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Considering the interest in the bioactive properties of saffron (Crocus sativus L.), as well as its limited production and high price, saffron-based food supplements (SFS) are highly susceptible to adulteration. However, their complex composition and the wide variety of potential fraudulent practices make the comprehensive assessment of SFS quality a challenging task that has been scarcely addressed. To that aim, a new multianalytical strategy based on gas chromatography coupled to mass spectrometry (GC-MS) and liquid chromatography with diode array detection coupled to mass spectrometry (HPLC-DAD-MS) was developed and validated in order to detect different frauds affecting SFS. Dried saffron stigmas and a commercial standardized saffron extract (affron®) were selected as reference samples (RS) to obtain an authenticity profile, which was further used to evaluate the quality of 17 SFS. Up to 17 crocins and crocetins, 5 kaempferol glycosides, picrocrocin (determined for the first time by GC-MS), safranal, furanone and isophorone-related compounds were determined in RS. Safranal and crocins were identified in all SFS except for one sample. However, discrepancies with the content declared were detected in 65% of the cases. Moreover, this multianalytical methodology also allowed identifying undeclared additives and the non-declared addition of vegetable sources other than saffron.

Food supplements based on saffron (Crocus sativus L.) dried stigma extracts are widely consumed due to their multiple bioactive properties. Saffron extract (SE) standardization is of crucial importance, as it determines the reproducibility of the product quality and is essential for the evaluation of its bioactive effect and safety. Although SEs are commonly standardized considering their safranal content, the lack of specificity of the official methods may give inaccurate measurements. In addition to the development of more precise methodologies, the evaluation of alternative saffron components, such as crocins and picrocrocin, for standardization purposes would also be of interest. Thus, in this study, qualitative and quantitative information regarding picrocrocin and crocin isomers of different commercial saffron extracts was first obtained by a validated methodology using liquid chromatography (HPLC) coupled to diode array (DAD) and mass spectrometer (MS) detectors. Principal component analysis (PCA) was applied to gain insight into the compositional variability and natural grouping of SE. These studies suggested the potential use of the relative content of crocin isomers and trans-/cis-crocins and trans-4 GG/picrocrocin ratios as novel criteria for SE standardization. Their reproducibility and stability under controlled storage conditions for 36 months was demonstrated in a commercial standardized SE (affron®).

Despite the widespread use of artichoke-based food supplements for obesity control (FSOC), studies on evaluation of the quality/authenticity of these commercial products are scarce. To that aim, a new multi- analytical strategy, based on the use of gas chromatography coupled to mass spectrometry (GC–MS) and high performance liquid chromatography coupled to ultraviolet and mass spectrometry detection (HPLC- UV-MS), in combination with chemometrics, has been developed. Twenty-one artichoke FSOC and dif- ferent bract and leaf extracts (used as reference samples) were analysed. Sugars, inositols, caffeoylquinic acids, dicaffeoylquinic acids, flavonoids and their glycosides were detected in reference samples and in most artichoke FSOC. Low concentrations of bioactives, and the presence of other compounds probably related to heat treatment during manufacturing (difructosyl anhydrides, 3-deoxyglucosone), or to the ad- dition of caloric additives (maltose, maltotriose) or non-declared plants (e.g. pinitol, disaccharides, silybin derivatives) were also detected in some FSOC by either GC–MS or HPLC-UV-MS. Application of Principal Component Analysis to the combined GC–MS + HPLC-UV data matrix, proved that this multi-analytical strategy provides advantages over single analytical techniques for the detection of the wide variety of fraudulent practices affecting authenticity of artichoke FSOC and for assessment of their quality.

Food supplements of plant origin for weight control are increasingly being demanded by consumers as a way to promote good health. Among them, those based on Garcinia cambogia (GCFS) are widely commercialized considering their bioactive properties, mainly due to (-)-hydroxycitric acid ((-)-HCA). However, recently, controversy has arisen over their safety; thus, further research and continuous monitoring of their composition is required. Hence, in this work, a multi-analytical approach was followed to determine not only (-)-HCA but also other constituents of 18 GCFS, which could be used as quality markers to detect fraudulent practices in these samples. Discrepancies between the declared (-)-HCA content and that experimentally determined were detected by LC–UV in 33% of the samples. Moreover, GC–MS analyses of GCFS allowed the detection of different compounds not present in G. cambogia fruits and not declared on supplement labels, probably related to heat exposure or to the addition of excipients or other extracts. This multi-analytical methodology is shown to be advantageous to address different fraudulent practices affecting the quality of these supplements.

