Search

Cocoa is the main component of chocolate. It is widely accepted that cocoa quality largely depends on the processing, especially the fermentation step. Traditionally, fermentation takes place spontaneously by the endogenous microbiota; however, the process can lead to poor quality and heterogeneity of the final product. In this study, we evaluated the influence of the starter culture on the profile of volatiles during fermentation of commercial volumes of Mexican cocoa. Volatiles were also analyzed in post-fermented cocoa samples obtained after drying, roasting, and conching. Our results revealed a most desirable volatile profile in cocoa fermented with starter culture, mainly due to the higher relative content of alcohols (40%) and aldehydes (3.5%), but also due to a lower acidity (<1%) as compared to endogenous fermentation (acids, 65%; alcohols, 2%; and aldehydes <0.5%). Additionally, it is remarkable, the higher content of pyrazines in the inoculated samples after processing. [Display omitted] • Influence of the starter culture has been evaluated in the volatile profile of processed cocoa. • A total of 41 volatiles, related to quality, was identified in inoculated and control samples. • Changes in volatiles were associated to the microorganisms involved in the fermentation. • Formation of volatiles associated to cocoa quality increases when processing with starter culture. • Formation of undesired volatiles decreases when processing with starting culture. [ABSTRACT FROM AUTHOR]

Abstract: A method for fast and selective determination of the main triterpenic compounds present in olive leaves — oleanolic, ursolic and maslinic acids as triterpenic acids and, uvaol and erythrodiol as triterpenic dialcohols — is reported here. Quantitative isolation of the analytes has been accomplished in 5min by microwave assistance using ethanol as extractant. Due to the medium polarity of triterpenic acids and dialcohols, different ethanol–water ratios were tested in order to select the optimum extractant composition for their solubilisation. Microwave assistance provided a significant shortening of the leaching time as compared to conventional procedures by maceration, which usually requires at least 5h. After extraction, determination was carried out by liquid chromatography–tandem mass spectrometry (LC–MS–MS) with a triple quadrupole (qQq) mass detector without any clean-up step prior to chromatographic analysis. Highly selective identification of triterpenes was confirmed by multiple reaction monitoring (MRM) using the most representative transitions from the precursor ion to the different product ions, while the most sensitive transitions were used for MS–MS quantitation. Total analysis performed in 25min enables the characterization of a fraction with particular interest in the pharmacological area. [Copyright &y& Elsevier]

Abstract: This review intends to show analytical chemists a very little known application of ultrasound for sample preparation: that dealing with liquid samples. The influence of this type of energy on the development of chemical reactions (e.g. depolymerization, redox, esterification, alkylation, addition, ethylation of organometallic compounds, complex formation) and that on heterogeneous liquid–liquid processes (e.g. liquid–liquid extraction, homogenization, emulsification, liposome formation) deserves to be taken into consideration in the analytical laboratory in order to take profit from its versatile effects to improve, accelerate or make possible a given process. [Copyright &y& Elsevier]

An approach for automated fast extraction of the fat content in bakery products based on focused microwave-assisted Soxhlet extraction (FMASE) and gravimetric determination is proposed. The main factors affecting the extraction efficiency—namely, power of irradiation, number of cycles and irradiation time—were optimized using experimental design methodology. The proposed method was applied to six samples, which were classified in two groups—namely, snacks and cookies. The results obtained agree with those provided by the AOAC 920.39 reference extraction method. No significant differences in the extraction efficiency of the fat content in bakery samples using FMASE versus the official method were found. Moreover, a drastic reduction in both the extraction time (60 and 35 min versus 16 and 8 h, respectively, for the two above commented groups) and sample handling are achieved with similar precision (expressed as repeatability and within-laboratory reproducibility standard deviation) to that provided by the AOAC 920.39 method. In addition, the proposed method is cleaner than the reference method as 75–80% of the extractant is recycled. [Copyright &y& Elsevier]

