Severidade da antracnose e qualidade dos frutos de maracujá-amarelo tratados com produtos naturais em pós-colheita

摘要

The objective of present study was evaluate the quality of yellow passion fruits treated with oils of soybean, nim, copaiba and jatoba wine, aiming the reduction of severity of antracnosis caused by the fungi Colletotrichum gloeosporioides. An in vitro experiment was installed in a completely randomized design in a factorial scheme 4X5 considering the four treatments in five concentrations: 0.0; 0.5; 1.0; 1.5 and 2.0 mL L-1 diluted in PDA media. For the in vivo experiment, yellow passion fruits were surfaced sterilized with sodium hypochlorite at 150 mg L-1 and inoculated with a suspension of 106 conidia L-1 of C. gloeosporioides. After 24 h the treatments were immersed for 10 min at the following concentrations: 0.5 mL-1 of jatoba wine, 0.25 mL-1 of copaiba oil, 0.5 mL-1 of soybean oil, 0.5 mL-1 of nim oil and control. A completely randomized design was adopted. Regression analysis were used for the in vivo experiments, and the severity evaluated by diagrammatic scale and the quantification of number of injuries/fruit and the lifetimes of the fruits were compared by the test of Kruskal Wallis at 5% of probability. The titratable total acidity (TTA), soluble solid total (SST), pH, ascorbic acid, and SST/TTA ratio were compared by Tukey test at 5% probability. In vitro the nim oil, copaiba oil and jatoba wine presented quadratic proceeding, being the concentrations of 1.56, 1.93 e 1.71 mL L-1 the most efficient in the reduction of fungi mycelial growth, respectively. The soybean oil reduced the fungi mycelial growth linearly with the increase of this concentration to the limit of 2 mL L-1. The oils of soybean and nim promoted more reduction of Anthracnose severity evaluated by diagrammatic scale. The nim oil also reduced the number of injuries / fruits and the soybean oil extended lifetime of passion fruits in four days. The fruits treated with soybean and copaiba oils presented more lifetime, TTA content and less SST/TTA ratio.