Development of an Extraction Method of Aflatoxins and Ochratoxin A from Oral, Gastric and Intestinal Phases of Digested Bread by In Vitro Model

Aflatoxin detoxification by thermal cooking treatment and evaluation of in vitro bioaccessibility from white and brown rice

Aflatoxins pose a severe risk to the human health. In this study, the detoxifying capacity of a thermal cooking treatment applied to white and brown rice spiked with aflatoxins B1, B2, G1 and G2 as well as the aflatoxin bioaccessibility in cooked rice after applying an in vitro digestion model was evaluated. The cooking treatment (boiling with water at 100 °C for 12 min) evidenced an important extraction capacity of the boiling water over aflatoxins (25 %-56 %), that was higher for brown rice. Moreover, aflatoxins G1 and G2 were unstable with losses around 35 %. The highest bioaccessibility percentage was obtained for white rice (60 %-83 %) compared to brown rice (28 %-47 %), due to aflatoxin losses from brown rice after the gastric step. These results confirm the potential of this thermal cooking treatment to reduce aflatoxins in rice and suggest the influence of the nutritional composition of each rice on aflatoxin behaviour.

Evaluation of the Bioaccessible Fraction of T-2 Toxin from Cereals and Its Effect on the Viability of Caco-2 Cells Exposed to Tyrosol

The bioaccessibility of mycotoxins is an important factor that has to be considered when assessing the risk they pose to human health. Bioactive compounds like phenolics could play a protective role against the toxic effects of contaminants. In this work, the bioaccessible fraction of the T-2 toxin (T-2) contained in breakfast cereals and its effect on the viability of Caco-2 cells were investigated. Furthermore, the effect of tyrosol (a polyphenol abundant in EVOO) on T-2-induced cytotoxicity was evaluated in the same cell line. After standardized in vitro gastrointestinal digestion, the T-2 toxin was released from T-2-spiked breakfast cereals and further quantified by UHPLC-MS/MS. The bioaccessible fraction of T-2 was 51 ± 4%. The cell viability study was performed by pre-treating the cells for 24 h with tyrosol (25, 50 and 100 µM) and subsequently adding T-2 at 15 nM or by treating the cells with a combination of tyrosol and T-2. In the simultaneous treatment, 25 µM tyrosol prevented the toxic effects produced by the exposure to T-2 at 15 nM; however, cytotoxic effects were observed for the other combinations tested. The pre-treatment of Caco-2 cells with tyrosol did not attenuate the cytotoxic effects caused by exposure to T-2. These results suggest that tyrosol at low concentrations (25 µM) could exert a cytoprotective effect on Caco-2 cells against 15 nM T-2 when administered simultaneously with T-2. However, more studies are required to corroborate this hypothesis.

Mycotoxins in Wheat Flours Marketed in Shanghai, China: Occurrence and Dietary Risk Assessment

The risk of exposure to mycotoxins through the consumption of wheat flours has long been a concern. A total of 299 wheat flours marketed in Shanghai Province of China were surveyed and analyzed for the co-occurrence of 13 mycotoxins through an ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. The detection rates of mycotoxins in wheat flours ranged from 0.7~74.9% and their average contamination levels in wheat flours (0.2~57.6 µg kg-1) were almost lower than the existing regulations in cereals. However, their co-contamination rate was as high as 98.1%, especially Fusarium and Alternaria mycotoxins. Comparative analysis of different types of wheat flours showed that the average contamination levels in refined wheat flours with low-gluten were lower. Based on these contamination data and the existing consumption data of Shanghai residents, point evaluation and the Monte Carlo assessment model were used to preliminarily evaluate the potential dietary exposure risk. The probable daily intakes of almost all mycotoxins, except for alternariol, were under the health-based guidance values for 90% of different consumer groups. Health risks of dietary exposure to alternariol should be a concern and further studied in conjunction with an internal exposure assessment.

Application of an In Vitro Digestion Model for Wheat and Red Beetroot Bread to Assess the Bioaccessibility of Aflatoxin B1, Ochratoxin A and Zearalenone and Betalains

Nowadays, the bakery industry includes different bioactive ingredients to enrich the nutritional properties of its products, such as betalains from red beetroot (Beta vulgaris). However, cereal products are considered a major route of exposure to many mycotoxins, both individually and in combination, due to their daily consumption, if the cereals used contain these toxins. Only the fraction of the contaminant that is released from the food is bioaccessible and bioavailable to produce toxic effects. Foods with bioactive compounds vary widely in chemical structure and function, and some studies have demonstrated their protective effects against toxics. In this study the bioaccessibility and bioavailability of three legislated mycotoxins (AFB₁, OTA and ZEN), individual and combined, in two breads, one with wheat flour and the other with wheat flour enriched with 20% Beta vulgaris, were evaluated. Bioaccessibility of these three mycotoxins from wheat bread and red beet bread enriched individually at 100 ng/g was similar between the breads: 16% and 14% for AFB1, 16% and 17% for OTA and 26% and 22% for ZEN, respectively. Whereas, when mycotoxins were co-present these values varied with a decreasing tendency: 9% and 15% for AFB1, 13% and 9% for OTA, 4% and 25% for ZEN in wheat bread and in red beet bread, respectively. These values reveal that the presence of other components and the co-presence of mycotoxins can affect the final bioavailability; however, it is necessary to assess this process with in vivo studies to complete the studies.

Pumpkin extract and fermented whey individually and in combination alleviated AFB1- and OTA-induced alterations on neuronal differentiation invitro

Food and feed are daily exposed to mycotoxin contamination which effects may be counteracted by functional compounds like carotenoids and fermented whey. Among mycotoxins, the most toxic and studied are aflatoxin B1 (AFB1) and ochratoxin A (OTA), which neurotoxicity is not well reported. Therefore, SH-SY5Y human neuroblastoma cells ongoing differentiation were exposed during 7 days to digested bread extracts contained pumpkin and fermented whey, individually and in combination, along with AFB1 and OTA and their combination, in order to evaluate their presumed effects on neuronal differentiation. The immunofluorescence analysis of βIII-tubulin and dopamine markers pointed to OTA as the most damaging treatment for cell differentiation. Cell cycle analysis reported the highest significant differences for OTA-contained bread compared to the control in phase G₀/G₁. Lastly, RNA extraction was performed and gene expression was analyzed by qPCR. The selected genes were related to neuronal differentiation and cell cycle. The addition of functional ingredients in breads not only enhancing the expression of neuronal markers, but also induced an overall improvement of gene expression compromised by mycotoxins activity. These data confirm that in vitro neuronal differentiation may be impaired by AFB1 and OTA-exposure, which could be modulated by bioactive compounds naturally found in diet.