AROYEUN SHAMSIDEEN OLUSEGUN COCOA RESEARCH INSTITUTE OF NIGERIA, NIGERIA
ADEGOKE GABRIEL OLANREWAJU, UNIVERSITY OF IBADAN, NIGERIA
VARGA JANOS, UNIVERSITY OF SZEGED, HUNGARY
Abstract: The factors and each levels used in this experiment included water activity aw (0.94 . 0.98), pH (5-9), Temperature TOC (15- 35OC) and essential oil of A.danielli (500ppm . 2500ppm). The effects of each environmental factor on reduction of A flavus growth and aflatoxin Bi production were determined by using a 4-factor, 5-level, Central Composite Rotatable Design (CCRD)..All experimental test runs were done in duplicate. The measure of fit of the data (R2) was quite high for all the dependent variables: .0.90 for Aspergillis flavus growth and 0.83 for aflatoxin B1 production. pH water activity, temperature and essential oil of Aframomum danielli affected growth of Aspergillus flavus and aflatoxin B1 production. The response surface methodology (RSM) plots had saddle points as stationary points which indicated the absence of unique maximum or minimum. The quadratic effects of temperature and A.danielli were highly significant (p< 0.01) with minimum A.flavus growth between T.oC of 20 . 25OC and A.danielli of 1500 ppm. In conclusion, the use of A.danielli in this study can form a synergy of barriers with other two or more environmental factors against production of aflatoxin B1 by Aspergillus flavus. At every combination of abiotic factors and A.danielli, where growth occurred, the level of aflatoxin B1 detected in contaminated cocoa bean. was less than the current regulatory standard of 20ug/kg for aflatoxin Bi in foods meant for human consumption.
Keywords: Cocoa beans, Response Surface Methodology, A.danielli. A.flavus Reduction, Essential Oil.