Chitosan is widely used in the preservation of fruits, vegetables, meat, and eggs. According to researches, chitosan with density of 0.02% is enough for the inhibition of bacillus; if the density is 0.005%, the inhibition rate could reach to 90% against escherichia coli and salmonella, while if the density rate comes up to 0.0075%, bacteria could be completely inhibited from growing.
Study proves that chitosan fresh-keeping film can prevent fruits and vegetables (including peaches, pears, Chinese gooseberry, cucumber, pepper, grapes, strawberries, mango, tomatoes, etc.) from getting rotted and going bad. It helps prolong the storage time and shelf life.
How it works:
Chitosan membrane could block both oxygen permeation and carbondioxide overflow that caused by fruit respiration. But it induces the ethylene gas to leak out, which generates after fruits become ripe. Through this way, it inhibits fungus from breeding and postpones fruits from going ripe.
Chitosan membrane coating could control fruits from turning yellow or brown and guarantee fruits quality by means of restraining the content of anthocyanin, flavonoid, and all the polyphenols in fruits from increasing.
For example, by using chitosan of 2% density for tomato coating, after the research of 15 days’ storage, the content of total acidity, sugar quantity and vitamin C of tomatoes stays close to the originals. Usually it could preserves tomatoes for 30 days, the storage effect of which is better than benzoic acid solution of 0.2% density. As to other fruits such as apples and pears, chitosan derivatives that combine with other additives could keep them fresh for 6 months in 10-25 degree temperature (over 99% are well-kept fresh).