Finding of pesticides in fashionable fruit juices by LC–MS/MS and GC–MS/MS

Products labelled as containing extracts from two mushrooms (cordyceps plus reishi) and the juices from açaí, goji, mangosteen, noni, pomegranate, and sea buckthorn have been analysed for 174 different pesticides, using the validated QuEChERS method for sample preparation and electrospray LC–MS/MS in the positive ion mode for analysis. Pesticides were found in 10 of the 21 samples analysed. Most pesticides found were below the tolerance levels (1–6 μg/g, depending on the pesticide), but some were not. This included boscalid, dimethomorph, iprovalicarb, pyridaben, pyrimethanil, and imazalil, for which there is no tolerance reported or zero tolerance in any fruit. However, genuine açaí that was harvested in the state of Pará and lyophilised in Rio de Janeiro had no detectable pesticides, when analysed by both LC–MS/MS and GC–MS/MS, which can detect 213 more pesticides and industrial chemicals. Likewise no pesticides were found in one sample each of cordyceps plus reishi, sea buckthorn and noni.     

Separation and identification of zinc-chelating peptides from sesame protein hydrolysate using IMAC-Zn and LC–MS/MS

The metal chelating peptides from sesame protein hydrolysates (SPH), treated by papain, alcalase and trypsin, respectively, were investigated. The hydrolysates treated by trypsin had the highest metal chelating ability. The metal chelating peptides were isolated from the trypsin hydrolysates using immobilized metal affinity chromatography (IMAC-Zn²⁺). Further, six zinc-chelating peptides were identified with reversed phase (RP)-HPLC and mass spectrometry (LC–MS/MS). Three of these metal-chelating peptides, Ser-Met, Leu-Ala-Asn and Asn-Cys-Ser, were synthesized and the metal-chelating ability of peptides was measured. The Asn-Cys-Ser peptide showed the highest zinc and iron chelating ability, which was even higher than reduced glutathione (GSH). The results confirm that the zinc or iron chelating activity of these peptides, and provide further support to its feasibility as natural metal chelating agents from sesame protein.     

Ultrahigh pressure extraction of bioactive compounds from plants—A review

Extraction of bioactive compounds from plants is one of the most important research areas for pharmaceutical and food industries. Conventional extraction techniques are usually associated with longer extraction times, lower yields, more organic solvent consumption, and poor extraction efficiency. A novel extraction technique, ultrahigh pressure extraction, has been developed for the extraction of bioactive compounds from plants, in order to shorten the extraction time, decrease the solvent consumption, increase the extraction yields, and enhance the quality of extracts. The mild processing temperature of ultrahigh pressure extraction may lead to an enhanced extraction of thermolabile bioactive ingredients. A critical review is conducted to introduce the different aspects of ultrahigh pressure extraction of plants bioactive compounds, including principles and mechanisms, the important parameters influencing its performance, comparison of ultrahigh pressure extraction with other extraction techniques, advantages, and disadvantages. The future opportunities of ultrahigh pressure extraction are also discussed.     

Quantification of folpet and phthalimide in tea and herbal infusions by LC– high-resolution MS and GC–MS/MS

Two methods based on a modified QuEChERS sample preparation and either LC coupled to atmospheric pressure ionisation and high-resolution MS or GC coupled to electron ionisation and tripled quadrupole MS have been assessed for the quantification of folpet and phthalimide in tea and other dry herbal infusions. Both methods have been fully validated in green tea and further checked in black tea, verbena and rooibos, and they performed according to the SANTE/11813/2017 criteria at the target LOQ concentration level (50 µg/kg). These methods allow the accurate quantification of folpet in the selected matrices according to the new EU residue definition, which includes phthalimide. Phthalimide is the main metabolite and degradation product of folpet, although according to recent studies, it could be generated from different sources than folpet breakdown, such as food processing or analysis by GC.     

Characterization of traditional and exotic apple varieties from Portugal. Part 2 – Antioxidant and antiproliferative activities

Apples are known to have many health-promoting activities, especially anticancer, antiradical and antioxidant effects. Most of these actions are believed to be due to their polyphenolic components which vary greatly between different varieties.In this work, four traditional Portuguese apple cultivars (Bravo de Esmolfe, Malápio Fino, Malápio da Serra and Pêro Pipo) and five exotic varieties (Golden, Starking, Fuji, Gala Galaxy and Reineta Parda) were evaluated in terms of their bioactivity using both cell-based and cell-free assays; 17 parameters were evaluated for each sample. Results obtained were submitted to principal component analysis (PCA) and it was possible to conclude that Malápio Fino and Bravo de Esmolfe apple varieties have the highest antioxidant effect and Reineta Parda variety is the best cultivar in promoting antiproliferative effect against human colon (HT29) and gastric (MKN45) cancer cells. Correlations of the data obtained showed that among phenolic compounds catechin, epicatechin and procyanidin B1 were the major contributors to the antioxidant activity of apples whereas procyanidins (B1 and B2), phloridzin and epicatechin played an important role against human cancer cell proliferation.     

