Avaliação in vitro da atividade fungitóxica de extratos de condimentos na inibição de fungos isolados de pães artesanais / In vitro evaluation of the fungitoxic activity of seasonings on the inhibition of fungi isolated from homemade breads

RESUMO

Objetivou-se, na presente pesquisa, avaliar a atividade antifúngica in vitro de alho, gengibre, orégano, cravo, canela e tomilho sobre a inibição e o desenvolvimento de Aspergillus ochraceus, Penicillium roqueforti, Rhizopus stolonifer, desenvolvidos em pães artesanais. Para cada planta foram preparados extratos alcólicos (EA10%, EA20% e EA25%), extrato aquoso (EAQ10%), extrator alcoólico puro (EAP) e testemunha sem extrato e álcool. Para alho, gengibre, orégano incluiu-se o extrato alcoólico da planta fresca (EAF 10%). Os experimentos foram instalados no Laboratório de Fitopatologia do EcoCentro/EPAMIG, Lavras, MG e no Laboratório de Fitopatologia do Incaper/CRDS-CS, em Domingos Martins, ES. Os tratamentos foram aplicados sobre os fungos inoculados em placas de petri, em meio BDA. Calcularam-se médias do Índice de Velocidade de Crescimento Micelial (IVCM) e esporulação. Os EA de plantas desidratadas a 10%, 20% e 25% inibiram totalmente o crescimento micelial dos fungos estudados, com exceção do EA 25% de alho sobre o Penicillium roqueforti e o EA 25% de gengibre sobre o desenvolvimento do Aspergillus ochraceus que não se diferenciaram da testemunha. O EA de alho teve um efeito não inibitório sobre P. roqueforti. Os EA, EAF e EAP apresentaram menor esporulação em relação à testemunha, exceto com gengibre e cravo sobre a esporulação do R. stolonifer e o EAQ apresentou um efeito semelhante ao da testemunha.

ABSTRACT

This research was carried out to evaluate the in vitro anti-fungus activity of alcoholic extracts of garlic, ginger, oregano, clove, cinnamon, and thyme on the inhibition and development of Aspergillus ochraceus, Penicillium roqueforti, and Rhizopus stolonifer, which develop in homemade breads. For each commercial seasoning, alcoholic extracts (AE) were prepared (AE10%, AE20% and AE25%) as well as aqueous extract (AQE) at 10%, pure alcoholic extract (PAE), and control without extract and alcohol. For garlic, ginger and oregano, a fresh plant alcoholic extract (FAE10%) was included. The experiments were installed at Plant Pathology Laboratories, EcoCentro/EPAMIG, MG and at Incaper/CRDS-CS in Domingos Martins, ES. The treatments were applied to thefungi inoculated on Petri dishes, on BDA medium. Mycelial Index Growth Speed (MIGS) and sporulation were calculated. All of the AE from dehydrated plants (10%, 20%, and 25%) showed significant inhibitory effect on the mycelial growth and fungus sporulation,and an unstable performance was observed when the AE seasoning concentration was 0%. The control presented higher MIGS and sporulation. Garlic AE25% on Penicillium roqueforti and ginger AE25% on Aspergillus ochraceus did not differ from the control.Garlic AE did not present an inhibitory effect on P. roqueforti. The AE, FAE and PAE presented lower sporulation in relation to the control, exception made to ginger and clove on the sporulation of R. stolonifer, and the AQE showed an effect similar to the control.