Genetic tools for identification of flaxes, chia, and sesame ingredients in seeds and processed foods

BRUNO, M.C.; POSIK, D.M.; ZAPPA, M.E.; WUNDERLIN, DANIEL; GIOVAMBATTISTA, GUILLERMO; PERAL GARCÍA, P.

Nantes

Congreso; 5th Food Integrity Conference; 2018

Food Integrity Project and Eurofins France

There is an increasing demand among consumers to know about the origin of their food and the accuracy of food labeling, which influences purchasing decisions. Thus, flax, chia, and sesame seeds, as well as processed food (e.g., cookies and cereals bars) containing these species became popular foods.For this reason, it is necessary to develop genetic tools to certificate the presence of these species. Taking this into account, the main objective when we started this work was developing and comparing different genetic tools that could be used to determine the originand the authenticity of flax, chia, and sesame products, based on the analysis of two regions from MaturaseK (matK) and Ribulosebisphosphatecarboxylase large chain (rbcL) genes through PCR-SBT, RT-PCR-HRM, and PCR-species pecific methods. First, different DNA extraction methods were tested for different matrix (seeds, commercial cookies, cereals bars and experimental homemade cookies), which showed that the combination between a mechanic lysis of Seed and bakery samples using the FastPrep-24 (MP Biomedicals) and the DNA purification from the grinding material using the FastDNA? Spin Kit for Plant and Animal Tissue were the most appropriate methods to obtain enough DNA quantity and/or quality to allow genotyping. PCR-SBT analysis showed that matK and rbcl genes exhibited a high percentage of identity with its own specie but a low value of diversity in this region among them. However, the observed diversity was enough to further develop RT-PCR-HRM and PCR-species pecific assays in the future. The analysis of 100 bp and 71 bp rbcL fragments of Flax, Chia, Sesame, Wheat by RT-PCR-HRM allowed us to discriminate these species according to melting temperatures. Finally, the implementation of these tools based on the characteristics of each product and the evaluation of the cost and benefit was discussed.