Snacks are routine light-food, consumed between meals by children or adults. It is important to enhance their safety properties and shelf life, without losing the acceptability. This investigation aimed to achieve that, using a modified rice straw (MRS), stabilized rice bran (SRB), and barley bran (BB) to substitute wheat flour (WF) in functional snacks. The microbiological-safety impact of substituted materials and their aflatoxins-prevention were evaluated. Antifungal properties against toxigenic fungi were arranged to descend as MRS>SRB> BB. Organoleptic characteristics were significantly decreased at a higher SRB and MRS substitution-values. The best snacks-acceptability was recorded for a 10% substitution ratio. Therefore, volatiles content was identified using GC-MS analysis at 10 % substituted snack. The most predominant volatiles were 2,3-butanedione, 3-methyl butanal, and 2-methyl butanal by concentrations of 26.84%, 11.48%, and 7.94%, respectively in control snacks. These volatiles activities are explaining degradation of aflatoxin-secretion.