## 1 Introduction  
One of the main problems of the nut industry is the reduction in the shelf-life and quality of food samples, specifically for those who have a high unsaturated fat content, due to oxidation reactions that lead to a deterioration of the flavor and aroma, color alteration and nutritional losses [1]. In fact, unsaturated fatty acids are substances quite sensitive to oxidation, but they are also essential in the diet since they play an important role against cardiovascular diseases [2]. Additionally, oxidation reactions produce potentially harmful substances, such as hydroperoxides or aldehydes and ketones, as primary and secondary oxidation products, with the consequent repercussion on the consumer's health [3]. Currently, to improve the shelf life of nut products, food industry uses different approaches, such as the addition of preservatives directly to foods. However, the use of additives is becoming less and less accepted by consumers concerned about the adverse effects they could cause, although their safety in terms of the frequency of consumption and the maximum allowable dietary level avoiding the generation of any adverse effect is always under investigation [4]. Modified atmosphere packaging (MAP) is another widely used alternative to increase the shelf life of packaged nuts [5]. However, the residual oxygen concentration in the package often remains between 0.5% and 5% despite using MAP and it can increase during storage [6] since oxygen can permeate through, even high-barrier polymeric matrices. To solve this problem, in the last years, some research studies have been focused on the development of new active packaging materials by the incorporation of an oxygen scavenger into the polymeric matrix [7]. These compounds remove oxygen from the headspace of the package thus reducing the possibility of food oxidizing, increasing its useful life, and maintaining its quality [8; 9]. The use of oxygen scavengers in food packaging is implemented in different ways. One is the incorporation into the packaging of separate elements such as bags, pads, sachets or labels, which contain the oxygen scavenger system. Different systems using these formats are commercially available such as OXYCatchTM, FreshPax(r) and Ageless(r). Alternatively, oxygen scavengers can be directly integrated into the packaging materials, either in mass by using extrusion or injection processes, or into the packaging surface by way of a coating [10]. To date, the best results are obtained by metals based scavenging systems, whose reaction requires activation by moisture and their incorporation by extrusion at the industrial level is a big challenge [11]. On the other hand, polybutadiene (PB), a synthetic rubber, is a well-known oxygen absorber due to its double bonds, which are oxidized upon exposure to atmospheric oxygen at room temperature producing polyketones [12]. Despite overcoming cast extrusion issues, its low oxygen scavenging capacity has sternly hindered its uses as an oxygen absorber. Accordingly, PB has been incorporated with a transition metal catalyst to promote oxidation process [13]. In this sense, [PERSON] et al. [14] developed an oxygen scavenging film consisting of a 1,2-polybutadiene with an iron complex by solvent casting reporting an oxygen scavenging capacity of 200 mL (oxygen gas at STP) g film\({}^{-1}\). Following this line, cobalt neodecanoate has also been incorporated together with PB by using cast extrusion [15] obtaining a scavenging capacity of 90 mL (oxygen gas at STP) g film\({}^{-1}\). However, the extrusion process led to unacceptable films in terms of optical and mechanical properties among others and cobalt applications are limited due to their high toxicity [16]. Recently, [PERSON] et al. [17] has described the improvement in oxygen absorption of PB due to the incorporation of TiO\({}_{2}\) as a photocatalyst.