Qualidade pós-colheita de cagaitas armazenadas sob iluminação de Led em diferentes comprimentos de onda e tempos de exposição

Abstract

Cagaita (Eugenia dysenterica) is native fruit from the brazilian cerrado, with oval, ellipsoid or flat shape, fragile yellow skin and pulp with a pleasant, slightly acidic flavor. Like most fruits that have climateric respiratory pattern, cagaita has a high degree of perishability due to the high metabolic activity after harvest, in which the process of changing characteristics through ripening occurs accelerated, leading to the fast deterioration of the fruit. Therefore, it is necessary the application of appropriate techniques to delay post-harvest deterioration of these to minimize the losses. In this sense, in recent years, the use of artificial light during storage has been suggested to preserve or even improve nutritional properties of fruits and vegetables. This way, the objective of this study was to evaluate the post-harvest quality of cagaitas stored under LED (Light-emitting diodes) lighting at different wavelengths and times of exposure. For both experiments, a completely randomized design was used, in a 5x6 double factorial scheme, with the first factor consisted in 4 different LED colors (red, green, blue and white) and control (no light) for the first experiment, 5 times of exposure to green LED light (2, 4, 8, 12 and 24 hours) for the second experiment and the second factor composed of the days of post-harvest storage (0, 1, 2, 3, 4 and 5 days. The fruits were analyzed for: mass loss (PM), firmness, pH, titratable acidity (TA), soluble solids (SS), ripeness index (MI), color (L*, °Hue and Chroma), vitamin C, total extractable polyphenols (PET) and antioxidant activity by ABTS and DPPH methods. In the first experiment, the green LED light promoted a greater increase in the variables: soluble solids, luminosity, chroma, vitamin C and antioxidant activity using the DPPH method, in addition to causing greater maintenance in the pH parameter, promoting beneficial effects on the physical, physicochemical and bioactives from cagaita. And in the case of the second experiment, it was proven that the longer exposure time (continuous exposure to LED light) caused a greater increase in the luminosity, chroma, vitamin C and antioxidant activity parameters using the ABTS and DPPH methods. Futhermore, it is worth highlighting that studies on post-harvest storage of cerrado fruits are still scarce, and the use of LEDs in fruit storage in general is a recent study. Thus, the results of these experiments are the first steps for further research with cagaita associated with this technique where various conditions can be studied and optimized.