Efeito do revestimento de própolis verde na qualidade de frutos de mamão formosa (Carica papaya L.)

Abstract

Coatings with natural edible products that can add nutritional or functional value in fruits are an innovative alternative to help in the conservation of these foods. The coatings have the function of protecting the fruits by forming a barrier to the attack of pathogenic microorganisms, controlling gaseous exchanges and water vapor, thus helping to maintain post-harvest quality of fruits, without losing their physical, chemical and sensorial characteristics. The objective of this work was to evaluate the effect of the green propolis extract (GPE) coated as a film on papaya fruits (Carica papaya L.). The fruits received were divided into two treated and untreated groups. In the treated fruits it was applied with the aid of spray, 20% GPE and stored for 8 days under ambient conditions. The variables analyzed were weight loss, maturation time (shell color) and coating influence on the incidence and severity of spontaneous diseases. To characterize the green propolis were analyzed spectrophotometry with the reagents FolinCiocalteau and aluminum chloride for phenolics and total flavonoids, respectively. Phenolic and flavonoid acids were also identified and quantified by reverse phase high performance liquid chromatography (HPLC). The antioxidant potential was assessed by DPPH radical sequestration and expressed in EC-50. The mean phenolic, total flavonoid and antioxidant potential contents were respectively 450.0 mg of gallic acid (GA) equivalents / 100 g; 8.84 mg of quercitin (EQ) equivalents / 100 g and 0.331 mg / mL. The fruits coated with EEP remained longer with the coloration of the bark with green tones than the fruits without propolis, since the change of the coloration of the bark to yellow-orange tones occurred on the 5th and 3rd day of evaluation, respectively. The use of the coating significantly influenced the reduction of mass loss, with the treated fruits losing 8.81% less than the untreated fruits. And in relation to the damages caused by post-harvest diseases, a significant difference was observed between the coated and control fruits. On the 8th day of evaluation, all fruits were contaminated, but it was observed that the fruits treated were on average 35% disease severity, while the untreated fruits had 50.5% disease severity. The high levels of flavonoids, phenolics and the antioxidant potential of green propolis influenced the increase in the shelf life of coated fruits, as well as delayed the symptoms of severity of post harvest diseases.