Comparing the Effects of Red, Black and Bell Pepper Extracts on Aflatoxin Production, Peroxide Value and Sensory Properties in Pistachio

The most important safety and quality concern of pistachio export is its contamination with aflatoxin and oxidation and hydrolysis of fats. Therfore, this study is aimed at investigating the effects of red pepper, black pepper, and bell pepper extracts on the amount of aflatoxin production and oxidation process in pistachio and its sensory properties. For this purpose, the antifungal activity of pepper extracts was first evaluated, and then, after coating pistachio samples with each type of pepper extracts by 0.1, 0.5, and 1 % (v/w) including nine treatments and one control, Aspergillus flavus was inoculated to pistachio samples. Then, aflatoxin amount, peroxide value, and sensory properties were measured and evaluated during the days of first, 30th and 60th of storage. The results showed the highest radial growth of fungal mycelium in control and the lowest radial growth of colonies was observed in red pepper extract at concentration of 105 µL/L, which had a significant difference with other concentration of this extract and with similar concentrations of black and bell pepper extracts (P<0.05). The lowest amount of aflatoxin was obtianed from treatments containing 1% of red pepper and black pepper extracts and highest in the control sample. Also, the results indicated that with increasing the extracts concentration, the peroxide value and sensory desirability decreased significantly. Treatment containing 0.5% of red pepper extract had the highest sensory desirability, and the extracts of 0.5% bell pepper and 0.5% black pepper were afterwards. The studied pepper extracts had a significant effect on reducing the amount of aflatoxin and improving the sensory properties of pistachio compared to the control during storage, and in general, pistachio sample coated with 0.5% red pepper extract is introduced as the best treatment.