Evaluation of storage time effect on saffron chemical profile using gas chromatography and spectrophotometry techniques coupled with chemometrics

A non-invasive, sensor-based approach to exploit the autofluorescence of saffron (Crocus sativus L.) for on-site evaluation of aging

So far, compliance with ISO 3632 standard specifications for top-quality saffron guarantees good agricultural and post-harvest production practices. Tracking early-stage oxidation remains challenging. Our study aims to address this issue by exploring the visible, fluorescence, and near-infrared spectra of category I saffron. Using a multi-spectral sensor, we tested fresh and artificially aged saffron in powder form. High autofluorescence intensities at 600-700 nm allowed calibration for the 'content of aged saffron'. Samples with minimum coloring strength (200-220 units) were classified as 70% aged, while those exceeding maximum aroma strength (50 units) as 100% aged. Consistent patterns across origin, age, and processing history indicated potential for objectively assessing early-oxidation markers. Further analyses uncovered multiple contributing fluorophores, including cis-apocarotenoids, correlated with FTIR-based aging markers. Our findings underscore that sensing autofluorescence of traded saffron presents an innovative quality diagnostic approach, paving new research pathways for assessing the remaining shelf-life along its supply chain.

Fingerprint of Characteristic Saffron Compounds as Novel Standardization of Commercial Crocus sativus Extracts

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^®).

A Novel FTIR-Based Chemometric Solution for the Assessment of Saffron Adulteration with Non-Fresh Stigmas

The development of fast, non-destructive, and green methods with adequate sensitivity for saffron authentication has important implications in the quality control of the entire production chain of this precious spice. In this context, the highly suitable sensitivity of a spectroscopic method coupled with chemometrics was verified. A total number of 334 samples were analyzed using attenuated-total-reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy; the collected spectra were processed by partial-least-squares discriminant analysis (PLS-DA) to evaluate the feasibility of this study for the discrimination between compliant saffron (fresh samples produced in 2020) and saffron samples adulterated with non-fresh stigmas produced in 2018 and 2016. PLS-DA was able to classify the saffron samples in accordance with the aging time and to discriminate fresh samples from the samples adulterated with non-fresh (legally expired) stigmas, achieving 100% of both sensitivity and specificity in external prediction. Moreover, PLS regression was able to predict the adulteration level with sufficient accuracy (the root-mean-square error of prediction was approximately 3-5%). In summary, ATR-FTIR and chemometrics can be employed to highlight the illegal blending of fresh saffron with unsold stocks of expired saffron, which may be a common fraudulent practice not yet considered in the scientific literature.

Detection of Saffron’s Main Bioactive Compounds and Their Relationship with Commercial Quality

This review aims to evaluate the state of saffron’s main bioactive compounds and their relationship with its commercial quality. Saffron is the commercial name for the dried red stigmas of the Crocus sativus L. flower. It owes its sensory and functional properties mainly to the presence of its carotenoid derivatives, synthesized throughout flowering and also during the whole production process. These compounds include crocin, crocetin, picrocrocin, and safranal, which are bioactive metabolites. Saffron’s commercial value is determined according to the ISO/TS3632 standard that determines their main apocatotenoids. Other techniques such as chromatography (gas and liquid) are used to detect the apocarotenoids. This, together with the determination of spectral fingerprinting or chemo typing are essential for saffron identification. The determination of the specific chemical markers coupled with chemometric methods favors the discrimination of adulterated samples, possible plants, or adulterating compounds and even the concentrations at which these are obtained. Chemical characterization and concentration of various compounds could be affected by saffron’s geographical origin and harvest/postharvest characteristics. The large number of chemical compounds found in the by-products (flower parts) of saffron (catechin, quercetin, delphinidin, etc.) make it an interesting aromatic spice as a colorant, antioxidant, and source of phytochemicals, which can also bring additional economic value to the most expensive aromatic species in the world.

Determination of Saffron Quality through a Multi-Analytical Approach

Currently, the specifications for the assessment of saffron quality are contained in the ISO 3632 technical standard. This norm evaluates saffron quality through a UV-Vis spectrophotometric method and grades the spice into three commercial categories. However, numerous studies have highlighted several weaknesses and limitations of the ISO method. For this reason, a new multi-analytical approach for the determination of saffron quality is proposed in this work. Different techniques were employed to assess saffron quality: UV-visible spectroscopy (UV-Vis), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX) and inductively coupled plasma—optical emission spectroscopy (ICP-OES). The results show that the commercial grading based on the ISO 3632 methodology is not always in line with the observations made with the other techniques. Moreover, the use of two new techniques in the field of saffron quality determination, i.e., SEM-EDX and ICP-OES, proved to be effective for the determination of elemental composition and metal content, which are two important parameters to take into consideration when assessing the quality of the spice.

Effective Isolation of Picrocrocin and Crocins from Saffron: From HPTLC to Working Standard Obtaining

Saffron is widely cultivated and used as a spice. Recently published data on the chemical composition and pharmacological potential of saffron determine its use in pharmacy and medicine. The proposed high-performance thin-layer chromatography (HPTLC) method allows good separation of 11 analytes. The saffron quality (Iran, Ukraine, Spain, Morocco samples) assessment was based on the European Pharmacopoeia monograph and ISO 3632. The HPTLC method for the safranal, crocin, and picrocrocin quantification was proposed and validated. The crocins content in Ukrainian saffron was from 17.80% to 33.25%. Based on qualitative and quantitative assessment results, the saffron sample from Zaporizhzhia (Ukraine) had the highest compounds content and was chosen to obtain the working standards of picrocrocin and crocins (trans-4GG, trans-2G, trans-3Gg) by preparative chromatography. The compounds were isolated from lyophilized extract of saffron using a Symmetry Prep C18 column (300 × 19 mm × 7 µm), and identified by spectroscopic techniques (HPLC-DAD, UPLC-ESI-MS/MS). The purity of crocins and picrocrocin was more than 97%. A novel method proposed to obtain working standards is simple and reproducible for the routine analysis of saffron quality control.

