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Drying of the delicate, red stigmas of the Crocus sativus L. flower is necessary to produce saffron, the most expensive spice in the world. So far, laborious and sample destructive methods were applied to get vital insight into this... more
Drying of the delicate, red stigmas of the Crocus sativus L. flower is necessary to produce saffron, the most expensive spice in the world. So far, laborious and sample destructive methods were applied to get vital insight into this process following key physicochemical changes. Vibrational spectroscopy tools that allow molecular fingerprinting of plant tissues via multivariate data analysis are still not exploited. This study aimed at gaining new insights into the Fourier-Transform Infrared (FTIR) spectra of saffron on different gentle drying treatments in vacuum or by short-time heating with varying sample loading, energy input, duration etc. Diagnostic spectral bands that were exposed using Principal Component Analysis were assigned to C=O stretching in vinyl or cyclic esters, amides or other inter-molecular interactions of importance for functionality. Above all, the peak at 1160 cm−1 (typical of C-O-C glycosidic bridges) proved a distinguishing feature of short-time heated vs v...
Fourier-Transform mid-infrared (FTIR) spectroscopy offers a strong candidate screening tool for rapid, non-destructive and early detection of unauthorized virgin olive oil blends with other edible oils. Potential applications to the... more
Fourier-Transform mid-infrared (FTIR) spectroscopy offers a strong candidate screening tool for rapid, non-destructive and early detection of unauthorized virgin olive oil blends with other edible oils. Potential applications to the official anti-fraud control are supported by dozens of research articles with a “proof-of-concept” study approach through different chemometric workflows for comprehensive spectral analysis. It may also assist non-targeted authenticity testing, an emerging goal for modern food fraud inspection systems. Hence, FTIR-based methods need to be standardized and validated to be accepted by the olive industry and official regulators. Thus far, several literature reviews evaluated the competence of FTIR standalone or compared with other vibrational techniques only in view of the chemometric methodology, regardless of the inherent characteristics of the product spectra or the application scope. Regarding authenticity testing, every step of the methodology workflow...
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The pan-European distributed Research Infrastructure for Promoting Metrology in Food and Nutrition (METROFOOD-RI) has evolved in the frame of the European Strategy Forum on Research Infrastructures (ESFRI) to promote high-quality... more
The pan-European distributed Research Infrastructure for Promoting Metrology in Food and Nutrition (METROFOOD-RI) has evolved in the frame of the European Strategy Forum on Research Infrastructures (ESFRI) to promote high-quality metrology services across the food chain. The METROFOOD-RI comprises physical facilities and electronic facilities. The former includes Reference Material plants and analytical laboratories (the ‘Metro’ side) and also experimental fields/farms, processing/storage plants and kitchen-labs (the ‘Food’ side). The RI is currently prepared to apply for receiving the European Research Infrastructure Consortium (ERIC) legal status and is organised to fulfil the requirements for operation at the national, European Union (EU) and international level. In this view, the METROFOOD-RI partners have recently reviewed the scientific plan and elaborated strategic priorities on key thematic areas of research in the food and nutrition domain to which they have expertise to co...
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A sustainable process for valorization of onion waste would need to entail preliminary sorting out of exhausted or suboptimal material as part of decision-making. In the present study, an approach for monitoring red onion skin (OS)... more
A sustainable process for valorization of onion waste would need to entail preliminary sorting out of exhausted or suboptimal material as part of decision-making. In the present study, an approach for monitoring red onion skin (OS) phenolic composition was investigated through Visible Near-Short-Wave infrared (VNIR-SWIR) (350–2500 nm) and Fourier-Transform-Mid-Infrared (FT-MIR) (4000–600 cm−1) spectral analyses and Machine-Learning (ML) methods. Our stepwise approach consisted of: (i) chemical analyses to obtain reference values for Total Phenolic Content (TPC) and Total Monomeric Anthocyanin Content (TAC); (ii) spectroscopic analysis and creation of OS spectral libraries; (iii) generation of calibration and validation datasets; (iv) spectral exploratory analysis and regression modeling via several ML algorithms; and (v) model performance evaluation. Among all, the k-nearest neighbors model from 1st derivative VNIR-SWIR spectra at 350–2500 nm resulted promising for the prediction of...