Phytoestrogenic activity of Aceriphyllum rossii and rapid identification of phytoestrogens by LC–NMR/MS and bioassay-guided isolation

Aceriphyllum rossii Engler (Saxifragaceae) has been used as a nutritious food in Korea, but only minimal studies on this plant have been undertaken. We have examined the estrogenic effect of A. rossii and have discovered its potent constituents. To identify the estrogenic activity of A. rossii, we measured the transactivation of the estrogen-responsive element (ERE) in MCF-7 cells transfected with an ERE-containing construct after treatment of the extract and fractions of A. rossii. A. rossii showed a potent estrogenic activity and gallic acid ethyl ester; quercetin and kaempferol were identified as major constituents of the active fractions by liquid chromatography–nuclear magnetic resonance spectroscopy/mass spectrometry. We confirmed quercetin and kaempferol are the major active constituents after activity-guided isolation of seven compounds: gallic acid ethyl ester (1), quercetin (2), kaempferol (3), quercetin-3-O-(6″-galloyl)-β-d-glucopyranoside (4), quercetin-3-O-β-d-glucopyranoside (5), kaempferol-3-O-(6″-galloyl)-β-d-glucopyranoside (6), and kaempferol-3-O-β-d-glucopyranoside (7). These results show A. rossii could be a possible candidate for the treatment of postmenopausal symptoms.     

Assessment of Indigo (Polygonum tinctorium Ait.) water extracts’ bioactive compounds,and their antioxidant and antiproliferative activities

There are a few investigations on Indigo (Polygonum tinctorium Ait.), as a medicinal plant. Therefore, the aim of this study was to assess the contents of bioactive compounds, antioxidant and antiproliferative activities and to compare with another medicinal plant Prolipid. It was found that the bioactive compounds from different parts of Indigo water extracts varied (P < 0.05): polyphenols and flavonoids were significantly higher in Prolipid, flavanols in Indigo seeds, and vitamin C similar in Indigo leaves and Prolipid. The antioxidant activity by ABTS, FRAP, CUPRAC and DPPH assays was significantly different (P < 0.05): the highest in Prolipid, following by Indigo mature leaves. DPPH kinetic measurements compared, distinguished and discriminated the antiradical activity among Indigo and Prolipid water extracts by multivariate analysis. The interaction between polyphenol extracts of Indigo mature leaves and BSA showed that Indigo has a strong ability, as other medicinal plants, to quench the intrinsic fluorescence of BSA by forming complexes. In conclusion, for the first time Indigo mature leaves were analyzed and compared with widely consumed Prolipid. The relatively high content of bioactive compounds, positive antioxidant, fluorescence and antiproliferative properties of Indigo justify the use of this plant as a new source of valuable antioxidants.     

Characterization of the key odor-active compounds in steamed meat of Coilia ectenes from Yangtze River by GC–MS–O

In this study, the key odor-active compounds in the steamed meat of Coilia ectenes from Yangtze River were isolated by headspace monolithic material sorptive extraction and analyzed by gas chromatography–mass spectrometry–olfactometry (GC–MS–O). A total of 49 volatile compounds were identified and quantified in the extract. The results of gas chromatography–olfactometry analysis combined with odor activity value showed that trimethylamine (fishy, ammonia-like), 3-methylbutanal (dark chocolate), decanal (green, oily), hexanal (green), (Z)-4-heptenal (fishy, boiled potato) and benzaldehyde (bitter almond) were the key odor-active compounds contributing primarily to the overall aroma of steamed Coilia ectenes meat. Among them, trimethylamine and (Z)-4-heptenal were the most potent odor-active compounds on the basis of their detection frequency at high odor intensities.     

