Influence of Soaking Corn Kernels (Zea mays L.) with or without potash on the Fungal and Physico-chemical Quality of Their Flour

Corn is one of the most consumed cereals in Cote d'Ivoire. The objective of this study is to assess the impact of the soaking time of corn kernels with or without potash on the fungal and physicochemical quality of their flour. The method used consisted of determining the pH of the different samples using a pH meter. For the water content, the method used was oven drying. Concerning the fungal load, the mould count was done on the DRBC medium and the subculture on the MEA medium. All these analyses were carried out with flour samples of two corn varieties (yellow and white corn with or without potash) according to three durations (6, 9 and 12 h) of grains soaking. The results obtained show that yellow or white corn flours without potash are acidic with pH values between 4.2 and 6.1 while those with potash are basic, with pH ranging from 7.7 to 9.9. The moisture content of all the flours obtained just after grinding the grains varies between 31.7 and 37.6%. Significant differences were observed between the water contents of the flours obtained at the three different soaking times. Thus, the water contents of the flour obtained after 6 h of soaking the grains are lower than those obtained after 9 and 12 h of soaking. All cornmeal samples analyzed showed high fungal loads (105 to 109 CFU/g). However, a slowdown in fungal growth was observed with the flour samples with potash. The different moulds isolated from corn flour and identified belong to the genera Aspergillus, Penicillium, Mucor and Rhizopus. The genera Aspergillus and Penicillium are potential producers of mycotoxins and therefore capable of causing poisoning in consumers of these flours.