level of evidence available in lite

level of evidence available in literature, bioactive peptides obtained from dietary sources 457 seems to do not impose a risk to human health but additional studies are necessary to 458 establish safety levels of ingestion for each hydrolysate/isolated bioactive peptide. 459 4.2. Effect in food 460 In contrast to living organisms, food displays an irreversible decay on its quality 461 characteristics that can be delayed from few hours to several months and even years when 462 appropriate strategies are applied. In this line, the use of antioxidant as food additives is a 463 common trend in the food industry (Franco et al., 2018; Granato et al., 2017; Horita et al., 464 2018; Lorenzo et al., 2018). However, consumer´s growing awareness for foods without 465 synthetic additives, due to their potentially harmful effects on health, has led both food 466 industry and researchers to explore new ways to obtain natural antioxidants. Moreover, they 467 are also showing an increased interest in the adequate ingestion of nutrients and bioactive 468 compounds due to their preventive actions against the development of non-communicable 469 diseases (Childs & Poryzees, 1997; Teratanavat & Hooker, 2006). This trend strengthens the 470 need for obtaining and using food additives of natural origin that also exert bioactivity. 471 In this scenario, antioxidant peptides have been used, at laboratory level, as potential food 472 additives. Few studies have been performed to evaluate the effect of antioxidant peptides in 473 real food matrices, which can support their potential use as additives (Table 4). Among the 474 several food products available, meat products are susceptible to lipid oxidation and require 475 additional protection against reactive species. However, controversial results were reported 476 in the scientific literature regarding the use of antioxidant peptides. 477 For example, the strategy of using starter cultures to release antioxidant peptides from 478 meat proteins and reduce the evolution of oxidation in dry-cured hams was evaluated (Okoń, 479 Stadnik, & Dolatowski, 2017). The authors explored the L. acidophilus and Bifidobacterium 480 animalis as starter cultures and obtained increasing antioxidant levels during ripening of 481 hams by the use of isolated or combined microorganisms. However, the authors reported 482 similar levels of antioxidant effect among all treatments.