Chitosan: A Solution for Food Packaging (Part 2)

In the previous article we talked about the chitosan film being a wonder solution for food packaging industry and there I talked a little about the Chitosan/biopolymer films and said that in next post I will write a detail article regarding the chitosan/biopolymer films. So, here I am with detail article regarding the chitosan/biopolymer films.

For those who didn’t read the earlier article please go through it for better understanding regarding this post. For those who didn't read it please  Click here.

Biopolymers as we know has many characteristics such as biodegradability, non-toxicity, biocompatibility due to these many characteristics biopolymers can be combined with chitosan to fabricate the film. This film will have combined characteristic of both the chitosan as well as biopolymer used. Researches were carried out on this and many were successful. Biopolymers like polysaccharide. Proteins, extracts, organic acids, etc. can be used with chitin to form films.

So let’s go through some of the chitosan/biopolymer films

Chitosan/polysaccharide film

Polysaccharide are widely known for forming blend with chitosan results in development of functional films.

Starch having low cost, wide availability and biodegradability can be used for this. Since starch is also having film forming capacity when it is blended with chitosan the obtained films exhibits reduced bacterial adhesion on the packaging, great antioxidant activity, and improved water vapour barrier property, which proved to be promising for active packaging film.

Similarly cellulose has been researched by many researchers to develop a film with improved mechanical properties. Nano cellulose and chitosan forms hydrogen bonds in between which results in the formation of the film. These obtained films showed excellent optical property, gas barrier property, antimicrobial property, sustainability, and bioactivity.

Chitosan and nanocellulose based film
(image from here )

Another polysaccharide ‘Alginate’ which is a natural linear and anionic polysaccharide have properties such as low toxicity and chemical versatility. The stable complex film based on chitosan/alginate were developed via electrostatic deposition of opposite charges. These charges on the chitosan/alginate film had a significant influence on properties, such as contact angle, microstructure, and thermal performances. The chitosan/alginate films showed excellent gas-exchange performance and water vapour permeability property, which provided the treated foods with attractive succulent appearance and high microbiological and physicochemical quality. This make it a very good choice for food packaging.

There are polysaccharides such as pectin, cyclodextrin, glucose, etc. which has properties of forming films with chitosan which can be used for food packaging. Properties of these films will vary with the properties of polysaccharide used with chitosan.

Chitosan/protein films

Proteins which are obtained from plant, animal and microorganism can be blended with chitosan to form films with different properties. Since proteins have many special groups attached to it, these films which are based on chitosan/protein have abundant functions which promote its application in food packaging.

Collagen and chitosan
(image from here )

Proteins like Caseinate, with excellent thermoplastic and film-forming properties, could combine with chitosan to prepare chitosan/caseinate film, through ionic interaction, with the final film properties being improved, like water vapor permeability.

Similarly, Collagen has attracted great interests from researchers as a potential alternative to synthetic polymer. After compositing with chitosan, the developed films obtained high thermal stability, good adhesion, and compatibility.

Proteins, derived from plants, presented great promise in food preservation, due to the rich sources and low cost. Chitosan/kidney bean protein isolate complex produces less rigid and more flexible films, with high surface hydrophobicity and low surface free energy, which were expected to work as antimicrobial packaging for food.

Also proteins from microorganism could also play an important role in packaging films. Nisin, an amphiphilic cationic peptide, is often obtained from microorganisms like Lactococcus lactis. The films based on chitosan and nisin could be favourably used for extending the shelf life of packaged food.

Chitosan/Extract based films

aloe vera gel and chitosan film
(image from here )

Extracts such as beeswax and propolis from bees can also be blended with chitosan to form a films for food packaging. Beeswax is a complex mixture having antimicrobial properties is widely used in food industry. The incorporation of beeswax with chitosan is to produce an environmental friendly alternative to control pathogenic microbes and to maintain food quality. The film formed have high antimicrobial activity which is good for preservation of food.

Extracts from plants are also natural and non-toxic in nature having antimicrobial activity. Their incorporation with chitosan also results in a modified and improved films having antimicrobial activity, antioxidant activity, barrier property, etc. depending upon the different extracts.

At last I would like to say that Chitosan/biopolymer films exhibit certain advantages such as enhanced antioxidant and antimicrobial activity which make it good for preserving the food quality and hence they have a great future ahead of them.

Thank you for reading

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