## 1 Introduction
However, the two systems need to be activated previously by using UV radiation, hindering their implementation in processing packaging plants since an additional step is needed. Consumer's preferences have steadily evolved to have a preference for natural over synthetic products because natural is seen as safer. Examples of naturally derived oxygen scavenging compounds are ascorbic acid and its salts, isoascorbic acid, tocopherol, hydroquinone, catechol, sorbose, lignin, gallic acid, and polyunsaturated fatty acids [16]. Unsaturated fatty acids can be used as oxygen absorbers without needing the presence of moisture for their activation, making them useful for low moisture food applications. However, the absorption mechanism involves a catalytic autoxidation reaction that generates aldehydes producing unpleasant odours. For peanut packaging, the use of sodium ascorbate in PE films was investigated by [PERSON] and [PERSON] [17]. The developed film was able to reduce the lipid oxidation process in peanuts using a GRAS (\"Generally Recognized As Safe\") categorised compound. Nevertheless, due to the characteristics of sodium ascorbate, the mechanical properties and water permeation of films were modified. Flavonoids have also been incorporated into different polymeric matrices [4, 6, 18]. It is important to note that film functionality is frequently verified by using traditional antioxidant capacity methods such as 2,2-diphenyl-1-picrylhydraz (DPPH) or 2,2\({}^{\prime}\)-azino-bis(3-ethylbenzothazoline-6-sulfonic acid) (ABTS) methodologies, but actual oxygen absorption is not verified. \(\beta\)-Carotene is a natural pigment characterised by its conjugated double bond system. It is well-known as a UV stabiliser and as a singlet oxygen quencher [19]. These properties can be useful for food preservation in the food industry. The antioxidant and preservative characteristics of carotenoids have been thoroughly studied in food products. In the packaging sector, \(\beta\)-carotene has received far less attention, probably because of its pigmentation capacity, although its use as a polymer stabiliser has been evaluated. Hence, [PERSON] et al. found that \(2\times 10^{-4}\) g \(\beta\)-carotene/ mL of polymer film increases their UV stability in various biopolymers including poly(lactic-acid) (PLA), poly(\(\varepsilon\)-caprolactone) (PCL), and poly(hydroxybutyrate-co-valerate) (PHBV) [20]. The additive also plasticized the biopolymer. This fact has also been demonstrated in a PE matrix. [PERSON] confirmed that the addition of \(\beta\)-carotene into an acrylonitrile-butadiene-styrene (ABS) matrix stabilised the copolymer due to its capability as a singlet oxygen quencher [19]. Moreover, it was also demonstrated \(\beta\)-carotene hindered oxidation process in the propagating step of the thermo-oxidation of ABS (interfering in the formation of peroxy and alkoxy radicals) because \(\beta\)-carotene levels decreased at the beginning of the thermal treatment. From the point of view of the effect of materials containing \(\beta\)-carotene on packaged foods, this compound has been used in materials developed to contain oils such as soybean and sunflower oils [21; 22]. Nevertheless, to our knowledge, it has not been employed for solid foods yet. Thus, the aim of the present study is the development of a double-function oxygen absorber and antioxidant films for active packaging by the incorporation of \(\beta\)-carotene into LDPE/PET based polymer matrices, at laboratory and pilot-scale. The effects of the addition of \(\beta\)-carotene on the oxygen absorption capacity, optical, and thermal properties of the films were studied. Moreover, the antioxidant capacity of the active films was evaluated by the oxidation induction time (Olt) measurements by differential scanning calorimetry (DSC). Overall migration tests were also analysed. In order to validate the developed materials, the efficiency of the films was evaluated by conducting a shelf-life-study with fried peanuts stored for 3 months at 40 \({}^{\circ}\)C.