Secagem em camada de espuma e liofilização da polpa de manga da variedade maranhão.

Abstract

In Brazil, the Northeast stands out for the production of different varieties of mangoes practically all year round. The Maranhão mango is cultivated in the Seridó regions of Paraíba and Rio Grande do Norte and has great socioeconomic importance for the region due to its wide adaptation to local soil and climate conditions and, in the agroecological context, can be called Creole or native. Due to its small exploration in research and food products, the objective of this work was to study the dehydration of the pulp of the Maranhão mango var. by the foam mat drying and freeze-drying method, evaluating the quality of the pulp and the powder produced, through their physical, chemical and physicochemical characteristics, the study of the stability of the powder during the accelerated shelf-life test under controlled conditions of temperature and relative humidity, and the determination of water adsorption isotherms. Empirical mathematical models were fitted to the experimental data on drying kinetics, and the effective diffusivity, thermodynamic properties and activation energy were calculated. In addition, water adsorption isotherms at temperatures of 20, 30 and 40 °C were determined, and the thermal stability of total phenolic compounds was evaluated during 28 days of storage at controlled temperatures of 20, 30 and 40 °C. The research results were divided into three articles. In the first article, the drying models, especially Midilli, Diffusion approximation and Page, fitted the drying kinetics well; the effective diffusivity ranged from 2.98 x 10-8 to 3.43 x 10-8 m2/s, with the influence of temperature demonstrated by the Arrhenius equation; The samples, rich in bioactive compounds, maintained good antioxidant activity after drying, correlated with total phenolic compounds, carotenoids, tannins and ascorbic acid; and the Maranhão mango pulp showed high processing potential, preserving the bioactive properties in powder form. In the second article, the degradation kinetics of total phenolic compounds (TPC) of the powders fitted well to the first-order model, with R² > 0.98; the half-life ranged from 1.9 to 3.2 weeks, decreasing with increasing storage temperature; the range of 20 to 30 ºC resulted in the highest Q10 values for the freeze-dried pulp and for the foam-layer-dried formulation, while the freeze-dried formulation had the highest Q10 in the range of 30-40 ºC; the powders presented greater luminosity in relation to the whole pulp, but maintained the yellow hue. In the third article, foam layer drying of sample F70 and freeze-drying of the whole pulp and the formulation were performed, resulting in powders with different densities; F70 stood out for its higher compacted density, better solubility and lower hygroscopicity; the Copace, GAB, Peleg and Scop models adjusted well to the data of the water adsorption isotherms, with Peleg standing out; and the samples proved to be good sources of minerals. In general, it is concluded that freeze-drying presented advantages in terms of preservation of bioactive compounds compared to convective drying. The samples are sources of several minerals, including calcium, phosphorus, potassium, magnesium, iron, manganese and zinc, which enrich the scientific understanding regarding the valorization of native fruits in the agricultural sector and the elaboration of powders with potential for use in high added-value foods.