Phenolic and aroma compositions of pitomba fruit (Talisia esculenta Radlk.) assessed by LC–MS/MS and HS-SPME/GC–MS

Pitomba (Talisia esculenta Radlk.) is a Brazilian exotic fruit consumed specially in the Amazonian region. Because of its large consumption and also due to the lack of knowledge regarding its chemical composition, pitomba fruit was studied in relation to its phenolic and aroma constitution. Using liquid chromatography tandem mass spectrometry (LC–MS/MS), 13 phenolic compounds (catechins, flavonoids and organic acids) were tentatively identified by comparison with standards and by fragmentation patterns. A validated method was applied to quantify common phenolic compounds of the pitomba pulp, for which quinic acid was the main compound (507.8 ± 7.4 μg g^− 1 DWP). Gas chromatography mass spectrometry (GC–MS) was employed along with headspace solid-phase microextraction (HS-SPME) to assess the aroma composition of pitomba fruit. A total of 27 volatile organic compounds (VOCs) were tentatively identified for pitomba fruit, for which 2-phenethyl acetate (17.89%) and isopentyl acetate (13.43%) esters were the main VOCs, contributing to the characteristic aroma of pitomba. The antioxidant capacity of the extract of pitomba fruit was evaluated by ABTS, DPPH and ORAC assays. We observed that pitomba has a moderate antioxidant activity.     

Rapid screening and identification of antioxidants in aqueous extracts of Houttuynia cordata using LC–ESI–MS coupled with DPPH assay

Houttuynia cordata Thunb. has been used traditionally as immune stimulant and anticancer agent. An aqueous extract of H. cordata tea showed high radical scavenging activity determined by off-line DPPH assays. Then, it was screened for its antioxidant components via an on-line DPPH radical scavenging technique coupled with a liquid chromatography–electrospray ionization mass spectrometer (LC–ESI–MS). Based on their mass spectra and fragmentation patterns; the antioxidant compounds were identified as quinic acid derivative, caffeic acid derivatives, procyanidin B, neo-chlorogenic acid, catechin, chlorogenic acid, crypto-chlorogenic acid and quercetin hexoside. LC–MS/MS in multiple reactions monitoring (MRM) mode was used to quantify these antioxidant compounds. Chlorogenic acid was found to be a major component in H. cordata tea.     

Chemical profiling of Punica granatum peels from Jordan using LC–MS/MS and study on their biological activities

A paucity of local information concerning the chemical profiles and biological activities of extracts obtained from less-studied P. granatum peel of Jordanian origin was considered in this study for the first time. Fractionation of the crude ethanol extracts was performed because of their higher phenolic and flavonoid contents compared to the water and acetone extracts. The chemical compositions of the respective samples, that is, extracts/fractions were identified by LC–MS/MS, and the elemental content of the raw materials was also analysed using atomic absorption spectrometry. Antioxidant activities of extracts and fractions were evaluated against DPPH and ABTS radical scavenging assays, and the antibacterial activities were investigated by disc diffusion method and MIC (Minimum Inhibitory Concentration). The LC–MS/MS results correlated strongly with the total phenolic and flavonoid contents, where ethanol displayed higher efficacy for extracting bioactive ingredients. Overall, a total of 19 phenolics were detected in the ethanolic peel extract of P. granatum. All of the analysed extracts showed strong antioxidant activities. Fractionation of ethanolic extracts resulted in fractions with almost similar chemical LC–MS/MS profiles, but the relative proportion of constituents was different. All fractions showed lower intensities of antioxidant capacities than crude extracts, highlighting the superiority of some components, either individually or combined, as well as their relative proportion on the biological activity of each fraction. The results of the present study emphasise the need to further explore the effect of putative interactions among plant bioactive ingredients and focus on possible interactions with drugs along with foods.     

Analysis of volatile compounds in New Zealand unifloral honeys by SPME–GC–MS and chemometric-based classification of floral source

New Zealand unifloral honeys have a higher commercial value than polyfloral honeys; however identification of floral source can be difficult and time-consuming. In this study, we aimed to establish a rapid and semi-automated method for identifying the floral source of New Zealand honeys. Volatile compounds from ten types of New Zealand unifloral honeys (a total of 234 samples) were analyzed by solid-phase microextraction (SPME) and gas chromatography coupled to mass spectrometry (GC–MS). For 37 compounds, probability plots of log₁₀[GC–MS peak area] versus cumulative probability enabled visual identification of those that could be possible markers used to discriminate floral source. GC–MS peak areas were also analyzed by hierarchical cluster analysis and principal component analysis. Results showed data falling into groups based on floral source, indicating that supervised pattern recognition could be used to build a model with which to classify honeys based on floral source. A model was built using WEKA (Waikato Environment for Knowledge Analysis) machine-learning software. The logistic model tree algorithm in WEKA produced a model that classified 89.8 % of samples correctly. Overall, results show that the methods employed here have the potential to be used as a basis for routine testing and classification of New Zealand unifloral honeys.     