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Essential oils (EOs) find application as flavoring agents in the food industry and are also desirable ingredients as they possess preservative properties. The Mediterranean diet involves the use of a lot of herbs and spices and their... more
Essential oils (EOs) find application as flavoring agents in the food industry and are also desirable ingredients as they possess preservative properties. The Mediterranean diet involves the use of a lot of herbs and spices and their products (infusions, EOs) as condiments and for the preservation of foods. Application of EOs has the advantage of homogeneous dispersion in comparison with dry leaf use in small pieces or powder. Among them, Laurus nobilis (bay laurel) L. EO is an interesting source of volatiles, such as 1,8-cineole and eugenol, which are known for their preservative properties. Its flavor suits cooked red meat, poultry, and fish, as well as vegetarian dishes, according to Mediterranean recipes. The review is focused on its chemistry, quality control aspects, and recent trends in methods of analysis and activity assessment with a focus on potential antioxidant activity and applications to olive industry products. Findings indicate that this EO is not extensively studie...
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In this study, it was investigated whether integration of microwave-heating into the pretreatment step of persimmon juice processing allows the concomitant production of both functional juice and added-value solid residue from the... more
In this study, it was investigated whether integration of microwave-heating into the pretreatment step of persimmon juice processing allows the concomitant production of both functional juice and added-value solid residue from the Diospyros Kaki “Jiro” cultivar. In this direction, persimmon pulp was treated under three different microwave-heating conditions (0.7, 4.2, and 8.4 kJ/g) prior to enzymatic maceration and compared to the non-heated material. Irrespective of microwave energy employed, the proposed hybrid treatment was highly efficient in terms of juice yield (70% w/w). The mildest heating conditions resulted in juice and residue that were both of inferior quality. Intensification of the microwave energy reduced the microbial load of the juice up to 2-log without compromising the content in total soluble solids, sugars, and L-ascorbic acid. Under the most drastic conditions, the juice was enriched in gallic acid, polyphenols, and potent DPPH● scavengers, but its orange color...
Research Interests: Chemistry, Food Science, Medicine, Foods, Gallic acid, and 4 moreAscorbic Acid, Pectin, Orange juice, and Polyphenol
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Research Interests: Chemical Engineering, Food, Biology, Medicine, Food Sciences, and 3 moreCurcuma, Iridaceae, and Crocus sativus
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Saffron is the most expensive spice in the world market and for this reason it is exposed to large quality manipulation, including plant, colorant and chemical additions. ISO 3632 has consequently established quality criteria for the... more
Saffron is the most expensive spice in the world market and for this reason it is exposed to large quality manipulation, including plant, colorant and chemical additions. ISO 3632 has consequently established quality criteria for the control of authenticity, quality and origin. However adulterants are not sufficiently considered in the in the ISO 3632 specifications or in any national legislation. NMR and other spectroscopic techniques which are largely adopted to verify purity and investigate additives exclusively based on spectrophotometric measurements. Spectroscopic analysis is a possible means for checking sample adulteration because many plant tissue adulterants could impair spectrophotometric quantifications of raw saffron samples. Additionally these analytical techniques, such as Infrared and Raman spectroscopy, are versatile, fast and non-destructive and can provide spectral fingerprints of a wide range of potential analytes. Thus far, advances in knowledge on saffron composition resulting from such analysis, along with new analytical tools and global market trends have contributed to the improvement of the ISO standard specifications and methods.
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Crocin Bleaching Assay (CBA) was applied to serum samples randomly collected from 22 obese donors, in order to investigate whether it could detect patients suffering from metabolic syndrome (MS), which is associated with oxidative stress.... more
Crocin Bleaching Assay (CBA) was applied to serum samples randomly collected from 22 obese donors, in order to investigate whether it could detect patients suffering from metabolic syndrome (MS), which is associated with oxidative stress. The same samples were also tested using the ORAC method, having analytical similarities with CBA (pH value, radical initiator and temperature) and commonly applied to biological fluids. Statistical analysis indicated that CBA was more promising in predicting the MS in obese subjects. The current study contributes to the commercial exploitation of saffron in the field of analytical chemistry.
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Erythrosine (E127, CI 45430) is not easily detected in adulterated saffron under the TLC and HPLC conditions proposed by ISO (3632-2, 2003) specifications for identification of artificial colorants in this precious plant material. In this... more
Erythrosine (E127, CI 45430) is not easily detected in adulterated saffron under the TLC and HPLC conditions proposed by ISO (3632-2, 2003) specifications for identification of artificial colorants in this precious plant material. In this study fluorescence is introduced for the first time as a means of detection after sample clean-up prior chromatographic separation according to aforementioned specifications at this stage of analysis. The mimimum required performance limit (MRPL) was found lower than that obtained using UV-Vis spectrophotometry by two-orders of magnitude. After chromatographic separation of erythrosine fluorescence detection at the same addition levels was less successful.
