Journal of Plant Biochemistry & Physiology
Open Access

Abstract

Aflatoxins in Natural Peanuts (Arachis hypogaea L.) of Mexico: Validation of the Biochemical Methods for Extraction and Quantification

Jose Rodrigo Alvarado-Hernández, Magda Carvajal-Moreno, Francisco Rojo-Callejas and Silvia Ruiz-Velasco

The peanut (Arachis hypogaea L.) is frequently contaminated with aflatoxins (AFs). Aflatoxins are toxic secondary metabolites – bifuran coumarins – produced by the fungi Aspergillus spp. AFs cause damage in animals and humans, including bleeding, vomiting, abortions, malformations, diarrhea and death. AFs can cause chronic liver damage and different cancers, immunosuppression, Reye’s syndrome, kwashiorkor and marasmus. For the present research, 58 samples of peanut were obtained: 48 were purchased from the three major markets of the 16 boroughs of Mexico City, and eight samples from Turkey and two from India were used for comparison. The extraction and quantification methods for AFs in peanut were validated. AFs from 25 g peanut samples were extracted with 100 mL of methanol/water (80:20 v/v) with one gram of salt. The roles of sample origin and types of AF were compared, and their significance was obtained through statistical analysis using the non-parametric Wilcoxon/Kruskal-Wallis tests. The limits of detection of AF (ng g-1) obtained from the calibration curves were AFB1 (0.1), AFB2 (0.01), AFG1 (0.01) and AFG2 (0.05). The results indicated that of the 58 samples, 80% were contaminated with AFB1, and all of them had total aflatoxins (AFt). The statistical analysis revealed a significant difference for AFB1, with the highest concentration of 44 μg kg-1 found in the Gustavo A. Madero Mexican borough. For AFB2, the highest concentration was 80 μg kg-1 from the Benito Juárez Mexican borough. Only traces of AFG1 were detected, with the highest of 0.64 μg kg-1 from the Tláhuac Mexican borough. Only traces of AFG2 were present. All samples had an average AFt of 8.53 μg kg-1.