# Development of Biodegradable Films Produced from Residues of Nixtamalization of Popcorn
## 1 Introduction  
Over the course of time, the industrialization of nixtamalized products has increased. Nixtamalization is an alkaline cooking of the corn grain process; in addition to that, nejayote is the residual water obtained through this procedure [1]. Later, nejayote is discarded with residues of the pericarp. [PERSON] et al. [2] reported that a production of 600 tons of corn per day generates between 1500 and 2000 m\({}^{3}\) of nejayote; accordingly, over 50 million m\({}^{3}\) of it is thrown out a year [3] at drainage sites or rivers. Furthermore, nejayote is wastewater that contains a large load of solids and suspended and dissolved organic matter (COD > 10 200 mg/L and BOD > 2.69 mg O\({}_{2}\)/L) [4], which causes the clogging of sewers and drainage, as well as a high content of calcium salts and a pH above 11 that affects the corrosion of the pipes. Consequently, this waste deteriorates the environmentafter being dumped into public sewers [1]; therefore, it is considered a global industrial, economic, and environmental problem, which is why many researchers have found a way to use the nejayote and pericarp. In other respects, nejayote and pericarp contain arabinoxylans, sugars, fibers, phenolic compounds, and calcium, which have the potential for value-added processing and utilization [5]. It was found that they have different uses, such as a culture medium for bacterial growth and for the production of bacterioxins [4], for animal feedstock [6], for the recovery of components with high added technological value (gelling capacity), and for use as bioactive compounds through their incorporation in food products and coatings [7; 8]. Additionally, nejayote is a source of microorganisms, which shows its capability to generate high-value molecules from agro-industrial by-products [9]. Because of the technological properties of the components of nejayote and pericarp, it is possible to incorporate and study them on coatings. In recent years, biodegradable coatings have been used as a means to preserve the quality attributes and extend the postharvest life of fruits [10; 11]; they preserve the organoleptic properties of the fruit without affecting it and without the need to keep it under refrigeration to extend its lifetime. A biodegradable coating is based on the concept of packaging materials, since these can prevent food spoilage by reducing the interaction between the food and the surrounding environment, thereby reducing food loss [11]. Currently, biodegradable coatings have also been studied that allow for a simpler and easier way to preserve the quality and prolong the life of the fruits without changing the temperature [10; 11]. The coatings have been formulated with various biopolymers, such as pectin [12], cellulose [13], bacterial cellulose [14], and other elements such as beeswax [10; 11] nanocomposites [15], and rice starch [16]. [PERSON] et al. [8] studied a phenolic extract from nejayote flour applied on alginate-based edible coatings in order to evaluate its antimicrobial activity, and they found that the alginate-based coating with 2.3% nejayote phenolic extract showed total and low growth inhibition for Gram (+) and Gram (-) bacteria, respectively. Additionally, [PERSON] et al. [17] extracted hemicelluloses from corn pericarp and formed a transparent film with mechanical strength and plasticity. Hence, it was demostrated that nejayote and pericarp could be alternatives for the development of biodegradable edible coatings, improving the quality and safety of food; however, more studies about their application on fruits are required. On the other hand, the avocado (_Persea americana_ Mill.) is a highly perishable tropical fruit of culinary relevance in the world, which completes its postharvest ripening process from five to seven days at 25 \({}^{\circ}\)C [18].