## 3 Effect of Food Processing and Culinary Preparations on PAs, TAs and OAs
### Infusion
This fact highlights that there are many parameters that may affect the efficiency of the transfer rate during the brewing process of teas and infusions, such as the tea-to-water ratio, the brewing method (i.e., temperature, time, acidic conditions), the homogeneity of the tea samples (e.g., particle size of the leaves), or even the type/source of contamination (e.g., differences among the PA-producing plants, contamination by flowers, leaves, etc.). For instance, [PERSON] et al. (2019) assessed the content of PAs and PANOs in infusions prepared with comminuted leaves and intact leaves [100]. The extraction efficiency was higher in the infusion prepared with comminuted leaves, showing PA concentration levels 1.1-4.1 times higher than in the infusions prepared with intact leaves [100]. Likewise, acidic conditions have shown to enhance the transfer rate of these alkaloids during the brewing process [98]. Nonetheless, it is unlikely that the pH of the brewed herbs would be low enough to have a significant effect on PA-extraction. Moreover, it seems that decreasing the tea-to-water ratio and increasing the steeping time contributes to increasing the transfer rate of PAs. [PERSON] et al. (2022) also compared the concentrations obtained for some PAs and PANOs in funnel and anise dry teas with the levels found of these alkaloids in their corresponding infusions (which were prepared following the instructions on the tea packaging) [70]. Although transfer rates were not provided by the authors, the results obtained showed a significant decrease in some PAs/PANOs in the hot drink (e.g., heliosipurine \(N\)-oxide, echinautine, europeine and intermediate), suggesting a transfer rate lower than 100% [70]. However, the concentration level of other analytes, such as retrovirus \(N\)-oxide and serecionine \(N\)-oxide, were much higher in the drink than in the dry tea [70]. These higher concentrations led to greater amounts of PAs/PANOs in the infusions than in the dry extracts analyzed by QuEChERS. This has also been reported by other authors [95; 98]. For instance, [PERSON] et al. (2018) determined a 2.4-fold content increase for infusions (aqueous medium at 100 \({}^{\circ}\)C) compared with aqueous acidic extraction at room temperature [95]. Therefore, the higher PA concentrations observed by some authors in hot tea drinks compared with the levels found in dry raw materials could be explained by the prolonged aqueous extraction at high temperatures, suggesting a lower extraction efficiency when other organic solvents in an acidic medium [70; 95; 98]. Hence, this fact is important when developing routine analytical methods to monitor the presence of these alkaloids, and thus legislation should contemplate these issues when establishing the maximum concentration limits in these types of product, as it seems to be more suitable to perform the analysis of infusions rather than of the dry product. In this sense, the analysis of infusions provides a more reliable scenario of the real intake and exposure of consumers to these alkaloids. However, due to the great variability of the data related to the transfer rate of PAs, more studies are needed to evaluate this phenomenon and carry out greater control of all the parameters that can influence it, so that a reliable PA transfer rate can be set. Likewise, it is important to determine if the transfer rate observed is associated to a degradation process or not. In some cases, the transfer rate can be lower because the compounds may be degraded by heat, while in other cases it may be lower due to a lower extraction efficiency. This aspect has not been discussed in any of the works reviewed. Moreover, it is also of high interest to determine if the lower transfer rate is due to a complete degradation of the compound because of the heat applied or if a transformation into other compounds is taking place. As previously indicated in Section 3.1, if new compounds derived from PAs are being formed during the brewing process, they should be identify and assessed for their toxicity.