# Pulsed Electric Fields (PEF) to Mitigate Emerging Myotoxins in Juices and Smoothies
## 3 Results and Discussion  
### Reduction of ENs and BEA Contents after PEF Treatment  
After PEF treatment, a significant reduction of ENA, ENA1, ENB, ENB1, and BEA was observed in all tested samples. For juice samples, the contents of emerging mycotoxins obtained were \(46.81\pm 0.8\)\(\mu\)g/L (ENA), \(52.23\pm 4.4\)\(\mu\)g/L (ENA1), \(56.98\pm 10.88\)\(\mu\)g/L (ENB), \(56.8\pm 2.79\)\(\mu\)g/L (ENB1), and \(54.04\pm 0.4\)\(\mu\)g/L (BEA), corresponding to reduction percentages from 43 to 53%, approximately (Figure 1).  
For smoothie samples, the contents after PEF treatment were \(44.35\pm 0.21\)\(\mu\)g/L (ENA), \(40.84\pm 2.12\)\(\mu\)g/L (ENA1), \(42.94\pm 14.56\)\(\mu\)g/L (ENB), \(40.12\pm 6.58\)\(\mu\)g/L (ENB1), and \(29.8\pm 9.8\)\(\mu\)g/L (BEA), corresponding with higher reduction percentages from 56 to 70%, approximately (Figure 1). Figure 2 shows the chromatograms of juice samples spiked with ENB1: PEF-treated vs. non-treated samples.  
Figure 1: Percentage of reduction (%) of enniatins (ENs) and beauvericin (BEA) in grape juice vs. smoothie samples after pulsed electric fields (PEF) treatment.  
During PEF treatment, temperatures around 70 \({}^{\circ}\)C were reached. The emerging mycotoxins were relatively sensible to temperature, therefore, experiments in H\({}_{2}\)O spiked with mycotoxins at the same conditions and heated at 70 \({}^{\circ}\)C during the same duration of PEF treatment were performed in order to check if the degradation observed was a consequence of the temperatures reached during the PEF treatment. The results obtained showed that temperature treatment caused degradations percentages of 26%.  
In previous studies, [PERSON] et al. [26] and [PERSON] et al. [27] observed similar ENB and ENB1 reductions after thermal treatments of cooking pasta and boiling fish at temperatures \(>\)100 \({}^{\circ}\)C, with reduction percentages from 14 to 49% for ENB and 53 to 65% for ENB1 after cooking pasta and to nearly 60% (ENB and ENB1) after boiling fish.  
As was mentioned above, scarce information is available in the literature about mycotoxin reduction after the PEF treatment. [PERSON] et al. [16] optimized the combination of thermal processing with PEF to reduce artificially spiked AFs in a potato, dextrose, and agar system, at different pH values. The combination treatment was found to be more effective than individual processes, with reduction percentages from 92.3 to 96.9% for AFB1 as a function of pH and from 82 to 95.7% for total AFs. These authors, [PERSON] et al. [17], also observed a reduction of AFB1 and AFs contents  
Figure 2: LC-MS/MS-IT chromatogram of juice sample contaminated by enniatin B1 (ENB1) treated by pulsed electric fields (PEF) vs. non-treated.  
from 77 to 97% after optimizing PEF methodology. These reductions were similar to those obtained in the present study for BEA in smoothie samples (70%).  
The same treatment applied to H\({}_{2}\)O revealed lower percentages of reduction (from 31 to 45%) (Figure 3). The lower percentages of reduction observed in water vs. grape juices and smoothies (43 to 70%) may be due to differences in the matrix and/or in pH. The pH values of the juices and smoothies employed in this study were measured to be 3.88 and 3.94, respectively. The effect of pH = 4 was assessed on ENs and BEA contents using a water model acidified with lemon juice. An additional degradation was observed when the H\({}_{2}\)O was acidified for BEA (56%) (Figure 3) compared with neutral H\({}_{2}\)O, but significant differences were not observed for ENs.  
As reported by other authors [28; 29], the degradation could be dependent of juice constituents. This fact may explain the different reductions observed in juices compared to the reductions observed in water, and the higher reductions observed in smoothie samples (from 56 to 70%) compared to grape juice samples (from 43 to 53%). Smoothies were made with different fruit juices, purees, and cereals, so they have a more complex matrix than that of grape juice.