Potential of chitosan-loaded nanoemulsions to control different Colletotrichum spp. and maintain quality of tropical fruits during cold storage

Abstract

Aims: To investigate the antifungal activity of conventional chitosan and chitosan-loaded nanoemulsions against anthracnose caused by Colletotrichum spp. isolated from different tropical fruits. Methods and Results:In vitro results illustrated that conventional chitosan onwards 1Á5% concentration inhibited radial mycelial growth, conidial germination, sporulation and dry weight of mycelia for Colletotrichum musae (Berk. & Curt) Arx. isolated from banana, Colletotrichum gloeosporioides (Penz.) Penz and Sacc. isolated from papaya and dragon fruits. For further investigations, chitosan-loaded nanoemulsions were prepared, and chitosan at 2Á0% concentration with 200 nm droplet size gave the best results in terms of all the in vitro parameters tested for C. musae and at the same concentration with 600 nm droplet size for both the isolates of C. gloeosporioides. However, the results obtained at 2Á0% chitosan concentration with different droplet sizes were nonsignificantly different with 1Á0 and 1Á5% concentrations. Therefore, for in vivo studies, only 1Á0% chitosan with different droplet sizes was used. In terms of fungicidal effects and maintaining postharvest quality of banana, papaya and dragon fruits, chitosan at 1Á0% concentration with a droplet size of 200 nm in banana and 600 nm in papaya and dragon fruits showed the best results in delaying the onset of anthracnose and maintaining quality of all the fruits for up to 28 days of cold storage. Conclusion: Chitosan used in a conventional form showed good results but not as effective as in the form of nanoemulsions. Significance and Impact of the Study: The results of this study suggest that instead of applying chitosan in a conventional form, chitosan in the form of nanoemulsions could be more effective as a biofungicide for controlling anthracnose of fresh fruits. Moreover, it could be cost-effective as the amount of chemical used is reduced when applied in the form of nanoemulsions.

Shelf life extension of fresh fruit and vegetables by chitosan treatment

“…Many swellings occurred in the hyphae or at their tips, whereas in the controls cells the walls and germ tubes were smooth with no swellings or vacuolation (Ali and Mahmud, 2008;Ali et al, 2010). The scanning electron micrographs showed normal growth of hyphae in the untreated controls for C. gloeosporioides, whereas there was hyphal agglomeration and formation of large vesicles in the mycelia in samples treated with chitosan-loaded nanoemulsions (Zahid et al, 2012). The fungal mycelia of Sclerotinia sclerotiorum exposed to chitosan were deformed, twisted and branched, or indeed, dead, with no visible cytoplasm in the fungal cells, whereas the untreated mycelia were normal in appearance (Cheah et al, 1997).…”

Cassava starch edible coating incorporated with propolis on bioactive compounds in strawberries

“…Edible coatings prepared from biopolymers consist of thin layers of edible material applied to foods that play an important role in their preservation and appearance (McHugh, 2000), acting as a barrier to different agents such as water vapor and some gases. Interest in the application of such treatments is becoming more popular due to the environmental protection feature and potential use in the food industry (Zahid et al, 2012). These materials also allow the addition of active compounds in their formulation, which may increase functional properties in order to enable them as potential alternatives in food preservation (Sánchez-González et al, 2011).…”

Uso combinado de radiación UV-C y biorecubrimiento de quitosán con aceites esenciales para el control de hongos en papaya Maradol

“…Siguiendo el procedimiento descrito por Zahid et al (2012), se prepararon las soluciones de esporas. Para esto, se obtuvieron frutos de papaya con síntomas de antracnosis y pudrición blanda colectados en campo, a los cuales se tomaron muestras del micelio maduro.…”