Source: SEAMEO BIOTROP's Research Grant | 2021
Abstract:
Unappropriate postharvest
handling of peanuts can facilitate the occurrence of fungi and mycotoxin
contamination, especially Aspergillus flavus which can produce
aflatoxins. The main factors affecting the growth of A. flavus during
storage are temperature, relative humidity, moisture content, water activity,
and carbondioxide (CO2). The objective of this research was to test and make a model describing the effect of
temperature, water activity (aw) and CO2 levels on A. flavus growth and aflatoxin
production in vitro and in
stored peanuts. Methodology of this research were 4 stages, i.e. 1) culturing of
strain toxigenic A. flavus BIO 3338, 2) in vitro testing on Potato
Dextrose Agar (PDA) mediua, and 3) in
vivo testing in peanuts at various temperature, aw and
CO2 using 6 replications for each treatments, and 4) statistical
analysis using Completely
Randomized Factorial Design for water activity and temperature
treatments, and Completely Randomized Design for carbondioxide treatment. Determination of
aflatoxin was conducted using Thin Layer Chromatography (TLC) for aflatoxin of A. flavus culture and Liquid
Chromatography Mass Spectro (LCMS). Result showed that temperature, aw,
and CO2 could control
toxigenic A.flavus BIO 3338 growth and aflatoxin production in PDA (in vitro) and in peanuts (in vivo).
Increasing of A. flavus growth was
influenced by increasing of water activity. The optimum A.
flavus growth was found on PDA and peanuts with 0.97 aw at
30°C and 35oC, respectively. Diameter of A. flavus and
aflatoxin production decreased with increasing CO2 concentrations. Formation
of conidia and sclerotia of A. flavus also
decreased with increasing of CO2.
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