An easy way for the hydrolysis, pre-concentration, and chemical stabilization of crocetin from saffron powder

To date there are no methods in the literature leading to crocetin selective concentration from saffron powder aqueous solutions. To this aim, we decided to test the performance of its heterogeneous extraction by means of a panel of 21 synthetic clays, 4 of which demonstrated to selectively retain crocetin in the solid phase after hydrolysis of its digentiobyosil ester (crocin) (and its isomers) and to its chemical stabilization (e.g., oxidation) over time. The best adsorption yield was obtained with zinc hydroxy chloride (66.18 ± 0.06 μg/g dry powder). This phenomenon was assessed by HPLC-DAD analyses after desorption of crocetin from the respective support and assessing its degradation along a period of 30 days. The method we established could represent a good mean to provide pure crocetin from saffron powder, preserving in the meantime its chemical properties for a concrete future exploitation for food pharmaceutical, and cosmetic purposes.

Comprehensive Evaluation of the Volatomic Fingerprint of Saffron from Campania towards Its Authenticity and Quality

The volatile profiles of eight saffron samples (seven cultivated and one spontaneous) grown in different geographical districts within the Campania region (southern Italy) were compared. Using headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry (HS-SPME/GC-MS), overall, 80 volatiles were identified in the eight landraces. Among them, safranal and its isomers and other related compounds such as isophorones, which are not only key odorants but also pharmacologically active metabolites, have been detected in all the investigated samples. Principal Component Analysis performed on the volatiles' compounds revealed that the spontaneous sample turned out to be an outlier. In particular, the volatile organic compounds (VOCs) profile of the spontaneous saffron presented four lilac aldehydes and four lilac alcohol isomers, which, to the authors' knowledge, have never been identified in the volatile signature of this spice. The multivariate statistical analysis allowed the discrimination of the seven cultivate saffron ecotypes in four well-separated clusters according to variety. Moreover, 20 VOCs, able to differentiate the clusters in terms of single volatile metabolite, were discovered. Altogether, these results could contribute to identifying possible volatile signature metabolites (biomarkers) or patterns that discriminate saffron samples grown in Campania region on a molecular basis, encouraging future biodiversity programs to preserve saffron landraces revealing valuable genetic resources.

The Relation between Drying Conditions and the Development of Volatile Compounds in Saffron (Crocus sativus)

Saffron is derived from the stigmas of the flower Crocus sativus L. The drying process is the most important post-harvest step for converting C. sativus stigmas into saffron. The aim of this review is to evaluate saffron's post-harvest conditions in the development of volatile compounds and its aroma descriptors. It describes saffron's compound generation by enzymatic pathways and degradation reactions. Saffron quality is described by their metabolite's solubility and the determination of picrocrocin, crocins, and safranal. The drying process induce various modifications in terms of color, flavor and aroma, which take place in the spice. It affects the aromatic species chemical profile. In the food industry, saffron is employed for its sensory attributes, such as coloring, related mainly to crocins (mono-glycosyl esters or di-glycosyl polyene).

Effect of Crocus sativus L. Stigmas Microwave Dehydration on Picrocrocin, Safranal and Crocetin Esters

The dehydration process is the basis to obtain high quality saffron and to preserve it for a long time. This process modifies saffron’s main metabolites that define its quality, and are responsible for the characteristic color, taste, and aroma of the spice. In this work, the effect of microwave dehydration on saffron main metabolites (picrocrocin, safranal and crocetin esters) from Crocus sativus L. stigmas at three determinate powers and different time lapses was evaluated. The results showed that this dehydration process obtained similar or lower crocetin esters content, and after three months of storage, higher concentration was shown in treatments at 440 W for 36 s, 55 s, and 73 s; at 616 W for 90 s; and at 800 W for 20 s. Picrocrocin content was lower and safranal content was higher in all treatments compared to the control both before and after storage. Regarding to commercial quality, microwave dehydration obtained Category I of saffron according to International Standard Organization (ISO) 3632. After three months of storage, treatments at 616 W for 83 s and 800 W for 60 s obtained lower categories. The results obtained suggest that microwave dehydration is a suitable process for obtaining high quality saffron, 800 W with 6 lapses of 20 s being the best conditions studied.

Recent Advances on the Anticancer Properties of Saffron (Crocus sativus L.) and Its Major Constituents

Cancer is the second leading cause of death globally with an estimated 9.6 million deaths in 2018 and a sustained rise in its incidence in both developing and developed countries. According to the WHO, about 1 in 6 deaths is due to cancer. Despite the emergence of many pioneer therapeutic options for patients with cancer, their efficacy is still time-limited and noncurative. Thus, continuous intensive screening for superior and safer drugs is still ongoing and has resulted in the detection of the anticancer properties of several phytochemicals. Among the spices, Crocus sativus L. (saffron) and its main constituents, crocin, crocetin, and safranal, have attracted the interest of the scientific community. Pharmacological experiments have established numerous beneficial properties for this brilliant reddish-orange dye derived from the flowers of a humble crocus family species. Studies in cultured human malignant cell lines and animal models have demonstrated the cancer prevention and antitumor activities of saffron and its main ingredients. This review provides an insight into the advances in research on the anticancer properties of saffron and its components, discussing preclinical data, clinical trials, and patents aiming to improve the pharmacological properties of saffron and its major ingredients.