The complex world of polysaccharides edited by Desiree Nedra Karunaratne

 

Is Chitosan a New Panacea? Areas of Application 

 

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35. Milk  

A few attempts have been made to evaluate the possibility of using chitosan to improve the 

quality and shelf life of milk. Ha and Lee in 200, investigated the effectiveness of water-

soluble chitosan (0.03%) to minimize the microbial (bacterial and yeast) spoilage of 

processed milk [200]. Complete inhibition of microbial growth was observed in the banana-

flavored milk containing chitosan, in contrast to that observed in control milk (without 

chitosan), during storage for 15 days at 4 and 10 ◦C. The banana-flavored milk containing 

chitosan also maintained relatively higher pH than that of control milk during storage for 15 

d at both temperatures [200]. 

36. Sausages 

Sodium nitrite is generally used as a curing agent for color and flavor development as well 

as preservative effect in sausages {201]. However, nitrite reacts with amine in meat and may 

produce nitrosoamine, a strong toxicant detrimental to human health. Several workers [202] 

have investigated the possible role of chitosan, in lieu of sodium nitrite, as curing agent in 

sausage, and found that addition of chitosan could reduce or replace the use of nitrite 

without affecting preservative effect and color development. 

37. Seafoods and seafood products 

Seafood products are highly susceptible to quality deterioration due to lipid oxidation of 

unsaturated fatty acids, catalyzed by the presence of high concentrations of hematin 

compounds and metal ions in the fish muscle [203]. Furthermore, seafood quality is highly 

influenced by autolysis, contamination by and growth of microorganisms, and loss of 

protein functionality [204]. 

The oxidative stability of fish flesh with added chitosans was compared with those added 

with conventional antioxidants, butylated hydroxyanisole + butylated hydroxytoluene 

(BHA + BHT, 200 ppm) and tert butylhydroquinone (TBHQ, 200ppm ), during storage at 4 

◦C. Chitosan was most effective in preventing lipid oxidation than the others. The 

antioxidant capacity of chitosan added to the fish muscle depended on the molecular 

weight and concentration of chitosan [204]. Similarly, Kim and Thomas in 2007 also 

observed that the antioxidative effects of chitosan in salmon depended on its molecular 

weight [205]. 

38. Chitosan in agriculture 

Due to the antifungal, antibacterial and antiviral properties of chitosan, it has been used 

successfully in agriculture in recent years: in plant protection, like growth promoter, in soil 

correction, enhancer of secondary metabolites production, and activator of defense 

mechanisms to mention a few.  

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The Complex World of Polysaccharides 

 

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39. Seed coating 

Chitosan application can be done by different ways: in the seed, in the soil or by foliar way. 

In seeds, it has been used as a coating material for cereals, nuts, fruits and vegetables [206-

208]. It has been shown that this way of application alters permeability of the seed plasma 

membrane, increasing the concentrations of sugars and proline, and enhancing peroxidase 

(POD), catalase (CAT), phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase 

(TAL) activities [207,209]. By this way, germination rates increases significantly [ 210] and 

seedlings germinate quicker, better, and vigorously [211-214]. Chitosan is used not only in 

seed coatings, but also in fruits and vegetables, because it gives more firmness and it 

promotes diminution of the normal microbiological charge [215] increasing the product life. 

40. Leaf coating  

Chitosan foliar application increases stomatal conductance and reduces transpiration, 

without affecting plant height, root length, leaf area or plant biomass [216]. When chitosan is 

sprayed in leaves, abscisic acid (ABA) content increases [217]. It promotes the activation of 

defense mechanisms which allow plants to deal with stress and to defend against diseases 

due to the antiviral, antifungal and antibacterial nature of chitosan [218,219].  

41. Fertilizer 

By applying chitosan in soil, it has been demonstrated that it stops plant wilting because it 

acts as a potent fertilizer due to the high concentration of nitrogen content in its molecular 

structure [220,221]. Also, it has been used as a soil amendment, controlling diseases caused 

by fungal species like Fusarium acuminatum, Fusarium sp, Cylindrocladium floridanum and 

Aspergillus flavus [208, 218, 222]. 

42. Plants growth promoter 

Chitosan acts as plant growth promoter in some crops like Faba bean plant, radish, 

passion fruit, potato, gerbera, cabbage, soybean and other crops when it is incorporated in 

solution, increasing plant production and protecting plants against pathogens too. 

Chitosan has a significant effect on growth rates of roots, shoots, flowering, and number 

of flowers [219, 223]. 

43. Plant self defense 

Plants react naturally against most of biological and environmental adverse conditions, but 

sometimes defense has to be induced in order to fight against harder threats. It has been 

reported that chitosan is a great biopolymer used for this purpose, because it induces 

defense reactions in some plants, sensitizing them in order to increase their responses 

against pathogens attack. Some substances that get favored due to the presence of chitin and 

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