Joint research project

Approcci innovativi di spettrometria di massa per la salvaguardia dell'autenticità dello zefferano e per combattere le frodi alimentari

Project leaders
Linda Monaci, Alice Bejjani
Agreement
LIBANO - CNRS-L - National Council for Scientific Research of Lebanon
Call
CNR/CNRS-L biennio 2018-2019 2018-2019
Department
Biology, agriculture and food sciences
Thematic area
Biology, agriculture and food sciences
Status of the project
New

Research proposal

Saffron is a valuable and highly appreciated spice derived from the dried red stigmas of the flowers of the cultivated plant Crocus sativus L. It is commonly used as a colouring and flavouring agent in food preparation andit is also widely used in herbal formulations and other botanical products for its health promoting properties (Melnyk et al., 2010). Saffron properties mainly depend on three main secondary metabolites: crocins, a family of yellow water-soluble pigments, picrocrocin, a colorless and bitter-tasting glycoside responsible for taste factor, and safranal a volatile oil responsible for the characteristic odor and aroma. In addition, saffron is rich in flavonoids, proteins, sugars, vitamins, amino acids, mineral matter, etc. To produce saffron spice, harvested stigma are exposed to a mild food processing which conditions depend on the region of production. In light of this, saffron is considered a traditional product, with an aroma and a chemical composition typical of the geographic location of production. Due to the high costs for its production, saffron is one of the most expensive spice commercialized across the world, and often susceptible of adulteration.Saffron adulterations include the addition of different plant based materials with similar color and morphology but less expensive and more readily available. The purpose is to increase the final spice weight and/or to improve its color properties. The most frequently materials employed as adulterants in saffron encounters cut and/or dyed C. sativus stamens, Calendula officinalis L. petals, Carthamus tinctorius L. petals and Curcuma longa L. powdered rhizomes (Hagh-Nazari et al., 2007, Kanti et al., 2011). The latter three materials are also involved in mislabeling issues of commercial saffron. Very recently the fruit extract of Gardenia jasminoides Ellis and the dye extracted from Buddleja officinalis Maxim. glowers were found as new fraudulently added materials (, Soffritti et al., 2016). They could be easily concealed in the saffron matrix due to their pigment composition very similar to crocins present in the spice. In light of these considerations searching and discovering markers for authentic saffron is of paramount importance also taking into account that substitution of saffron with other low value spices or equivalent not only delivers a product of lower quality, but might introduce also some risks for consumers.
Several analytical methods have been reported in literature for the detection of plant adulterants in saffron. They are, based on UV-vis spectrophotometric measurements, near infrared spectroscopy, Raman and nuclear magnetic resonance spectroscopy (NMR) (e.g. Tarantilis et al., 2004), capillary electrophoresis, and high-performance liquid chromatography with and without mass spectrometry (MS) detection (e.g. Sabatino et al., 2011, Guijarro-Díez et al., 2017). Up to date, saffron is classified by its aroma, flavor, and color strength and its quality is certificate using the ISO 3632-1 (2011) methods, which combines UV spectrophotometric measurements of picrocrocin and safranal, and chromatographic profiles of polar dye and pigments (crocins) along with apolar dyes that can be toxic (as Sudan dyes) (ISO 3632-1; ISO 3632-2). Moreover, the ISO 3632 technical standard set at 1% (w/w) the maximum mass fraction of foreign matter permitted in third class products. Anyway, it has been demonstrated that ISO 3632 standards are non-specific and unable to adequately separate authentic from the adulterated saffron. For example, adulteration with safflower, marigold or turmeric up to 20% (w/w) were not detectable with ISO 3632 procedures (Sabatino et al., 2011).
Searching markers for authenticity instead of markers for adulteration would be a promising alternative for promptly detecting saffron adulteration. In this context the implementation of a metabolomic based integrated approach provides a good tool to face this challenge. The main advantage of metabolomics in food authentication relies in its untargeted nature which allows making sample comparative studies with consequent classification by using chemometric tools. It also enables characterization of the investigated samples by obtaining typical fingerprinting which allows discovering new emerging frauds or selecting molecules as markers for authenticity assessment. Untargeted metabolic fingerprinting using UPLC-HRMS has also been employed for saffron authentication/traceability according to the geographical origin together with the identification of some peculiar markers (Rubert, et al., 2016). In this research project we aim at developing an integrated MS based approach using DART technology coupled with an Orbitrap mass analyser and complementary TOF-SIMS platform, both considered rapid and sensitive methods for the identification of sensitive and reliable markers to safeguard saffron authenticity.

References
Guijarro-Díez, M., Castro-Puyana, M., Crego, A. L., Marina, M. L. (2017). J. Food Compost. Anal., 55, 30-37.
Hagh-Nazari, S., Kei, N. (2007). Acta Hortic., 39, 411-416.
Kanti, R., Sushma, K., Gandhi, R. (2011). JTMP, 12(1), 135-140.
Maghsoodi, V., Kazemi, A., Akhondi, E. (2012). Iran J. Chem. Chem. Eng., 31(2), 85-89.
Rubert, J., Lacina, O., Zachariasova, M., Hajslova, J. (2016). Food Chem., 204, 201-209.
Sabatino, L., Scordino, M., Gargano, M., Belligno, A., Traulo, P., Gagliano, G. (2011). Nat.Prod.Commun., 6,1873-1876.
Soritti, G., Busconi M., Sánchez R.A., Thiercelin J.-M., Polissiou M., Roldán M., Fernández J.A. (2016). Molecules, 21, 343.
Tarantilis, P.A., Polissiou, M.G. (2004). Acta Horticult., 650, 447-461.
The International Organization for Standardization, International Standard ISO 3632-1. Geneva, 2011.
The International Organization for Standardization, International Standard ISO3632-2. Geneva, 2010.

Research goals

The main objective of this project is to develop an integrated rapid, simple and sensitive analytical method enabling assessment of saffron authenticity. With this aim we propose a multiple and integrated MS-based metabolomic approach, comparing both untargeted profiling and targeted marker identification for saffron authenticity. This will employ High Resolution Mass Spectrometry method coupled with DART or LC techniques. In fact, DART technology offers several advantages compared to conventional techniques, such as the possibility to analyze sample directly in the open atmosphere without previous chromatographic separation, high sample throughput and minimal, or no sample preparation requirements.
In addition, we propose a spectroscopic and imaging identification of all saffron components using the Time of Flight Secondary Ion Mass Spectrometry. This technique, which probes the chemistry and the structure of the outer surface, is known for its molecular specificity, relatively high mass resolution, and high sensitivity. It is also considered a non-destructive technique that analyzes samples in the micro scale. Compared to conventional techniques, TOF-SIMS turns very useful technique in case of very low quantity of samples available and does not require a chemical sample preparation. The goal of the project would be to identify marker to safeguard saffron authenticity by using an integrated approach.

Last update: 27/11/2021