Garcinia gummi-gutta based food supplements (GFS) are widely commercialized due to their antiobesity activity, which has been mainly attributed to their high content in (−)-hydroxycitric acid [(−)-HCA]. In order to overcome the limitations related to selectivity and sensitivity of the HPLC-UV methods usually employed for the analysis of this compound, a GC–MS method was fully developed for the first time and validated. Water with 0.1 % formic acid was used for the solubilization of (−)-HCA stabilized in the form of salt in GFS. After a drying step, different derivatization solvents were tested and only trifluoroacetic acid (TFA) allowed the complete dissolution of (−)-HCA. Regarding silylation, the best results were obtained by cold dropwise addition of hexamethyldisilazane and subsequent heating at 45 °C for 90 min. After optimizing the chromatographic conditions, the stability of derivatives for 1 month was also assessed. This new methodology was also applied to determine the (−)-HCA content of 12 commercial GFS. Experimental values ranged from 0.86 to 61%. Forty-two percent of the analyzed samples did not meet the (−)-HCA content declared on the label and 2 GFS showed HCA concentrations lower than 10% (0.86 and 6.0%), which puts into question their effectiveness in regulating obesity. One advantage of this new methodology is that it allows the qualitative and quantitative analysis of (−)-HCA in GFS without coelutions with other interfering compounds and it avoids the solubility problems presented by HCA salts. Moreover, the coupling of GC to MS provides more reliable identification of compounds present in GFS.

A microwave-assisted extraction (MAE) method was developed for the extraction of bioactive inositols (D-chiro- and myo-inositols) from lettuce (Lactuca sativa) leaves as a strategy for the revalorization of these agrofood residues. Gas chromatography-mass spectrometry was selected for the simultaneous determination of inositols and sugars (glucose, fructose, and sucrose) in these samples. A Box–Behnken experimental design was used to maximize the extraction of inositols based on the results of single factor tests. Optimal conditions of the extraction process were as follows: liquid-to-solid ratio of 100:1 v/w, 40°C, 30 min extraction time, 20:80 ethanol:water (v/v), and one extraction cycle. When compared with conventional solid-liquid extraction (SLE), MAE was found to be more effective for the extraction of target bioactive carbohydrates (MAE 5.42 mg/g dry sample versus SLE 4.01 mg/g dry sample). Then, MAE methodology was applied to the extraction of inositols from L. sativa leaves of different varieties (var. longifolia, var. capitata and var. crispa). D-chiro- and myo-inositol contents varied between 0.57–7.15 and 0.83–3.48 mg/g dry sample, respectively. Interfering sugars were removed from the extracts using a biotechnological procedure based on the use of Saccharomyces cerevisiae for 24 h. The developed methodology was a good alternative to classical procedures to obtain extracts enriched in inositols from lettuce residues, which could be of interest for the agrofood industry.

Currently there is great interest in exploitation of agrofood by-products, such as those from legumes, as source of bioactive ingredients. To that aim, characterization of cyclitol and sugar composition of pods and seeds from different legume species has been carried out. A green Microwave Assisted Extraction (MAE) method was optimized for extraction of bioactive inositols, and both pod and seed yields were compared with those obtained by conventional reflux extraction. A subsequent Saccharomyces cerevisiae treatment was also evaluated for removal of interfering coextracted sugars. myo-Inositol was present in all legume pods and seeds and galactinol in most seeds. chiro-Inositol was found in soybean and basul, whereas outstanding pinitol concentrations were only detected in soybean. The optimized MAE method provided extracts rich in pinitol from soybean pods (41.5–58.0 mg g) and seeds (5.3–7.5 mg g). Removal of 97% of interfering sugars in MAE soybean pod extracts was achieved by yeast treatment.

Byproducts from artichoke represent the majority of the mass collected from the plant and constitute an interesting source of bioactive compounds such as inositols and caffeoylquinic acids. In this work, a microwave assisted extraction (MAE) methodology was developed for the simultaneous extraction of these compounds from artichoke stalks, leaves, receptacles and external bracts. Optimal MAE conditions to maximize the extraction of these bioactives and the antioxidant activity were 97 °C, 3 min, ethanol:water (50:50, v/v). Moreover, a GC–MS methodology was also developed for the simultaneous determination of these compounds in a single run; optimal derivatization conditions were achieved using hexamethyldisilazane and N,O-bis(trimethylsilyl)trifluoroacetamide with 1% trimethylchlorosilane. Artichoke receptacle extracts were the richest in caffeoylquinic acids (28–35 mg g dry sample), followed by the bracts (9–18 mg g dry sample), while those from leaves showed the highest concentrations of inositols (up to 15 mg g dry sample). Receptacle extracts also had the highest antioxidant activity (123 mg TE g dry sample) and the greatest concentration of total phenolic compounds (47 mg GAE g dry sample). Therefore, the developed methodology could be considered as a valuable procedure to obtain and characterize bioactive ingredients with industrial interest from artichoke byproducts, opening new routes of revalorization of artichoke agro-industrial residues.

Novel methodologies for the improved extraction of bioactive carbohydrates that fulfill the principles of green chemistry have been reviewed in this manuscript. As an alternative to conventional water extraction methods, advantages of the use of new green solvents such as ionic liquids and deep eutectic solvents have been discussed. Recent applications of advanced techniques such as ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), pressurized liquid extraction (PLE), supercritical fluid extraction (SFE) and enzyme-assisted extraction (EAE) have also been revised. Special attention has been paid to those procedures based on the combination of several of these techniques which provide a better performance [e.g. ultrasound-microwave-assisted extraction (UMAE)] or show an improved selectivity [e.g. microwave-assisted aqueous two-phase extraction (MAATPE), microwave-assisted enzymatic extraction or enzymolysis-ultrasound-assisted extraction (MAEE or EUAE), etc.]. Finally, future perspectives regarding the possible application of these new eco-friendly methodologies at industrial scale together with the advances required to that aim are presented.