Antioxidants as potential anti-inflammatory components in processed meat products

Abstract: In 2015, the World health organisation (WHO) released a press statement together with the International Agency for Research in Cancer (IARC) classifying processed meat as carcinogenic. Since then, research in this area has been focused on finding the underlying mechanism(s) responsible for the link between processed meat and the increased prevalence of colorectal cancer. One of the main hypotheses is that the heme iron present in the meat catalyses lipid oxidation which increases the levels of Reactive Oxygen Species (ROS) and toxic lipid oxidation secondary products which are harmful to our health.This thesis focuses on this lipid oxidation reaction, and the inhibition thereof, to gain further knowledge in the etiology of colorectal cancer caused by consumption of processed meat products. First, sustainable plant antioxidants were screened for their efficiency and content. Next, a commonly consumed meat product was manufactured based on its proneness to oxidise. When this was done, the most efficient antioxidants previously screened were added to these meat products for inhibition of lipid oxidation. And finally, the five most efficientantioxidants were tested in meatballs, together with relevant controls, for health evaluating purposes in an in vivo trial.We found several natural antioxidants which effectively decreased the level of lipid oxidation in our meat product. For instance, a freeze-dried summer savory (Satureja hortensis L.) powder, decreased the level of lipid oxidation to 13.8 % compared to the meat product with no added antioxidants at 200 ppm concentration. A water extract of sea buckthorn (Hippophae rhamnoides L.) leaves and sprouts lowered the oxidation to 22.9 % at 100 ppm concentration. However, we also found some antioxidants with highly pro-oxidant properties in a meat model pretrial. This is of importance, showing the great complexity of both antioxidants and matrices studied. As for the in vivo trial, some differences between trial groups were found. However, the results from this screening wereunfortunately not as conclusive as we expected, but gave nonetheless great inspiration and knowledge for further studies in the area. It is clear that lipid oxidation is not the sole mechanism behind the increase in colorectalcancer prevalence amongst processed meat consumers, but important differences could be seen in mice after only four months of trial in terms of microflora composition and certain immunological reactions between trialgroups.