Does Chitosan Extend the Shelf Life of Fruits?

Tahsin Islam Sakif,Kelly Russell,Tofazzal Islam,Adam Dobriansky

doi:10.4236/abb.2016.78032

Tahsin Islam Sakif, Kelly Russell + Show 2 more

Open Access

https://doi.org/10.4236/abb.2016.78032

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Abstract

The use of hazardous formalin in increasing shelf life of fruits and protecting them from microbial decay by unscrupulous traders is a big health concern for the consumers in Bangladesh. Chitosan is a natural biopolymer produced from the exoskeletons of shrimp and crab, which slows antimicrobial activities and induces immunity of plants against microbial pests. This study aimed to evaluate the efficacy of chitosan on the shelf life extension of some local ripened fruits compared to untreated control. Three doses of chitosan solution viz. 0, 500 and 1000 ppm were sprayed in alternate day on banana (cvs. Shabri and Champa), strawberry, tomato, and oranges. It revealed that chitosan extended shelf life of all fruits by delaying the decay; however, level of protection varied in different kinds of fruits as well as in doses of the chitosan used. Among the tested fruits, decay of tomatoes was most delayed by chitosan. Spraying of both 500 and 1000 ppm of chitosan equally protected 100% decay in tomatoes until 8 days of treatments at room temperature. More than 80% protection of other fruits viz. banana, orange and strawberries by chitosan were recorded at 8, 8 and 4 day after treatment, respectively, which were remarkably higher than the untreated control. Interestingly, 500 ppm of chitosan spray gave better protection than 1000 ppm in all the tested fruits. These results suggest that lower doses of chitosan can be utilized as a natural preservative of fruits alternative to hazardous formalin. A further study with higher number of fruits, and at varying temperature and chitosan doses are needed for recommending it for practical application as a fruit preservative.

Highlights

The detection of formalin in fruits, fishes, and other perishable food items in Bangladesh over the last couple of years poses a serious threat to human health
Other materials and chemicals used in the investigation were PET bottles (1 L and 500 mL), plastic container (500 ml), distilled water, hydrochloric acid (HCl), sodium hydroxide (NaOH), and pipette tips were available in the laboratory of Department of Biotechnology of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh
Chitosan generally delayed the decay of fruits compared to the untreated control

Summary

Introduction

The detection of formalin in fruits, fishes, and other perishable food items in Bangladesh over the last couple of years poses a serious threat to human health. Formalin is a big threat to human health in this country as increasing number of food items such as fruits, fishes, and vegetables have been found contaminated with this hazardous chemical [4]. The Bangladesh Atomic Energy Commission develops a method of using gamma irradiation to produce low cost chitosan from the shrimp waste, which opens an opportunity for testing this well known natural antimicrobial agent as a safe preservative of fruits [7]. Chitosan is a non-toxic, biodegradable, biofunctional and biocompatible compound It has no health hazards as it is produced from nature

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