Antioxidant/pro-oxidant properties of model phenolic compounds. Part II: Studies on mixtures of polyphenols at different molar ratios by chemiluminescence and LC–MS

The behaviour of four known antioxidants (quercetin, ascorbic acid, catechin and caffeic acid) and their mixtures at different molar ratios was studied in view of elaborating predictions over an eventual pro-oxidant or synergistic antioxidant activity. The Co(II)–EDTA luminol chemiluminescence showed that the mixture of quercetin and ascorbic acid at ratio 2:1 had the most pronounced antioxidant activity, while that of quercetin and caffeic acid at ratio 1:2 showed the least antioxidant activity, which may be interpreted as a strong propensity for pro-oxidant behaviour. The LC–MS analysis for the two mixtures revealed a significant amount of unoxidised quercetin in the case of quercetin with ascorbic acid, whereas in the case of quercetin with caffeic acid this amount was negligible. This observation supports the fact that the first combination was more antioxidant than the second, through efficient quercetin recycling (reduction of the quinone by ascorbic acid; redox cycling of quinones).     

Analysis of volatile compounds by GC–MS of a dry fermented sausage: chorizo de Pamplona

The profile of volatile compounds of a typical Spanish dry fermented sausage, chorizo de Pamplona, has been analyzed by GC–MS, using a simultaneous distillation-extraction (SDE) system. Qualitative and quantitative differences were found in the volatile profiles obtained in the five analyzed commercial brands. One hundred and ninety-three different substances were isolated, the group of acids being the most important from a quantitative point of view in all brands, accounting at least for the 60% of the total area. Aldehydes, basically from lipid oxidation, contributed between 7.72 and 13.97% to the total amount. Acids and aldehydes were the chemical families that showed the lowest variability among brands. In contrast, esters showed the highest coefficient of variation among brands (111%), followed by phenols (82%) and terpenes (76%). The variability observed in these three families could be attributed respectively to the different starter cultures, smoking process and spices employed in their production. Butylated hydroxytoluene (added as an antioxidant, E-321) was the third most abundant compound in three of the five brands.     

Characterisation and identification of key cardboard-like off-odour compounds and possible origins in yoghurt using HS-SPME-GC–MS

Cardboard-like off-odour in yoghurt can negatively impact consumer acceptability. Herein, a method has been developed to analyse off-odorants in yoghurt using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry. Of 56 volatile organic compounds identified, 8 were active compounds responsible for cardboard-like off-odour, including 2, 2-dimethyl-propanoic acid and 3-methyl-2-pentanone, which were newly identified in yoghurt. Hexanol and hexanal were found to be indicators of quality deterioration. The off-odour may be caused by packaging materials and temperature changes during logistic activities. Overall, identifying off-odorants can help producers to determine which part of the yoghurt-producing process can be changed to avoid contamination.     

Monitoring the oxidation of almond oils by HS-SPME–GC–MS and ATR-FTIR: Application of volatile compounds determination to cultivar authenticity

In this study, the oxidative process of Spanish and American almond oils was monitored by using headspace solid-phase microextraction/gas chromatography–mass spectrometry (HS-SPME/GC–MS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Oxidative stability of samples was evaluated after thermal treatment at 100 °C for 1, 3, 5, 7, 10, 15 and 20 days, in order to accelerate the lipid oxidation process. Variations observed in bands of infrared spectra were used to monitor the progress of the oxidation process of almond oils. HS-SPME–GC–MS was used for isolation and determination of volatile compounds in oxidised almond oils. The following aldehydes were identified in all samples: hexanal, (E)-2-heptenal, (E)-2-octenal, nonanal, (E)-2-nonenal, (E,E)-2,4-nonadienal and (E,E)-2,4-decadienal. Determination of volatile compounds resulting from lipid oxidation from three different almond cultivars (Spanish Guara and Marcona and Butte from USA) was performed to obtain a set of parameters for discrimination between Spanish and American cultivars. Successful discrimination was obtained in samples kept under thermal treatment for 7 days, by using HS-SPME/GC–MS combined with multivariate stepwise linear discriminant analysis (LDA).     