Steroidogenesis is a set of metabolic reactions where the enzymes play a key role to control the physiological levels of steroids. A deficiency in steroidogenesis induces an accumulation and/or insufficiency of steroids in human blood and can lead to different pathologies. This issue added to the low levels of steroids (pg mL−1 to ng mL−1) in this biofluid make of their determination an analytical challenge. In this research, we present a high-throughtput and fully automated method based on solid-phase extraction on-line coupled to liquid chromatography with tandem mass spectrometry detection (SPE–LC–MS/MS) to quantify estrogens (estrone and estradiol), androgens (testosterone, androstenedione, dihydrotestosterone and dehydroepiandrosterone), progestogens (progesterone, pregnenolone, 17-hydroxyprogesterone and 17-hydroxypregnenolone), glucocorticoids (21-hydroxyprogesterone, 11-deoxycortisol, cortisone, corticosterone and cortisol) and one mineralocorticoid (aldosterone) in human serum. The performance of the SPE step and the multiple reaction monitoring (MRM) mode allowed reaching a high sensitivity and selectivity levels without any derivatization reaction. The fragmentation mechanisms of the steroids were complementary studied by LC–MS/MS in high-resolution mode to confirm the MRM transitions. The method was characterized with two SPE sorbents with similar physico-chemical properties. Thus, limits of quantification were at pg mL−1 levels, the variability was below 25% (except for pregnenolone and cortisone), and the accuracy, expressed as bias, was always within ±25%. The proposed method was tested in human serum from ten volunteers, who reported levels for the sixteen target steroids that were satisfactorily in agreement with the physiological ranges reported in the literature. Image 1 • A fully automated method is proposed for analysis of 16 steroids in human serum. • Shortening of the analysis time due to the sample preparation protocol. • Quantitation limits at pg mL−1 without derivatization reactions. • Complete study fragmentation mechanisms. • Characterization of the method with two SPE sorbents. [ABSTRACT FROM AUTHOR]

Acylcarnitines (ACs) are metabolites involved in fatty acid β-oxidation and organic acid metabolism. Metabolic disorders associated to these two processes can be evaluated by determining the complete profile of ACs. In this research, we present an overall strategy for identification, confirmation, and quantitative determination of acylcarnitines in human serum. By this strategy we identified the presence of 47 ACs from C2 to C24 with detection of the unsaturation degree by application of a data-independent acquisition (DIA) liquid chromatography–tandem mass spectrometry (LC–MS/MS) method. Complementary, quantitative determination of ACs is based on a high-throughput and fully automated method consisting of solid-phase extraction on-line coupled to LC–MS/MS in data-dependent acquisition (DDA) to improve analytical features avoiding the errors associated to sample processing. Quantitation limits were at pg mL–1 level, the intra-day and between-day variability were below 15–20%, respectively; and the accuracy, expressed as bias, was always within ± 25%. The proposed method was tested with 40 human volunteers to determine the relative concentration of ACs in serum and identify predominant forms. Significant differences were detected by comparing the ACs profile of obese versus non-obese individuals. [ABSTRACT FROM AUTHOR]

To know the bioavailability of virgin olive oil (VOO) phenols and its impact on health, it is necessary to determine the levels of phenols excreted in urine. We present here a novel strategy for in-syringe solid-phase extraction and analysis of the extract by liquid chromatography–tandem mass spectrometry (LC–MS/MS), using ammonium fluoride as ionization agent to enhance sensitivity. This approach allows avoiding additional steps such as solvent evaporation or analytes derivatization. The method can be used with a previous acid hydrolysis for quantitative determination of tyrosol and hydroxytyrosol to estimate metabolized phenols. We tested this application by analysis of a cohort of volunteers (n = 20) after a standardized intake of VOO. Additionally, the method can be used as such for metabolite profiling of phenolic derivatives in urine using LC–MS/MS in high-resolution data-independent acquisition (DIA). Information about the phenolic profile of the consumed VOO and the human metabolism is thus obtained. The proposed approach represents a simple and versatile tool for qualitative and quantitative characterization of VOO phenolic metabolism. [Display omitted] • Simple method for evaluation of olive oil phenolic metabolism. • Determination of phenols in urine by in-syringe SPE and LC–MS/MS. • In-syringe SPE allowed simplifying sample processing. • Use of NH 4 F as ionization agent enhanced sensitivity in the determination of tyrosol. • A previous hydrolysis enables quantitation as tyrosol and hydroxytyrosol derivatives. [ABSTRACT FROM AUTHOR]

