Are you discarding cucumber peels after preparing your salad? They may soon find their way back to your kitchen in the form of eco-friendly food packaging developed by researchers at the Indian Institute of Technology (IIT), Kharagpur.
According to the team of researchers, cucumber peels have greater cellulose content than other peel waste. Cellulose nanocrystals derived from these peels can be used for making food packaging material which is biodegradable and has low oxygen permeability.
"While single-use plastic is consciously being avoided by consumers, they still remain largely in circulation as food packaging items. Natural biopolymers are unable to make their way in this industry as they lack strength, elongation, barrier property, optical property, and in some cases even biological safety," said Jayeeta Mitra, Assistant Professor, IIT Kharagpur.
"In India, cucumber finds wide use in salads, pickles, cooked vegetables or (is even) consumed raw and also in the beverage industry, leading to a large volume of peel biowaste which is rich in cellulose content.
"Cucumbers generate about 12 per cent residual wastes obtained after processing either the peels or whole slices as waste. We have used the celluloses, hemicellulose, pectin extracted from this processed material for deriving new bio-materials which are useful as nano-fillers in bio-composites," she added.
Talking about the findings of the research, Mitra said, "Our study shows that cellulose nanocrystals derived from cucumber peels possess modifiable properties due to the presence of abundant hydroxyl groups, which resulted in better biodegradability and biocompatibility."
"These nanocellulose materials emerged as strong, renewable and economic material of the near future due to unique properties like a high surface area to volume ratio, light in weight, and excellent mechanical properties. Thereby, such nanocrystals, when reinforced as nano-fillers in bio-composites films, can produce effective food packaging materials with low oxygen permeabilities," she said.
The study revealed that cucumber peels possessed greater cellulose content (18.22 pc) than other peel waste. It also provided better insights into their crystalline, thermal and colloidal properties of cucumber cellulose.
"This non-toxic, biodegradable and biocompatible product has no adverse effects on health and environment and hence could have a huge market potential by rendering management of organic waste with high cellulose content profitable," said Sai Prasanna, a research scholar at the institute.
Apart from the food packaging and beverage industries, the researchers are optimistic about its scope in various fields like thermo-reversible and tenable hydrogels making, paper making, coating additives, bio-composites, optically transparent films, and as stabilisers in oil-water emulsion.
"Also, CNCs find good potential applications in biopharmaceutical applications such as drug delivery and fabricating temporary implants like sutures, stents, etc.," Prasanna said.