Rapid determination of volatile composition from Polygala furcata Royle by MAE–HS-SPME followed by GC–MS

Based on microwave-assisted extraction (MAE) and headspace solid-phase microextraction (HS-SPME) followed by gas chromatography mass spectrometry (GC–MS) was developed for the fast determination of volatile chemical compositions of Polygala furcata Royle, the experimental parameters of the MAE–HS-SPME were optimized by orthogonal experimental design. The results indicated that the optimum condition of the determination of the volatile compounds in P. furcata Royle. was achieved with the experimental parameters including microwave power of 400 W and irradiation time of 4 min, sample size 2.0 g. Under the optimal conditions, for the first time, 52 volatile compounds were separated and identified from the fresh plants of P. furcata Royle. The highest content component of the 52 compounds was 2-hydroxybenzoic acid methyl ester (21.65%). The relative standard deviation values <7% showed that the method of MAE–HS-SPME followed by GC–MS has good precision. The experimental results demonstrated that it is a simple, time-saving and solvent-free method, and it is a potential analytic tool for the determination of the volatile compounds of the vegetations materials and other materials.     

Effects of selenate supplemented fertilisation on the selenium level of cereals — identification and quantification of selenium compounds by HPLC–ICP–MS

Laboratory experiments were carried out to investigate whether the selenium content of different kinds of cereals grown on Austrian soil could be raised by the application of compound fertilisers containing selenium as selenate. An anion exchange chromatographic system coupled to an HP 4500 inductively coupled plasma mass spectrometer (ICP–MS) was used for the identification and quantification of selenium compounds in cereal samples. The HPLC–ICP–MS system was optimized for the separation of selenite, selenate, selenocystine, and selenomethionine using a Hamilton PRP-X100 column. Separation was obtained, with a 10 mM citrate buffer (pH 5), 2% methanol as mobile phase and a flow rate of 1.5 ml min⁻¹. Four baseline separated chromatographic peaks were obtained within 6 min. The retention behavior of a further five selenium [selenohomocystine (Sehcys), selenocystathionine (Secysta), selenoethionine (Seet), trimethylselenonium iodide (TmSe), and dimethyl(3-amino-3-carboxy-1-propyl)selenonium iodide (DmpSe)] compounds was investigated. Aqueous extraction and enzymatic hydrolysis of the biological materials were also compared with respect to the amount of selenium extracted. In the aqueous extracts only 3–9% of the total concentration of selenium was found. When the cereal samples were exposed to an enzymatic hydrolysis, recovery rates ranging from 80 to 95% were obtained. A major part of the selenate, which had been taken up by the cereals was converted to selenomethionine.     

Monitoring of the amphetamine-like substances in dietary supplements by LC-PDA and LC–MS/MS

Recently, amphetamine-like substances derived from the β-phenylethylamine core structure have been detected in dietary supplements. Especially, β-methylphenylethylamine (BMPEA), an amphetamine isomer, has been found in dietary supplements labeled as containing Acacia rigidula. The U. S. Food and Drug Administration determined that BMPEA is not naturally present in food and does not meet the statutory definition of a dietary ingredient. In addition, BMPEA has been classified as a psychotropic drug in South Korea and a doping substance by the World Anti-Doping Agency. The aim of this study was to determine whether dietary supplements contained amphetamine and amphetamine-like substance, including β-phenylethylamine (β-PEA) and BMPEA using LC-PDA and LC–MS/MS. In 10 of 110 samples, illegally added compounds were detected in the following ranges; β-PEA 1.4–122.0 mg/g and BMPEA 4.7–37.6 mg/g. This study will contribute to enhancement of food safety in the South Korea.     

Antioxidant and antiacetylcholinesterase activities of essential oils from Cymbopogon schoenanthus L. Spreng. Determination of chemical composition by GC–mass spectrometry and C NMR

Cymbopogon schoenanthus L. Spreng, is an aromatic herb consumed in salads and used to prepare traditional meat recipes in Tunisia. The chemical composition, antioxidant activities and acetylcholinesterase inhibitory properties of the essential oils from fresh leaves, dried leaves and roots collected from three different locations in southern Tunisia, were evaluated. Essential oils were analysed by GC–mass spectrometry and ¹³C NMR. The major components were limonene (10.5–27.3%), β-phellandrene (8.2–16.3%), δ-terpinene (4.3–21.2%) and α-terpineol (6.8–11.0%). Antioxidant activity was measured by DPPH assay. The results ranged from 36.0% to 73.8% (2 μl of essential oil per mL of test solution).