Antifungal effect of chitosan on the growth of Aspergillus parasiticus and production of aflatoxin B1

Abstract

Contamination of agricultural products by toxigenic fungi and the presence of mycotoxins cause serious economic damage, and toxic effects to humans and animals. In this study the effect of chitosan as a natural alternative for the control of the fungus Aspergillus parasiticus was evaluated. Chitosans were obtained from chitin previously extracted from shrimp heads using chemical (CS) and biological (CB) processes. The chitosan yields were 5.74 and 6.20% for CS and CB methods, respectively, with an amount of residual protein and ash below 1%, low molecular weight and degree of deacetylation of 80–82%. Chitosan showed fungistatic activity against A. parasiticus, with 6.71 and 10.66 g L−1 (CI50) of CS and CB, respectively, being required to delay fungal growth by 50% at 122 h. Chitosan (CI50) inhibited both radial growth up to 122 h, and germination of spores before 8 h higher than 50%. Chitosan also increased the average diameter of the spores and hyphae (P ≤ 0.05), reduced the septation process and increased the number of mitotic divisions of spores during germination. However, compared with control, chitosan decreased (P ≤ 0.05) aflatoxin B1 production at 8 days but increased (P ≤ 0.05) the total aflatoxins production by A. parasiticus. Copyright © 2011 Society of Chemical Industry

Control of mycotoxigenic fungi with microcapsules of essential oils encapsulated in chitosan

“…In addition, chitosan alone has the ability to inhibit aflatoxin production due to the Ca 2+ chelation. However, Cota-Arriola et al (2011) found that this inhibition did not occurred in corn grain, probably because the polymer is not able to penetrate into the grain, and thus limiting the ability for calcium chelation.…”

“…Four controls were prepared following the same procedure with no microparticles with EDs addedI: CS, water, and TPP with the inoculum and the fourth contained just 10 mL of water without inoculum. The extraction and quantification of fumonisin and aflatoxin was carried out according to Rosas-Burgos et al (2011) and Cota-Arriola et al (2011), respectively. Each treatment was replicated three times.…”

Preparation of chitosan matrices with ferulic acid: physicochemical characterization and relationship on the growth ofAspergillus parasiticus

“…Controls consisted of agar Czapek dox at pH 5.6 with and without FA at pH 5.6, CS 0.5% pH 5.6, and TPP 2% pH 5.6. The number of germinated spores, the percentage of spore germination inhibition, and the germination rate (spores h −1 ) were determined as described by Cota-Arriola et al (2011). Spore germination inhibition (FI) was calculated as follow:…”

“…Spore germination is the first stage of fungal growth and is indicative of adaptation to the medium, because at this stage, the fungus produces the necessary compounds for its development (Cota-Arriola et al, 2011). It has been reported that calcium (Ca + ) and some enzymes, such as chitin synthase among others, play a fundamental role in the germination, mainly in the development of hyphae Table 2.…”

By-Products From Jumbo Squid (Dosidicus gigas): A New Source of Collagen Bio-Plasticizer?

“…Chitosan, the main deacetylated derivative of chitin, is a biocompatible, non-toxic, edible, biodegradable polymer, and it possesses antimicrobial activity against bacteria, yeast and fungi, including toxigenic fungi (Cota-Arriola et al, 2011). This polymer is the only natural cationic polysaccharide, which special characteristics makes it useful in numerous applications and areas, such medicine, cosmetics, food packing, food additives, water treatment, antifungal agent, among others (Hu et al, 2009).…”