Anthracnose, the most critical disease affecting olive fruits, is caused by Colletotrichum species. While developing olive fruits are immune to the pathogen regardless of the cultivar, the resistance level varies once the fruit ripens. The defense mechanisms responsible for this difference in resistance are not well understood. To explore this, we analyzed the phenolic metabolic pathways occurring in olive fruits and their susceptibility to the pathogen during ripening in two resistant cultivars ('Empeltre' and 'Frantoio') and two susceptible cultivars ('Hojiblanca' and 'Picudo'). Overall, resistant cultivars induced the synthesis of aldehydic and demethylated forms of phenols, which highly inhibited fungal spore germination. In contrast, susceptible cultivars promoted the synthesis of hydroxytyrosol 4-O-glucoside during ripening, a compound with no antifungal effect. This study showed that the distinct phenolic profiles between resistant and susceptible cultivars play a key role in determining olive fruit resistance to Colletotrichum species. • Fruits at turning stage show varied pathogen resistance due to phenolic profile changes. • Susceptible cultivars' drupes convert secoiridoids to hydroxytyrosol-4-O-glucoside, reducing anthracnose tolerance. • Oleuropein, ligstroside, and their derivatives are key in inhibiting spore germination. • Resistant cultivars maintain high fungicidal phenolic compounds (>90% of total phenols) during ripening. [ABSTRACT FROM AUTHOR]

Virgin olive oil (VOO) phenols are valued for their health and organoleptic properties. The phenolic content of VOO is influenced by several factors, with particular emphasis on cultivar. However, the cultivar influence is a combination of several variables, including genotype, fatty acid (FA) profile, and fruit moisture; the last two variables condition the polarity of the extraction phases. Here, we evaluated the phenolic variability by extracting the effect of the fruit moisture and the FA profile from the cultivar factor. In a set of 40 cultivars monitored for three crop seasons, the cultivar effect was represented by differences in the conversion from oleuropein and ligstroside aglycones to oleacein and oleocanthal. Complementary, the fruit moisture positively favored the enrichment of VOOs in oleocanthal (285 mg/kg vs 380 mg/kg in the low and high moisture groups, respectively) while oleic acid showed a positive effect on the enrichment of VOOs in aglycone isomers of oleuropein (181 mg/kg vs 233 mg/kg in the low and high C18:1 content groups, respectively) and ligstroside (178 mg/kg vs 217 mg/kg in the low and high C18:1 content groups, respectively). • Methylesterase activity is a relevant factor which explain the cultivar effect. • High fruit moisture was associated with a high oleacein and oleocanthal content. • VOOs with a moderate C18:1 content were enriched in oleacein and oleocanthal. • The polarity conditions the distribution of phenols between pomace and VOO. • Enzymatic activity was favoured by medium with high polarity. [ABSTRACT FROM AUTHOR]

