## 1 Introduction  
The packaging of food materials provides protection, assists shelf-life, and facilitates both communication to consumers and the transportation of food products. Materials such as paper, plastic, metal, and glass are predominantly used in food packaging. Plastic is the primary packaging material used in the food industry due to its light weight, flexibility, high performance, and low cost [1]. The proliferation of plastic products in the last few decades has been extraordinary and in 2019 global plastic production was at 368 million metric tons and continuing to grow by 4% every year [1,2]. Packaging is the largest end-use market segment of single-use plastics and it accounts for over 40% of total plastic usage [3]. Despite the practical benefits, the downsides of using plastic and the mismanagement of plastic waste have become critical for individuals, communities, and the whole ecosystem [4,5]. Of all the plastic produced, 50% is for single-use purposes; less than 9% of all plastics gets recycled; 10 million tons of plastics are dumped in the ocean every year; around 1 million marine animals are killed every year [3], and currently the ocean is expected to contain more plastic than fish by the year 2050 [6]. In a study by the University of Newcastle, Australia, researchers revealed the impact of plastic pollution on humans and reported that an average person may ingest about 5 g of plastic every week [7]. Therefore, immediate tactical action and strategic adjustment across the plastic trade chain and its life cycle are needed to stop leakage and the further accumulation of plastic in nature. Among the other strategies, banning problematic single-use plastics has the potential to lower plastic use up to 40% by the year 2030 [8]. The packaging sector is the dominant generator of plastic waste and in 2015 it produced almost half the global plastic waste [9], as shown in Figure 1; of which the food packaging industry accounts for 50% of plastic use [10]. Therefore, packaging has been under scrutiny as it constantly produces a high amount of plastic waste and this has forced researchers and the industry to consider sustainable alternatives [10; 11]. Bioplastics have received significant attention owing to their application as one of the most promising sustainable alternatives to replace synthetic plastics [10; 12; 13; 14; 15]. The demand for bioplastics has augmented over the years as these polymers are nontoxic, biocompatible, renewable, and biodegradable [4; 16]. In 2020, global bioplastic production capacity was 2.11 million tons, which is only about 1% of the total plastic and set to increase to approximately 2.87 million tons in the next five years [17]. Of the total bioplastic produced, 58.1% is biodegradable and there are more than 20 groups of these biodegradable bioplastics [18]. However, only three groups of biopolymers are being commercially explored and they account for 95% of the production capacity as shown in Figure 2: (a) starch blend; (b) polybutylene (polybutylene succinate (PBS), and polybutylene adipate terephthalate (PBAT)); and (c) PLA [18]. Other biopolymers such as polysaccharide-based cellulose [19], sodium alginate [20], pectin [21], zein [22], carrageenan [23], chitosan [24], protein-based: casein [25], whey protein [26], gelatin [27], and keratin [28] are also being explored to develop packaging materials. However the biopolymer-based packaging materials have certain shortcomings due to their inherent properties like hydrophilicity, the high risk of microbial contamination, poor barrier, and mechanical properties, low thermal stabil  
Figure 1: Global plastic waste generation by industrial sector, measured in tons per year, Reprinted from Ref. [9]. ity, low surface functionality, poor printability, and adhesiveness when compared with conventional plastics [29, 30, 31, 32, 33, 34, 35].