Avaliação da atividade antifúngica e antibacteriana do óleo essencial de alecrim (Rosmarinus officinalis) na aplicação em extrato de tomate

Abstract

Tomato puree is a very sensitive product to degradation so there is an indication of the manufacturers to keep it chilled and consume within few days, generally five to seven days. This is due to the fact that fungi and bacteria are potentially benefited by the conditions of the tomato puree. In contrast, essential oils have been widely studied for their antifungal and antibacterial actions, and can contribute to reduce the degradation of food products. Thus, the objective of this paper is to assess the influence of the antifungal and antibacterial action that the essential oil of rosemary can exert when applied in tomato puree. Initially, rosemary and tomato were grown to obtain a homogeneous sampling in terms of climate and soil. Later, the extraction of essential oil from rosemary was carried out and its anti-oxidants antibacterial and antifungal composition were analyzed. Regarding the antibacterial activities, the cultures of common food poisoning bacteria were used for analyses. Rosemary essential oil proved to be a growth inhibitor and bactericidal agent for all bacteria studied, having the best results against gram-negative Escherichia coli and Salmonella typhi, presenting values for both 5,19 μL mL-1 and 20,75 μL mL-1 for MIC and MBC respectively. The antifungal activity was analyzed against three genera of fungi isolated from tomato puree containing mycelia: Mucor sp; Aspergilus sp; Penicillium sp. For all genera in the concentration 4.00 mg mL-1 the inhibition halo was higher even in the antifungal clotrimazole in the concentration 3.0 mg mL-1. In regard to the application of essential oil in tomato puree at the concentration of 1.0% (m / m) the negative field values found by Howard's adapted method, in tomato extract 7 days after opened and stored in refrigerator were twice higher when compared to tomato extract without the presence of essential oil. After 14 days the negative field values continued higher proving the antifungal power of rosemary essential oils when applied to this product.