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Research Interests: Engineering, Chemistry, Organic Chemistry, Physical Chemistry, Structure, and 15 moreCarotenoids, Medicine, Agricultural food, Gallic acid, CHEMICAL SCIENCES, Phenols, Phenolic compound, Assay, Hydroxylation, Structure activity Relationship, Vanillin, Ferulic Acid, Caffeic Acid, Syringic Acid, and Radical scavenging activity
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Examination of the crocin bleaching assay performance and in-house validation were focused on probe and test compound characteristics, conditions for peroxyl radical generation, reaction monitoring, and expression of results. HPLC and... more
Examination of the crocin bleaching assay performance and in-house validation were focused on probe and test compound characteristics, conditions for peroxyl radical generation, reaction monitoring, and expression of results. HPLC and spectrometric examination showed that any authentic commercial saffron (origin, grade) can be used for probe preparation given that (a) interferences, such as tocopherols, are removed, (b) working solution concentration is adequately adjusted, and (c) stock probe solution changes during storage are not neglected. As suggested by log P values, calculated for a great number of radical scavengers (AHs), any AH more polar than Trolox (common reference compound) can be tested in the aqueous environment of the assay. AH activities order obeyed principles of structure-activity relationships. The assay was robust toward preheating of the azo-initiator (2,2'-azobis(2-aminopropane) dihydrochloride). Reaction monitoring through periodic UV-vis spectra recording was very informative. An alternative expression of results as "percent inhibition of crocin bleaching value", % Inh = [(DeltaA(0) - DeltaA)/DeltaA(0))] x 100, is proposed for [AH]/[crocin] = 1, instead of the so far used k(rel) values. The above findings also lead to analysis cost and time reduction.
Research Interests: Engineering, Chemistry, Physical Chemistry, Chromatography, Kinetics, and 14 moreCarotenoids, Medicine, Spectrophotometry, Agricultural food, High Pressure Liquid Chromatography, CHEMICAL SCIENCES, Crocus, Reproducibility of Results, Agricultural and Food Chemistry, Trolox, Aqueous Solution, Stock Solution, Peroxides, and Crocin
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A screening method for the detection of artificial colours (naphthol yellow, tartrazine, quinoline yellow, Sunset yellow, Allura red, amaranth, azorubine, Ponceau 4R and Red 2G) in saffron is described. The method involves removal of... more
A screening method for the detection of artificial colours (naphthol yellow, tartrazine, quinoline yellow, Sunset yellow, Allura red, amaranth, azorubine, Ponceau 4R and Red 2G) in saffron is described. The method involves removal of crocins by precipitation of crocetin (pH 0.1, 90 degrees C) before adsorption of the artificial colours on polyamide SPE cartridges (pH 2). After washing with methanol, acetone and methanol, elution was done with a methanol:ammonia solution (95:5 v/v), and detection was performed by derivative spectrometry. Sample pretreatment changes the UV-Vis saffron extract profile in such a way that second derivative spectra can be used to identify the presence of added colours. Erythrosine, which was found to be pH dependent, could not be detected under the above conditions. The lowest detectable amount for each colour was strongly dependent on chemical structure. The recovery of carminic acid was very low possibly due to irreversible retention on the polyamide. This procedure can replace the current ISO TLC method (2003) and be used alternatively or in combination with HPLC procedures adopted in the same standard.
Research Interests: Engineering, Chemistry, Chromatography, Carotenoids, Medicine, and 15 moreAntioxidants, Methanol, CHEMICAL SCIENCES, Food Additives, Crocus, Chemical Precipitation, Spectrum analysis, Spices, Food Contamination, Saffron, Hydrolysis, Condiments, Chemical Structure, Anthraquinone, and Medical and Health Sciences
The last years, non-targeted fingerprinting by Fourier-transform infrared (FT-IR) spectroscopy has gained popularity as an alternative to classical gas chromatography (GC)-based methods because it may allow fast, green, non-destructive... more
The last years, non-targeted fingerprinting by Fourier-transform infrared (FT-IR) spectroscopy has gained popularity as an alternative to classical gas chromatography (GC)-based methods because it may allow fast, green, non-destructive and cost-effective assessment of quality of essential oils (EOs) from single plant species. As the relevant studies for Laurus nobilis L. (bay laurel) EO are limited, the present one aimed at exploring the diagnostic potential of FT-IR fingerprinting for the identification of its botanical integrity. A reference spectroscopic dataset of 97 bay laurel EOs containing meaningful information about the intra-species variation was developed via principal component analysis (PCA). This dataset was used to train a one-class model via soft independent modelling class analogy (SIMCA). The model was challenged against commercial bay laurel and non-bay laurel EOs of non-traceable production history. Overall, the diagnostic importance of spectral bands at 3060, 13...
