**2. Need of edible packaging**

Food packaging is very crucial for various purposes such as labelling, protecting the contained food, caring for the food, measuring, attracting the consumers, etc. Mostly, plastic is used as food packaging material. Globally, factories produce 400 MT of plastic per year approximately [10]. About 12.7 metric tons of plastic waste enters the ocean every year which affects the life of marine lives ([11] https://www.condorferries.co.uk/plastic-in-the-ocean-statistics). From total plastic waste about 79% is dumped in land, 12% incinerated and 9% is recycled. This plastic waste can take up to 400 years to break down in the landfill harming animal life, polluting cities or devastating landfills [12]. Dumped plastic affects (i.e. reduces) the moisture and oxygen transfer rate of soil and deteriorates the quality of the land. **Figure 1** shows state-wise plastic waste generation of India. It seems that Maharashtra state produces plastic waste in higher percentage. To overwhelm the harmful environmental effects as well as health effects of plastic and improvement of food, many companies are trying to replace excess plastic packaging with such packaging material which will be degraded, which does not produce much waste and does not have any negative effect on human health, food as well as an environment like edible packaging materials which do not produce packaging waste, and if may consumer throw the edible packaging, then it is degraded which required the same period as its contained food.

(https://cpcb.nic.in/uploads/plasticwaste/Annual\_Report\_2019-20\_PWM.pdf)

#### **2.1 Impact of edible packaging on environment**

Some packaging material has exclusive use, and that may be thrown away after it's used rather than recycled or reused [13]. Such plastic waste goes into rather in landfill, incinerate or in ocean which polluted the soil (land), air or water, respectively. As consumer demanded for the plastic-free food due to its negative health effect, companies are affording to get solution on it. The best way to contend the plastic in food

#### **Figure 1.**

*State-wise plastic waste generation. Source: https://www.business-standard.com/article/markets/plastic-banmaharashtra-gujarat-among-top-indian-plastic-waste-producers-122070400736\_1.html.*

packaging and also feasible to get zero plastic waste from food industry is by encouraging the customer to eat food along with its wrapper [14]. But this is only possible when that wrapper is GRAS for eating. Edible packaging is the finest solution to the plastic for reducing the waste which affects the environment and health of consumer. Nowadays, companies produce edible packaging in the form of pouches, wrappers, sachets, containers, plates, etc.

Commonly, edible packaging can be eaten, and in some amount, it is not eaten by consumers, but there is no need to reject the waste or no need to recycle it because edible packaging has biodegradability as it is composed of edible and environmentally safe components which biodegrade in less period of time [15]. The demand of edible packaging could rise by 6.9% yearly till the 2024, and market worth could be almost \$2 billion, informed by global research firm TMR (Transparency Market Research) [14].

#### **2.2 History**

Edible coating and films have been used for centuries to protect foods. The history of packaging is given in **Table 1**, the idea is derived from the natural protective coating on some foods such as the skin of fruits and vegetables [16]. In the twelfth and thirteenth centuries, China used a wax coating to decrease water loss, on lemon and oranges. In 1856, the first cellulose EF was developed, and in 1907, phenol-formaldehyde (Bakelite) resin was used. This was the starting point of a series of developments and inventions giving birth to a great range of packaging materials that nowadays are employed [17].

#### **2.3 Classification of edible films and coating**

Edible film and coating are classified based on their raw material sources, i.e. protein, polysaccharide, lipids and composites. They possess various functions such as retarding loss of moisture and volatile compounds, acting as a barrier for fat and


#### **Table 1.**

*History of packaging.*

oil and having a high selective gas permeability ratio of CO2/O2 as compared with conventional packaging [18].

### *2.3.1 Protein-based edible films*

Technological and functional properties of protein may improve by changing the structure of protein for preparing edible film and coating [19]. Protein-based edible films have additional stimulating mechanical and barrier properties than polysaccharides [20]. They have the capacity to slab the gases due to its structure in which hydrogen-bonded network is packed tightly [21]. Food quality is declined mostly due to oxidation of lipid which can be preserved by using protein-based edible film having ability to inhibit oxygen permeation [22]. Many protein materials have been tried: collagen, corn zein, wheat gluten, soy protein isolates, fish proteins, ovalbumin, whey protein isolate, casein, etc [23]. In addition to their nutritional value, milk protein such as casein has several key physical characteristics for active performance in edible films such as emulsification and water solubility [24]. Sesame seed protein was mostly used in manufacturing of edible film [25]. Protein-based edible films transfer various additives such as plasticisers, antioxidants, essential oil, antimicrobial agents, etc. The diffusion of additives components from the surface to the interior is controlled by keeping the film on the food surface [15]. Nuts, cashew nuts and beans require special packaging which is fulfilled by the protein-based film [26].

### *2.3.1.1 Collagen*

Collagen is a protein obtained from animal which is rich in glycine, proline and hydroxyproline and hydrophilic in nature [27]. Among all protein-based edible film, collagen is most commercial and successfully used film. For production of homogeneous surface film, high concentration of hydrolysed collagen is used [28]. Collagen powder and fibres were revealed to be suitable for the production of the bio-composite film in which fibres act as fillers and boost the effect [29].
