast liquid chromatography tandem atmospheric-pressure-chemical-ionization mass spectrometry. Then the TAGs in BJO were individually collected, by target-fraction collection via high-performance liquid chromatography coupled with an evaporative-light-scattering detector (HPLC-ELSD), and their recoveries were calculated by use of a novel non-standard evaluated recovery strategy (NSER). The results revealed that the collection procedure was feasible and reliable. Finally, modified commercial TAG assay kits using glycerol as the marker were used to determine the absolute abundance of individual TAGs in the plant oils. Comparing the result with that obtained by HPLC-ELSD analysis using triolein standard, the content of triolein determined by AQAMS was closely matched. The proposed strategy is a practical measure for solving the problem of the lack of chemical standards, and provides a new method for absolute quantification in natural products of multi-components with the same backbone.

Charged aerosol detection to characterize components of dispersed-phase formulations

Colloidal formulations based on biocompatible phospholipids, emulsifiers, and oils are employed in a wide range of applications including medicine, food, and cosmetics. However, characterization of these dispersed-phase components may be difficult to analyze by traditional HPLC with UV, visible, or fluorescence detection modalities due to lack of chromophores or fluorophores. Charged aerosol detection (CAD) is increasingly used for analysis of dispersed-phase components due to its broad applicability and high sensitivity for non-chromophore containing components found in many colloidal systems, such as lipid-based molecules. In this review, we summarize the recent applications of CAD reported in the literature as well as our own laboratory for the analysis of widely used components of dispersed-phase systems. In particular, we discuss the advantages and disadvantages of CAD compared to other HPLC detection methods, as well as the various sample preparation methods suitable for colloidal formulations prior to HPLC-CAD analysis.

Characterization of triacylglycerol enantiomers using chiral HPLC/APCI-MS and synthesis of enantiomeric triacylglycerols

In this work, the first systematic characterization of triacylglycerol (TG) enantiomers in real samples using chiral high-performance liquid chromatography (HPLC) with atmospheric pressure chemical ionization mass spectrometry (APCI-MS) is performed. Our chiral HPLC/APCI-MS method is based on the use of two cellulose-tris-(3,5-dimethylphenylcarbamate) columns connected in series using a gradient of hexane-2-propanol mobile phase. All TG enantiomers containing 1-8 DBs and different fatty acyl chain lengths are separated using our chiral HPLC method except for TGs having a combination of saturated and di- or triunsaturated fatty acyls in sn-1 and sn-3 positions. In our work, the randomization reaction of monoacyl TG standards is used for the preparation of all TG enantiomers and regioisomers in a mixture, while the stereospecific esterification of 1,2- or 2,3-isopropylidene-sn-glycerols by selected fatty acids is used for the synthesis of TG enantiomers. The composition of TG enantiomers and regioisomers in hazelnut oil and human plasma samples is determined. Unsaturated fatty acids are preferentially esterified in sn-2 position in hazelnut oil, while no significant preference of saturated or unsaturated fatty acyls is observed in case of human plasma sample. Fatty acids with the higher number of DBs are preferred in sn-1 position of TG enantiomers in hazelnut oil unlike to moderate sn-3 preference in human plasma. The characterization of cholesteryl esters from TG fraction of human plasma sample using our chiral HPLC/APCI-MS method is presented as well.

New Developments in Liquid Chromatography Mass Spectrometry for the Determination of Micropollutants

The combination of liquid chromatography (LC) with mass spectrometry (MS) in the environmental field has appeared as a valuable tool for the determination of micropollutants. Several groups of compounds have been considered as particularly relevant (e.g., pharmaceuticals, hormones and other endocrine-disrupting, personal care products and their metabolites, flame retardants, surfactants, and plasticizers, among others) since the same ones are continuously being released in the environment mainly as a result of the manufacturing processes, the disposal of unused or expired products, and the excreta. Because these micropollutants are not completely removed in the environment, very specific and sensitive analytical procedures are needed for their identification and quantification. High performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) (or LC-MS2) and especially time-of-flight mass spectrometry (TOF/MS), has allowed that many environmental contaminants that are highly polar or nonvolatile or have a high molecular weight to be analyzed or identified. In this work we present an overview focused on the developments of liquid chromatography mass spectrometry applied to the analysis of the main classes of micropollutants in aqueous and solid environmental samples. Various aspects of methodologies based on these techniques, including sample preparation (extraction/preconcentration) and matrix effects, are discussed.

Quantification aspects of constant pressure (ultra) high pressure liquid chromatography using mass-sensitive detectors with a nebulizing interface

The present contribution investigates the quantitation aspects of mass-sensitive detectors with nebulizing interface (ESI-MSD, ELSD, CAD) in the constant pressure gradient elution mode. In this operation mode, the pressure is controlled and maintained at a set value and the liquid flow rate will vary according to the inverse mobile phase viscosity. As the pressure is continuously kept at the allowable maximum during the entire gradient run, the average liquid flow rate is higher compared to that in the conventional constant flow rate operation mode, thus shortening the analysis time. The following three mass-sensitive detectors were investigated: mass spectrometry detector (MS), evaporative light scattering detector (ELSD) and charged aerosol detector (CAD) and a wide variety of samples (phenones, polyaromatic hydrocarbons, wine, cocoa butter) has been considered. It was found that the nebulizing efficiency of the LC-interfaces of the three detectors under consideration changes with the increasing liquid flow rate. For the MS, the increasing flow rate leads to a lower peak area whereas for the ELSD the peak area increases compared to the constant flow rate mode. The peak area obtained with a CAD is rather insensitive to the liquid flow rate. The reproducibility of the peak area remains similar in both modes, although variation in system permeability compromises the 'long-term' reproducibility. This problem can however be overcome by running a flow rate program with an optimized flow rate and composition profile obtained from the constant pressure mode. In this case, the quantification remains reproducibile, despite any occuring variations of the system permeability. Furthermore, the same fragmentation pattern (MS) has been found in the constant pressure mode compared to the customary constant flow rate mode.

Characteristics of papaya seed oils obtained by extrusion-expelling processes

BACKGROUND

In general, about 300 g kg(-1) of the weight of papaya fruits appears as waste materials during processing, including a considerable amount of papaya seeds. To make a more efficient use of papaya, it is worth investigating the utilization of the seeds. The aim of this study was to comprehensively assess the lipid characteristics of papaya seed oil obtained by expelling processes.

RESULTS

Papaya seed oil was found to have several unique characteristics, including its high oleic content, the relative ratio of saturated/monounsaturated/polyunsaturated fatty acids of 29/68/3, the polyunsaturated fatty acids merely accounting for 3.34% and its triacylglycerol composition being very similar to that of olive oil. Also, this oil was rich in chemopreventive benzyl isothiocyanate, the level ranging from 4.0 to 23.3 g kg(-1) dependent on the various processing methods for the pretreatment of papaya seeds.

CONCLUSION

On the basis of our results, papaya seed oil can be considered as a high-oleic oil with a chemoprotective effect, and may be viewed as a healthy alternative in the functional food industry.