Post Harvest Technologies
5th January 2018
Chitosan Coating Increases Fruit Shelf-life
Fresh fruits have short shelf-life. Within a week of harvest, they become overripe, lose colour, taste and firmness, reducing marketability. Thus, many fruits and vegetables are spoiled before they reach consumers.
A team of researchers from the Indian Agriculture Research Institute, New Delhi has now developed an eco-friendly approach to increase fruit shelf-life: chitosan-coating.
The researchers harvested mature plums of the “Santa rosa” cultivar and coated them with chitosan, a non-toxic edible polysaccharide.
For 35 days, the scientists kept the coated plums under cold storage. Every week, they assessed the plums for weight loss, peel colour and firmness. They found that weight loss was less in coated than in uncoated plums. The coated plums also retained peel colour longer and appeared glossier.
The researchers evaluated respiration rate. They found that coating leads to the closing of pores which suppresses respiration. Rate of production of ethylene, the hormone involved in ripening, was also reduced.
The team determined the content of soluble solids and titratable acids. Chitosan coated plums retained low soluble solids but had high acid content. This further established that the ripening process is indeed retarded in coated-plums.
The team noted reduction in anthocyanin and phenolic content in the coated fruits which explains why plums retained the glossy appearance longer .
They then evaluated the malondialdehyde and pectin methylesterase responsible for maintaining firmness. Chitosan-coated plums produced less of both.
Being non-toxic and low-cost, chitosan-coating on fruits and vegetables can reduce economic loss without causing harm to consumers.