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Near-infrared reflectance spectroscopy has been applied for the first time to saffron spice to determine the chemical composition and geographical origin of 111 samples from the there main... more
Near-infrared reflectance spectroscopy has been applied for the first time to saffron spice to determine the chemical composition and geographical origin of 111 samples from the there main producers' countries: Iran, Greece, and Spain. The validation procedures with the results obtained by UV-vis and HPLC-DAD measurements demonstrated that this technique is appropriate to determine the following parameters: moisture and volatile content, coloring strength, (250 nm), and (330 nm), established on the ISO 3632 Technical Specification Normative and used to certify saffron quality in the international market. Also, it can be used to estimate the content of the five main crocetin glycosides, the compounds responsible for saffron color, the best correlations being for trans-crocetin di-(beta-D-gentibiosyl) ester (R2= 0.93), trans-crocetin (beta-D-glucosyl)-(beta-D-gentibiosyl) (R2= 0.94), and picrocrocin (R2= 0.92), the compound accepted as responsible for saffron bitterness. Finally, a discriminant analysis among the three geographical origins reveals that Iranian samples are the most different, whereas Greek and Spanish samples are more similar. All of these results reveal that NIRS spectroscopy has an enormous potential for its application to saffron quality control as the results are obtained in 2 min and without any sample manipulation.
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Structure–activity relationships (SARs) were sought among protocatechuic aldehyde 1, syringaldehyde 2, vanillin 3, p-hydroxybenzaldehyde 4 and salicylaldehyde, 5 using various in vitro antioxidant assays (crocin bleaching assay, ABTS,... more
Structure–activity relationships (SARs) were sought among protocatechuic aldehyde 1, syringaldehyde 2, vanillin 3, p-hydroxybenzaldehyde 4 and salicylaldehyde, 5 using various in vitro antioxidant assays (crocin bleaching assay, ABTS, DPPH, Rancimat and liposomes). These aldehydes are known to contribute to the evolution of flavor during aging of alcoholic beverages in wood barrels and as natural preservatives. Their acid counterparts (1′–5′) were
Research Interests: Engineering, Chemical Engineering, Thermodynamics, Organic Chemistry, Physical Chemistry, and 37 moreFree Radicals, Food, Food Chemistry, Flavonoids, Multidisciplinary, Free Radical, Biological Sciences, Antioxidants, Hydrogenation, Liposomes, Quantitative Structure Activity Relationship, Iron, Partition Coefficient, Lipid peroxidation, High Pressure Liquid Chromatography, CHEMICAL SCIENCES, Antioxidant Activity, Phenols, Ascorbic Acid, Plant extracts, Time Factors, Fatty Acid, Quercetin, Food Sciences, Agricultural and Food Chemistry, Bioorganic and medicinal Chemistry, Flavonols, Structure activity Relationship, Catechin, Amidines, Low Density Lipoprotein (LDL), Chemical Structure, Edetic Acid, Molecular Structure, Nitric oxide donors, Total Antioxidant Activity, and Cumulant
The Crocin Bleaching Assay (CBA) appears in literature as an in vitro method for measuring antioxidant and prooxidant capacity of model dietary antioxidants, food formulations, pharmaceuticals, and biological samples. The assay is based... more
The Crocin Bleaching Assay (CBA) appears in literature as an in vitro method for measuring antioxidant and prooxidant capacity of model dietary antioxidants, food formulations, pharmaceuticals, and biological samples. The assay is based on simple competitive reactions between a colored probe, crocin, and the test compounds/constituents for scavenging peroxyl radicals generated after thermolysis of a water-soluble azo-initiator. So far, several researchers in the fields of food chemistry, nutrition and clinical biochemistry have sporadically addressed critical views about advantages, limitations and potential field of CBA application. This chapter presents step-by-step critical aspects of CBA in order to assist standardization of its performance. Detailed procedures for calculation of two attributes of peroxyl radical scavenging reactions, the relative rate constant and "total antioxidant capacity", are also presented.
