Papaia fermentada: estratégias para monitorizar e melhorar a fermentação das amostras - estudo preliminar

Abstract

Introduction: Fermented papaya is known as a nutraceutical, with a unique composition and several health benefits. Its fermentation, being a central process of metabolism, converts the sugars in the fruit into alcohols or acids, with the intermediate formation of pyruvic acid. However, there is a lack of control and uniformity in terms of processes. Objectives: Carry out fermentation cycles of papaya in order to determine which conditions contribute to improving the pyruvic acid content and verify if there is any change of it after freezing preservation. Methodology: The papaya was washed with distilled water and cut into small cubes. About a quarter of each fruit was divided into two sterile flasks, adding ultrapure water, and placing it at 30°C. The flasks were manually shaken every 24 hours, an aliquot was taken for pH measurement. At the end of each fermentation cycle, the sample was subjected to centrifugation followed by gravity filtration and storage at -20°C. At the time of analysis, the aliquots were thawed, and the pH was measured again. The sodium pyruvate content (sodium salt of pyruvic acid) was quantified through a method adapted from another study and validated by this research team. The various fermentation cycles were carried out in duplicate, with changes in the fermentation conditions. Results: The highest content of sodium pyruvate was obtained at the end of the fermentation cycle where the whole fruit (pulp, peel and seeds) was used with sucrose supplementation (1 g.L-1). This indicates that the peel and seeds of papaya, due to their phytochemical composition, have constituents that improve the fermentation process while reducing food waste. The lowest content of sodium pyruvate was obtained on the second day of the fermentation cycle where only fresh papaya pulp and seeds were used, confirming that the presence of the peel is fundamental, probably due to the existence of autochthonous flora in the fruit that contributes to the fermentation process. Furthermore, it was also possible to verify that the pH does not change with the freezing process, indicating that there was no alteration of the pyruvic acid content during the preservation period. Conclusion: It was found that the fermentation conditions that promote a higher content of pyruvic acid is using the whole fruit and sucrose, at 30°C, for 7 days. However, other temperatures, as well as other fermentation conditions, should still be tested in order to understand if the fermentation process can be improved.