Aplicação dos óleos essenciais de Rosmarinus officinalis l. e Origanum vulgare l. no controle de fungos patógenos pós-colheita em Vitis labrusca l. (Uva Isabel)

Abstract

The Isabella grape (Vitis labrusca L.), whose clusters have berries ripening fast and very crowded, it is a non-climacteric fruit with low physiological activity, very sensitive to dehydration and fungal infection during handling in post-harvest processing. The difficulty in the treatment and control of fungal infections and increasing recognition of their impact on fruit production has encouraged the search for alternative methods capable of controlling the growth of pathogens and thereby reducing post-harvest losses. The use of essential oils for use in foods has been shown as a promising method of preservation due to its antimicrobial properties and antioxidants. The present study evaluated the efficacy of the application of the essential oils of O. vulgare L. (OVEO) and R. officinalis L. (ROEO) alone and in combinations to inhibit R. stolonifer URM 3728, A. flavus URM 4540 and A. niger URM 5842 on laboratory media and on grapes (Vitis labrusca L.) and its influence on the autochthonous mycoflora, physical, physicochemical and sensory characteristics of the fruits during storage at room temperature (25 ° C for 12 days) and chilled (12 ° C for 24 days). The OVEO and ROEO revealed MIC values of 0.25 and 1 μL / ml, respectively, against all fungi tested. The application of essential oils in different concentrations (MIC ROEO 1 μL / ml, MIC OVEO 0.25 μL / mL, ½ MIC OVEO 0.125 L / μL + ½ MIC ROEO 0.5 μL / mL, ¼ CIM OVEO 0.06 μL / mL + ¼ MIC ROEO 0.25 μL / mL) inhibited the mycelial growth (95.18 to 99.46%) and spore germination (> 75%) of the assayed fungi strains in artificially infected grapes as well as the autochthonous mycoflora of grapes stored at both room and cold temperature. In general, the application of a coating composed of OVEO and or ROEO at sub-inhibitory amounts preserved the quality of grapes, which were measured by their physical attributes (color, firmness, weight loss), physico-chemical (acidity, soluble solids and relative acidity / soluble solids) and sensory over time storage evaluated. These results demonstrate the potential of the OVEO and ROEO to control post-harvest pathogenic fungi in fruits, in particular, R. stolonifer, A. flavus and A. niger in table grapes.