Genetic and Epigenetic Approaches for the Possible Detection of Adulteration and Auto-Adulteration in Saffron (Crocus sativus L.) Spice

Abstract

Saffron (Crocus sativus L.) is very expensive and, because of this, often subject to adulteration. Modern genetic fingerprinting techniques are an alternative low cost technology to the existing chemical techniques, which are used to control the purity of food products. Buddleja officinalis Maxim, Gardenia jasminoides Ellis, Curcuma longa L., Carthamus tinctorius L. and Calendula officinalis L. are among the most frequently-used adulterants in saffron spice. Three commercial kits were compared concerning the ability to recover PCR-grade DNA from saffron, truly adulterated samples and possible adulterants, with a clear difference among them, mainly with the processed samples. Only one of the three kits was able to obtain amplifiable DNA from almost all of the samples, with the exception of extracts. On the recovered DNA, new markers were developed based on the sequence of the plastid genes matK and rbcL. These primers, mainly those developed on matK, were able to recognize saffron and the adulterant species and also in mixtures with very low percentages of adulterant. Finally, considering that the addition of different parts of saffron flowers is one of the most widespread adulterations, by analyzing the DNA of the different parts of the flower (styles, stamens and tepals) at the genetic and epigenetic level, we succeeded in finding differences between the three tissues that can be further evaluated for a possible detection of the kind of fraud.

Epigenetic Variability Among Saffron Crocus (Crocus sativus L.) Accessions Characterized by Different Phenotypes

“…DNA extractions were carried out using the commercial kit GeneElute Plant Genomic DNA Miniprep Kit (Sigma-Aldrich) according to the manufacturer’s instructions with one minor modification. In detail, we added 4% w/w of PVP (polyvinylpyrrolidone; Soffritti et al, 2016 ) to each sample during DNA extraction to facilitate the removal of secondary metabolites, such as polyphenols, and to produce a purer DNA for the subsequent analysis.…”

“…Interestingly, despite at least 3 years of co-cultivation and vegetative propagation in the same field, accessions with different geographic origins still possessed different epigenotypes, making it possible to separate the accessions of different origin, at least in some cases. In another study, based on differences in the MS-AFLP profile of different parts of the flower, the possible utility of epigenetics for detecting stamen adulteration of saffron production was suggested ( Soffritti et al, 2016 ). Finally, Busconi et al (2018) evidenced that epigenetic structure in saffron is highly stable and can stably persist over the years, supporting again the possible involvement of epigenetics in determining alternative saffron phenotypes.…”

Use of Microsatellites to Study Agricultural Biodiversity and Food Traceability

“…Dishonest producers may substitute, partially or totally, some food products with others less expensive to increase the profit. For this reason, certifying the origin and composition of a certain food is becoming more and more important [76][77][78]. Molecular analysis is one of the most recently developed methods to trace food products.…”

Optimization of an Untargeted DART-HRMS Method Envisaging Identification of Potential Markers for Saffron Authenticity Assessment

“…Due to the high costs and labor required for plantation and production, together with the huge number of flowers needed to obtain the spice, saffron could be considered one of the most expensive agricultural products of the world [15]. In the last years, its high value has prompted a rapid increase of fraudulent market so that saffron has been described as one of the most commonly adulterated food ingredients.…”