## 4 Discussion
Mixing of the peptides-minerals complexes allowed to increase the ORAC value, in particular in the case of collagenase B and cathepsin B \(<\) 3000 Da fractions mixing, where 100 g of peptides-minerals complexes in the liquid form compare with 100 g of tomato and with 100 g of extra-virgin oil enriched with parsley or basil [30]. If the 100 g of dry matter are considered, significant higher ORAC values were found (Table 4); they compare with spices, herbs and brans (like cocoa, cumin, dried marjoram and dried parsley, sorghum brain), which globally have significant higher ORAC values with respect to vegetables and oils. The reducing capacity of Fe(III) to Fe(II) of the peptides-minerals complexes was significant and compared with food of plant origin [31]. Sterilization and concentration significantly improved the antioxidant activity. The highest reducing power was found for the cathepsin B fraction, a result that could be explained by the lower amount of free amino acids in this fraction and then by the lower amount of electrons acceptors amino acids (such as threonine) and bivalent amino acids (such as glycine) that can compete with Fe(III) in receiving an electron; this also likely explains the negative correlation of FRAP values with threonine and glycine. Some researches previously carried out, and in particular by [PERSON] at al. [31], highlighted that plant-based food show higher FRAP antioxidant power with respect to food of animal origin or mixed plant/animal food. In this regards, the positive results of our study can then support the finding that animal proteins, such as collagen, can be a source of peptides that have higher antioxidant activity than the protein itself, and these peptides can compare with plant origin food. When assessing the antioxidant activity towards lipids peroxidation for food such as bovine meat and butter, the peptides-minerals complexes showed interesting results that could promote their application in industry. As expected, the volume of peptides-minerals complexes to add to have a comparable TBArs inhibition in meat and butter was lower (however not linearly proportional) in the case of meat (Figures 8 and 9) since the amount of lipids is lower with respect to butter. The values of the TBArs essay for meat significantly correlated with the ORAC values, which agrees with the target of both essays which are peroxyl radicals. A positive correlation was also find with butter albeit less significant. Lipid peroxidation refers to the oxidative degradation of lipids that contain in their structure carbon-carbon double bonds, as, for exemple, unsaturated fatty acids (including \(\omega 3\) and \(\omega 6\)), phospholipids, glycolipids, etc., [32]. Malondialdehydehyde (MDA) is the main product of unsaturated lipid oxidation and it can negatively affect the nutritional quality of food due to the formation of adducts with food proteins [23; 33]. From a biological point of view, in the human body, MDA levels increase with age and this can give rise to pro-inflammatory and pro-fibrogenic effects as a consequence of the formation of MDA-proteins and MDA-DNA (deoxyribonucleic acid) adducts. In this regard, patients affected by the _Parkinson's_ disease, have showed higher levels of MDA with respect to healthy individuals [33]. These finding suggest that the effect of bovine bone collagen peptides-minerals complexes could be also tested in aging and in neurodegenerative disease status such as the _Parkinson's_ sickness. Apart the antioxidant capacity, the peptides-minerals complexes could be also regarded as a nutritional source of calcium, phosphorous and magnesium. They are essential minerals for the growth and health of bones and teeth, and particular important in the prevention of osteoporosis; also, they are indispensable for a number of biochemical reactions such as the biosynthesis of phospholipids, DNA, adenosine triphosphate, stabilisation of cells membranes, etc. [19; 34].