Determination of vitamin D levels in human biological specimens has gained a high relevance over the last decades, essentially because low levels have been associated with several biological disorders. In fact, vitamin D deficiency has become a worldwide health concern covering all ages and genders. The storage of biofluids has to be considered for determination of vitamin D and metabolites in order to fully preserve matrices status. This study attempts to evaluate lyophilization of serum and plasma as a pre-processing step for sample storage prior to quantitative analysis of vitamin D 3 and its main hydroxylated metabolites −25(OH)D 3 , 24,25(OH) 2 D 3 and 1,25(OH) 2 D 3. The protocol including sample lyophilization was characterized in terms of analytical features and compared to the same method, based on SPE–LC–MS/MS, without lyophilization. Sensitivity, precision and accuracy were not affected when we operated with lyophilized serum and plasma and results provided by a set of twenty-four serum samples from DEQAS (Vitamin D External Quality Assessment Scheme) were in agreement with reported concentrations for 25(OH)D 3 and 1,25(OH) 2 D 3. A stability study programmed for 9 months allowed ensuring that the concentration of vitamin D 3 and metabolites in lyophilized serum and plasma stored at room temperature was not affected during this period. This research has demonstrated that the quantitation of target metabolites is not under the influence of lyophilization. Therefore, including lyophilization prior to analysis could reduce shipment and storage costs, avoid delays of sample processing, and increase the stability of the target analytes due to an effective quenching process. Image 1 • Lyophilization as mid-term storage strategy prior to analysis of vitamin D 3 metabolites. • Quantitation of vitamin D 3 metabolites was not affected by lyophilization. • Metabolites were stable for nine months in lyophilized samples at room temperature. • Lyophilization ensures sample stabilization. [ABSTRACT FROM AUTHOR]

Sex steroids are involved in biological functions that encompass from the complete sexual development of individuals up to the deregulation of metabolic pathways leading to some pathologies. Steroids are present in blood at low concentration levels from pg mL−1 to ng mL−1. For this reason, a high sensitive and selective method based on gas chromatography–negative chemical ionization–tandem mass spectrometry (GC–NCI–MS/MS) is here proposed to quantify either androgens (androstenedione, dehydroepiandrosterone, dihydrotestosterone and testosterone), estrogens (estrone and estradiol) and a progestogen (progesterone) in human plasma. The sample preparation steps, protein precipitation and solid phase extraction, were optimized to ensure the sample matrix removal and to extract steroids with high efficiency. The NCI–MS/MS detection approach was compared with that based on electron impact to evaluate the incidence of the ionization source in the determination of steroids. The quantification limits for determination of these analytes were in a range from 10 pg mL−1 to 5 ng mL−1, with a high sensitivity for estrogens, typically found at low concentrations. The proposed method was tested for the determination of steroids in male blood samples, in which 6 out of 7 steroids were detected and quantified to report concentration values in agreement with those described in the literature. Image 1 • A GC–NCI–MS/MS method is proposed for analysis of sex steroids in human plasma. • Sample preparation was optimized to improve selectivity and sensitivity. • Quantitation limits at pg mL−1 level were reached using a QTOF analyzer. • The incidence of NCI and EI sources was evaluated in the determination of steroids. [ABSTRACT FROM AUTHOR]

Elucidation of Cannabis composition is required to evaluate the potential of this plant for pharmacological uses, but also for implementation in breeding programs with agronomical purposes. The aim of the present study was to develop a method for untargeted analysis of polar and non-polar Cannabis extracts. For this purpose, extracts from 17 cultivars of Cannabis sativa L. were analyzed by gas chromatography–time-of-flight/mass spectrometry (GC–TOF/MS) and liquid chromatography quadrupole time-of-flight tandem mass spectrometry (LC–QTOF MS/MS) in high resolution mode. One hundred sixty-nine compounds were identified in the extracts by searching MS and MS/MS information. Among identified families, there were mainly cannabinoids, terpenoids, lipids and flavonoids, but also some interesting compounds such as amino and organic acids, among others. Relative contents of terpenoids and cannabinoids in the same cultivars grown in greenhouse and field were compared. Compositional differences in the profile of terpenoids and cannabinoids between both types of grown conditions were found. Image 1 • Cannabis characterization by GC–TOF/MS and LC–QTOF MS/MS. • Untargeted metabolomics analysis of Cannabis sativa L. • Platforms for identification of polar and non-polar compounds in Cannabis. • Comparation of secondary metabolites in Cannabis produced in field and greenhouse. • Profile of different cultivars of medicinal cannabis. [ABSTRACT FROM AUTHOR]