Biofilmes a base de amido, gelatina e extrato de Tetradenia riparia na conservação de morango

Abstract

Strawberry is a non-climacteric pseudofruit and has a short shelf life after harvest. Among the factors responsible for the loss of quality of strawberries are high metabolic activity and high susceptibility to microbial attack. Therefore, studies with edible coverings or coverings are being one of the most appropriate alternatives to assist in the post harvest conservation of fruits, especially non-climacteric ones such as strawberry. These coatings have excellent barrier properties, mainly to the transport of gases and water vapor, among other factors that contribute to the maintenance of fruit quality. Therefore, the objective of this work was to evaluate the effect of edible films produced from gelatine, native starch, sorbitol and Tetradenia riparia extract (antimicrobial agent) in the post harvest harvesting of strawberries (Fragaria ananassa). The films were analyzed for thickness, solubility, opacity, colorimetry, TVA (water vapor transmission) and mechanical analysis. The films that received the addition of Tetradenia riparia extract became thicker with lower solubility and opacity, and greater luminosity. These data corroborated the mechanical analysis, in which the films with extract were more elastic, in addition, it was necessary to apply a greater force to break, that is, more resistant. Regarding the fruits, the analyzes were performed on alternate days, during 10 days of storage, under temperature and humidity of refrigerator with temperature of 8ºC at 10ºC and relative humidity of approximately 75%, being evaluated the loss of mass, microbiological analysis, analysis Antioxidant, calorimetry, vitamin C contents, total soluble solids (TSS), titratable total acidity (TTA) and the relationship between both SST / ATT. The loss of mass increased with the prolongation of the storage, that is to say, when adding the extract of Tetradenia riparia both in medium and in high inhibition the losses of mass of the fruits were superior to 10% in the 4th day of storage, for the two treatments mentioned above. As for the contents of total soluble solids and titratable total acidity the contents increased with the increase of the storage period, this fact may be related to the respiratory process and consumption of organic acids. Regarding the vitamin C content, only the treatments that did not receive the addition of extract continued to increase the contents at the end of the experiment. This proves the importance of using biofilm as a protective agent, it is also observed that these fruits that the coloration decreases, leaving the less looking less shiny. Microbiological analysis showed that the most effective treatment was the high inhibition of starch film (FAAI), that is, 500 μg / ml of Tetradenia riparia extract was enough to decrease the number of colony forming units at the end of experiment. For the antioxidant activity it was observed that the most efficient treatments were those with the addition of T. riparia extract to the films that is, when adding 500μg / ml or 1000μg / ml, they presented a decrease of the antioxidant activity, indicating that the Extract may reduce metabolic activity and delay fruit senescence.