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

ZAPPA ME; PERAL GARCIA P; POSIK DM,; GIOVAMBATTISTA G; BRUNO MC; WUNDERLING D

Nantes

Congreso; 5th FoodIntegrity Conference: Assuring the integrity of the food chain: Delivering real world solutions; 2018

FoodIntegrity

Genetic tools for identification of flaxes, chia, and sesame ingredientsin seeds and processed foodsBruno C, Posik DM, Zappa ME, Wunderling D, GiovambattistaG, Peral García P Instituto de GenéticaVeterinaria (IGEVET, CONICET-UNLP) Thereis an increasing demand among consumers to know about the origin oftheir food and the accuracy of food labeling, which influences purchasingdecisions. Thus, flax, chia, and sesame seeds, as well as processedfood (e.g., cookies and cereals bars) containing these species became popularfoods.For this reason, it is necessary to develop genetic tools to certificatethe presence of these species. Taking this into account, the main objectivewhen we started this work was developing and comparing different genetic tools thatcould be used to determine  the originand the authenticity of flax, chia, and sesame products, basedon the analysis of two regions from MaturaseK (matK) and Ribulosebisphosphatecarboxylase large chain (rbcL) genesthrough PCR-SBT, RT-PCR-HRM, and PCR-speciespecific methods. First, different DNA extraction methods were tested fordifferent matrix (seeds, commercial cookies, cereals bars and experimentalhomemade cookies), which showed that the combination between a mechanic lysisof Seed and bakery samples using the FastPrep-24 (MP Biomedicals) and the DNApurification from the grinding material using the FastDNA? Spin Kit for Plantand Animal Tissue were the most appropriate methods to obtain enough DNAquantity and/or quality to allow genotyping. PCR-SBT analysis showed that matKand rbcl genes exhibited a high percentage of identity with its own specie buta low value of diversity in this region among them. However, the observeddiversity was enough to further develop RT-PCR-HRM and PCR-speciespecific assays in the future. The analysis of 100 bp and 71 bp rbcL fragmentsof Flax, Chia, Sesame, Wheat by RT-PCR-HRM allowed us to discriminate thesespecies according to melting temperatures.Finally,  the implementation of these tools based onthe characteristics of each product and the evaluation of the cost and benefit wasdiscussed.