Impact of ozonisation on quality parameters, nutritional aspects and inactivation of Listeria innocua in beans

Beans are one of the most consumed legumes, due to theirhigh content of proteins, complex carbohydrates, fibers, vitaminsand also antioxidant substances, such as polyphenols. Antioxidants are substances that can slow down or inhibit oxidative damage by playing a role in preventing chronic diseases. However,the bean quality can be affected by microbial contamination or the methods used to avoid it. Ozone (O3) is a gas with high oxidizing potential, considered a “green chemical process” and recognized as GRAS (Generally Recognized As Safe). It can be used for microbial inactivation in different agricultural products, as well as for mycotoxins degradation in grains and derivate. However, it can also negatively impact the product quality due to oxidative processes. Consequently, the objective of this study was to evaluate the effect of processing beans with ozone on their phenolic compounds and antioxidant capacity, as well as their impact on the physical properties(water activity, color) and inactivation of Listeria innocua, as a target microorganism. Three different beans were evaluated:black, redand catarinobeanswith 10 and 40% moisture content.The sampleswere processed, in a reactorusing a gas flow of 5 g/h with ozone concentration of37.06g/L, for up to240min. The total phenolic content was evaluated through the method of Folin–Ciocalteu, while theantioxidant capacitywas evaluated through the method ofABTSThe results demonstratesthatit was possible toreduce 2.0Logcycles of Listeria innocuaafter 240 min of processing. The catarinobean was affected in the phenolic content when moistened. On the other hand, the ozone processing did not affected (p≤0.05)the total phenolic content,antioxidant capacity, and color of the beans. Therefore, the present study demonstrated that the ozonation can reduce the microbiologycontentin beans, without impact its nutritional quality.