Molecular Genetic Analysis for Identification of Açaí and Juçara in Commercial Samples by DNA Barcoding and High Resolution Melting

Name: Magda Delorence Lugon
Type: PhD thesis
Publication date: 02/07/2021
Advisor:

Namesort descending Role
Greiciane Gaburro Paneto Advisor *

Examining board:

Namesort descending Role
Gonçalo Apolinário de Souza Filho External Examiner *
Greiciane Gaburro Paneto Advisor *
Jose Aires Ventura (M/D) Internal Examiner *
Marcia Flores da Silva Ferreira Internal Examiner *
Rodrigo Soares de Moura Neto External Examiner *

Summary: LUGON, M.D. Molecular Genetic Analysis for Identification of Açaí and Juçara in Commercial Samples by DNA Barcoding and High Resolution Melting. 2021. 85f. Thesis (Doctoral in Biotechnology) – Postgraduation Biotechnological Programme, UFES, Espirito Santo. Brazil.
Açaí is an Amazon fruit with antioxidant and anti-inflammatory properties used in the preparation of energy drinks consumed mainly in Brazil and lately exported to the whole world. It is obtained from two palm species, Euterpe oleracea and Euterpe precatoria. However, it may be mistaken with the fruit of a non-Amazon sister species (Euterpe edulis), called juçara, due to its morphological similarities. There is an increasing need for faster, more reliable, and reproducible methods that ensure all the ingredients included in a foodstuff, match the parameters claimed by the manufacturer or distributor in order to comply with regulations. Industrialized products can lose the original chemical and physical characteristics of their content. Even when these characteristics are preserved, the similarities between closely related species make their identification difficult. In recent years, DNA-based methods have contributed to guarantee the authenticity of food components and food products. DNA barcoding and High Resolution Melting (HRM) have been used with success in food safety. In this work, the main objective was to establish a DNA barcoding method to discriminate the three Euterpe species, and it was successfully applied to authenticate açaí commercial products sold in the Brazilian market. After testing nine regions as DNA barcoding candidates in reference samples, through conventional PCR and DNA sequencing, psbK-I region was elected for the authentication method. As result, 88.6% of the samples were classified as authenticated and 11.4% were classified as adulterated products. Authenticated açaí products showed clustered with E. oleracea reference plants. Four adulterated açaí products showed clustered with E. edulis. No products showed clustered with E. precatoria. Furthermore, the combination of two primers pairs, HRMpsbKI and HRMycf1b, in HRM technique was successfully useful to authenticate açaí products, enabling the identification of the species E. oleracea and E. precatoria, and differentiating the E. edulis. Admixtures of species E. edulis and E. oleracea were detected from 10% using HRMpsbKI primers. HRM was superior to DNA sequencing in authenticating samples. The HRM analysis presented higher resolution and cost effectiveness than DNA sequencing when authenticating commercial samples of açaí. These results bring us concern about the correct identification of species in food and about the occurrence of misleading advertising on labeled açaí products.

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