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An on-line HPLC (high performance liquid chromatography) method for the rapid screening of individual antioxidants in mixtures was developed using crocin as a substrate (i.e. oxidation probe) and... more
An on-line HPLC (high performance liquid chromatography) method for the rapid screening of individual antioxidants in mixtures was developed using crocin as a substrate (i.e. oxidation probe) and 2,2'-azobis(2-amidinopropane dihydrochloride (AAPH)) in phosphate buffer (pH 7.5) as a radical generator. The polyene structure of crocin and AAPH-derived peroxyl radicals resemble the lipidic substrates and radicals found in true food more closely than the popular, albeit artificial, DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS(+) (2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonate)) do. After separation by a C18 (octadecyl silica) column and UV (ultraviolet) detection, antioxidative analytes react with peroxyl radicals at 90°C and the inhibition of crocin oxidation (i.e. bleaching) is detected as a positive peak by an absorbance detector at 440 nm. The method is simple, uses standard instruments and inexpensive reagents. It can be applied for isocratic HPLC runs using mobile phases containing 10-90% organic solvent in water, weak acids or buffers (pH 3.5-8.5). With baseline correction, gradient runs are also feasible. The radical scavenging activity of several natural antioxidants and a green tea extract was studied. After optimisation of conditions such as reagent concentrations and flows, the limit of detection varied from 0.79 to 7.4 ng, depending on the antioxidant.
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Research Interests: Engineering, Chemical Engineering, Thermodynamics, Organic Chemistry, Physical Chemistry, and 37 moreFree Radicals, Food, Food Chemistry, Flavonoids, Multidisciplinary, Free Radical, Biological Sciences, Antioxidants, Hydrogenation, Liposomes, Quantitative Structure Activity Relationship, Iron, Partition Coefficient, Lipid peroxidation, High Pressure Liquid Chromatography, CHEMICAL SCIENCES, Antioxidant Activity, Phenols, Ascorbic Acid, Plant extracts, Time Factors, Fatty Acid, Quercetin, Food Sciences, Agricultural and Food Chemistry, Bioorganic and medicinal Chemistry, Flavonols, Structure activity Relationship, Catechin, Amidines, Low Density Lipoprotein (LDL), Chemical Structure, Edetic Acid, Molecular Structure, Nitric oxide donors, Total Antioxidant Activity, and Cumulant
The present study aimed to extend application of the FT-MIR technique to the quality control of traded saffron that suffers various types of fraud or mislabelling. Spectroscopic data were obtained for samples stored for different periods... more
The present study aimed to extend application of the FT-MIR technique to the quality control of traded saffron that suffers various types of fraud or mislabelling. Spectroscopic data were obtained for samples stored for different periods in the dark. Samples with the highest quality according to ISO 3632 specifications produced a typical spectrum profile (reference set). Principal Component Analysis (PCA) of spectroscopic data for this set along with HPLC-DAD analysis of major apocarotenoids assisted identification of FT-IR bands that carry information about desirable sensory properties that weaken during storage. The band at 1028cm(-1), associated with the presence of glucose moieties, along with intensities in the region 1175-1157cm(-1), linked with breakage of glycosidic bonds, were the most useful for diagnostic monitoring of storage effects on the evaluation and test set samples. FT-IR was found to be a promising, sensitive and rapid tool in the fight against saffron fraud.
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Objective(s)Comparison of prooxidant-antioxidant balance (PAB) assay with crocin assay.Materials and MethodsTwenty eight serum samples were chosen, PAB and the total antioxidant capacity were measured by PABassay and crocin, respectively,... more
Objective(s)Comparison of prooxidant-antioxidant balance (PAB) assay with crocin assay.Materials and MethodsTwenty eight serum samples were chosen, PAB and the total antioxidant capacity were measured by PABassay and crocin, respectively, and the correlation of both assays, along with their correlation with otherclinical and biochemical parameters, were determined.ResultsA significant negative correlation was established between PAB assay and crocin assay. Also a significantnegative correlation was established between PAB and uric acid and creatinine.ConclusionThe results showed that by increasing the total antioxidant capacity, which is showed by crocin, the PABshifts in favor of antioxidants, which is showed by PAB assay. Now, it could be considered that the PAB,along with other risk factors, might help in the prediction of the risk for cardiovascular events; and furtherresearch could clarify whether by application of PAB assay and appropriate interventions for correctingoxidative...